Primacy in the Effects of Face Exposure: Perception Is Influenced More by Faces That Are Seen First

Abstract

Exposure to faces biases perceptions of subsequently viewed faces. In literature on memory, there are prominent effects of primacy in which people remember things better if they are at the beginning of a list. Here, we tested for primacy in face exposure by exposing people to faces that had been transformed in opposite directions twice. For example, in one condition, we exposed people to “plus” faces and measured how much they thought plus faces appeared normal and then exposed them to “anti” faces and again measured how much they thought plus faces appeared normal. A primacy effect would be seen if, after the second measurement, judgments of plus faces were unchanged from the first measurement whereas no primacy effect would be seen if, after the second exposure, judgments of plus faces were different from the first measurement. We found no change in normality judgment between the first and second judgments, supporting a primacy effect. Our results indicated a primacy effect in adaptation in which faces seen first affected perception more than faces seen later. This primacy effect could lead to long-lasting effects of exposure to faces.