Size matters - larger images are better remembered during free viewing

Abstract

We are constantly exposed to multiple visual scenes, and while freely viewing them without an intentional effort to memorize or encode them, only some are remembered. It has been suggested that image memorability is influenced by multiple factors as depth of processing (1-3), familiarity (4), and visual category (5-7). However, this is typically investigated with intentional (8, 9) or unintentional (10, 11) encoding tasks. Furthermore, since visual memory relies on size-invariant visual perception (12-14), image size is not considered a contributing factor. Here we reasoned that during naturalistic free viewing of images without an encoding task, bigger images would be better remembered due to multiple factors (as vaster expanse of activated visual cortex (15, 16), deeper processing). In an extensive set of experiments participants (n=117) freely viewed small to large images (3{degrees}-24{degrees}) without any encoding task. Subsequently, they were presented with mid-sized images (50% already seen) and were asked to report if they recall seeing them or not. Larger images were better remembered (~23% more than smaller images), image memorability was proportional to image size, faces were better remembered, and outdoors the least. These were independent of image set, presentation order, or screen resolution. While multiple factors affect image memorability (1-7), here we show that during free viewing with no encoding task, a basic physical image dimension influences its memorability.