Why don't we see the gorilla? Looking in the wrong places, attending to the wrong stuff, or doing the wrong task?

摘要

Observers counting basketball passes often do not notice an unexpected "gorilla" (Simons & Chabris, 1999). They notice it more often when counting black-team passes (83%), than white-team passes (42%). Supposedly, when counting black-team passes, the gorilla's similarity to the attended team leads to its capture by attention, and subsequent conscious perception. However, other attentional factors may play a role. We find that: (1) Fixations differ in important ways when counting black vs. white-team passes. "Black-team fixations" land closer to the gorilla (m=6.9 deg horizontal distance) than "white-team fixations" (m=10.0 deg, t(57)=2.31, p=0.02, display=40x30 deg). (2) However, observers with a known gorilla discrimination task (150 ms presentation of individual video frames) are equally good with either white-team fixations (d'=2.30) or black-team (d'=2.27). (Umbrella woman d'3.25) (3) Na?ˉve observers (n=11) with white-team fixations, attending to the black team for a numerosity task (static images, 150 ms), rarely notice anything unusual (54%), whereas with black-team fixations (n=10) they often do (80%). These results suggest that attentional selection of similar items is not the whole story. Rather, an interaction between looking the wrong places, and not knowing the "real" gorilla detection task helps render the gorilla invisible. Other recent work, from our lab and others, has questioned the role of selective attention in search; has shed new light on what determines dual-task difficulty; and has questioned the notion that certain tasks "require attention", while others do not. We will discuss the implications of these results for what "attention" might mean and how the visual system might adapt to the task at hand.