Deindividuation is a concept in social psychology that is generally thought of as the loss of self-awareness in groups, although this is a matter of contention (see below). Sociologists also study the phenomenon of deindividuation, but the level of analysis is somewhat different. For the social psychologist, the level of analysis is the individual in the context of a social situation. As such, social psychologists emphasize the role of internal psychological processes. Other social sciences, such as sociology, are more concerned with broad social, economic, political, and historical factors that influence events in a given society.
- 2Major theoretical approaches and history
- 3Major empirical discoveries
- 3.1Milgram (1963)
- 3.2Philip Zimbardo (1969)
- 3.3Philip Zimbardo (1971)
- 3.4Diener, Fraser, Beaman, and Kelem (1976)
- 3.5Nadler, A., Goldberg, M., Jaffe, Y. (1982)
- 3.6Dodd, D. (1985)
- 3.7Reicher, S., Levine, R. M., Gordijn, E. (1998)
- 3.8Lee, E.J. (2007)
- 6See also
- 8External links
Theories of deindividuation propose that it is a psychological state of decreased self-evaluation and decreased evaluation apprehension causing antinormative and disinhibited behavior. Deindividuation theory seeks to provide an explanation for a variety of antinormative collective behavior, such as violent crowds, lynch mobs, etc. Deindividuation theory has also been applied to genocide and been posited as an explanation for antinormative behavior online and in computer-mediated communications.
Although generally analyzed in the context of negative behaviors, such as mob violence and genocide, deindividuation has also been found to play a role in positive behaviors and experiences. There still exists some variation as to understanding the role of deindividuation in producing anti-normative behaviors, as well as understanding how contextual cues affect the rules of the deindividuation construct.
Major theoretical approaches and history
In contemporary social psychology, deindividuation refers to a diminishing of one's sense of individuality that occurs with behavior disjointed from personal or social standards of conduct. For example, someone who is an anonymous member of a mob will be more likely to act violently toward a police officer than a known individual. In one sense, a deindividuated state may be considered appealing if someone is affected such that he or she feels free to behave impulsively without mind to potential consequences. However, deindividuation has also been linked to "violent and anti-social behavior".
Gustave Le Bon was an early explorer of this phenomenon as a function of crowds. Le Bon introduced his crowd psychology theory in his 1895 publication The Crowd: A study of the Popular Mind. The French psychologist characterized his posited effect of crowd mentality, whereby individual personalities become dominated by the collective mindset of the crowd. Le Bon viewed crowd behavior as "unanimous, emotional, and intellectually weak". He theorized that a loss of personal responsibility in crowds leads to an inclination to behave primitively and hedonistically by the entire group. This resulting mentality, according to Le Bon, belongs more to the collective than any individual, so that individual traits are submerged. The idea of a "group mind" is comparable to the shared autism theory, which holds that individuals within a group may develop shared beliefs that have no basis in reality ("delusions"). Already, Le Bon was tending toward the conception of deindividuation as a state brought on by a lowering of accountability, resulting from a degree of anonymity due to membership within a crowd, where attention is shifted from the self to the more stimulating, external qualities of the group’s action (which may be extreme).
Essentially, individuals of Le Bon's crowd are enslaved to the group's mindset and are capable of conducting the most violent and heroic acts. Le Bon's group-level explanation of behavioral phenomena in crowds inspired further theories regarding collective psychology from Freud, McDougall, Blumer, and Allport. Festinger, Pepitone, and Newcomb revisited Le Bon's ideas in 1952, coining the term deindividuation to describe what happens when persons within a group are not treated as individuals. According to these theorists, whatever attracts each member to a particular group causes them to put more emphasis on the group than on individuals. This unaccountability inside a group has the effect of "reducing inner restraints and increasing behavior that is usually inhibited." Festinger et al., agreed with Le Bon’s perception of behavior in a crowd in the sense that they believed individuals do become submerged into the crowd leading to their reduced accountability. However, these relatively modern theorists distinguished deindividuation from crowd theory by reforming the idea that the loss of individuality within a crowd is replaced by the group’s mindset. Instead, Festingeret al., argued that the loss of individuality leads to loss of control over internal or moral constraints.
Alternatively, R. C. Ziller (1964) argued that individuals are subject to deindividuation under more specific situational conditions. For instance, he suggested that under rewarding conditions, individuals have the learned incentive to exhibit individualized qualities in order to absorb credit for themselves; whereas, under punishing conditions, individuals have the learned tendency to become deindividuated through submergence into the group as a means of diffusing responsibility.
P. G. Zimbardo (1969) suggested "the expression of normally inhibited behavior" may have both positive and negative consequences. He expanded the proposed realm of factors that contribute to deindividuation, beyond anonymity and loss of personal responsibility, to include: "arousal, sensory overload, a lack of contextual structure or predictability, and altered consciousness due to drugs or alcohol," as well as "altered time perspectives...and degree of involvement in group functioning" Zimbardo postulated that these factors lead to "loss of identity or loss of self-consciousness," which result in unresponsiveness to external stimuli by the individual and the loss of "cognitive control over motivations and emotions." Consequently, individuals reduce their compliance with good and bad sanctions held by influences outside the group.
Zimbardo was consistent with Festingeret al. in his suggestion that loss of individuality leads to a loss of control, causing affected persons to behave intensely and impulsively, having let go of internal restraints. However, he developed this model by specifying the "input variables" (situational factors) that lead to this loss of individuality, as well as the nature of behaviors that result (emotional, impulsive, and regressive). Zimbardo further developed existing deindividuation theory by suggesting these outcome behaviors are "self-reinforcing" and therefore difficult to cease. Moreover, Zimbardo did not restrict his application to group situations; he also applied deindividuation theory to "suicide, murder, and interpersonal hostility."
In the late seventies, Ed Diener began to express dissatisfaction with the current deindividuation hypothesis, which he deemed invalid without specific focus on the psychological processes that yield a deindividuated state. Not only was Zimbardo's model deficient in that respect, but the role of his input variables in causing anti-normative behaviors was not uniform. Consequently, Diener took it upon himself to refine Zimbardo's model by specifying further the internal processes which lead to deindividuation. In 1980, he argued that paying attention to one's personal values through self-awareness increases the ability of that person to self-regulate. In a group context, when attention is distributed outward (in line with this model) away from the self, the individual loses the ability to plan his actions rationally and substitutes planned behaviors with a heightened responsiveness to environmental cues. Thus, according to Diener, the reduction of self-awareness is the "defining feature of deindividuation". Diener proposed that the strict focus on anonymity as the primary factor of deindividuation had created an empirical obstacle, calling for a redirection of empirical research on the topic.
While Diener was able to take the focus away from anonymity in the theoretical evolution of deindividuation, he was unable to empirically clarify the function of reduced self-awareness in causing disinhibited behavior. In response to this ambiguity, Prentice-Dunn and Rogers (1982, 1989) extended Diener's model by distinguishing public self-awareness from private self-awareness. Public self-awareness they theorized to be reduced by "accountability cues," like diffusion of responsibility or anonymity. Such factors, according to these theorists, cause members of a crowd to lose a sense of consequences for their actions; thus, they worry less about being evaluated and do not anticipate punishment. Private self-awareness (where attention is shifted away from the self), however, was reduced by "attentional cues," e.g. group cohesiveness and physiological arousal. This reduction leads to "an internal deindividuated state" (comprising decreased private self-awareness and altered thinking as a natural by-product) that causes "decreased self-regulation and attention to internalized standards for appropriate behavior." The "differential self-awareness" theorists suggested both forms of self-awareness could lead to "antinormative and disinhibited behavior" but only the decreased private self-awareness process was in their definition of deindividuation.
The most recent model of deindividuation, the social identity model of deindividuation effects (SIDE), was developed by Russell Spears and Martin Lea in 1995. The SIDE model argues that deindividuation manipulations can have the effect of decreasing attention to individual characteristics and interpersonal differences within the group. They outlined their model by explaining that social identity performance can fulfill two general functions:
- Affirming, conforming, or strengthening individual or group identities.
- Persuading audiences into adopting specific behaviors.
This model attempts to make sense of a range of deindividuation effects which were derived from situational factors such as group immersion, anonymity, and reduced identifiability. Therefore, deindividuation is the increased salience of a group identity that can result from the manipulation of such factors. The SIDE model is in contrast to other deindividuation explanations which involve the reduced impact of the self. Further explanations by Reicher and colleagues state that deindividuation manipulations affect norm endorsement through not only their impact on self-definition, but also their influence on power relations between group members and their audience.
Classical and contemporary approaches agree on the main component of deindividuation theory, that deindividuation leads to "anti-normative and disinhibited behavior" as seen in Dissociative identity disorder, or split personalities.
Major empirical discoveries
Stanley Milgram's study is a classic study of blind obedience, however, many aspects of this study explicitly illustrate characteristics of situations in which deindividuation is likely to occur. Participants were taken into a room and sat in front of a board of fake controls. They were then told by the experimenter that they were completing a task on learning and that they were to read a list of word pairs to the “learner” and then test the learner on accuracy. The participant then read a word and four possible matches. If the confederate got the match wrong, they were to administer a shock (which was not real, unbeknownst to the participant) from the fake control panel they were sitting in front of. After each wrong answer, the intensity of the shock increased. The participant was instructed by the experimenter to continue to administer the shocks, stating that it was their duty in the experiment. As the voltage increased, the confederate began to complain of pain, yelled out discomfort, and eventually screamed the pain was too much and sometimes they even began to bang on the wall. At the greatest amount of voltage administered, the confederate stopped speaking at all. The results of the study showed that 65 percent of experiment participants administered the experiment’s final, and most severe, 450-volt shock. Only 1 participant refused to administer shocks past the 300- volt level. The participants, covered by a veil of anonymity, were able to be more aggressive in this situation than they possibly would have in a normal setting. Additionally, this is a classic example of diffusion of responsibility in that participants looked to an authority figure (the experimenter) instead of being self-aware of the pain they were causing or engaging in self-evaluation which may have caused them to adhere to societal norms.
Philip Zimbardo (1969)
This study prompted Zimbardo to write his initial theory and model of deindividuation based on the results of his research. In one study, participants in the experimental condition were made to be anonymous by being issued large coats and hoods which largely concealed their identity. These New York University women were dressed up like Ku Klux Klan members in groups of four. In contrast, the participants in the control condition wore normal clothes and name tags. Each participant was brought into a room and given the task of “shocking” a confederate in another room at different levels of severity ranging from mild to dangerous (similar to Stanley Milgram’s study in 1963.) Zimbardo noted that participants who were in the anonymous condition “shocked” the confederates longer, which would have caused more pain in a real situation, than those in the non-anonymous control group. However, a second study using soldiers was done which showed the exact opposite results. When the soldiers were identifiable, they shocked longer than the unidentifiable soldiers. Zimbardo proposed that as a result of anonymity, the soldiers may have felt isolated from their fellow soldiers. These studies motivated Zimbardo to examine this deindividuation and aggression in a prison setting, which is discussed in the next study listed.
Philip Zimbardo (1971)
Now a more widely recognized study since the publication of his book, The Lucifer Effect, the Stanford Prison Experiment is infamous for its blatant display of aggression in deindividuated situations. Zimbardo created a mock prison environment in the basement of Stanford University’s psychology building in which he randomly assigned 24 men to undertake the role of either guard or prisoner. These men were specifically chosen because they had no abnormal personality traits (e.g.: narcissistic, authoritarian, antisocial, etc.) The experiment, originally planned to span over two weeks, ended after only six days because of the sadistic treatment of the prisoners by the guards. Zimbardo attributed this behavior to deindividuation due to immersion within the group and creation of a strong group dynamic. Several elements added to the deindividuation of both guards and prisoners. Prisoners were made to dress alike, wearing stocking caps and hospital dressing gowns, and also were identified only by a number assigned to them rather than by their name. Guards were also given uniforms and reflective glasses which hid their faces. The dress of guards and prisoners led to a type of anonymity on both sides because the individual identifying characteristics of the men were taken out of the equation. Additionally, the guards had the added element of diffusion of responsibility which gave them the opportunity to remove personal responsibility and place it on a higher power. Several guards commented that they all believed that someone else would have stopped them if they were truly crossing the line, so they continued with their behavior. Zimbardo's prison study would have not been stopped if one of Zimbardo's graduate students, Christina Maslach, had not pointed it out to him.
Diener, Fraser, Beaman, and Kelem (1976)
In this classic study, Diener and colleagues had a woman place a bowl of candy in her living room for trick-or-treaters. An observer was placed out of sight from the children in order to record the behaviors of the trick-or-treaters. In one condition, the woman asked the children identification questions such as where they lived, who their parents were, what their name was, etc. In the other condition, children were completely anonymous. The observer also recorded whether children came individually or in a group. In each condition, the woman invited the children in, claimed she had something in the kitchen she had to tend to so she had to leave the room, and then instructed each child to take only one piece of candy. The anonymous group condition far outnumbered the other conditions in terms of how many times they took more than one piece of candy. In 60% of cases, the anonymous group of children took more than one piece, sometimes even the entire bowl of candy. The anonymous individual and the identified group condition tied for second, taking more than one piece of candy 20% of the time. The condition which broke the rule the least amount of times was the identified individual condition, which took more than one piece of candy only in 10% of cases.
Nadler, A., Goldberg, M., Jaffe, Y. (1982)
This study by Nadler, Goldberg, and Jaffe measured the effects that deindividuating conditions (anonymity vs. identifiable) had on two subject conditions (self-differentiated vs. undifferentiated individuals). The self-differentiated individual is said to have definite boundaries between inner characteristics identified as self and the social environment. In the undifferentiated individual, such a distinction is less marked. Subjects who were preselected as being self-differentiated or undifferentiated were observed under conditions of high or low anonymity. Each subject was exposed to transgressions and donations made by confederates, and then their own transgressive and prosocial actions were measured. Also, measures of verbal aggression directed toward the experimenter and measures of internal state of deindividuation were taken. Major findings of the study:
- Within the undifferentiated groups, a greater frequency of subsequent subject transgressive behavior occurred in the anonymity more than in the identifiability conditions.
- Undifferentiated individuals are affected by deindividuating circumstances and they tend to transgress more after observing the model in the experiment.
- In terms of verbal aggression, self-differentiated individuals' level of verbal aggression was equal under anonymity and identifiability conditions. However, undifferentiated individuals tended to model the confederates' aggression and were more verbally aggressive when anonymous than when identifiable.
- The study found that undifferentiated individuals were less self-conscious and less inhibited in the anonymity condition.
Overall, the study supports the hypothesis that deindividuating conditions cause behavioral changes in undifferentiated individuals but have relatively little effect on the behavior of self-differentiated individuals.
Dodd, D. (1985)
Dodd’s experiment evaluates the association between deindividuation and anonymity. Dodd measured his subjects by asking them what they would do (within the realm of reality) if their identity were kept anonymous and they would receive no repercussions. The responses were grouped into four categories: prosocial, antisocial, nonnormative, and neutral. Results of his study yielded that 36% of the responses were antisocial, 19% nonnormative, 36% neutral and only 9% prosocial. The most frequent responses recorded were criminal acts. This study on deindividuation exhibits the importance of situational factors, in this case anonymity, when reporting antisocial behavior. Furthermore, this study demonstrates that personal traits and characteristics are not much of predictor when predicting the behavior. Overall, this study is supportive of the concept of deindividuation as Dodd found that behavior changes from what would be normal of a certain individual, to a behavior that is not representative of normal behavioral decisions.
Reicher, S., Levine, R. M., Gordijn, E. (1998)
Following the social models of identity proposed by deindividuation, the study conducted by Reicher, Levine and Gordijn expresses the strategic effects of visibility on the ingroup. The experimenters suggest that increasing visibility amongst the in-group members subsequently increases their ability to support each other against the outgroup—this also leads to an increase in the traits of the in-group that would normally be sanctioned by the out-group. The study was based on the debate over whether fox hunting should or should not be banned. The experimenters were mainly concerned with the participants that defined themselves as ‘anti-hunting;’ The participants involved thirty male and female students in the first year of their A-level psychology course located in a rural town in South West England—the mean age was 17 years. The study involved two separate sessions where the participants completed a pre-test and were assigned to the pro- or anti- hunting groups. A spokesperson representing each view was brought in to discuss their opinions individually with each participant. The pro-hunting group was taken to another room and did not take further part in the study. For the in-group low-visibility condition part of the anti-hunting participants were taken to individual booths where they were not visible to others in the experiment. The remaining anti-hunting participants who were categorized under the in-group high visibility condition, were seated in a circle where each was visible to all throughout the experiment. At this point both groups were shown a video. After watching the video the participants were handed a questionnaire. They were asked to write their names on the front so that the out-group spokesperson would be able to identify the authors of the questionnaire before discussing the comments individually. To the experimenters’ surprise the experiment demonstrated the inverse of their hypothesis. The study showed that more participants were more likely to express normative behaviors that are punishable by powerful out-group when they are visible to fellow members of the same in-group. Experimenters also found that in-group participants actually expressed opposition to the roles imposed by the experimenters themselves. Instead of just uniting against hunt, some of the in-group participants resented being told that their group supported certain views—some regarded themselves as moderate pro- or anti- hunters instead. In this case, the experimenters themselves triggered a response from the in-group, which was later analyzed through follow up experiments.
Lee, E.J. (2007)
This study conducted by Lee investigates the effects of deindividuation on group polarization. Group polarization refers to the finding that following group discussion, individuals tend to endorse a more extreme position in the direction already favored by the group. In Lee’s study subjects were either assigned to a deindividuation or individuation condition. Next, each subject answered questions and provided an argument about a given dilemma. They were then shown their partners’ decisions and the subjects were asked to indicate how convincing and valid the overall arguments were. In analyzing her results, Lee came to several conclusions:
- Group identification was positively correlated with group polarization.
- She confirmed her hypothesis that the subjects would show stronger group identification and greater opinion polarization when deindividuated than when individuated.
- Lee found that the more the participants identified with their partners, the more positive their evaluations of the partners’ arguments were, manifesting in-group favoritism.
- Her findings suggest that both higher group identification and deindividuated subjects reported a significantly higher level of public-self-awareness.
Overall, this study provides solid research for which the previous findings regarding deindividuation can be solidified. The finding that deindividuation was associated with stronger group polarization and identification corresponds with the basis of deindividuation: individuals that are more polarized and identified with a group will be more apt to act out of character and display anti-normative behavior.
Deindividuation is the perceived loss of individuality and personal responsibility that can occur when someone participates as part of a group. It can cause a person to be more likely to donate a large amount of money to charity, but also cause them to be more likely to engage in mob violence. There are many instances in which the effects of deindividuation can be seen in real-world instances. Deindividuation can occur in as varied instances as in the police force, the military, the internet, sports teams, gangs, cults, and social organizations. Although they may seem very different on the surface, these groups share many traits that make them conducive to, and even contingent on, deindividuation. All of the examples share the strong drive towards group cohesiveness. Police officers, soldiers, and sports teams all wear uniforms that create a distinct in-group while eliminating the individual differences of personal style. Men in the military are even required to shave their heads in order to better unify their appearance. Although gangs, cults, and fraternities and sororities do not require the same degree of physical uniformity, they also display this tendency towards unifying the exterior in order to unify their group. For example, gangs may have a symbol that they tattoo on their bodies in order to identify themselves as part of the in-group of their gang. Members of fraternities and sororities often wear clothing marked with their “letters” so that they can quickly be identified as part of their specific group. By reducing individual differences, these various groups become more cohesive. The cohesiveness of a group can make its members lose their sense of self in the overwhelming identity of the group. For example, a young man in the military might identify himself through a variety of individual constructs, however while in uniform with a shaved head and dog tags around his neck, he might suddenly only identify himself as a soldier. Likewise, a girl wearing the letters of her sorority on her shirt, and standing in a crowd of her sorority sisters, may feel less like herself, and more like a “Chi-Oh” or “Tridelt.” Physically normalized to the standards of their respective groups, these various group members are all at risk to feel deindividuized. They may begin to think of themselves as a mere part of the group, and lose the awareness that they are an individual with the capacity to think and act completely separately from their group. They could do things they might not usually do out of shyness, individual morality, self-consciousness, or other factors. Due to reduced feelings of accountability, and increased feelings of group cohesion and conformity, these group members could act in a manner of non-normative ways. Deindividuation is a prevalent feature of the internet. Deindividuation online has been thought to be responsible for a widespread willingness to illegally download software. One researcher tested the hypothesis that “Persons who prefer the anonymity and pseudonymity associated with interaction on the Internet are more likely to pirate software,” but found that neither anonymity nor pseudonymity predicted self-reported software piracy From buying drinks for an entire bar of strangers to committing violence as dire as murder or rape, deindividuation can lead a variety of people to act in ways they may have thought impossible.
Questions have been raised about the external validity of deindividuation research. As deindividuation has evolved as a theory, some researchers feel that the theory has lost sight of the dynamic group intergroup context of collective behavior that it attempts to model. Some propose that deindividuation effects may actually be a product of group norms; crowd behavior is guided by norms that emerge in a specific context. More generally, it seems odd that while deindividuation theory argues that group immersion causes antinormative behavior, research in social psychology has also shown that the presence of a group produces conformity to group norms and standards. Certain experiments, such as Milgram’s obedience studies (1974) demonstrate conformity to the experimenter’s demands; however the research paradigm in this experiment is very similar to some employ in deindividuation studies, except the role of the experimenter is usually not taken into account in such instances.
A larger criticism is that our conception of the antinormative behaviors which deindividuation causes is based on social norms, which is problematic because norms by nature are variable and situation specific. For instance, Johnson and Downing (1979) demonstrated that group behaviors vary greatly depending on the situation. Participants who dressed in Ku Klux Klan robes shocked a research confederate more, but participants dressed as nurses actually shocked less regardless of whether they were identifiable or anonymous. They explained these results as a product of contextual cues, namely the costumes. This explanation runs counter to Zimbardo’s initial theory of deindividuation which states that deindividuation increases antinormative behavior regardless of external cues. Researchers who examine deindividuation effects within the context of situational norms support a social identity model of deindividuation effects.
- ^"Deindividuation". changingminds.org.
- ^Aronson, Wilson, and Akert. Social Psychology. 7th ed. Rentice Hall:2010.
- ^Diener, E., Lusk, R., DeFour, D. & Flax, R. (1980). Deindividuation: Effects of group size, density, number of observers, and group member similarity on self-consciousness and disinhibited behavior. Journal of Personality and Social Psychology, 39, 449-459 10.1037/0022-3514 .39.3.449.
- ^ abDiener, E., Fraser, S. C., Beaman, A. L., & Kelem, R. T. (1976). Effects of deindividuation variables on stealing among Halloween trick-or-treaters. Journal of Personality & Social Psychology, 33, 178-183. *1976-20842-00110 .1037//0022-3514.33 .2.178
- ^Staub, E. (1996). Cultural-societal roots of violence: The examples of genocidal violence and of contemporary youth violence in the United States. American Psychologist, 51, 117-132.1996-02655 -00310.1037//0003 -066X.51.2.117
- ^Kiesler, S., & Sproull, L. (1992). Group decision making and communication technology. Organizational Behavior & Human Decision Processes, 52, 96-123.1992-39104 -001
- ^ abcdeRoeckelein, Jon. Deindividuation theory. Elsevier's Dictionary of Psychological Theories. Amsterdam: Elsevier B.V., 2006.
- ^"The Crowd". Encyclopædia Britannica. 15 April 2011.
- ^ abcdePostmes, Tom (2001). "Deindividuation". Archived from the original on 2009-03-07. Retrieved 2002-02-12. About deindividuation theory, a social psychological account of the individual in the crowd and an attempt to explain anti-normative collective action
- ^ abcdePostmes, T. & Spears, R. (1998). Deindividuation and antinormative behavior: A meta-analysis. Psychological Buttetin, 123, 238-259.
- ^ abcReicher, S., Spears, R., & Postmes, T. (1995). A social identity model of deindividuation phenomena. In W. Stroebe & M. Hewstone (Eds.), European review of social psychology (vol. 6, pp. 161-198). Chichester, England: Wiley.
- ^Reicher, S. D. (1987). Crowd behaviour as social action. In J. C. Turner, M. A. Hogg, P. J. Oakes, S. D. Reicher, & M. S. Wetherell (Eds.), Rediscovering the social group: A self-categorization theory (pp. 171–202). Oxford, England: Basil Blackwell
- ^Milgram, S. (1963). Behavioural study of obedience. Journal of Abnormal & Social Psychology 67, 371-8.
- ^Zimbardo, P. G. (1969). The human choice: Individuation, reason, and order vs. deindividuation, impulse, and chaos. *In W. J. Arnold & D. Levine (Eds.), Nebraska Symposium on Motivation(pp. 237-307). lincoln: university of nebraska press.
- ^"The Stanford Prison Experiment: A Simulation Study of the Psychology of Imprisonment". prisonexp.org.
- ^ abNadler, A. , Goldberg, M. , & Jaffe, Y. . (1982). Effect of self-differentiation and anonymity in group on deindividuation. Journal of Personality and Social Psychology, 42(6), 1127-1136.
- ^Dodd, D. (2002). Robbers in the classroom: a deindividuation exercise. Handbook for teaching introductory psychology, 3, 251-253.
- ^Reicher, S., Levine, R. M., Gordijn, E. (1998). More on deindividuation, power relations between groups and the expression of social identity: Three studies on the effects of visibility to the in-group. British Journal of Social Psychology, 37, 15-40.
- ^Lee, E. (2007). Deindividuation effects on group polarization in computer-mediated communication: the role of group identification, public-self-awareness, and perceived argument quality. Journal of Communication, 57(2), 385-403.
- ^Morris, M. (1996). By Force of Arms: Rape, War, and Military Culture . Duke Law Journal,45(4), 651-781.
- ^Abrams, D. (1989). Self-Consciousness and Social Identity: Self-Regulation as a Group Member. Social Psychology Quarterly, 52(4), 311-318. Retrieved April 6, 2011, from the Jstor database.
- ^Hazelwood, L. (1998). The Effects of Juror Anonymity on Jury Verdicts. Law and Human Behavior, 22(6), 695-713. Retrieved April 6, 2011, from the Jstor database.
- ^Hinduja, S. (2008). Deindividuation and Internet Software Piracy. Cyberpsychology & Behavior, 11(4), 391-398. doi:10.1089/cpb.2007.0048
- ^Deutsch, M., & Gerard, H. B. (1955). A study of normative and informational social influences upon individual judgment. Journal of Personality & Social Psychology, 51, 629-636.1987-00135 -00110.1037//0022 -35220.127.116.119
- ^Milgram, S. (1974). Obedience to authority. New York: Harper & Row.
- ^Johnson, R. D. & Downing, L. L. (1979). Deindividuation and valence of cues: Effects of prosocial and antisocial behavior. Journal of Personality & Social Psychology, 37, 1532-1538 10.1037//0022-3514 .37.9.1532.
A thought experiment (German: Gedankenexperiment,Gedanken-Experiment or Gedankenerfahrung) considers some hypothesis, theory, or principle for the purpose of thinking through its consequences. Given the structure of the experiment, it may not be possible to perform it, and even if it could be performed, there need not be an intention to perform it.
The common goal of a thought experiment is to explore the potential consequences of the principle in question: "A thought experiment is a device with which one performs an intentional, structured process of intellectual deliberation in order to speculate, within a specifiable problem domain, about potential consequents (or antecedents) for a designated antecedent (or consequent)" (Yeates, 2004, p. 150).
Examples of thought experiments include Schrödinger's cat, illustrating quantum indeterminacy through the manipulation of a perfectly sealed environment and a tiny bit of radioactive substance, and Maxwell's demon, which attempts to demonstrate the ability of a hypothetical finite being to violate the 2nd law of thermodynamics.
The ancient Greek δείκνυμι(transl.: deiknymi), or thought experiment, "was the most ancient pattern of mathematical proof", and existed before Euclidean mathematics, where the emphasis was on the conceptual, rather than on the experimental part of a thought-experiment. Perhaps the key experiment in the history of modern science is Galileo's demonstration that falling objects must fall at the same rate regardless of their masses. This is widely thought to have been a straightforward physical demonstration, involving climbing up the Leaning Tower of Pisa and dropping two heavy weights off it, whereas in fact, it was a logical demonstration, using the 'thought experiment' technique. The 'experiment' is described by Galileo in Discorsi e dimostrazioni matematiche (1638) (literally, 'Discourses and Mathematical Demonstrations') thus:
Salviati. If then we take two bodies whose natural speeds are different, it is clear that on uniting the two, the more rapid one will be partly retarded by the slower, and the slower will be somewhat hastened by the swifter. Do you not agree with me in this opinion?
Simplicio. You are unquestionably right.
Salviati. But if this is true, and if a large stone moves with a speed of, say, eight while a smaller moves with a speed of four, then when they are united, the system will move with a speed less than eight; but the two stones when tied together make a stone larger than that which before moved with a speed of eight. Hence the heavier body moves with less speed than the lighter; an effect which is contrary to your supposition. Thus you see how, from your assumption that the heavier body moves more rapidly than the lighter one, I infer that the heavier body moves more slowly.
Although the extract does not convey the elegance and power of the 'demonstration' terribly well, it is clear that it is a 'thought' experiment, rather than a practical one. Strange then, as Cohen says, that philosophers and scientists alike refuse to acknowledge either Galileo in particular, or the thought experiment technique in general for its pivotal role in both science and philosophy. (The exception proves the rule — the iconoclastic philosopher of science, Paul Feyerabend, has also observed this methodological prejudice.)
Instead, many philosophers prefer to consider 'Thought Experiments' to be merely the use of a hypothetical scenario to help understand the way things are.
Thought experiments have been used in a variety of fields, including philosophy, law, physics, and mathematics. In philosophy, they have been used at least since classical antiquity, some pre-dating Socrates. In law, they were well-known to Roman lawyers quoted in the Digest. In physics and other sciences, notable thought experiments date from the 19th and especially the 20th century, but examples can be found at least as early as Galileo.
Origins and use of the literal term
Johann Witt-Hansen established that Hans Christian Ørsted was the first to use the Latin-German mixed term Gedankenexperiment (lit. thought experiment) circa 1812. Ørsted was also the first to use its entirely German equivalent, Gedankenversuch, in 1820.
Much later, Ernst Mach used the term Gedankenexperiment in a different way, to denote exclusively the imaginary conduct of a real experiment that would be subsequently performed as a real physical experiment by his students. Physical and mental experimentation could then be contrasted: Mach asked his students to provide him with explanations whenever the results from their subsequent, real, physical experiment differed from those of their prior, imaginary experiment.
The English term thought experiment was coined (as a calque) from Mach's Gedankenexperiment, and it first appeared in the 1897 English translation of one of Mach’s papers. Prior to its emergence, the activity of posing hypothetical questions that employed subjunctive reasoning had existed for a very long time (for both scientists and philosophers). However, people had no way of categorizing it or speaking about it. This helps to explain the extremely wide and diverse range of the application of the term "thought experiment" once it had been introduced into English.
Thought experiments, which are well-structured, well-defined hypothetical questions that employ subjunctive reasoning (irrealis moods) – "What might happen (or, what might have happened) if . . . " – have been used to pose questions in philosophy at least since Greek antiquity, some pre-dating Socrates. In physics and other sciences many thought experiments date from the 19th and especially the 20th Century, but examples can be found at least as early as Galileo.
In thought experiments we gain new information by rearranging or reorganizing already known empirical data in a new way and drawing new (a priori) inferences from them or by looking at these data from a different and unusual perspective. In Galileo’s thought experiment, for example, the rearrangement of empirical experience consists in the original idea of combining bodies of different weight.
Thought experiments have been used in philosophy (especially ethics), physics, and other fields (such as cognitive psychology, history, political science, economics, social psychology, law, organizational studies, marketing, and epidemiology). In law, the synonym "hypothetical" is frequently used for such experiments.
Regardless of their intended goal, all thought experiments display a patterned way of thinking that is designed to allow us to explain, predict and control events in a better and more productive way.
In terms of their theoretical consequences, thought experiments generally:
- challenge (or even refute) a prevailing theory, often involving the device known as reductio ad absurdum, (as in Galileo's original argument, a proof by contradiction),
- confirm a prevailing theory,
- establish a new theory, or
- simultaneously refute a prevailing theory and establish a new theory through a process of mutual exclusion
Thought experiments can produce some very important and different outlooks on previously unknown or unaccepted theories. However, they may make those theories themselves irrelevant, and could possibly create new problems that are just as difficult, or possibly more difficult to resolve.
In terms of their practical application, thought experiments are generally created to:
- challenge the prevailing status quo (which includes activities such as correcting misinformation (or misapprehension), identify flaws in the argument(s) presented, to preserve (for the long-term) objectively established fact, and to refute specific assertions that some particular thing is permissible, forbidden, known, believed, possible, or necessary);
- extrapolate beyond (or interpolate within) the boundaries of already established fact;
- predict and forecast the (otherwise) indefinite and unknowable future;
- explain the past;
- the retrodiction, postdiction and hindcasting of the (otherwise) indefinite and unknowable past;
- facilitate decision making, choice and strategy selection;
- solve problems, and generate ideas;
- move current (often insoluble) problems into another, more helpful and more productive problem space (e.g.: functional fixedness);
- attribute causation, preventability, blame and responsibility for specific outcomes;
- assess culpability and compensatory damages in social and legal contexts;
- ensure the repeat of past success; or
- examine the extent to which past events might have occurred differently.
- ensure the (future) avoidance of past failures
Scientists tend to use thought experiments as imaginary, "proxy" experiments prior to a real, "physical" experiment (Ernst Mach always argued that these gedankenexperiments were "a necessary precondition for physical experiment"). In these cases, the result of the "proxy" experiment will often be so clear that there will be no need to conduct a physical experiment at all.
Scientists also use thought experiments when particular physical experiments are impossible to conduct (Carl Gustav Hempel labeled these sorts of experiment "theoretical experiments-in-imagination"), such as Einstein's thought experiment of chasing a light beam, leading to special relativity. This is a unique use of a scientific thought experiment, in that it was never carried out, but led to a successful theory, proven by other empirical means.
Relation to real experiments
The relation to real experiments can be quite complex, as can be seen again from an example going back to Albert Einstein. In 1935, with two coworkers, he published a paper on a newly created subject called later the EPR effect (EPR paradox). In this paper, starting from certain philosophical assumptions, on the basis of a rigorous analysis of a certain, complicated, but in the meantime assertedly realizable model, he came to the conclusion that quantum mechanics should be described as "incomplete". Niels Bohr asserted a refutation of Einstein's analysis immediately, and his view prevailed. After some decades, it was asserted that feasible experiments could prove the error of the EPR paper. These experiments tested the Bell inequalities published in 1964 in a purely theoretical paper. The above-mentioned EPR philosophical starting assumptions were considered to be falsified by empirical fact (e.g. by the optical real experiments of Alain Aspect).
Thus thought experiments belong to a theoretical discipline, usually to theoretical physics, but often to theoretical philosophy. In any case, it must be distinguished from a real experiment, which belongs naturally to the experimental discipline and has "the final decision on true or not true", at least in physics.
The first characteristic pattern that thought experiments display is their orientation in time. They are either:
- Antefactual speculations: experiments that speculate about what might have happened prior to a specific, designated event, or
- Postfactual speculations: experiments that speculate about what may happen subsequent to (or consequent upon) a specific, designated event.
The second characteristic pattern is their movement in time in relation to “the present moment standpoint” of the individual performing the experiment; namely, in terms of:
- Their temporal direction: are they past-oriented or future-oriented?
- Their temporal sense:
- (a) in the case of past-oriented thought experiments, are they examining the consequences of temporal “movement” from the present to the past, or from the past to the present? or,
- (b) in the case of future-oriented thought experiments, are they examining the consequences of temporal “movement” from the present to the future, or from the future to the present?
Generally speaking, there are seven types of thought experiments in which one reasons from causes to effects, or effects to causes:
Prefactual (before the fact) thought experiments — the term prefactual was coined by Lawrence J. Sanna in 1998 — speculate on possible future outcomes, given the present, and ask "What will be the outcome if event E occurs?"
Counterfactual (contrary to established fact) thought experiments — the term counterfactual was coined by Nelson Goodman in 1947, extending Roderick Chisholm's (1946) notion of a "contrary-to-fact conditional" — speculate on the possible outcomes of a different past; and ask "What might have happened if A had happened instead of B?" (e.g., "If Isaac Newton and Gottfried Leibnizhad cooperated with each other, what would mathematics look like today?").
The study of counterfactual speculation has increasingly engaged the interest of scholars in a wide range of domains such as philosophy, psychology, cognitive psychology, history, political science, economics, social psychology, law, organizational theory, marketing, and epidemiology.
Semifactual thought experiments — the term semifactual was coined by Nelson Goodman in 1947 — speculate on the extent to which things might have remained the same, despite there being a different past; and asks the question Even though X happened instead of E, would Y have still occurred? (e.g., Even if the goalie had moved left, rather than right, could he have intercepted a ball that was traveling at such a speed?).
Semifactual speculations are an important part of clinical medicine.
The activity of prediction attempts to project the circumstances of the present into the future. According to David Sarewitz and Roger Pielke (1999, p123), scientific prediction takes two forms:
- (1) “The elucidation of invariant — and therefore predictive — principles of nature”; and
- (2) “[Using] suites of observational data and sophisticated numerical models in an effort to foretell the behavior or evolution of complex phenomena”.
Although they perform different social and scientific functions, the only difference between the qualitatively identical activities of predicting, forecasting, and nowcasting is the distance of the speculated future from the present moment occupied by the user. Whilst the activity of nowcasting, defined as “a detailed description of the current weather along with forecasts obtained by extrapolation up to 2 hours ahead”, is essentially concerned with describing the current state of affairs, it is common practice to extend the term “to cover very-short-range forecasting up to 12 hours ahead” (Browning, 1982, p.ix).
The activity of hindcasting involves running a forecast model after an event has happened in order to test whether the model's simulation is valid.
In 2003, Dake Chen and his colleagues “trained” a computer using the data of the surface temperature of the oceans from the last 20 years. Then, using data that had been collected on the surface temperature of the oceans for the period 1857 to 2003, they went through a hindcasting exercise and discovered that their simulation not only accurately predicted every El Niño event for the last 148 years, it also identified the (up to 2 years) looming foreshadow of every single one of those El Niño events.
The activity of retrodiction (or postdiction) involves moving backwards in time, step-by-step, in as many stages as are considered necessary, from the present into the speculated past to establish the ultimate cause of a specific event (e.g., reverse engineering and forensics).
Given that retrodiction is a process in which "past observations, events and data are used as evidence to infer the process(es) the produced them" and that diagnosis "involve[s] going from visible effects such as symptoms, signs and the like to their prior causes", the essential balance between prediction and retrodiction could be characterized as:
- retrodiction : diagnosis :: prediction : prognosis
regardless of whether the prognosis is of the course of the disease in the absence of treatment, or of the application of a specific treatment regimen to a specific disorder in a particular patient.
The activity of backcasting — the term backcasting was coined by John Robinson in 1982 — involves establishing the description of a very definite and very specific future situation. It then involves an imaginary moving backwards in time, step-by-step, in as many stages as are considered necessary, from the future to the present to reveal the mechanism through which that particular specified future could be attained from the present.
Backcasting is not concerned with predicting the future:
- The major distinguishing characteristic of backcasting analyses is the concern, not with likely energy futures, but with how desirable futures can be attained. It is thus explicitly normative, involving 'working backwards' from a particular future end-point to the present to determine what policy measures would be required to reach that future.
According to Jansen (1994, p. 503:
- Within the framework of technological development, “forecasting” concerns the extrapolation of developments towards the future and the exploration of achievements that can be realized through technology in the long term. Conversely, the reasoning behind “backcasting” is: on the basis of an interconnecting picture of demands technology must meet in the future — “sustainability criteria” — to direct and determine the process that technology development must take and possibly also the pace at which this development process must take effect.
- Backcasting [is] both an important aid in determining the direction technology development must take and in specifying the targets to be set for this purpose. As such, backcasting is an ideal search toward determining the nature and scope of the technological challenge posed by sustainable development, and it can thus serve to direct the search process toward new — sustainable — technology.
In philosophy, a thought experiment typically presents an imagined scenario with the intention of eliciting an intuitive or reasoned response about the way things are in the thought experiment. (Philosophers might also supplement their thought experiments with theoretical reasoning designed to support the desired intuitive response.) The scenario will typically be designed to target a particular philosophical notion, such as morality, or the nature of the mind or linguistic reference. The response to the imagined scenario is supposed to tell us about the nature of that notion in any scenario, real or imagined.
For example, a thought experiment might present a situation in which an agent intentionally kills an innocent for the benefit of others. Here, the relevant question is not whether the action is moral or not, but more broadly whether a moral theory is correct that says morality is determined solely by an action's consequences (See Consequentialism). John Searle imagines a man in a locked room who receives written sentences in Chinese, and returns written sentences in Chinese, according to a sophisticated instruction manual. Here, the relevant question is not whether or not the man understands Chinese, but more broadly, whether a functionalist theory of mind is correct.
It is generally hoped that there is universal agreement about the intuitions that a thought experiment elicits. (Hence, in assessing their own thought experiments, philosophers may appeal to "what we should say," or some such locution.) A successful thought experiment will be one in which intuitions about it are widely shared. But often, philosophers differ in their intuitions about the scenario.
Other philosophical uses of imagined scenarios arguably are thought experiments also. In one use of scenarios, philosophers might imagine persons in a particular situation (maybe ourselves), and ask what they would do.
For example, in the veil of ignorance, John Rawls asks us to imagine a group of persons in a situation where they know nothing about themselves, and are charged with devising a social or political organization. The use of the state of nature to imagine the origins of government, as by Thomas Hobbes and John Locke, may also be considered a thought experiment. Søren Kierkegaard explored the possible ethical and religious implications of Abraham's binding of Isaac in Fear and Trembling Similarly, Friedrich Nietzsche, in On the Genealogy of Morals, speculated about the historical development of Judeo-Christian morality, with the intent of questioning its legitimacy.
An early written thought experiment was Plato's allegory of the cave. Another historic thought experiment was Avicenna's "Floating Man" thought experiment in the 11th century. He asked his readers to imagine themselves suspended in the air isolated from all sensations in order to demonstrate human self-awareness and self-consciousness, and the substantiality of the soul.
The scenario presented in a thought experiment must be possible in some sense. In many thought experiments, the scenario would be nomologically possible, or possible according to the laws of nature. John Searle's Chinese room is nomologically possible.
Some thought experiments present scenarios that are not nomologically possible. In his Twin Earth thought experiment, Hilary Putnam asks us to imagine a scenario in which there is a substance with all of the observable properties of water (e.g., taste, color, boiling point), but is chemically different from water. It has been argued that this thought experiment is not nomologically possible, although it may be possible in some other sense, such as metaphysical possibility. It is debatable whether the nomological impossibility of a thought experiment renders intuitions about it moot.
In some cases, the hypothetical scenario might be considered metaphysically impossible, or impossible in any sense at all. David Chalmers says that we can imagine that there are zombies, or persons who are physically identical to us in every way but who lack consciousness. This is supposed to show that physicalism is false. However, some argue that zombies are inconceivable: we can no more imagine a zombie than we can imagine that 1+1=3. Others have claimed that the conceivability of a scenario may not entail its possibility.
Interactive thought experiments in digital environments
The philosophical work of Stefano Gualeni focuses on the use of virtual worlds to materialize thought experiments and to playfully negotiate philosophical ideas. His arguments were originally presented in his 2015 book Virtual Worlds as Philosophical Tools.
Gualeni's argument is that the history of philosophy has, until recently, merely been the history of written thought, and digital media can complement and enrich the limited and almost exclusively linguistic approach to philosophical thought. He considers virtual worlds to be philosophically viable and advantageous in contexts like those of thought experiments, when the recipients of a certain philosophical notion or perspective are expected to objectively test and evaluate different possible courses of action, or in cases where they are confronted with interrogatives concerning non-actual or non-human phenomenologies .
Among the most visible thought experiments designed by Stefano Gualeni:
Other examples of playful, interactive thought experiments:
- Artificial brain
- Avicenna's Floating Man
- Beetle in a box
- Bellum omnium contra omnes
- Big Book (ethics)
- Brain-in-a-vat (epistemology, philosophy of mind)
- Brainstorm machine
- Buridan's ass
- Changing places (reflexive monism, philosophy of mind)
- China brain (physicalism, philosophy of mind)
- Chinese room (philosophy of mind, artificial intelligence, cognitive science)
- Coherence (philosophical gambling strategy)
- Condillac's Statue (epistemology)
- Experience machine (ethics)
- Gettier problem (epistemology)
- Ḥayy ibn Yaqẓān (epistemology)
- Hilary Putnam's Twin Earth thought experiment in the philosophy of language and philosophy of mind
- How many men? (taxation as theft)
- Inverted spectrum
- Kavka's toxin puzzle
- Mary's room (philosophy of mind)
- Molyneux's Problem (admittedly, this oscillated between empirical and a-priori assessment)
- Newcomb's paradox
- Original position (politics)
- Philosophical zombie (philosophy of mind, artificial intelligence, cognitive science)
- Plank of Carneades
- Ship of Theseus, The (concept of identity)
- Simulated reality (philosophy, computer science, cognitive science)
- Social contract theories
- Survival lottery, The (ethics)
- Swamp man (personal identity, philosophy of mind)
- Shoemaker's "Time Without Change" (metaphysics)
- Ticking time bomb scenario (ethics)
- Teleportation (metaphysics)
- The Transparent eyeball
- Trolley problem (ethics)
- The Violinist (ethics)
- Utility monster (ethics)
- Zeno's paradoxes (classical Greek problems of the infinite)
- ^Perkowitz, Sidney (February 12, 2010). "Gedankenexperiment". Encyclopædia Britannica Online. Retrieved March 27, 2017.
- ^See occurrences on Google Books.
- ^Robert Brown, James (August 12, 2014). "Thought Experiments". Stanford Encyclopedia of Philosophy. Retrieved March 27, 2017.
- ^"[C]onjectures or hypotheses ... are really to be regarded as thought "experiments" through which we wish to discover whether something can be explained by a specific assumption in connection with other natural laws." —Hans Christian Ørsted("First Introduction to General Physics" ¶16-¶18, part of a series of public lectures at the University of Copenhagen. Copenhagen 1811, in Danish, printed by Johan Frederik Schulz. In Kirstine Meyer's 1920 edition of Ørsted's works, vol.III pp. 151-190. ) "First Introduction to Physics: the Spirit, Meaning, and Goal of Natural Science". Reprinted in German in 1822, Schweigger's Journal für Chemie und Physik36, pp. 458–488, as translated in Ørsted 1997, pp. 296–298
- ^Szábo, Árpád. (1958) " 'Deiknymi' als Mathematischer Terminus fur 'Beweisen' ", Maia N.S. 10 pp. 1–26 as cited by Imre Lakatos (1976) in Proofs and Refutations p.9. (John Worrall and Elie Zahar, eds.) Cambridge University Press ISBN 0-521-21078-X. The English translation of the title of Szábo's article is "'Deiknymi' as a mathematical expression for 'to prove'", as translated by András Máté, p.285
- ^Cohen, Martin, "Wittgenstein's Beetle and Other Classic Thought Experiments", Blackwell, (Oxford), 2005, pp. 55–56.
- ^"Galileo on Aristotle and Acceleration". Retrieved 2008-05-24.
- ^See, for example, Paul Feyerabend, 'Against Method', Verso (1993)
- ^Catholic Encyclopedia (1913)/Pandects "every logical rule of law is capable of illumination from the law of the Pandects."
- ^Witt-Hansen (1976). Although Experiment is a German word, it is derived from Latin. The synonym Versuch has purely Germanic roots.
- ^Mach, Ernst (1883), The Science of Mechanics (6th edition, translated by Thomas J. McCormack), LaSalle, Illinois: Open Court, 1960. pp. 32-41, 159-62.
- ^Mach, Ernst (1897), "On Thought Experiments", in Knowledge and Error (translated by Thomas J. McCormack and Paul Foulkes), Dordrecht Holland: Reidel, 1976, pp. 134-47.
- ^Rescher, N. (1991), "Thought Experiment in Pre-Socratic Philosophy", in Horowitz, T.; Massey, G.J., Thought Experiments in Science and Philosophy, Rowman & Littlefield, (Savage), pp. 31–41.
- ^Brendal, Elke, "Intuition Pumps and the Proper Use of Thought Experiments". Dialectica. V.58, Issue 1, p 89–108, March 2004
- ^Jaynes, E.T. (1989).Clearing up the Mysteries, opening talk at the 8th International MAXENT Workshop, St John's College, Cambridge UK.
- ^French, A.P., Taylor, E.F. (1979/1989). An Introduction to Quantum Physics, Van Nostrand Reinhold (International), London, ISBN 0-442-30770-5.
- ^Wheeler, J.A, Zurek, W.H., editors (1983). Quantum Theory and Measurement, Princeton University Press, Princeton.
- ^d'Espagnat, B. (2006). On Physics and Philosophy, Princeton University Press, Princeton, ISBN 978-0-691-11964-9
- ^Yeates, 2004, pp.138-143.
- ^Taken from Yeates, 2004, p.143.
- ^See Yeates, 2004, pp.138-159.
- ^Sanna, L.J., "Defensive Pessimism and Optimism: The Bitter-Sweet Influence of Mood on Performance and Prefactual and Counterfactual Thinking", Cognition and Emotion, Vol.12, No.5, (September 1998), pp.635-665. (Sanna used the term prefactual to distinguish these sorts of thought experiment from both semifactuals and counterfactuals.)
- ^Taken from Yeates, 2004, p.144.
- ^Goodman, N., "The Problem of Counterfactual Conditionals", The Journal of Philosophy, Vol.44, No.5, (27 February 1947), pp.113-128.
- ^Chisholm, R.M., "The Contrary-to-Fact Conditional", Mind, Vol.55, No.220, (October 1946), pp.289-307.
- ^Roger Penrose (Shadows of the Mind: A Search for the Missing Science of Consciousness, Oxford University Press, (Oxford),1994, p.240) considers counterfactuals to be "things that might have happened, although they did not in fact happen".
- ^In 1748, when defining causation, David Hume referred to a counterfactual case: "…we may define a cause to be an object, followed by another, and where all objects, similar to the first, are followed by objects similar to the second. Or in other words, where, if the first object had not been, the second never had existed …" (Hume, D. (Beauchamp, T.L., ed.), An Enquiry Concerning Human Understanding, Oxford University Press, (Oxford), 1999, (7), p.146.)
- ^Goodman, N., "The Problem of Counterfactual Conditionals", The Journal of Philosophy, Vol.44, No.5, (27 February 1947), pp.113-128; Brown, R, & Watling, J., "Counterfactual Conditionals", Mind, Vol.61, No.242, (April 1952), pp.222-233; Parry, W.T., "Reëxamination of the Problem of Counterfactual Conditionals", The Journal of Philosophy, Vol.54, No.4, (14 February 1957), pp.85-94; Cooley, J.C., "Professor Goodman’s Fact, Fiction, & Forecast", The Journal of Philosophy, Vol.54, No.10, (9 May 1957), pp.293-311; Goodman, N., "Parry on Counterfactuals", The Journal of Philosophy, Vol.54, No.14, (4 July 1957), pp.442-445; Goodman, N., "Reply to an Adverse Ally", The Journal of Philosophy, Vol.54, No.17, (15 August 1957), pp.531-535; Lewis, D., Counterfactuals, Basil Blackwell, (Oxford), 1973, etc.
- ^Fillenbaum, S., "Information Amplified: Memory for Counterfactual Conditionals", Journal of Experimental Psychology, Vol.102, No.1, (January 1974), pp.44-49; Crawford, M.T. & McCrea, S.M., "When Mutations meet Motivations: Attitude Biases in Counterfactual Thought", Journal of Experimental Social Psychology, Vol.40, No.1, (January 2004), pp.65-74, etc.
- ^Kahneman, D. & Tversky, A., "The Simulation Heuristic", pp.201-208 in Kahneman, D., Slovic, P. & Tversky, A. (eds), Judgement Under Uncertainty: Heuristics and Biases, Cambridge University Press, (Cambridge), 1982; Sherman, S.J. & McConnell, A.R., "Dysfunctional Implications of Counterfactual Thinking: When Alternatives to reality Fail Us", pp.199-231 in Roese, N.J. & Olson, J.M. (eds.), What Might Have Been: The Social Psychology of Counterfactual Thinking, Lawrence Erlbaum Associates, (Mahwah), 1995;Nasco, S.A. & Marsh, K.L., "Gaining Control Through Counterfactual Thinking", Personality and Social Psychology Bulletin, Vol.25, No.5, (May 1999), pp.556-568; McCloy, R. & Byrne, R.M.J., "Counterfactual Thinking About Controllable Events", Memory and Cognition, Vol.28, No.6, (September 2000), pp.1071-1078; Byrne, R.M.J., "Mental Models and Counterfactual Thoughts About What Might Have Been", Trends in Cognitive Sciences, Vol.6, No.10, (October 2002), pp.426-431; Thompson, V.A. & Byrne, R.M.J., "Reasoning Counterfactually: Making Inferences About Things That Didn't Happen", Journal of Experimental Psychology: Learning, Memory, and Cognition, Vol.28, No.6, (November 2002), pp.1154-1170, etc.
- ^Greenberg, M. (ed.), The Way It Wasn’t: Great Science Fiction Stories of Alternate History, Citadel Twilight, (New York), 1996; Dozois, G. & Schmidt, W. (eds.), Roads Not Taken: Tales of Alternative History, The Ballantine Publishing Group, (New York), 1998; Sylvan, D. & Majeski, S., "A Methodology for the Study of Historical Counterfactuals", International Studies Quarterly, Vol.42, No.1, (March 1998), pp.79-108; Ferguson, N., (ed.), Virtual History: Alternatives and Counterfactuals, Basic Books, (New York), 1999; Cowley, R. (ed.), What If?: The World’s Foremost Military Historians Imagine What Might have Been, Berkley Books, (New York), 2000; Cowley, R. (ed.), What If? 2: Eminent Historians Imagine What Might have Been, G.P. Putnam’s Sons, (New York), 2001, etc.
- ^Fearon, J.D., "Counterfactuals and Hypothesis Testing in Political Science", World Politics, Vol.43, No.2, (January 1991), pp.169-195; Tetlock, P.E. & Belkin, A. (eds.), Counterfactual Thought Experiments in World Politics, Princeton University Press, (Princeton), 1996; Lebow, R.N., "What’s so Different about a Counterfactual?", World Politics, Vol.52, No.4, (July 2000), pp.550-585; Chwieroth, J.M., "Counterfactuals and the Study of the American Presidency", Presidential Studies Quarterly, Vol.32, No.2, (June 2002), pp.293-327, etc.
- ^Cowan, R. & Foray, R., "Evolutionary Economics and the Counterfactual Threat: On the Nature and Role of Counterfactual History as an Empirical Tool in Economics", Journal of Evolutionary Economics, Vol.12, No.5, (December 2002), pp.539-562, etc.
- ^Roese, N.J. & Olson, J.M. (eds.), What Might Have Been: The Social Psychology of Counterfactual Thinking, Lawrence Erlbaum Associates, (Mahwah), 1995; Sanna, L.J., "Defensive Pessimism, Optimism, and Simulating Alternatives: Some Ups and Downs of Prefactual and Counterfactual Thinking", Journal of Personality and Social Psychology, Vol.71, No.5, (November 1996), pp1020-1036; Roese, N.J., "Counterfactual Thinking", Psychological Bulletin, Vol.121, No.1, (January 1997), pp.133-148; Sanna, L.J., "Defensive Pessimism and Optimism: The Bitter-Sweet Influence of Mood on Performance and Prefactual and Counterfactual Thinking", Cognition and Emotion, Vol.12, No.5, (September 1998), pp.635-665; Sanna, L.J. & Turley-Ames, K.J., "Counterfactual Intensity", European Journal of Social Psychology, Vol.30, No.2, (March/April 2000), pp.273-296; Sanna, L.J., Parks, C.D., Meier, S., Chang, E.C., Kassin, B.R., Lechter, J.L., Turley-Ames, K.J. & Miyake, T.M., "A Game of Inches: Spontaneous Use of Counterfactuals by Broadcasters During Major League Baseball Playoffs", Journal of Applied Social Psychology, Vol.33, No.3, (March 2003), pp.455-475, etc.
- ^Strassfeld, R.N., "If...: Counterfactuals in the Law", George Washington Law Review, Volume 60, No.2, (January 1992), pp.339-416; Spellman, B.A. & Kincannon, A., "The Relation between Counterfactual (“but for”) and Causal reasoning: Experimental Findings and Implications for Juror’s Decisions", Law and Contemporary Problems, Vol.64, No.4, (Autumn 2001), pp.241-264; Prentice, R.A. & Koehler, J.J., "A Normality Bias in Legal Decision Making", Cornell Law Review, Vol.88, No.3, (March 2003), pp.583-650, etc.
- ^Creyer, E.H. & Gürhan, Z., "Who's to Blame? Counterfactual Reasoning and the Assignment of Blame", Psychology and Marketing, Vol.14, No.3, (May 1997), pp.209-307; Zeelenberg, M., van Dijk, W.W., van der Plight, J., Manstead, A.S.R., van Empelen, P., & Reinderman, D., "Emotional Reactions to the Outcomes of Decisions: The Role of Counterfactual Thought in the Experience of Regret and Disappointment", Organizational Behavior and Human Decision Processes, Vol.75, No.2, (August 1998), pp.117-141; Naquin, C.E. & Tynan, R.O., "The Team Halo Effect: Why Teams Are Not Blamed for Their Failures", Journal of Applied Psychology, Vol.88, No.2, (April 2003), pp.332-340; Naquin, C.E., "The Agony of Opportunity in Negotiation: Number of Negotiable Issues, Counterfactual Thinking, and Feelings of Satisfaction", Organizational Behavior and Human Decision Processes, Vol.91, No.1, (May 2003), pp.97-107, etc.
- ^Hetts, J.J., Boninger, D.S., Armor, D.A., Gleicher, F. & Nathanson, A., "The Influence of Anticipated Counterfactual Regret on Behavior", Psychology & Marketing, Vol.17, No.4, (April 2000), pp.345-368; Landman, J. & Petty, R., "“It Could Have Been You”: How States Exploit Counterfactual Thought to Market Lotteries", Psychology & Marketing, Vol.17, No.4, (April 2000), pp.299-321; McGill, A.L., "Counterfactual Reasoning in Causal Judgements: Implications for Marketing", Psychology & Marketing, Vol.17, No.4, (April 2000), pp.323-343; Roese, N.J., "Counterfactual Thinking and Marketing: Introduction to the Special Issue", Psychology & Marketing', Vol.17, No.4, (April 2000), pp.277-280; Walchli, S.B. & Landman, J., "Effects of Counterfactual Thought on Postpurchase Consumer Affect", Psychology & Marketing, Vol.20, No.1, (January 2003), pp.23-46, etc.
- ^Randerson, J., "Fast action would have saved millions", New Scientist, Vol.176, No.2372, (7 December 2002), p.19; Haydon, D.T., Chase-Topping, M., Shaw, D.J., Matthews, L., Friar, J.K., Wilesmith, J. & Woolhouse, M.E.J., "The Construction and Analysis of Epidemic Trees With Reference to the 2001 UK Foot-and-Mouth Outbreak", Proceedings of the Royal Society of London Series B: Biological Sciences, Vol.270, No.1511, (22 January 2003), pp.121-127, etc.
- ^Taken from Yeates, 2004, p.144.
- ^Goodman, N., "The Problem of Counterfactual Conditionals", The Journal of Philosophy, Vol.44, No.5, (27 February 1947), pp.113-128.
- ^Goodman's original concept has been subsequently developed and expanded by (a) Daniel Cohen (Cohen, D., "Semifactuals, Even-Ifs, and Sufficiency", International Logic Review, Vol.16, (1985), pp.102-111), (b) Stephen Barker (Barker, S., "Even, Still and Counterfactuals", Linguistics and Philosophy, Vol.14, No.1, (February 1991), pp.1-38; Barker, S., "Counterfactuals, Probabilistic Counterfactuals and Causation", Mind, Vol.108, No.431, (July 1999), pp.427-469), and (c) Rachel McCloy and Ruth Byrne (McCloy, R. & Byrne, R.M.J., "Semifactual 'Even If' Thinking", Thinking and Reasoning, Vol.8, No.1, (February 2002), pp.41-67).
- ^Taken from Yeates, 2004, p.145.
- ^Sarewitz, D. & Pielke, R., "Prediction in Science and Policy", Technology in Society, Vol.21, No.2, (April 1999), pp.121-133.
- ^Nowcasting (obviously based on forecasting) is also known as very-short-term forecasting; thus, also indicating a very-short-term, mid-range, and long-range forecasting continuum.
- ^Browning, K.A. (ed.), Nowcasting, Academic Press, (London), 1982.
- ^Murphy, and Brown — Murphy, A.H. & Brown, B.G., "Similarity and Analogical Reasoning: A Synthesis", pp.3-15 in Browning, K.A. (ed.), Nowcasting