Set recognition as a window to perceptual and cognitive processes.

The Set visual perception game is a fertile research platform that allows investigation of perception, with gradual processing culminating in a momentary recognition stage, in a context that can be endlessly repeated with novel displays. Performance of the Set game task is a play-off between perceptual and conceptual processes. The task is to detect (among the 12 displayed cards) a 3-card set, defined as containing cards that are either all similar or all different along each of four dimensions with three possible values. We found preference and reduced response times (RTs) for perceiving set similarity (rather than span) and for including cards sharing the most abundant value in the display, suggesting that these are searched preferentially (perhaps by mutual enhancement). RT decreases with number of sets in the display according to a horse race model, implying independence of simultaneous searches. Central cards are included slightly more often, but set card proximity seems irrelevant. A supplementary experiment determining dimensional salience showed consistent but individual preferences, yet these seemed not to affect set identification. Training induced gradual improvement, which generalized to a new version of the game, suggesting high-level learning. We conclude that elements of perception such as similarity detection are basic for finding sets in this task, as in other real-world perceptual and cognitive tasks, suggesting the presence of basic similarity-perceiving mechanisms. The findings confirm the conclusion that conceptual processes are affected by perception.