Another early study of Inattentional Blindness

Back in October on our Psychology Today blog, I posted about my re-discovery of what I then thought was the earliest systematic study of inattentional blindness. Turns out I was wrong.

Inattentional blindness is the failure to notice a fully-visible but unexpected object when you are focusing attention on something else. It is the phenomenon illustrated by our invisible gorilla studies. That study was conducted in the 1950s by a Tony Cornell, a parapsychology researcher — he found that people often didn’t notice him while he pranced around campus dressed as a ghost! (check out the post — it is one of my favorites. I’ll eventually repost it here).

As it turns out, there was at least one earlier experiment. Fifty years earlier, in fact. Just this week, my colleague Ira Hyman (he of unicycling clown fame) pointed me to a section of a chapter from a book by Hugo Munsterberg, written in 1908!

Image of Hugo Munsterberg's book

Hugo Munsterberg's book on eyewitness psychology. Source:

In it, he describes the following experimental result:

I stood on a platform behind a low desk and begged the men to watch and to describe everything which I was going to do from one given signal to another. As soon as the signal was given, I lifted with my right hand a little revolving wheel with a colour-disk and made it run and change its color, and all the time, while I kept the little instrument at the height of my head, I turned my eyes eagerly toward it. While this was going on, up to the closing signal, I took with my left hand, at first, a pencil from my vest-pocket and wrote something at the desk; then I took my watch out and laid it on the table; then I took a silver cigarette-box from my pocket, opened it, took a cigarette out of it, closed it with a loud click, and returned it to my pocket; and then came the ending signal. The results showed that eighteen of the hundred had not noticed anything of all that I was doing with my left hand. Pencil and watch and cigarettes had simply not existed for them.

That’s a pretty clear example of inattentional blindness, with at least some failure to notice objects and events happening outside the focus of attention. It has the flavor of a magician’s misdirection, with social cues directed to the other hand (see Kuhn, 2009 for an example).

My favorite part of Munsterberg’s report, though, was his description of his own mistaken intuitions. He too suffered from an illusion of attention, the belief that people typically notice salient and distinctive events.

I had made my movements of the left are so ostentatiously, and I had beforehand so earnestly insisted that they ought to watch every single movement, that I hardly expected to make any one overlook the larger part of my actions.

Just as we had expected people to notice when a person in a gorilla suit walked through a scene and thumped her chest at the camera, Munsterberg also had the wrong intuition about what people would and wouldn’t notice.

I might try to replicate his method in my own lab — it’s one of the few real-world studies of inattentional blindness and provides a nice intermediary to magical misdirection and laboratory studies of focused attention and inattention.

Sources Cited:

Munsterberg, Hugo (1908). On the Witness Stand: Essays on Psychology and Crime. Clark Boardman Co., NY, New York.

Munsterberg’s book is available online here.

Kuhn, G., Tatler, B., & Cole, G. (2009). You look where I look! Effect of gaze cues on overt and covert attention in misdirection Visual Cognition, 17 (6), 925-944 DOI: 10.1080/13506280902826775

Hyman, I., Boss, S., Wise, B., McKenzie, K., & Caggiano, J. (2009). Did you see the unicycling clown? Inattentional blindness while walking and talking on a cell phone Applied Cognitive Psychology, 24 (5), 597-607 DOI: 10.1002/acp.1638

Cornell, A. D. (1959). An experiment in apparitional observation and findings. Journal of the Society for Psychical Research, 40(701), 120-124.

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