Contraction: On the Decision-Theoretical Origins of Minimal Change and Entrenchment

We present a decision-theoretically motivated notion of contraction which, we claim, encodes the principles of minimal change and entrenchment. Contraction is seen as an operation whose goal is to minimize loses of informational value. The operation is also compatible with the principle that in contracting A one should preserve the sentences better entrenched than A (when the belief set contains A). Even when the principle of minimal change and the latter motivation for entrenchment figure prominently among the basic intuitions in the works of, among others, Quine and Ullian (1978), Levi (1980, 1991), Harman (1988) and Gärdenfors (1988), formal accounts of belief change (AGM, KM – see Gärdenfors (1988); Katsuno and Mendelzon (1991)) have abandoned both principles (see Rott (2000)). We argue for the principles and we show how to construct a contraction operation, which obeys both. An axiom system is proposed. We also prove that the decision-theoretic notion of contraction can be completely characterized in terms of the given axioms. Proving this type of completeness result is a well-known open problem in the field, whose solution requires employing both decision-theoretical techniques and logical methods recently used in belief change.     

Salesperson brand attachment: a job demands-resources theory perspective

Sales researchers have largely ignored the idea that salespeople form attachments to the brands that they sell, and that these attachments hold important consequences for sales outcomes. Drawing on job demands-resources theory, the authors suggest that salesperson brand attachment (SBA) serves as a unique psychological resource for salespeople. Using data from 154 salespeople from the beverage industry, they provide evidence that SBA increases selling effort toward the brand, and ultimately job satisfaction. In addition, they show that salesperson's brand attachment acts as a buffer against perceived job demands, including job codification and hierarchy of authority. In general, results support the job demands-resources framework and confirm that SBA is a resource that may be leveraged to offset job demands, under certain situations.     

The Role of Interest in Understanding the Career Choices of Female and Male College Students

Mismatch between college students' work goals and perceived goal affordances of physical/mathematical science careers may help explain gender differences in interest and career choice. In Study 1, the desire for interesting work was cited by most students in the sample (89% White, 6% Asian, 5% other). Compared to men, women reported interpersonal work goals more and high pay and status work goals less frequently. In Study 2, students (79% White, 12% Latino, 5% Asian, 4% other, predominantly middle class) perceived physical/mathematical science careers as less likely to afford interpersonal goals and more likely to afford high pay and status goals compared to other careers. Interpersonal goal affordances predicted greater interestingness for all careers, whereas high pay and status goal affordances predicted greater interestingness only for physical/mathematical sciences. Interestingness positively predicted likelihood of career choice.     

A variable-threshold,variable-gain,infrared photoplethysmograph

The design of a versatile, low-cost, hermetically sealed, infrared photoplethysmograph is described. The device can be used for optical readings of changes in blood volume which occur with cardiovascular events. Advantages of the device are discussed.     

A portable biofeedback device for autonomic responses

The design of a versatile and programmable transducer amplifier device with analogue display for self-monitoring of autonomic responses is described. The design features low cost, portability, and flexibility across direct-current transducer options (e.g., photoplethysmograph or thermistor). The device can be used for the visual or auditory display of continuous blood volume pulse or temperature measures where the relative amplitude or pulse rate is of concern. Auditory or visual biofeedback may be provided via the choice of a stacked bar-graph display or piezoelectric buzzer. A common circuit design to allow programming options for the estimation of heart rate, inter-beat interval, or pulse duration is provided.     

Children and Videogames: Leisure Activities,Aggression, Social Integration,and School Performance1

A survey was conducted among 346 children from the 7th and 8th grade of 7 elementary schools to examine possible positive and negative effects of playing videogames. Analyses revealed that playing videogames did not appear to take place at the expense of children's other leisure activities, social integration, and school performance. A gender difference arose: Boys spent more time playing videogames than did girls. There was no significant relationship between the amount of time children spent on videogames and aggressive behavior. A negative relationship between time spent playing videogames and prosocial behavior was found; however, this relationship did not appear in separate analyses for boys and girls. Furthermore, a positive relationship was found between time spent on videogames and a child's intelligence.     

Effects of electrocutaneous ready—signal variation on visual reaction time

Two ready-signal variables (direction of change in electrocutaneous stimulation and method of presentation: “trace” or “delayed”) were combined in a 2 by 2 by Ss design. Neither variable produced a significant main effect but yielded a highly significant interaction. Results were interpreted in terms of arousal. intersensory. and conditioning explanations of ready-signal effects.