Object-based representations govern both the storage of information in visual short-term memory and the retrieval of information from it

Interest is growing in how information is retained in visual short-term memory (VSTM). We describe an experiment that assesses VSTM within the context of multidimensional signal detection theory. On every trial, participants were presented with a 250-ms display containing four colored shapes. They were then probed 900 ms later with a colored shape and made separate old/new judgments about the color and the shape. In any particular trial, one, both, or neither of the probed features had been presented. Performance differed according to whether both probed features belonged to a single object or to two different objects. When both probed features belonged to the same object, featural retrieval was better than would be predicted by independent feature storage. When both probed features belonged to two different objects, featural retrieval was worse than would be predicted by independent feature storage. We conclude that storage in and retrieval from VSTM operate on the basis of object-based representations.     

Listeners invest in an assumed other's perspective despite cognitive cost

We explored perspective-taking behavior in a visuospatial mental rotation task that requires listeners to adopt an egocentric or “other-centric” frame of reference. In the current task, objects could be interpreted relative to the point-of-view of the listener (egocentric) or of a simulated partner (other-centric). Across three studies, we evaluated participants’ willingness to consider and act on partner-specific information, showing that a partner’s perceived ability to contribute to collaborative mutual understanding modulated participants’ perspective-taking behavior, either by increasing other-centric (Study 2) or egocentric (Study 3) responding. Moreover, we show that a large proportion of participants resolved referential ambiguity in terms of their partner’s perspective, even when it was more cognitively difficult to do so (as tracked by online movement measures), and when the presence of a social partner had to be assumed (Studies 1 and 2). In addition, participants continued to consider their partner’s perspective during trials where visual perspectives were shared. Our results show that participants will thoroughly invest in either an other-centric or egocentric mode of responding, and that perspective-taking strategies are not always dictated by minimizing processing demands, but by more potent (albeit subtle) factors in the social context.     

Individual differences in dispositional focus of attention predict attentional blink magnitude

When identifying two targets presented in a rapid serial visual presentation stream, one’s accuracy on the second target is reduced if it is presented shortly (within 500 msec) after the first target—an attentional blink (AB). Individuals differ greatly in the size of their AB. One way to learn about the AB is to understand what underlies these individual differences. Recent studies have suggested that when a broadened or diffused attentional state is induced, the AB deficit can be attenuated. The present study examined whether natural (dispositional) individual differences in focus and diffusion of attention as assessed by the global/local task could predict performance on the AB task. Performance that was consistent with diffusion correlated negatively with AB size, and performance that was consistent with focusing correlated positively with AB size, showing that dispositional focus and diffusion of attention can predict individual differences in the AB. These findings are consistent with the Olivers and Nieuwenhuis (2006) overinvestment hypothesis.     

Predictors of verdict and punitive damages in high-stakes civil litigation

This research investigated demographic and attitudinal- psychological predictors of verdict and amount of punitive damages awarded in high-stakes civil litigation. Four hundred and forty-six surrogate jurors, selected to be representative of actual jurors, were exposed to realistic case presentations in insurance, tobacco, and pharmaceutical cases that were about to go to trial. Hierarchical regression revealed that perceptions of the existence of a litigation crisis predicted verdict in the tobacco and pharmaceutical cases after controlling for all other variables. Demographic variables predicted verdict and punitive damage awards only modestly and in different ways in the three cases. Need for cognition, strength of will and rationality, and a perception that there is a litigation crisis predicted the amount of punitive damages awarded in the tobacco case. Litigation crisis also predicted the amount of punitive damages awarded in the pharmaceutical case. Implications for jury selection are discussed.     

Bochenski on Property Identity and the Refutation of Universals

An argument against multiply instantiable universals is considered in neglected essays by Stanislaw Lesniewski and I.M. Bochenski. Bochenski further applies Lesniewski’s refutation of universals by maintaining that identity principles for individuals must be different than property identity principles. Lesniewski’s argument is formalized for purposes of exact criticism, and shown to involve both a hidden vicious circularity in the form of impredicative definitions and explicit self-defeating consequences. Syntactical restrictions on Leibnizian indiscernibility of identicals are recommended to forestall Lesniewski’s paradox.     

Propositions, Sets, and Worlds

If we agree with Michael Jubien that propositions do not exist, while accepting the existence of abstract sets in a realist mathematical ontology, then the combined effect of these ontological commitments has surprising implications for the metaphysics of modal logic, the ontology of logically possible worlds, and the controversy over modal realism versus actualism. Logically possible worlds as maximally consistent proposition sets exist if sets generally exist, but are equivalently expressed as maximally consistent conjunctions of the same propositions in corresponding sets. A conjunction of propositions, even if infinite in extent, is nevertheless itself a proposition. If sets and hence proposition sets exist but propositions do not exist, then whether or not modal realism is true depends on which of two apparently equivalent methods of identifying, representing, or characterizing logically possible worlds we choose to adopt. I consider a number of reactions to the problem, concluding that the best solution may be to reject the conventional model set theoretical concept of logically possible worlds as maximally consistent proposition sets, and distinguishing between the actual world alone as maximally consistent and interpreting all nonactual merely logically possible worlds as submaximal. I am grateful to the Netherlands Institute for Advanced Study in the Humanities and Social Sciences (NIAS), Royal Netherlands Academy of Arts and Sciences (KNAW), for supporting this among related research projects in philosophical logic and philosophy of mathematics during my Resident Research Fellowship in 2005-2006.