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Zimbardo, P. (2008). The Lucifer Effect, New York: Random House.

Take Away Thoughts

I want to leave you with four thoughts.

1. There are ongoing differences of scholarly opinion about how to interpret the results of the SPE, and whether Zimbardo's interpretation is correct. Carnahan and McFarland have raised questions about self selection bias. (You folks taking methods should know all about this). They suggested that people volunteering for studies of prison life are more aggressive than those volunteering for other types of studies. Haney and Zimbardo have refuted this, suggesting it is an attempt to deny the power of the situation, and bring dispositional explanations - the fundamental attribution error and correspondence bias - back in.

Denying dispositional explanations gets you halfway to denying the relevance of personality factors. Social psychologists and personality psychologists have had this running gun battle for decades (Hogan et al., 1977). It will continue long after you and I are gone.

2. Different prison experiment setups lead to different results. The results of the BBC prison experiment are perhaps the most interesting. There the guards refused to be guards. Does this confirm the situationist view: if you alter the parameters of the situation, different things happen? Particularly interesting in that study was the idea of promoting a prisoner to be a guard, and how things shifted after that happened.

3. The recent research (Leidner et al. 2009) asking respondents about demands for justice in response to alleged abuses or killing suggests that moral disengagement discussed by Zimbardo is complicated, and in some situations linked to in-group glorification. There is definitely something going on here in terms of how we respond to aggressive, violent or unjust actions of others. What those are specifically, and how those apply to those who engage in these behaviors, are challenging questions. This gets us back to the racial epithets of the marauders in Darfur.

4. Ecological validity, i.e., the generalizability of SPE to other situations, is an empirical not a conceptual question (Taylor 1994: 161). Social psychologists as a group believe that in their stripped down laboratory experiments with random assignment the essence of process will be revealed. Even with an experiment as chaotic as SPE there are a lot of questions about how this links to situations outside that setting.

We know that real prisons are powerful settings, and how people respond on the inside and outside to prisoners and prison riots are enormously complicated (Wicker 1975). We also know that the effects of prison environments on inmates, called prisonization effects, are similarly powerful (Wheeler, 1961). Whether the SPE has added further insight into the dynamics inside those real places, is for you to decide.


Carnahan, T., and McFarland, S. (2007). "Revisiting the Stanford Prison Experiment: Could participant self-selection have led to the cruelty?" Personality and Social Psychology Bulletin, 33, 603-614.

Haney, C., and Zimbardo, P. G. (2009). "Persistent Dispositionalism in Interactionist Clothing: Fundamental Attribution Error in Explaining Prison Abuse." Personality and Social Psychology Bulletin, 35(6), 807-814.

Hogan, R., DeSoto, C. B., and Solano, C. (1977). "Traits, tests, and personality research." American Psychologist, 33, 255-264.

Leidner, B., Castano, E., Zaiser, E., and Giner-Sorolla, R. (2010). "Ingroup glorification, moral diesngagement, and justice in the context of collective violence." Personality and Social Psychology Bulletin, 36(8), 1115-1129.

McFarland, S., and Carnahan, T. (2009). "A Situation's first powers are attracting volunteers and selecting participants: A Reply to Haney and Zimbardo (2009)." Personality and Social Psychology Bulletin, 35(5), 815-818.

Reicher, S., and Haslam, S. A. (2004). "Rethinking the psychology of tyranny: The BBC prison study." British Journal of Social Psychology, 45(1-40).

Taylor, R. B. (1994). Research Methods in Criminal Justice, New York: McGraw Hill.

Wheeler, S. (1961). "Socialization in correctional communities." American Sociological Review, 26, 697-712.

Wicker, T. (1975). A Time to Die, New York: Quadrangle.