Human Memory for Real-World Solid Objects Is Not Predicted by Responses to Image Displays

In experimental psychology and neuroscience, computerized image stimuli are typically used as artificial proxies for real-world objects to understand brain and behavior. Here, in a series of five experiments (n = 165), we studied human memory for objects presented as tangible solids versus computerized images. We found that recall for solids was superior to images, both immediately after learning, and after a 24-hr delay. A "realness advantage" was also evident relative to three-dimensional (3-D) stereoscopic images, and when solids were viewed monocularly, arguing against explanations based on the presence of binocular depth cues in the stimulus. Critically, memory for solids was modulated by physical distance, with superior recall for objects positioned within versus outside of observers' reach, whereas recall for images was unaffected by distance. We conclude that solids are processed quantitatively and qualitatively differently in episodic memory than are images, suggesting caution in assuming that artifice can always substitute for reality. Public Significance Statement Scientists study vision, thinking, and memory by running controlled laboratory experiments; results from the laboratory are then generalized to understand brain function in real-world contexts. In laboratory studies of human memory, scientists measure responses to visual stimuli (such as common objects) which are typically presented as images on a computer screen, rather than as real-world solid objects. Here, we show that memory for real-world objects cannot be predicted based on responses to artificial image displays. This work suggests that stimulus realism influences how information is processed in the brain, questioning how well results from studies of artificial stimuli generalize to explain behavior in the natural world.