Joachim Krueger (1998) What can Individual Differences in Reasoning Tell us?. Psycoloquy: 9(77) Social Bias (12)

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PSYCOLOQUY (ISSN 1055-0143) is sponsored by the American Psychological Association (APA).
Psycoloquy 9(77): What can Individual Differences in Reasoning Tell us?

Reply to Stanovich on Krueger on Social-Bias

Joachim Krueger
Department of Psychology
Brown University, Box 1853
Providence, RI 02912


The study of individual differences in social-perceptual biases can illuminate both normative models of judgment and patterns and co-occurrences among biases. Empirical research on the latter is especially important because some hasty claims about the relationships among biases have already been made. The putative mutual exclusivity of social projection and self-enhancement serves as an illustration.


individual differences, cognitive biases, projection, self-enhancement
1. Stanovich (1998) outlines a fascinating research program aimed at uncovering correlations among individual differences in various reasoning biases and indices of cognitive capacity and style. Aside from its rich exploratory potential, this approach offers opportunities to validate normative models of social perception. If rationality is linked to intelligence or other cognitive abilities (see also Rickert 1998 and Krueger 1998a), and if the normative model for rational judgment is correct, the correlations between biases and intelligence should be negative. Stanovich and West (1998) reported negative correlations for some biases, but not for others. Projection bias in particular was unrelated to cognitive ability. This bias was assessed as the correlation between the rater's own responses and that rater's consensus estimates while actual consensus values were statistically controlled.

2. Stanovich suggests that this lack of a correlation between projection bias and cognitive ability supports the view that projection is a rational strategy for inductive reasoning. I hesitate to draw this conclusion because I think it would require a strong positive correlation. That is, one might expect that smart people are especially good at inductive reasoning. Raw projection (i.e., uncorrected for actual consensus) increases the accuracy of social predictions, and smart people might realize that. It seems more likely that cognitive ability and projection are independent because either ability or the normative model of projection (or both) are irrelevant. Most people project from themselves to others, and some do so more than others. If differences in ability cannot explain these differences, what can?

3. I have argued that projection is egocentric in the sense that it occurs automatically, uncontrollably, and fast (Krueger 1998b). Its end result, consensus estimates that are fairly accurate, seems to suggest that people reason inductively. This interpretation is challenged, however, by the finding that people tend to ignore the behaviors of other individual when they make predictions about the group. They are egocentric in the sense that they rely selectively on information that is tied to the self. Ignoring information tied to others violates inductive reasoning. Incidentally, this example illustrates a rare case in which a null hypothesis represents irrationality. Suppose, for instance, subjects 'A' and 'B' favor the same of two novels they have read. They are both informed about the preference of a randomly drawn third reader. 'A' learns that the reader's preference agrees with his own, whereas 'B' learns that the reader disagrees. If 'A' and 'B' give the same estimates as to how well the two novels will sell, they have irrationally ignored relevant information.

4. If projection is independent of cognitive ability, the search for other predictors should continue. One hypothesis is that projection is related to other egocentric tendencies. Stanovich and West (1998) found correlations around 0.2 with overconfidence bias. Another candidate is self-enhancement. It is important to examine the relationship between projection and self-enhancement because it is possible that various biases cluster together in an egocentric pattern. Perhaps those people who project the most also self-enhance the most and are most confident in their own predictions. The individual differences approach might thus be able to help establish useful taxonomies of social perceptual tendencies.

5. A final reason for studying the relationship between projection and self-enhancement is that some questionable claims have been made without supporting data. Among others, Augoustinos and Walker (1995) and Markus and Kitayama (1991) have suggested that self-enhancement is the opposite of false consensus (i.e., projection). In their view, to believe oneself to be better than average (self-enhancement) is to falsely believe oneself to be unique. In my target article (Krueger 1998c), I cautioned against designing studies that all but guarantee that either one of two opposite biases (e.g., false consensus or false uniqueness) will be found. The evidence for self-enhancement and projection comes from different studies, and so there remains the question of how the same participants could possibly be prone to both false consensus and false uniqueness.

6. The answer, of course, is that self-enhancement and projection are separable tendencies. One can both believe that one is more honest than the average person (self-enhancement) and that most people are honest rather than dishonest (projection). One can judge desirable traits as being more descriptive of oneself and of another person than undesirable traits. This assumed similarity expresses projection. At the same time, one can judge desirable traits as being more descriptive of oneself than of the other, and undesirable traits as being less descriptive of oneself than of the other. These discrepancies express self-enhancement. In other words, the relationships among various self-related biases require careful study, and the individual-differences approach is one promising way to get answers.


Augoustinos, M. & Walker, I. (1995). Social cognition: An integrated introduction. London: Sage.

Krueger, J. (1998a). Rationality is intelligent. PSYCOLOQUY 9(68)

Krueger, J. (1998b) On the perception of social consensus. Advances in Experimental Social Psychology 30: 163-240.

Krueger, J. (1998c). The bet on bias: A forgone conclusion? PSYCOLOQUY 9(46)

Markus, H. R. & Kitayama, S. (1991). Culture and the self: Implications for cognition, emotion, and motivation. Psychological Review, 98: 224- 253.

Rickert, N. W. (1998) Intelligence is not rational. Psycoloquy 9(51)

Stanovich, K. E. (1998). Individual differences in cognitive biases. PSYCOLOQUY 9(75)

Stanovich, K. E., & West, R. F. (1998). Individual differences in rational thought. Journal of Experimental Psychology: General, 127: 161-188.

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