Inattentional Blindness Experiment
Can you spot the unexpected? This classic experiment demonstrates how focused attention can make us blind to surprising events.
Frequently Asked Questions
Have another question? Let us know.
What is inattentional blindness?
Inattentional blindness is a psychological phenomenon where people fail to notice fully visible but unexpected objects or events when their attention is engaged on another task. In the classic experiment behind this demo, about 50% of observers missed a surprising unexpected event while counting basketball passes — what that event was is revealed only after you finish.
Why does inattentional blindness occur?
Our attention is a limited resource. When we focus intensely on one task, our brains filter out information that seems irrelevant to that task. This is actually adaptive - it helps us focus - but it means we can miss obvious things that we're not expecting.
What are real-world implications of inattentional blindness?
It matters wherever attention is split: drivers can miss pedestrians while talking or navigating, radiologists can miss anomalies while scanning for others, and machine operators can miss warning signals while focused on a display. The implication is not that people are careless, but that no one's attention is unlimited.
Can inattentional blindness be prevented?
While inattentional blindness is a normal part of how attention works, being aware of our limitations can help. Strategies include: expecting the unexpected, taking breaks to refresh attention, and understanding that looking is not the same as seeing.
Show Details
What is Inattentional Blindness?
Inattentional blindness is a psychological phenomenon where people fail to notice fully visible but unexpected objects or events when their attention is engaged on another task. The classic 1999 experiment by Simons and Chabris showed that about 50% of observers missed a surprising unexpected event while counting basketball passes — the event itself is revealed only after you complete the demo.
How It Works
In this experiment, you'll watch players passing basketballs. Your task is to count how many times players in WHITE shirts pass the ball. The second trial is slightly different — we'll explain afterwards. Most people focused on counting completely miss what changes, demonstrating the powerful effect of selective attention.
Real-World Applications
Understanding inattentional blindness has important implications for driving safety, aviation, medical diagnostics, and security screening. It explains why drivers may fail to see pedestrians when focused on traffic signals, or why radiologists might miss unexpected findings when searching for specific abnormalities.
Research Background
This experiment is based on the famous study by Daniel Simons and Christopher Chabris (1999) published in Perception. Their research demonstrated that even obvious events can go unnoticed when attention is directed elsewhere, challenging assumptions about visual awareness and the nature of consciousness.
References
- Simons, D. J., & Chabris, C. F. (1999). Gorillas in our midst: Sustained inattentional blindness for dynamic events. Perception, 28(9), 1059-1074. 10.1068/p281059
- Mack, A., & Rock, I. (1998). Inattentional blindness. MIT Press.
- Most, S. B., Scholl, B. J., Clifford, E. R., & Simons, D. J. (2005). What you see is what you set: Sustained inattentional blindness and the capture of awareness. Psychological Review, 112(1), 217-242. 10.1037/0033-295X.112.1.217
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About This Experiment
This experiment is an educational adaptation for demonstration purposes. It is not a clinical diagnostic tool. Results reflect your performance in this specific session and should not be interpreted as an assessment of your cognitive abilities.
Data Privacy
Your experiment data is processed and stored locally in your browser. No data is uploaded to any server unless you explicitly export it.
