Contextual cueing based on specific and categorical properties of the environment

Theories of visual search have generally assumed that rejected distractors are marked so as to avoid further processing of these items (memory-driven search). To test this assumption, Horowitz and Wolfe (1998) developed the randomized search paradigm, in which standard static search is compared to dynamic search where items are randomly replotted at new locations throughout a trial. Memory-driven search predicts that search slopes should double in the dynamic condition. After reviewing earlier findings that slopes were similar in the two conditions, we present two new experiments. Experiment 1 replicated and extended our previous findings using a larger range of set sizes, a slower rate of change, and adding a fixed location dynamic condition. Experiment 2 employed stimuli that required overt fixation. Neither experiment showed evidence for memory-driven search. We conclude that visual search is best understood as a series of successive judgements of the momentary probability of target presence.     

The competitive bargaining set for cooperative n-person games

The continuum of solutions constituting the bargaining set for n-person games in characteristic function form (n ≥ 4) reflects various degrees of determinateness to form a coalition, different requirements of stability, or different levels of competition among the players. At one end of this continuum is the kernel solution. A new solution, called the competitive bargaining set, constitutes the other extreme. It incorporates the concept of a multiobjection, which is based on the idea that threats may be perceived and considered simultaneously even though their simultaneous implementation is impossible.For the simple homogeneous majority games [n ? 2, 1, 1, …, 1] the competitive bargaining set (1) yields unique outcomes for each coalition structure, (2) coincides with von Neumann and Morgenstern's main simple solution for certain coalition structures, and (3) converges to Shapley value as n → ∞ when the grand coalition forms.Mathematical and experimental implications of the new solution are discussed briefly.     

Integrating fieldwork into employment counseling for methadone‐treatment patients

An innovative employment counseling model, Customized Employment Supports, was developed for methadone‐treatment patients, a population with historically low employment rates. The effectiveness of a key component of the model, “vocational fieldwork,” the delivery of services in the community rather than only within the clinic, was assessed through a quasi‐experimental study of the first 55 patients receiving the model in 2 clinics. Employment outcomes after 6 months were compared between patients who received vocational fieldwork (n = 18) and those who did not (n = 37). Logistic regression analysis demonstrated that patients receiving vocational fieldwork had significantly better outcomes for competitive work, informal work, and any paid work.     

Externalism, the environment, and thought-tokens

In “Contents just are in the head” (Erkenntnis 54, pp. 321–4.) I have presented two arguments against the thesis of semantic externalism. In “Contents just aren’t in the head” Anthony Brueckner has argued that my arguments are unsuccessful, since they rest upon some misconceptions regarding the nature of this thesis. (Erkenntnis 58, pp. 1–6.) In the present paper I will attempt to clarify and strengthen the case against semantic externalism, and show that Brueckner misses the point of my arguments.     

The what–where trade-off in multiple-identity tracking

Observers are poor at reporting the identities of objects that they have successfully tracked (Pylyshyn, Visual Cognition, 11, 801-822, 2004; Scholl & Pylyshyn, Cognitive Psychology, 38, 259-290, 1999). Consequently, it has been claimed that objects are tracked in a manner that does not encode their identities (Pylyshyn, 2004). Here, we present evidence that disputes this claim. In a series of experiments, we show that attempting to track the identities of objects can decrease an observer's ability to track the objects' locations. This indicates that the mechanisms that track, respectively, the locations and identities of objects draw upon a common resource. Furthermore, we show that this common resource can be voluntarily distributed between the two mechanisms. This is clear evidence that the location- and identity-tracking mechanisms are not entirely dissociable.