Abstract
What does making perceptual decisions in one setting teach us about making decisions in another? For example, dermatologists could screen for skin cancer in a morning clinic (low prevalence – few targets) and might evaluate suspicious cases in the afternoon (higher prevalence). The quality of feedback about their diagnoses could also vary. Our previous work shows that low target prevalence can shift decision criterion in a conservative direction when observers get feedback and in a liberal direction without feedback. How does experiencing one prevalence and feedback combination in one block influence the next block? Using an online, medical image labeling app, 803 individuals with medical knowledge rated images of skin lesions as either "melanoma" (skin cancer) or "nevus" (a skin mole). Blocks could have high (50%) or low (20%) target prevalence and could provide feedback or not. Os could participate in up to four different conditions a day on each of six days. We collected >300,000 trials in a week. On average, a low prevalence block with feedback made Os more conservative on any subsequent block. A high prevalence block with feedback made Os more liberal on any type of subsequent block. No feedback conditions had no significant impact on the subsequent block. Interestingly, the effect on the second half of Block 2 was just as large as in the first half. Moreover, delay between Blocks 1 and 2 over a range of minutes to days had no significant effect. These persistent effects of experience with feedback could be used as training to adjust decision criteria in real world tasks like medical screening, where feedback is not routinely available.