|
In psychology, the prevalence effect is the phenomenon that one is more likely to miss (or fail to detect) a target with a low prevalence (or frequency) than a target with a high prevalence or frequency. A real-world application of this phenomenon occurs in airport security screening; since a very small proportion of those going through security checkpoints carry weapons, security staff may fail to detect those attempting to carry weapons onto a plane.〔J. M. Wolfe, D. N. Brunelli, J. Rubinstein, T. S. Horowitz. Prevalence effects in newly trained airport checkpoint screeners: Trained observers miss rare targets, too. Journal of Vision, 2013; 13 (3): 33 DOI: 10.1167/13.3.33〕 In visual perception, target prevalence describes the salience (or visibility) of an object or objects in the environment and influences visual search.〔Wolfe, J. and Van Wert, M. (2010) Varying Target Prevalence Reveals Two Dissociable Decision Criteria in Visual Search. Current Biology 20, 121-124.〕 An experiment〔Wolfe, J. M., Horowitz, T. S., & Kenner, N. M. (2005). Rare items often missed in visual searches. Nature, 435, 439-440.〕 similar to an x-ray baggage search at an airport reveals how likely one is to make errors when searching for low-prevalence targets. A 50-percent prevalence produced a seven-percent error rate, typical for laboratory search tasks of this sort; a 10-percent prevalence produced a 16-percent error rate, and prevalence under one percent produced a 30-percent error rate. Humans normally search for common things, such as a favorite jelly-bean flavor in a collection of flavors. When they look for rare things (such as a jelly bean in a bag of lollipops), they are likely to abandon the search quickly because the probability of success and the stakes are low. Some searches combine low prevalence with high stakes; medical screenings such as mammography or cytopathology, is an important search for a target rarely present (typically under one percent).〔Fenton, J. J., Taplin, S. H., Carney, P. A., Abraham, L., Sickles, E. A., D’Orsi, C., et al. (2007). Influence of computer-aided detection on performance of screening mammography. New England Journal of Medicine, 356, 1399–1409.〕 Missing a rare target, such as a weapon smuggled onto an airplane, may have serious consequences. == Past experience or future prospect == The prevalence effect is influenced by top-down control of a future prospect or the bottom-up priming of past experience. Top-down refers to the expectation effect: knowledge of what will happen next. The bottom-up, repetition effect is produced by the sharing of properties by current and preceding stimuli. Observers may miss rare targets because they knew that the targets are (or were) rare. Research has attempted to distinguish these possibilities by creating situations in which past experience is different from the future prospect; the target has been frequent in the past, but is known to be rare in the future. It was found that the prevalence effect is a consequence of bottom-up experience and unaffected by top-down control.〔Lau, J. S. H., & Huang, L. (2010). The prevalence effect is determined by past experience, not future prospects. Vision research, 50(15), 1469-1474.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Prevalence effect」の詳細全文を読む スポンサード リンク
|