Attention: Effect of Breakdown

Behavioral Phenomena

One of the most striking examples of the breakdown in the attentional system, caused by sensory overload, was demonstrated by Daniel Simmons and his colleagues. The authors conducted a series of experiments that revolved around a simple scenario—a young man (one of the experimenters) approaches a passerby (unsuspecting participant in this experiment) asking for directions on how to get to one of the buildings on campus. In the middle of the conversation, however, two people carrying a door (experimental accomplices) walk in between the experimenter and the participant briefly obstructing the participant's view of the experimenter. During the time that the experimenter was invisible to the subject, another person trades places with the experimenter, so that once the door has passed, the participant is left talking to a new person! This experiment found that only 50% of the participants noticed that, after the interruption, the identity of the person they were conversing with was switched, even though the two experimenters were dissimilar in build, had different haircuts, had different pitched voices, and wore dissimilar clothing. This example is particularly potent because the experiment was conducted not in the contrived laboratory environment, but rather in our natural environment (i.e., outside) with innocent bystanders serving as participants. In addition, this experiment was not conducted in the middle of a hustle and bustle of, say, Times Square (an environment that we often think of as being conducive to sensory overload). This experiment demonstrates a striking breakdown of attention in our day-to-day environment, even under conditions when part of the stimulus was attended (few would argue that two people who are carrying a conversation with one another do not, at least on some level, pay attention to each other's identity). The breakdown of attention in this experiment could be attributed to competition from a multitude of sensory and mental events related and unrelated to the actual task at hand of giving directions—for example, remembering the campus layout, remembering landmarks on the way, hearing birds chirping in the background, or feeling faint pain from a blister on the left foot. All these cognitive tasks place enormous constraints on attentional selection, ultimately resulting in a failure of perception.

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