Two Distinct Bases of Inhibition of Behaviour: Viewing Biological Phenomena Through the Lens of Psychological Theory

Constructs concerning reward and threat sensitivity can be organised in several ways (along with other ideas). Which conceptual organisation is used channels interpretations of phenomena ostensibly reflecting the sensitivities. For example, a two-mode organisation in which behavioural inhibition can follow either from threat sensitivity or from effortful control (planful restraint) yields an interpretation of serotonergic function quite different from what many assume. In this view, accumulated evidence suggests that serotonergic function relates to effortful control, rather than threat sensitivity. Neurobiological tools are useful, but their usefulness often depends on psychological theory. Copyright # 2008 John Wiley & Sons, Ltd. The idea that approach and avoidance tendencies are building blocks of elaborate behaviour is prominent again in personality psychology, as is the idea that individual differences in responsiveness of systems for approach and avoidance underlie dimensions of personality. There are, however, several ways to use those ideas (in conjunction with other ideas). Smillie (this issue) described one organisation, following Gray and McNaughton (2000). I favour a somewhat different organisation, outlined later. Smillie’s main point is the desirability of using new techniques to determine true reward and threat sensitivities (as opposed to self-reported sensitivities). Though the techniques outlined doubtlessly are useful, I offer a caution: Apart from behavioural paradigms, the techniques Smillie touted all require linking an observed biological phenomenon to an inferred psychological one. Unfortunately, there are many psychological third variables in that process. Focusing on a salient but noncritical psychological variable can induce errors in linking the biological to the psychological. These links easily become unquestioned assumptions. Assumptions about the psychological meaning of biological data must be reexamined repeatedly. This cannot be done once and for all. Change in psychological model can suggest a change in meaning for the link from biological to psychological. I illustrate this below with a case in which I believe Smillie’s discussion reflects a misinference. The psychological model displayed in Smillie’s Figure 1 leads easily to the misinference. An alternative model, however, suggests a very different interpretation. Impulsivity, anxiety and constraint. Consider three theoretical organisations involving approach and avoidance. Smillie’s Figure 1 reflects Gray’s (1981) initial theory proposing It is a little ironic that Smillie expressed concern about the validity of inferences made from human self-reports, but seemed less concerned about building a theory of human personality by observing rats’ behaviour and making inferences about their emotional states. 388 Discussion Copyright # 2008 John Wiley & Sons, Ltd. Eur. J. Pers. 22: 385–409 (2008)