Abstract
We are constantly exposed to many images, and although we do not actively try to remember or encode them, some of them are remembered. It has been suggested that such non-intentional memory is influenced by the depth of processing, but it is yet unclear what precisely defines the depth of processing for visual images. Here we reasoned that bigger images may entail deeper level of processing and may thus be remembered better than smaller ones. We ran a series of five studies (n= 91, each person participated in only one study) where each study started with an exposure experiment followed by a memory assessment experiment. To mimic non-intentional memory, in the exposure experiment participants were only instructed to freely view the images without being informed about any proceeding task. In this experiment they were exposed to hundreds of photographs of different categories and different sizes (3x3 to 24x24 vis. deg.). Following this, in the memory assessment experiment, each participant was shown a set of images of intermediate size (~8x8 vis. deg.), only half of them presented earlier, and for each image was asked to report if she/he recall seeing it earlier or not. We found that across experiments, larger images were incidentally remembered better, and this was true regardless of order effects, image set, or spatial resolution. While it is clear that multiple factors affect image memorability during incidental exposure, here we found that the physical dimension of image size seems to play an important role in this process.