Change blindness is an interesting phenomenon that has many implications for theories of vision. Click on the following link of an animated gif that shifts between two slightly different images and see how long it takes you to notice what is different between the two. Likely, it will take you longer than you expect.
Why does this phenomenon exist? Change blindness challenges traditional “stream of vision” theories that describe vision as a process of building up detailed representations of the world around us. The phenomenon of change blindness shows us that this idea of “visual richness” is deeply flawed. Clearly, we need a new conceptual framework for perception that allows for the continuity of vision while accounting for the illusion of rich perceptual representations. As a matter of fact, I discussed such a theory in the previous post: that of James Gibson’s ecological perception.
Another name for this approach to vision is enactive perception. As the name applies, this theory views perception as a form of action. Looking is an evolved skill, like everything else, and it is an exploratory process. Under this conceptual framework, change blindness can be explained in the following way: When we look at a picture, what we see is not a representation of reality. While this seems counterintuitive, it is quite obvious when you think about the fact that one never confuses a two-dimensional picture with the real world. Whenever you look at a picture, you are always aware that you are looking at a flat surface with information on it within the real three-dimensional world. What we see is rather a collection of information, not a representation or symbol of anything.
It is this embedded information that we actively seek out whenever we look at a picture. So in the change blindness example, it takes time to fully explore and extract all information in the picture. I want to really emphasize the process of exploration, because it is this active process that gives enactive perception its rich explanatory power. In addition to change blindness, enactive perception can potentially explain the phenomena of inattentional blindness, where you fail to perceive what is available for you to see. These effects are usually explained in terms of a limited cognitive capacity for attention, but I believe these attentional theories need to be placed in a broader conceptual framework for perception, and this is where enactive perception comes in. Under this framework, attention, looking, and perception are all brought under the same conceptual umbrella: that of seeking out information offered to us by the environment.