What have we learned about prevalence in visual search and can we apply our findings to medical image perception?

Abstract

Interpretation of medical images is a socially critical application of visual search. The prevalence of targets in medical image search tasks varies widely. While a screening mammographer will see one cancer for every 300 cases, a pathologist interpreting biopsies will see mostly positive cases. How does prevalence affect visual search? Do low and high prevalence exert similar effects? Can findings from the basic vision science literature be generalized to the medical image perception context? I have previously reported a meta-analysis results show that basic cognitive psychology and applied medical image perception studies converge on an account of the low prevalence effect: sensitivity (d') is constant with prevalence, but criterion (c) shifts to a more conservative level at low prevalence (Horowitz, 2017). Here I show that these results generalize to the high prevalence effect: sensitivity does not change at high prevalence, but criterion shifts to a more liberal level. I synthesize findings from both vision science and medical image perception, I will identify practical suggestions for medical image professionals and theoretical insights for vision scientists.