Specific and Nonspecific Factors in the Causation of Behavior

In dealing with patterned behavior, an immediate question concerns the degree to which different component activities are separate from one another in their control. Models of integrative specificity stress separate control mechanisms for different behavioral components. Nonspecific models stress mechanisms that are shared among many different activities. Each of these models has certain merits but also certain limitations. Section II of this paper provides a brief outline of some of the major aspects of both the action-specific models and the diffuse activation models of integrated behavioral control. It is suggested that much of the apparent controversy is due to inconsistent application of classificatory criteria which are often not adequately defined. For the purpose of illustration, these issues are discussed in terms of the ethological construct of “action-specific” control and the neuropsychological dimension of “nonspecific” activation. A possible alternative position that stresses overlapping control systems and partial specificity is introduced. Section III concerns aspects of classification and analysis plus some related conceptual issues that appear most relevant to current thoughts about specific vs. nonspecific behavioral control. It is pointed out that themost strict criterion for specific control is a system that involves only a single input and a single output and that is entirely independent in its operation from other activities in other control systems, while the most strict definition of nonspecific control is that all inputs affect all outputs, identically. Neither of these criteria is likely to be met, and a more limited operational approach is suggested. It is particularly clear that the problem of input specificity is partially separable from that of output specificity, and that “nonspecific” models at one level of analysis may reflect the operation of “multispecific” mechanisms at a different level of analysis. It is emphasized that input/output analyses provide a logic for the interpretation of intervening processes and do not permit simple S-R models. Section IV provides a detailed literature review that illustrates these and related issues. The data indicate a need to consider separately, and then synthesize, the operation of (1) qualitative variables (which inputs and which outputs), (2) quantitative variables (how much of these inputs and/or outputs), and (3) temporal variables (which part of the input/output sequence). The possible importance of encoding mechanisms (e.g., habit strength) is also briefly considered. Section V reviews the ethological literature on displacement activities as a particularly clear illustration of major issues in specific vs. nonspecific control. It is demonstrated that recent emphasis upon (1) disinhibition as a result of behavioral competition and (2) the operation of specific exogenous and peripheral stimuli provides a useful supplement to models of “nonspecific” endogenous activation. However, it is also suggested that endogenous excitatory processes may be partially shared among competing behavior patterns under certain circumstances and in that sense be “nonspecific.” Section VI provides a synopsis of the major issues discussed previously and outlines a “boundary-state” approach that appears to avoid many of the difficulties of strict specific and nonspecific models. This approach stresses both partial and shifting overlap among control systems as a function of intensity and temporal parameters. An analogy is suggested to the center/surround organization of control systems at the neurological level. Integrative pathways are viewed to become more or less focused as a function of the balance between excitatory and inhibitory mechanisms. This balance between excitation and inhibition may shift in a systematic manner as a joint function of qualitative, quantitative, and temporal dimensions employed in a given analysis.