Stress-induced breakdown of an appetitive discrimination

Rats trained to discriminate between S^D and S^Δ for food reinforcement showed marked impairments in this discrimination when strong, unavoidable shocks occurred at the termination of a third stimulus. The predominant feature of this impairment was a supernormal rate of unreinforced (S^Δ) behavior. Shocks delivered without exteroceptive warning also led to a discriminative breakdown. The effect was a direct function of shock intensity. When behavior was strongly suppressed in the third stimulus by response-correlated shock (“punishment”), instead of unavoidable shock, breakdowns were only temporary; as soon as responding recovered from its overall suppression, discriminative performance returned to normal. The discriminative deterioration may be interpreted as an emotional by-product of frequent aversive stimulation, but accidental contingencies could also have played a role.     

Searching working memory for the source of dual-task costs

Dual-task costs depend on the specific pairings of stimulus and response modalities. Such findings are analogous to domain-specific effects in the working memory (WM) literature, in which items compete for limited capacity when they involve related types of information. The present study explicitly examines the relationship between modality-pairing effects on dual-task costs and domain-specificity effects on WM capacity. Participants maintained a sequence of either locations or tones in WM, and then performed a choice reaction time task in which they responded either vocally or manually. The stimuli for the choice reaction time task were held constant, but its response modality affected the interference observed in WM: vocal responses interfered with WM for tones and manual responses interfered with WM for locations. These findings indicate that response selection engages domain-specific WM processes and that interference within these processes may account for modality-pairing effects.     

Hempel’s Provisos and <Emphasis Type="Italic">Ceteris Paribus</Emphasis> Clauses

The problem of ceteris paribus clauses and Hempel’s problem of provisos are closely-related difficulties. Both challenge advocates of accounts of scientific theories involving laws understood as universal generalizations, and they have been treated as identical problems. Earman and Roberts argue that the problems are distinct. Towards arguing against them, I characterize the relationship between Hempel’s provisos and one way of expressing ceteris paribus clauses. I then describe the relationship between the problems attributed to the clauses, suggesting that they form a single problem-cluster. However, Hempel’s way of formulating provisos and discussing what they involve entangles provisos with the problem of skepticism. This creates a departure in Hempel’s discussion of provisos from the distinctive problem of vacuity which characterizes the problem of ceteris paribus clauses, though for different reasons than Earman and Roberts suggest.     

Virtual Reality Exposure Therapy for PTSD symptoms after a road accident: an uncontrolled case series

This report examined whether Virtual Reality Exposure Therapy (VRET) could be used in the treatment of posttraumatic stress disorder (PTSD) symptoms in the aftermath of a serious motor vehicle accident. Six individuals reporting either full or severe subsyndromal PTSD completed 10 sessions of VRET, which was conducted using software designed to create real-time driving scenarios. Results indicated significant reductions in posttrauma symptoms involving reexperiencing, avoidance, and emotional numbing, with effect sizes ranging from d=.79 to d=1.49. Indices of clinically significant and reliable change suggested that the magnitude of these changes was meaningful. Additionally, high levels of perceived reality ("presence") within the virtual driving situation were reported, and patients reported satisfaction with treatment. Results are discussed in light of the possibility for VRET to be useful in guiding exposure in the treatment of PTSD following road accidents.     

Visualization,pattern recognition,and forward search: effects of playing speed and sight of the position on grandmaster chess errors

A new approach examined two aspects of chess skill, long a popular topic in cognitive science. A powerful computer‐chess program calculated the number and magnitude of blunders made by the same 23 grandmasters in hundreds of serious games of slow (“classical”) chess, regular “rapid” chess, and rapid “blindfold” chess, in which opponents transmit moves without ever seeing the actual position. Rapid chess led to substantially more and larger blunders than classical chess. Perhaps more surprisingly, the frequency and magnitude of blunders did not differ in rapid versus blindfold play, despite the additional memory and visualization load imposed by the latter. We discuss the involvement of various cognitive processes in human problem‐solving and expertise, especially with respect to chess. Prior opposing views about the basis of general chess skill have emphasized the dominance of either (a) swift pattern recognition or (b) analyzing ahead, but both seem important and the controversy appears currently unresolvable and perhaps fruitless.     

A note on the analysis of designs in which subjects receive each stimulus only once

In social psychological experiments, the manipulations of interest are often presented to subjects along with, or as part of, some stimulus. An example would be a manipulation of the verbal label associated with a stimulus photograph, in a person perception study. Ordinarily it is not possible for stimuli to be completely crossed with treatments because subjects cannot be exposed to any stimulus more than once. In such designs it is wise to counterbalance the assignment of stimuli to treatment conditions, but this gives rise to difficulties in the analysis of the experimental data. Data from such designs have frequently been misanalyzed in the published literature. This paper presents a method of constructing a counter-balancing scheme to simplify the analysis, and appropriate methods of analysis for both the simplified and the general case. It is emphasized that stimuli are generally best treated as a random factor in such designs, permitting increased generalizability, but the case where the stimulus factor is fixed is also considered.     

Domain-specific conflict adaptation without feature repetitions

An influential account of how cognitive control deals with conflicting sources of information holds that conflict is monitored by a module that automatically recruits attention to resolve the conflict. This leads to reduced effects of conflict on the subsequent trial, a phenomenon termed conflict adaptation. A prominent question is whether control processes are domain specific—that is, recruited only by the particular type of conflict they resolve. Previous studies that have examined this question used two-choice tasks in which feature repetition effects could be responsible for domain-specific adaptation effects. We report two experiments using four-choice (Experiment 1) and five-choice (Experiment 2) tasks that contain two types of irrelevant sources of potentially conflicting information: stimulus location (Simon conflict) and distractors (flanker conflict). In both experiments, we found within-type conflict adaptation for both types of conflict after eliminating trials on which stimulus features were repeated from one trial to the next. Across-type conflict adaptation, however, was not significant. Thus, conflict adaptation was due to domain-specific recruitment of cognitive control. Our results add converging evidence to the idea that multiple independent control processes are involved in reactive cognitive control, although whether control is always local remains to be determined.