In most contexts, individuals are more inclined to believe someone who is confident (Penrod & Cutler, 1995)--that is, someone who maintains their position confidently and assuredly rather than reservedly. This tendency to apply confidence as a means to predict accuracy is sometimes called the confidence heuristic (Price & Stone, 2004& Thomas & McFadyen, 1995).
The confidence heuristic has been observed in many contexts (see Bradfield & Wells, 2000& Sporer, Penrod, Read, & Cutler, 1995), but is often examined in legal and police settings (see Wells, Memon, & Penrod, 2006). Furthermore, the confidence heuristic has often been examined in group settings. That is, confidence individuals tend to be regarded as more influential in group contexts (e.g., Zarnoth & Sniezek, 1997).
Confidence can be expressed with both words and numbers. For example, predictions attached to high probabilities are more credible than unconfident predictions attached to low probabilities, because they instill a sense of certainty (Keren & Teigen, 2001).
Several explanations have been proposed to expain the evolution of this confidence heuristic--this tendency to assume that confident assertions are more likely to be correct. First, confidence imparts a sense of certainty (Keren & Teigen, 2001). When individuals experience this certainty, they are less likely to entertain conflicting perspectives
Second, social benefits might accrue if individuals agree with someone who is confident (Zarnoth & Sniezek, 1997).
Finally, in practice, confident assertions might ultimately be more likely to be correct. That is, individuals might know when their propositions are correct (Yates, Price, Lee, & Ramirez, 1996), and this knowledge could affect the level of confidence they demonstrate
Several studies, however, have shown the confidence heuristic is applied only if individuals have not been able to establish whether a person can estimate the legitimacy of their predictions (Tenney, MacCoun, Spellman, & Hastie, 2007& Tenney, Spellman, & MacCoun, 2008). That is, some individuals can estimate whether or not their predictions or propositions, such as "I will complete 5 reports next week", are likely to be fulfilled. If certain, they will show confidence, such as utter phrases like "I am sure". If uncertain, they will utter qualifications like "At least, I think so". In other words, they can calibrate their confidence appropriately.
Other individuals do not calibrate their confidence appropriately. An outcome they predict confidently might not transpire, for example.
If individuals cannot establish whether or not a person can calibrate their confidence appropriately, they are more inclined to believe a statement that is uttered confidently (Tenney, MacCoun, Spellman, & Hastie, 2007& Tenney, Spellman, & MacCoun, 2008)--called the presumption of calibration. If individuals have established that a person cannot calibrate their confidence appropriately, the confidence heuristic does not apply (for empirical evidence, see Tenney, Spellman, & MacCoun, 2008).
Bradfield, A. L., & Wells, G. L. (2000). The perceived validity of eyewitness identification testimony: A test of the five Biggers criteria. Law and Human Behavior, 24, 581-594.
Keren, G., & Teigen, K. H. (2001). Why is p = 90 better than p = .70? Preference for definitive predictions by lay consumers of probability judgments. Psychonomic Bulletin and Review, 8, 191-202.
Penrod, S. D., & Cutler, B. L. (1995). Witness confidence and witness accuracy: Assessing their forensic relation. Psychology, Public Policy, and Law, 1, 817-845.
Price, P. C., & Stone, E. R. (2004). Intuitive evaluation of likelihood judgment producers: Evidence for a confidence heuristic. Journal of Behavioral Decision Making, 17, 39-57.
Sporer, S. L., Penrod, S., Read, D., & Cutler, B. (1995). Choosing, confidence, and accuracy: A meta-analysis of the confidence-accuracy relation in eyewitness identification studies. Psychological Bulletin, 118, 315-327.
Tenney, E. R., MacCoun, R. J., Spellman, B. A., & Hastie, R. (2007). Calibration trumps confidence as a basis for witness credibility. Psychological Science, 18, 46-50.
Tenney, E. R., Spellman, B. A., & MacCoun, R. J. (2008). The benefits of knowing what you know (and what you donÃ”Ã‡Ã–t): How calibration affects credibility. Journal of Experimental Social Psychology, 44, 1368-1375.
Thomas, J. P., & McFadyen, R. G. (1995). The confidence heuristic: A game theoretic analysis. Journal of Economic Psychology, 16, 97-113.
Van Swol, L. M., & Sniezek, J. A. (2005). Factors affecting the acceptance of expert advice. British Journal of Social Psychology, 44, 443-461.
Wells, G. L., Memon, A., & Penrod, S. D. (2006). Eyewitness evidence: Improving its probative value. Psychological Science in the Public Interest, 7, 45-75.
Yates, J. F., Price, P. C., Lee, J., & Ramirez, J. (1996). Good probabilistic forecasters: The 'consumer's' perspective. International Journal of Forecasting, 12, 41-56.
Zarnoth, P., & Sniezek, J. A. (1997). The social influence of confidence in group decision making. Journal of Experimental Social Psychology, 33, 345-366.
Last Update: 6/1/2016