Academic journal article Psychonomic Bulletin & Review

The Role of Response Mechanisms in Determining Reaction Time Performance: Piéron's Law Revisited

Academic journal article Psychonomic Bulletin & Review

The Role of Response Mechanisms in Determining Reaction Time Performance: Piéron's Law Revisited

Article excerpt

A response mechanism takes evaluations of the importance of potential actions and selects the most suitable. Response mechanism function is a nontrivial problem that has not received the attention it deserves within cognitive psychology. In this article, we make a case for the importance of considering response mechanism function as a constraint on cognitive processes and emphasized links with the wider problem of behavioral action selection. First, we show that, contrary to previous suggestions, a well-known model of the Stroop task (Cohen, Dunbar, & McClelland, 1990) relies on the response mechanism for a key feature of its results-the interference-facilitation asymmetry. Second, we examine a variety of response mechanisms (including that in the model of Cohen et al., 1990) and show that they all follow a law analogous to Piéron's law in relating their input to reaction time. In particular, this is true of a decision mechanism not designed to explain RT data but based on a proposed solution to the general problem of action selection and grounded in the neurobiology of the vertebrate basal ganglia. Finally, we show that the dynamics of simple artificial neurons also support a Piéron-like law.

A response mechanism is the component of any model of human decision making that takes evaluations of the importance of potential actions and selects the most suitable action. Despite appearances, the design of a biologically plausible switching mechanism is a nontrivial problem (Redgrave, Prescott, & Gurney, 1999). In this article, we argue that response mechanisms are an important part of cognitive models, that their function is an important area for investigation, and that the processes of the response mechanism have consequences for performance in diverse areas of human behavior. The importance of the study of response mechanisms is highlighted by the emergence of the topic in disciplines apart from cognitive psychology. Thus, ethology, robotics, and neuroscience have come to recognize the importance of the "action selection problem" (Prescott, Redgrave, & Gurney, 1999; Tyrrell, 1992). From these perspectives, a response mechanism is necessary to deal with the resolution of conflicts between functional units that are in competition for behavioral expression. For example, a food-deprived animal should reevaluate the importance of feeding if a predator is detected, thereby requiring a response selection to the new stimulus (e.g., continue feeding, flee, or fight).

Appropriate behavioral selection is also clearly an issue of central importance to cognitive psychologists, but response mechanisms have generally not received their due emphasis. All cognitive models must explicitly or implicitly contain a response mechanism. In many formal models, this may be no more than a simple threshold, above which activations indicate a response. Even such a minimal feature fulfills the role of the response mechanism, although this kind of mechanism is functionally impoverished (Ratcliff, Van Zandt, & McKoon, 1999; Stafford, 2003). A response mechanism should be designed to cope with the multiple, conflicting demands of the behaving organism (Redgrave et al., 1999). Something about the way these demands are reconciled in humans may be shown by studies of reaction times in tasks such as the Stroop task (Stroop, 1935) and other simple choice paradigms (Luce, 1986). Conversely, of course, the study of response mechanisms and of the action selection problem should illuminate facets of performance in these paradigms.

Within cognitive psychology, the study of response mechanisms in their own right has largely been restricted to the modeling of decision mechanisms that can mimic the pattern of reaction time in simple choice paradigms (Luce, 1986; Ratcliff & Rouder, 1998). Furthermore, although response mechanisms have been studied in this "choice theory" context, little is known about the brain regions where they might be instantiated, nor has there been an attempt to create models based on neurophysiological principles or constrained by known neuroanatomy. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.