In Simmons and Chabris' inattentional blindness experiment, what percentage of participants noticed the unexpected gorilla?

• A. 20%
• B. 54%
• C. 75%
• D. 100%

Answer: (B)

Attention acts as a filter, so focusing on one task can cause us to miss other obvious events happening in our field of view. In the Simons and Chabris gorilla study, participants watched a video of people passing basketballs and were asked to count the passes, while a gorilla walked through the scene. Even though the gorilla was highly salient, a substantial portion of participants failed to notice it. The actual finding is that about 46% noticed the unexpected gorilla, meaning roughly 54% did not. This result highlights inattentional blindness: when attention is tightly directed at a task, salient events outside that focus can go unnoticed.