Constrained action selection in children with developmental coordination disorder

The effect of advance ('precue') information on short aiming movements was explored in adults, high school children, and primary school children with and without developmental coordination disorder (n=10, 14, 16, 10, respectively). Reaction times in the DCD group were longer than in the other groups and were more influenced by the extent to which the precue constrained the possible action space. In contrast, reaction time did not alter as a function of precue condition in adults. Children with DCD showed greater inaccuracy of response (despite the increased RT). We suggest that the different precue effects reflect differences in the relative benefits of priming an action prior to definitive information about the movement goal. The benefits are an interacting function of the task and the skill level of the individual. Our experiment shows that children with DCD gain a benefit from advance preparation in simple aiming movements, highlighting their low skill levels. This result suggests that goal-directed RTs may have diagnostic potential within the clinic.     

Gricean Communication and Transmission of Thoughts

Gricean communication is communication between utterers and their audiences, where the utterer means something and the audience understands what is meant. The weak transmission idea is that, whenever such communication takes place, there is something which is transmitted from utterer to audience; the strong transmission idea adds that what is transmitted is nothing else than what is communicated. We try to salvage these ideas from a seemingly forceful attack by Wayne Davis. Davis attaches too much significance to the surface structure of sentences of the type ‘S communicates the belief (desire …) that p to A’ by assuming that the communicated entity is denoted by the grammatical object following ‘communicates’. On our proposal, what is communicated in all Gricean cases is a thought. And since S communicates the thought that p to A only if S means that p and A understands what S means, the thought that p will be transmitted from S to A.     

Social Ontology as Convention

I will argue that social ontology is constituted as hierarchical and interlocking conventions of multifarious kinds. Convention, in turn, is modeled in a manner derived from that of David K. Lewis. Convention is usually held to be inadequate for models of social ontologies, with one primary reason being that there seems to be no place for normativity. I argue that two related changes are required in the basic modeling framework in order to address this (and other) issue(s): (1) a shift to an intentional model—among other reasons, in order to account for normativity—and (2) moving away from the belief-desire, propositional attitude, framework for understanding the intentional realm toward an interactive, pragmatic model of intentionality. These shifts provide natural approaches to: (1) understanding the normativities of social realities; (2) the sense in which social ontology is often constituted in implicit relations among the participants rather than elaborated and iterated explicit beliefs and desires; (3) and language.     

Reducing contrast makes speeds in a video-based driving simulator harder to discriminate as well as making them appear slower

We investigated the effect of reducing image contrast on speed perception using a video-based driving simulator in which participants viewed pairs of scenes and were asked to judge whether the second scene was faster or slower than the first scene. We predicted two outcomes: (i) that vehicle speeds would become harder to discriminate, and (ii) that vehicle speeds would appear slower. There is previous evidence confirming the latter prediction in a less realistic computer-based driving simulation, but none demonstrating the former. Our results supported both predictions, each of which may have traffic-safety implications when reduced-contrast conditions are experienced in real life, such as with fog or when the driver has cataracts.     

What is the reference in reference repulsion?

Reference repulsion is a mechanism posited to explain systematic biases of direction judgment of single drifting dot displays (Rauber and Treue, 1998 Perception 27 393-402). Rauber and Treue obtained systematic but, surprisingly, very different effects depending upon whether standard and comparison stimuli were presented simultaneously or successively. Successive effects were described as exhibiting repulsion from both vertical and horizontal cardinal axes, whereas simultaneous effects showed repulsion from horizontal only. We contend that the proposed mechanism makes no testable predictions because the so-called reference can only be specified a posteriori, a fact acknowledged by Rauber and Treue. We attempted to replicate Rauber and Treue's experiments, but we obtained no systematic biases of direction judgment. Comparisons across several studies suggest that errors in direction judgments of single drifting dot patterns vary widely in magnitude and direction, as might be expected with what are essentially baseline or pretest measures. In our view, reference repulsion describes neither a real perceptual mechanism nor a predictable pattern of direction misjudgments.     

SAMPLES AS SYMBOLS

Nelson Goodman and, following him, Catherine Z. Elgin and Keith Lehrer have claimed that sometimes a sample is a symbol that stands for the property it is a sample of. The relation between the sample and the property it stands for is called ‘exemplification’ (Goodman, Elgin) or ‘exemplarisation’ (Lehrer). Goodman and Lehrer argue that the notion of exemplification sheds light on central problems in aesthetics and the philosophy of mind. However, while there seems to be a phenomenon to be captured, Goodman's account of exemplification has several flaws. In this paper I will offer an alternative account of exemplification that is inspired by Grice's idea that one can communicate something by providing one's audience with intention‐independent evidence and letting them draw the obvious conclusion for themselves. This explication of exemplification will solve the problems that arose for Goodman's theory in the spirit of his approach. 1     

Cosmic inflation and the past hypothesis

The past hypothesis is that the entropy of the universe was very low in the distant past. It is put forward to explain the entropic arrow of time but it has been suggested (e.g. [Penrose, R. (1989a). The emperor’s new mind. London:Vintage Books; Penrose, R. (1989b). Annals of the New York Academy of Sciences, 571, 249–264; Price, H. (1995). In S. F. Savitt (Ed.), Times’s arrows today. Cambridge: Cambridge University Press; Price, H. (1996). Time’s arrow and Archimedes’ point. Oxford: Oxford University Press; Price, H. (2004). In C. Hitchcock (Ed.), Contemporary debates in philosophy of science. Oxford: Blackwell]) that it is itself in need of explanation. It has also been suggested that cosmic inflation could provide the explanation, but Price (2004) raises a serious objection to this suggestion, which has otherwise received very little attention in the philosophical literature. Price points out that the standard inflationary explanation involves a double standard: although the evolution of the universe described by the inflationary model seems natural from the standard temporal perspective it looks highly unnatural from the reversed temporal perspective. The main purpose of this paper is to propose a novel form of the inflationary explanation that avoids this objection. It is argued that the inflationary model would not involve a double standard (but would still explain the past hypothesis) if we construct the model with a global “boundary” condition instead of a conventional boundary condition: if we assume that the universe is as generic as possible overall, rather than as generic as possible at some given point (e.g. the Big Bang) as is assumed in the standard inflationary model. This novel form of the inflationary explanation is then compared with Price’s 1996 preferred explanation, a version of the so-called “Weyl hypothesis”.     

What Motivates People to Participate More in Community‐based Coalitions?

The purpose of this study was to identify potential opportunities for improving member participation in community-based coalitions. We hypothesized that opportunities for influence and process competence would each foster higher levels of individual member participation. We tested these hypotheses in a sample of 818 members within 79 youth-oriented coalitions. Opportunities for influence were measured as members' perceptions of an inclusive board leadership style and members' reported committee roles. Coalition process competence was measured through member perceptions of strategic board directedness and meeting effectiveness. Members reported three types of participation within meetings as well as how much time they devoted to coalition business beyond meetings. Generalized linear models accommodated clustering of individuals within coalitions. Opportunities for influence were associated with individuals' participation both within and beyond meetings. Coalition process competence was not associated with participation. These results suggest that leadership inclusivity rather than process competence may best facilitate member participation.     

Coordinating cognition: the costs and benefits of shared gaze during collaborative search

Collaboration has its benefits, but coordination has its costs. We explored the potential for remotely located pairs of people to collaborate during visual search, using shared gaze and speech. Pairs of searchers wearing eyetrackers jointly performed an O-in-Qs search task alone, or in one of three collaboration conditions: shared gaze (with one searcher seeing a gaze-cursor indicating where the other was looking, and vice versa), shared-voice (by speaking to each other), and shared-gaze-plus-voice (by using both gaze-cursors and speech). Although collaborating pairs performed better than solitary searchers, search in the shared gaze condition was best of all: twice as fast and efficient as solitary search. People can successfully communicate and coordinate their searching labor using shared gaze alone. Strikingly, shared gaze search was even faster than shared-gaze-plus-voice search; speaking incurred substantial coordination costs. We conclude that shared gaze affords a highly efficient method of coordinating parallel activity in a time-critical spatial task.