The visible gorilla: Unexpected fast-not physically salient-Objects are noticeable

Abstract

It is widely believed that observers can fail to notice clearly visible unattended objects, even if they are moving. Here, we created parametric tasks to test this belief and report the results of three high-powered experiments (total n = 4,493) indicating that this effect is strongly modulated by the speed of the unattended object. Specifically, fast-but not slow-objects are readily noticeable, whether they are attended or not. These results suggest that fast motion serves as a potent exogenous cue that overrides task-focused attention, showing that fast speeds, not long exposure duration or physical salience, strongly diminish inattentional blindness effects.

Keywords: endogenous attention; exogenous attention; inattentional blindness; selective attention; visual motion.

Fig. 1.

Proportion of participants reporting a relevant unexpected event. (A) x-Axis: Relative Gorilla speed in traversing the screen, relative to the longest duration. y-Axis: Proportion reported. Solid line: Participants reporting passes by the Black team. Dashed line: Participants reporting passes by the White team. Error bars indicate SEM. (B) As in (A), but comparing the performance of participants in the smoothly walking vs. leaping gorilla (otherwise time matched—spending 10 s on the screen) condition.

Fig. 2.

(A) Schematic of task and stimulus display. (B) Proportion of participants reporting a relevant unexpected object, by experimental condition. x-Axis: Speed of object relative to baseline. y-Axis: Proportion reporting noticing the unexpected object. Solid line: Participants reporting dot crossings by black dots. Dashed line: Participants reporting dot crossings by white dots. Error bars indicate SEM.

Fig. 3.

(A) The proportion of participants reporting a relevant unexpected object, by condition. x-Axis: Attention/UMO color conditions—W = White, B = Black. The first letter in each combination represents the UMO color and the second the color of the dots participants were instructed to count. y-Axis: Proportion of participants reporting an unexpected object. (B) The proportion of participants reporting a relevant unexpected object, as a function of speed. x-Axis: Speed of UMO relative to speed of counted dots. y-Axis: Proportion of participants reporting the unexpected object. Solid line: Participants presented with a UMO matching the color of the dots they were instructed to count (i.e., Black/Black and White/White). Dashed line: Participants presented with a UMO of a different color than the dots they were instructed to count (White/Black and Black/White). Error bars indicate 95% CIs in (A) and the SEM in (B).

Fig. 4.

Bootstrap analysis of slopes. Histograms of bootstrapped slopes for slow to similar (blue) and similar to fast (green) conditions. The solid black lines indicate the empirical slopes, whereas the dashed red lines denote the respective 95% CIs.