Social Interactions cause Spatial Distortions in Visual Memory, not Perception

Visual perception of social interactions is an essential everyday skill that has recently drawn substantial attention. Notable effects include increased attention to interacting dyads and better memory for individuals within these dyads. It has also been established that individuals in socially interacting dyads are judged to be closer together than those that are not interacting. It is not known whether this spatial contraction of interindividual distance originates in perception or visual memory. Investigating this question is particularly difficult as perceptual distortions would affect both original stimulus and any reproduction (“El Greco fallacy”). The present series of studies uses the well-established kappa effect to solve this problem: When presented with a series of flashing lights, observers will judge the interval between flashes as longer when the lights are perceived to be further apart. Experiment 1 used a variation of this effect and presented participants with three faces, two of which were arranged into a facing dyad, the other facing away from that dyad. Faces flashed in repeated succession and participants were asked to adjust the temporal position of the middle face such that the two resulting intervals were of equal duration. No effects consistent with perceptual distortions of distance were found. Experiment 2 used a memory task where participants were presented with facing or non-facing dyads. After a blank interval that same dyad reappeared at a different location. Participants were required to assess whether this dyad kept the same interindividual distance as before or whether it had changed. Responses were consistent with memory distortions such that facing dyads were remembered as closer together. These results firmly place spatial distortions due to social interactions into visual memory and provide details on the magnitude of these distortions at various timepoints throughout memory.