The satisfaction and stress of being a market maven: A social network perspective

Compared with the average consumer, market mavens possess a unique set of characteristics including a greater depth of knowledge of the marketplace and its products, as well as a strong social network. Based on a field study of an emerging social network of Canadian undergraduate students (N = 71), we examine the level of satisfaction and stress that market mavens experience as a result of their network participation. First, market mavens (versus non‐mavens) are more satisfied with their network if they occupy central network positions. Simultaneously, however, mavens incur more stress if they occupy these central positions. Further, market mavens have a lower rate of network growth and build a more a selective network of like‐minded others over time. This suggests that market mavens seek to interact with other market mavens more so than with non‐mavens about product‐related and market‐related information. Together, we provide new insights into the personal outcomes of market mavens' network positions and their networking behavior. Copyright © 2015 John Wiley & Sons, Ltd.     

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.     

Aging and individual differences in rapid two-choice decisions

The effects of aging on performance were examined in signal detection, letter discrimination, brightness discrimination, and recognition memory, with each subject tested on all four tasks. Ratcliff’s (1978) diffusion model was fit to the data for each subject for each task, and it provided a good account of accuracy and the distributions of correct and error response times. The model’s analysis of the components of processing showed that aging had three main effects: The nondecision components of processing were slower and the decision criteria were more conservative for 60- to 74-year-old and 75- to 85-year-old subjects than for college students, but the quality of the evidence on which decisions were based was as good for the older subjects as for college students on some of the tasks. Individual differences among subjects in components of processing tended to be preserved across the tasks, as was shown by strong correlations across the tasks in the parameters of the model that represent the components of processing. For example, if the evidence on which a subject’s decisions were based was good in one task, it tended to be good in all four tasks.     

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.