Uncovering mental representations with Markov chain Monte Carlo

A key challenge for cognitive psychology is the investigation of mental representations, such as object categories, subjective probabilities, choice utilities, and memory traces. In many cases, these representations can be expressed as a non-negative function defined over a set of objects. We present a behavioral method for estimating these functions. Our approach uses people as components of a Markov chain Monte Carlo (MCMC) algorithm, a sophisticated sampling method originally developed in statistical physics. Experiments 1 and 2 verified the MCMC method by training participants on various category structures and then recovering those structures. Experiment 3 demonstrated that the MCMC method can be used estimate the structures of the real-world animal shape categories of giraffes, horses, dogs, and cats. Experiment 4 combined the MCMC method with multidimensional scaling to demonstrate how different accounts of the structure of categories, such as prototype and exemplar models, can be tested, producing samples from the categories of apples, oranges, and grapes.     

Internet abuse in the workplace: Issues and concerns for employers and employment counselors

This article gives an overview of some of the main issues in the most serious form of Internet abuse (i.e., Internet addiction) before examining other types of workplace Internet abuse (cybersexual Internet abuse, online friendship/relationship abuse, Internet activity abuse, online information abuse, criminal Internet abuse, and miscellaneous Internet abuse) and why they occur. A few specific types of Internet abuse (online pornography use, sexually related Internet crime, online gambling) are also highlighted as issues for employers. The author concludes that Internet abuse should be taken seriously by all employers who use the Internet in their day‐to‐day business.     

Discriminative stimulus effects of diazepam and buspirone in normal volunteers.

A within-subject design was used to characterize the effects of dose manipulations on discriminative and self-reported effects of oral diazepam and buspirone. Subjects were trained to discriminate diazepam (10 mg) versus placebo (n = 10), or buspirone (10 or 15 mg) versus placebo (n = 9). The compounds were identified to subjects by letter code before discrimination training began. In later sessions, correct identifications at 2 hr after the oral administration of drug earned money. All subjects showed accurate discrimination performance during the test-of-acquisition phase. In a low-dose generalization phase, diazepam and buspirone produced dose-related increases in drug identifications across a four-fold range of doses. In a subsequent low-dose training phase, in which subjects were trained to discriminate progressively lower drug doses, the median lowest discriminable dose of diazepam and buspirone was 2.5 and 7.5 mg, respectively. Dose-response functions for drug identifications were shifted leftward in the low-dose training phase relative to the low-dose generalization phase, suggesting that reinforcement of progressively lower doses enhances drug discriminability. The self-reported effects of diazepam and buspirone were similar (e.g., both drugs increased ratings of drug strength and clumsy/uncoordinated) and different (e.g., diazepam but not buspirone increased ratings of drowsy/sleepy; buspirone but not diazepam increased ratings of tense/nervous). This study demonstrates discriminative and self-reported effects of diazepam and buspirone at doses lower than previously shown to be behaviorally active, and suggests that at commonly used clinical doses, diazepam is relatively more discriminable than buspirone.     

Downsizing,changes in work,and self-rated health of employees: A 7-year 3-wave panel study

Abstract

The question of whether changes in work and interpersonal relationships mediate the adverse effects of downsizing on health of employees was explored. Longitudinal data from a 7-year study of 550 municipal workers in a variety of jobs was collected before, immediately after, and 4 years after downsizing. The degree of downsizing for each job category was assessed using organizational records of contracted days worked. Downsizing predicted adverse changes in work characteristics and a long-lasting decline in self-rated health. Decreased job control, high job insecurity and increased physical demands, in combination, appeared to be the linking mechanism between downsizing and general health. Interestingly, social conflict did not play a role in the mediation process.     

Changes in cue associability across training in human causal learning

A series of experiments studied the amount learned about two food cues (A and B) whose presentation in a meal was followed by an allergy (+) in a fictitious patient. Participants were trained with A+ and C+ in Phase 1 and then with AB+ or AB++ in Phase 2. Subsequent testing revealed that BC was more allergenic than AD, showing that more had been learned about B than A in Phase 2. Participants were also trained with A+, then with AB+, and finally with AB++. The results of interpolating AB+ between A+ and AB++ training were consistent with the hypothesis that pretraining with Cue A selectively suppressed attention to its associate across the AB+ trials and, thereby, reduced the amount subsequently learned about B on AB++ trials.     

A rational analysis of rule-based concept learning

This article proposes a new model of human concept learning that provides a rational analysis of learning feature-based concepts. This model is built upon Bayesian inference for a grammatically structured hypothesis space—a concept language of logical rules. This article compares the model predictions to human generalization judgments in several well-known category learning experiments, and finds good agreement for both average and individual participant generalizations. This article further investigates judgments for a broad set of 7-feature concepts—a more natural setting in several ways—and again finds that the model explains human performance.     

Attitudes toward Indigenous Australians: the role of empathy and guilt

Previous research in Perth, Western Australia, finds a disturbing amount of prejudice against Indigenous Australians. At the forefront of much prejudice research has been the distinction between old‐fashioned and modern prejudice. We constructed an Attitude Toward Indigenous Australians scale from items originating from qualitative data. We found that negative attitudes were predicted by collective guilt about past and present wrongs to Indigenous Australians (collective guilt directly linked to Indigenous issues, as well as collective guilt generally). Negative attitudes were also predicted by a lack of empathy for Indigenous Australians, and affective perspective taking generally. Socio‐demographics (e.g. a lack of education) predicted negative attitudes, which indicate the necessity of taking both social‐psychological and socio‐demographic factors into account when examining the nature of prejudice. A number of practical implications arise from these findings. Copyright © 2004 John Wiley & Sons, Ltd.     

Demographic factors and playing variables in online computer gaming.

Despite the growing popularity of online game playing, there has been no primary survey of its players. Therefore, an online questionnaire survey was used to examine basic demographic factors of online computer game players who played the popular online game Everquest (i.e., gender, age, marital status, nationality, education level, occupation). The survey also examined playing frequency (i.e., amount of time spent playing the game a week), playing history (i.e., how long they had been playing the game, who they played the game with, whether they had ever gender swapped their game character), the favorite and least favorite aspects of playing the game, and what they sacrifice (if anything) to play the game. Results showed that 81% of online game players were male, and that the mean age of players was 27.9 years of age. For many players, the social aspects of the game were the most important factor in playing. A small minority of players appear to play excessively (over 80 h a week), and results suggest that a small minority sacrifice important activities in order to play (e.g., sleep, time with family and/or partner, work, or schooling).