Change detection and the ensemble coding of faces

Change blindness, the inability to detect change in a given scene, is a phenomenon due to our human brain’s limited capacity to process everything in the environment. Nevertheless, this is mitigated by heuristics such as ensemble perception, the accurate and consistent ability to extract an average percept from a set of perceptually similar objects. Several studies have demonstrated that even in the presence of change blindness, observers are able to distinguish the difference in average of one set from another. The aim of this study was to further investigate this how these two processes are integrated and also to examine its effects on explicit self-confidence ratings. It was hypothesized that there would be higher sensitivity towards a global change than a local change which in turn might result in higher confidence. Observers performed a change detection and localization task after looking at sets of faces which may or may not have changed in the consecutive set. Unexpectedly, results showed overall better performance in the local change condition. However, there also seemed to be an overconfidence in reporting change. This suggests possible consequences for scenarios where accurate judgements of a group of people need to be made, such as a criminal line up.Bachelor of Art