Behavioral Illusion

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Press the "Run" button to start. You will see a spider and a small box above a horizontal line. The spider keeps trying to get out of the box and move toward you. Your job is to keep the spider in the box. You do this by moving the mouse left when the spider moves out of the box to the right and by moving the mouse right when the spider moves out of the box to the left. The cursor that is associated with mouse movements should be kept below the horizontal line so that it doesn't block the view of the spider and box. Only left-right movements of the cursor affect the spider's position.

You will actually be doing two sessions of "spider boxing", called "Take 1" and "Take 2". Take 2 occurs right after Take 1; there is no break. When both sessions are completed (it takes about 1 minute total) you will see a graph of your results. This graph illustrates a control phenomenon known as the behavioral illusion.

The behavioral illusion occurs when an observer of a control system sees the relationship between the disturbance to a controlled variable and the compensating action as indicating something about the characteristics of the system itself when, actually, this relationship depends on properties of the feedback connection between the system's action and the variable under control: the controlled variable. Since the disturbance to a controlled variable is typically seen as a stimulus (S)in psychological experiments while the compensating action is seen as a response (R), the behavioral illusion in psychology is the illusion that the relationship between S and R reflects characteristics of the organism under study, in fact, it may reflect nothing more than characteristics of the organism's environment, which is what determines the nature of the connection between compensating actions (R) and the controlled variable.

In the present study you are asked to control the position of a spider, keeping it in the little box. So the controlled variable in this study is the position of the spider relative to the box and the reference state for this variable is "in the box". The disturbance to this variable is the spider's efforts to push its way out of the box. So the spider's pushes are the stimulus (S) in this study. The compensating action is your horizontal movements of the mouse, which "push back" against the spider; your mouse movements are the response (R) in this study.

Once you have finished Take 1 and Take 2, a graph of the results appears. The graph shows your apparent sensitivity to the spider's pushes during the two Takes. Sensitivity is measured in terms of the amount of your push back (R) -- shown on the vertical axis of the graph -- per unit spider push (S) -- shown on the horizontal axis. High sensitivity to spider pushes is indicated by a steeply sloping line, which is what you should see in the results for Take 1. Low sensitivity is indicated by a line with a shallow slope, which is what you should see for Take 2.

So the results of this study show that you appear to be highly sensitive to the spider's pushes during Take 1 and much less so during Take 2. That is, you appear to react strongly (R) to the approaching (pushing) spider (S) during Take 1 but much less strongly during Take 2. These results appear to show that you were more fearful of the spider during Take 1 and less so during Take 2. But, of course, you were equally fearful (or fearless) -- that is, you were equally sensitive to the spider's pushes -- during both Takes. The observed difference in sensitivity during Takes 1 and 2 is only apparent; it is an illusion-- the behavioral illusion . It resulted from a difference in your environment, not in your psychology, during the two Takes.

The difference between Takes 1 and 2 was in the nature of the connection between your mouse and the spider. This connection, which occurs through the "environment" of the computer, is called feedback because it connects your output (mouse movement) back to the input (the spider position, the controlled variable) that is causing that output. During Take 1, this feedback connection was weak in the sense that a lot of mouse movement (push) was required to counter the spider's efforts to push out of the box. During Take 2, the feedback connection was strong in the sense that very little mouse movement was required to counter the spider's push. The result is that a large amount of response (R) was needed to compensate for the spider's push (S) and keep it in the box during Take 1 while far less response (R) was needed to compensate for the same amount of push (S) and keep the spider in the box during Take 2.

This study shows how a simple change in the environment (connection between mouse and spider) can result in an apparent change in psychology (sensitivity to spiders). While it is relatively easy to demonstrate this behavioral illusion, it is anything but easy to understand its implications for scientific psychology. You can read more about the behavioral illusion in these papers:

Powers, W. T. (2005) Behavior: the control of perception (2nd ed.). New Canaan, CN: Benchmark.

Powers, W. T. (1973) Behaviorism and feedback control, Science, 181, 1118-1120.

Cziko, G. (2000) The things we do: Using the lessons of Bernard and Darwin to understand the what, how and why of our behavior. Cambridge, MA: MIT Press.

Last Modified: June 1, 2014