Why Higher Working Memory Capacity May Help You Learn: Sampling,Search, and Degrees of Approximation

Algorithms for approximate Bayesian inference, such as those based on sampling (i.e., Monte Carlo methods), provide a natural source of models of how people may deal with uncertainty with limited cognitive resources. Here, we consider the idea that individual differences in working memory capacity (WMC) may be usefully modeled in terms of the number of samples, or “particles,” available to perform inference. To test this idea, we focus on two recent experiments that report positive associations between WMC and two distinct aspects of categorization performance: the ability to learn novel categories, and the ability to switch between different categorization strategies (“knowledge restructuring”). In favor of the idea of modeling WMC as a number of particles, we show that a single model can reproduce both experimental results by varying the number of particles—increasing the number of particles leads to both faster category learning and improved strategy‐switching. Furthermore, when we fit the model to individual participants, we found a positive association between WMC and best‐fit number of particles for strategy switching. However, no association between WMC and best‐fit number of particles was found for category learning. These results are discussed in the context of the general challenge of disentangling the contributions of different potential sources of behavioral variability.     

Cholinergic neurons mediate CaMKII-dependent enhancement of courtship suppression

In Drosophila, calcium/calmodulin-dependent protein kinase II (CaMKII) activity is crucial in associative courtship conditioning for both memory formation and suppression of courtship during training with a mated female. We have previously shown that increasing levels of constitutively active CaMKII, but not calcium-dependent CaMKII, in a subset of neurons can decrease the initial level of courtship and enhance the rate of suppression of courtship in response to a mated female. In this study, we demonstrate that a subpopulation of noncholinergic, nondopaminergic, non-GABAergic neurons can cause CaMKII-dependent reductions in initial courtship, but only cholinergic neurons enhance training-dependent suppression. These data suggest that processing of pheromonal signals in two subpopulations of neurons, likely antennal lobe projection neurons, is critical for behavioral plasticity.     

A new method for calibrating perceptual salience across dimensions in infants: the case of color vs. luminance

We report a new method for calibrating differences in perceptual salience across feature dimensions, in infants. The problem of inter-dimensional salience arises in many areas of infant studies, but a general method for addressing the problem has not previously been described. Our method is based on a preferential looking paradigm, adapted to determine the relative salience of two stimuli. We report here on the case of stimuli differing in color and luminance, though the method has wider potential. We were able to determine on a psychophysical curve the point at which a color contrast was equally salient to infants as a given luminance contrast. We then used these calibrated, 'iso-salient' stimuli in an object memory study. Results showed that 6.5-month-old infants noticed a color, but not a luminance, change while tracking an occluded object. Our method should have numerous applications in the study of bottom-up effects on infant attention and visual working memory.     

Attentional fixation in panic disorder

According to Beck's (1988) clinical observations, patients with panic disorder describe a fixation on their distressing physical and psychological symptoms and an inability to access corrective information during panic attacks. The present study sought to evaluate empirically the notion that attentional fixation is characteristic of these patients. A subset of panic patients participating in 3 cognitive therapy clinical trials completed the Attentional Fixation Questionnaire (AFQ) at intake, during treatment and at termination. The AFQ had adequate internal consistency at all time intervals, and it correlated positively with measures of depression, anxiety and distorted cognitive content. At termination, the AFQ total score and nearly all single items decreased significantly, and patients who continued to meet diagnostic criteria for panic disorder scored higher on most items than patients who no longer met diagnostic criteria for panic disorder. These preliminary data suggest that attentional fixation is an important dimension of cognition relevant to panic disorder.     

Due process model of procedural justice in performance appraisal: promotion versus termination scenarios

In a laboratory study, 318 student participants (148 male, 169 female, and one who did not report sex; M age 25.0, SD = 6.0) in introductory organizational behavior classes responded to scenarios in which performance appraisal resulted in either employee promotion or termination. Each scenario had varying levels of three procedural justice criteria for performance appraisal. For both promotion and termination outcomes, analysis showed that, as the number of criteria increased, perceptions of procedural fairness increased. A comparison between the two outcomes showed that perceptions of fairness were significantly stronger for the promotion outcome than for termination.     

The Structure of Female Subgroups: An Exploration of Ambivalent Stereotypes

The present research concerns the stereotypes associated with subgroups of women. Previous researchers have considered the ambivalent nature of stereotypes, particularly along the dimensions of warmth and competence (Glick, Diebold, Bailey-Werner, & Zhu, Personality and Social Psychology Bulletin 23:1323–1334, 1997). In Study 1, we looked at the degree to which the superordinate social category of “women” is differentiated into distinct subgroups and whether warmth and competence are the primary dimensions of this differentiation. In Study 2, we assessed the degree to which businesswomen and homemakers are automatically associated with warmth and competence. Results showed that men and women differ in the valence associated with specific subgroups, and it is this valence, rather than stereotype content, that is automatically associated with these female subgroups.