Machines Like Us

Symbols redirect attention -- in some ways, that is their intended purpose -- but this "reorienting" is a surprisingly literal and involuntary effect. Even when we know symbols are irrelevant to our current circumstances, they still influence our behavior.

A simple experiment demonstrates this nicely. Hommel et al. showed that letters appearing in unpredictable locations can be identified more quickly when their location is compatible with a preceeding symbol -- even if those symbols are totally irrelevant to the task, and subjects are explicitly told to ignore them!

For example, a letter appearing at the top of the screen is identified more quickly when preceeded by the word "up" or an upward-pointing arrow than when preceeded by "left" or a left pointing arrow. This is true even when the location of the target letter had been cued by more than 300 msec previously -- a scenario in which people are usually slower to identify a target in a cued-location (known as inhibition of return). Again, these effects of symbols appear to be automatic and involuntary.

Read full story in Developing Intelligence