Confidence-accuracy relations for faces and scenes: roles of features and familiarity

Using naturalistic scenes, we recently demonstrated that confidence-accuracy relations differ depending on whether recognition responses are based on memory for a specific feature or instead on general familiarity: When confidence is controlled for, accuracy is higher for familiarity-based than for feature-based responses. In the present experiment, we show that these results generalize to face recognition. Subjects studied photographs of scenes and faces presented for varying brief durations and received a recognition test on which they (1) indicated whether each picture was old or new, (2) rated their confidence in their response, and (3) indicated whether their response was based on memory for a feature or on general familiarity. For both stimulus types, subjects were more accurate and more confident for their feature-based than for their familiarity-based responses. However, when confidence was held constant, accuracy was higher for familiarity-based than for feature-based responses. These results demonstrate an important similarity between face and scene recognition and show that for both types of stimuli, confidence and accuracy are based on different information.