Poster C103, Sunday, March 25, 1:00-3:00 pm, Exhibit Hall C
Ultra-rapid Serial Visual Presentation of Images Reveals Unconscious Perceptual Neural Signature of Memorability
Yalda Mohsenzadeh1, Aude Oliva1, Dimitrios Pantazis1; 1MIT
Not all images are treated equally within the visual system. Recent behavioral studies revealed that irrespective of subjective experiences certain images are consistently remembered whereas others are forgotten. The current study investigates this intrinsic image property, termed Memorability, by examining the neural circuitry subserving this normative memory. To capture neuronal traces of memorability, we used an RSVP paradigm (11 images presented with the speed of 34ms per picture). We collected MEG data while participants (N=15) viewed these sequences of images and performed a face detection task. Half of the trials include a random face image in the middle. When there was no face in the sequence, we embedded some specific scene images in the middle, half with high and half with low memorability scores. The distractors were randomly sampled from 150 scene images with mid-level memorability scores. After the RSVP experiment, subjects performed an unanticipated memory test on the middle scenes intermixed with a novel matching set of images. Analysis of the subsequent memory test showed that subjective memory performance was at chance level. Therefore, we isolated memorability from memory or attentional confounds. We used MEG pattern vectors at each time point to train a SVM classifier to decode each pair of scene images with a leave-one-out cross-validation procedure. MEG decoding time series were similar at early time points but high memorable scenes showed higher decoding starting at 150ms. This indicates high memorable scenes benefit from stronger initial representation in perception which results in their higher likelihood of memory encoding.
Topic Area: PERCEPTION & ACTION: Vision