The effect of search time on perception

E. E. Christensen, R. C. Murry, K. Holland, J. Reynolds, M. J. Landay, J. G. Moore

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


A group of 100 carefully selected chest radiographs was read by ten observers, five experienced and five inexperienced. The radiographs were chosen to present the readers with a disproportionately large number of both subtle abnormalities and nonpulmonary lesions. Each reader was allowed to search the radiographs for as long as appropriate, up to a maximum of four minutes. The length of time taken for each observation was recorded to the nearest second. The time-perception data were plotted on both linear and semilogarithmic graphs. The results showed that experienced readers concluded their visual search while they were still making a significant number of true-positive observations and while the true-positive detection rate was higher than the rate for false-positives. For lesions in the central portions of the radiograph (heart, lungs, and pleura), the time-perception curves were biphasic, with both a rapid and a slow component of perception. If these data are plotted on a semilogarithmic scale, each of the two components plots as a straight line. For lesions in the periphery of the radiograph (chest wall and upper abdomen), the time-perception curve is monophasic, showing only a slow component.

Original languageEnglish (US)
Pages (from-to)361-365
Number of pages5
JournalUnknown Journal
Issue number2
StatePublished - Jan 1 1981

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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