Statistical Learning as a Reference Point for Memory Distortions: Swap and Shift Errors

Humans use regularities in the environment to facilitate learning, often without awareness or intent. How might such regularities distort long-term memory? Here, participants studied and reported the colors of objects in a long-term memory paradigm, unaware that certain colors were sampled more frequently overall. When participants misreported an object’s color, these errors were often centered around the average studied color. We found that these swap errors reflected both false memory (where objects were misremembered as the average studied color) as well as biased guessing (where participants reported the average studied color when uncertain). Although less robust than swap errors, evidence was also observed for subtle shift errors towards or away from the average color dependent on the color distance between the memory item and the average studied color. These findings provide converging evidence for memory distortion mechanisms induced by a reference point, bridging a gap between visual working memory and visual long-term memory literature.