Seeing the world as it isn't

An earlier version of this post appeared on my Psychology Today blog on April 30, 2010.

When we look at the world around us, we feel that we are seeing it as it is. Most of the time, we are — but not because our visual system perceives the world precisely as it is. Rather, our visual system makes informed guesses about the contents of the world based on the compressed signal projected onto our eyes. And, for most practical purposes, those guesses are pretty good. Moreover, this “guessing” system work so seamlessly that we rarely notice any discrepancy between our guesses and reality. Only when we “break” the system can we reveal these default assumptions.

My 7-minute long talk at TEDxUIUC in February 2011 explains why we have to break the visual system to understand how it works. As an added bonus, I showed some terrific illusions and demos from Julian Beever, Bart Anderson, and Bill Geisler. Check it out:

Just as we can’t intuit the mechanisms of vision, we lack insight into the mechanisms of memory, reasoning, and thinking. Only when forced to confront what we’re missing do we realize that we’ve unwittingly made assumptions. We often have no idea how limited our abilities can be. The following change blindness video illustrates one such limitation:

When Dan Levin and I conducted that person-change study, we found that about 50% of people didn’t notice they were talking to a different person. That sort of person-change rarely (if ever) happens in the world. You might assume, without doing the study, that people actually keep track of all of the details of the people they interact with. Only by making a change can you reveal the extent of their change blindness. In fact, people who missed the change would never have known anything was amiss had we not asked them. This effect reveals what Chris Chabris and I call the “Illusion of Memory” — we think we remember far more than we actually do.

This sort of cognitive, everyday illusion is akin to a visual illusion. When you view a visual illusion, you are seeing the world as it isn’t — the illusion capitalizes on one of the shortcuts your brain takes when processing visual information, with the result that you see the world the way you assume it to be rather than the way it actually is. With cognitive illusions like change blindness, we think we see and remember far more than we actually do because we are unaware of the shortcuts our brain takes when representing the world. For the most part, we simply assume the world to be unchanging, and typically we’re right. We just don’t realize we’re making that assumption.

Source cited:
Simons, D. J., & Levin, D. T. (1998). Failure to detect changes to people during a real-world interaction Psychonomic Bulletin and Review, 5, 644-649 : 10.3758/BF03208840

4 comments to Seeing the world as it isn’t

  • Yasser Saiyad

    I just came across your reply for my question, despite the delay in my current response , i just want to extend my thanks for taking the time to answer. I really enjoyed the book and look forward to what you will be putting out next.
    I understand how one would easily be led to believe in untapped parts of the brain, given varying examples of specific individuals who seem to posses extra ordinary capacities ( such as that of being able to depict a an accurate drawing of a city landscape from one viewing) . I may still have to spend some time to get my head round that one !! None the less again thanks for your time and your very useful insight into the matter.
    Best wishes
    Y:S

  • The idea of photographic memory is actually based on a false intuition. It is not possible for anyone to take a single glance at something and remember it like a photograph because our visual system doesn’t give us much detail in the periphery. We really only have detailed visual information for a tiny part of our world, exactly where we focus our eyes. It might be possible for some people to build up a more detailed internal “picture” of a scene by scanning it for some time, but it’s still not like a photograph. That said, there are individual differences in how well people can keep track of details. And, you can train yourself to recall some types of information more efficiently. For example, you can train yourself, through extensive practice, to be able to recall a list of 50+ numbers. Note, though, that the training won’t help you remember other sorts of things, just lists of numbers. We all have great potential to improve ourselves through training, practice, and hard work. But, we can’t magically release hidden potential through quick fixes. The idea that we only use 10% of our brain is a myth, and there is not some hidden, unused part of our brain waiting to be tapped. What we can do is to maximize the skills we do have through training and practice.

  • yasser saiyad

    hi, I found your book very enjoyable , and the ted presentation very interesting as well. I have lent the hardcover copy to various people and many also found it interesting though some people feel your skepticism to many deeply held beliefs to be rather uncomfortable. In one conversation regarding the capacity of the human brain ( the belief that we only use 10% of the brain ) one person mention the ability of certain people to be able to for example to have perfect fotographic memory, or to be able to do extra ordinary mathematical sums, etc- the reason goes that these things being possible in some , creates the possibility that others can do it as well, – if only we used the full potential of the brain – what is your view on this if any?
    Thanks for your time

  • [...] Video: Invisible Gorilla: Seeing the world as it isn’t – via Invisible Gorilla Blog – When we look at the world around us, we feel that we are seeing it as it is. Most of the time, we are — but not because our visual system perceives the world precisely as it is. Rather, our visual system makes informed guesses about the contents of the world based on the compressed signal projected onto our eyes. And, for most practical purposes, those guesses are pretty good. Moreover, this “guessing” system work so seamlessly that we rarely notice any discrepancy between our guesses and reality. Only when we “break” the system can we reveal these default assumptions. [...]