What is a response? Behavior analysts define responses both structurally (in terms of the form of the response) and functionally (the effect of the response). Sometimes these two definitions are complementary and sometimes they are quite different from one another.

Consider the lever press response of a rat. A lever press is defined as any downward force on the lever sufficient to operate an electric switch attached to it. Each separate switch operation constitutes one response. This is a structural or formal definition. Now, with this definition the only criterion for a “lever press response” is switch closure. The form or topography of the response doesn’t matter. The rat can activate the switch with its front paw or its back paw, or it can bite the lever with its mouth. The sole criterion for the response to have occurred is that the electric switch be operated. The response is defined in terms of a common effect on the environment. This constitutes a functional definition of the response. So, in this case the structural and functional definitions of the response are the same.

In everyday life, typing on a keyboard can be maintained by many different consequences. The consequences of typing can be to avoid missing a deadline or it can be to gain access to needed information. In this case the topography or form of the two responses is identical, but the consequences are different. In the first example the response is maintained because it avoids an aversive consequence and in the second example it is maintained because it results in a positive consequence. Are the two responses the same? Structurally, yes, but functionally no.

The devices displayed in this room all are attempts to establish precision in defining a response. This precision is achieved by defining the response electromechanically, usually by means of some type of electric switch operation. In many situations outside the laboratory, however, it is not possible to define the response in this way. Under such circumstances, it becomes necessary to achieve precision in measuring the response by having multiple human observers, well-trained in observing the response, watching for the response and recording its occurrence. Precision is achieved when there is a high level of agreement between the observers with respect to instances of occurrence, and nonoccurrence, of the target response.

A Comment on Labeling Response Recording Devices: In much of the traditional psychological literature, a response measurement device is referred to as a manipulandum (plural: manipulanda). In behavior analysis, however, it is more common to refer to such a device as an operandum (plural: operanda). The note pictured above from the Journal of the Experimental Analysis of Behavior offers Skinner’s perspective on describing response measurement devices.

Response Transducers for Pigeons

Response Transducers for Rats

Response Transducers for Other Species



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