Encouraging Cooperation: Revisiting Solidarity and Commitment Effects in Prisoner's Dilemma Games1

Pre‐play discussion consistently increases cooperation in dilemma interactions. Most explanations of this “cheap‐talk” effect are based on either commitment or group solidarity effects. Because discussion about the upcoming dilemma allows participants to make promises and creates group solidarity, the 2 explanations are often confounded. This paper aims to clarify past results by having participants engage in an unrelated discussion prior to a dilemma interaction. We find that solidarity effects can be induced by minimal group categorizations, but are relatively weak. Discussions involving consequential but unrelated coordination tasks are shown to prime cooperative norms and increase cooperation with both in‐group and out‐group members. Our findings suggest that cheap talk may work for even cheaper reasons than previously thought.     

An inexpensive infrared detector to verify the delivery of food pellets

The reproducibility of experimental outcomes depends on consistent control of independent variables. In food-maintained operant performance, it is of utmost importance that the quantity of food delivered is reliable. To that end, some commercial food pellet dispensers have add-on attachments to sense the delivery of pellets. Not all companies, however, offer such add-ons. Aside from availability, cost and temporary reduction in throughput may be a problem for smaller labs. The present paper outlines our recent development of a simple, inexpensive infrared device to detect and confirm the delivery of pellets. The in-line construction of the detector routes the falling pellet through a barrel so that it passes between an infrared emitter and receiver. The circuitry was designed to be compatible with all commercially available behavioral measurement systems, and so may be retrofit to any existing system. Our tests with the detector so far have shown that it is 100% accurate in detecting pellet delivery. The individual unit cost is approximately 25 dollars. The low cost and versatility of the device offer an easy method to ensure the integrity of food delivery in operant settings.     

Truthmaker commitments

On the truthmaker view of ontological commitment [Heil (From an ontological point of view, 2003); Armstrong (Truth and truthmakers, 2004); Cameron (Philosophical Studies, 2008)], a theory is committed to the entities needed in the world for the theory to be made true. I argue that this view puts truthmaking to the wrong task. None of the leading accounts of truthmaking—via necessitation, supervenience, or grounding—can provide a viable measure of ontological commitment. But the grounding account does provide a needed constraint on what is fundamental. So I conclude that truthmaker commitments are not a rival to quantifier commitments, but a needed complement. The quantifier commitments are what a theory says exists, while the truthmaker commitments are what a theory says is fundamental.

A Comparison of “Direct” Versus “Derived” Extinction of Avoidance Responding

The Psychological Record - To establish a series of derived relations between arbitrary stimuli, 20 subjects were exposed to nonarbitrary and arbitrary relational training and testing procedures....     

Rethinking Cognition: On Coulter on Discourse and Mind

This paper responds to, and comments on, Coulter's (1999) critique of discursive psychology with particular reference to how cognition is conceptualised theoretically and analytically. It first identifies a number of basic misreadings of discursive psychological writings, which distort and, at times, reverse its position on the status of cognition. Second, it reviews the main ways in which cognition, mental states, and thoughts have been analytically conceptualised in discursive psychology (respecification of topics from mainstream psychology, studies of the psychological thesaurus in action, and studies of the way psychological issues are managed). Third, it considers two of Coulter's substantive issues: the role of correct usage and the role of conceptual vs. empirical analysis. A series of problems are identified with Coulter's development of both of these issues.     

A Research Tool to Increase Attention to Experimental Materials: Manipulating Presentation Format

Experimental approaches require researchers in a variety of applied business disciplines to design experimental materials. This research is often busy and difficult to secure high-level professionals; thus, researchers must ensure sufficient attention to experimental materials to provide usable data. The current study suggests an experimental design feature to encourage participants to thoroughly process information contained in experimental materials. Based on Reynolds' (1992) selective attention strategy (SAS) model, variations in presentation format were expected to influence the relative salience of information presented. Two aspects of presentation format were manipulated to increase salience: display (paragraph vs. bullet point) and typeface (standard vs. bold underlined). Results indicate display improved ability to retrieve information, but typeface did not. Implications for the design of experimental materials are discussed.