Perception and Action

132 Inattentional Blindness

Learning Objectives

Be able to define change blindness.

Know that object-selective neurons fail to respond to many things which go unattended.

Change blindness refers to the perceptual phenomenon that the observer fails to identify when there is a change in a visual stimulus. We fail to perceive so many things that go unattended. Classic change blindness demos, such as this one with static images or this one with real people, show how much of a scene we do not perceive. If you don’t have some kind of bottom-up salience cue (motion, color contrast, etc.), you need some top-down attention allocation if you’re going to be aware of something. This relates to how object-selective neurons fail to respond to many things that go unattended. For example, a major source of image motion is eye motion—we’re making a saccade every few hundred milliseconds. How does our brain handle that? Saccadic masking: our brains blank out all the wild motion created by saccades. It would be impossible for our neurons to respond to every motion created by saccades.


Fig.12.5.1 Change Blindness. For the picture on the left, it represents what the participant is able to see through their visual perspective. The picture on the right depicts what they actually see. The key takeaway from this representation is that the tree branch present in the left side picture fails to be identified by the viewer due to the emphasis on other details. It is very common that the swaying of a tree branch goes unattended when our eyes focus on greater details such as the world monument in the center or the immense body of water behind it. Other visual phenomena that many of us instantly may have missed are the people and the vertical building in the background that are in the left photo and are nowhere to be seen in the right one.

Watch this video on the Monkey Business Illusion to learn more about inattentional blindness!


Cheryl Olman PSY 3031 Detailed Outline
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Introduction to Sensation and Perception Copyright © 2022 by Students of PSY 3031 and Edited by Dr. Cheryl Olman is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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