Bayesian integration of spatial information

Spatial judgments and actions are often based on multiple cues. The authors review a multitude of phenomena on the integration of spatial cues in diverse species to consider how nearly optimally animals combine the cues. Under the banner of Bayesian perception, cues are sometimes combined and weighted in a near optimal fashion. In other instances when cues are combined, how optimal the integration is might be unclear. Only 1 cue may be relied on, or cues may seem to compete with one another. The authors attempt to bring some order to the diversity by taking into account the subjective discrepancy in the dictates of multiple cues. When cues are too discrepant, it may be best to rely on 1 cue source. When cues are not too discrepant, it may be advantageous to combine cues. Such a dual principle provides an extended Bayesian framework for understanding the functional reasons for the integration of spatial cues.     

Verisimilitude and Content

Popper’s original definition of verisimilitude in terms of comparisons of truth content and falsity content has known counter-examples. More complicated approaches have met with mixed success. This paper uses a new account of logical content to develop a definition of verisimilitude that is close to Popper’s original account. It is claimed that Popper’s mistake was to couch his account of truth and falsity content in terms of true and false consequences. Comparison to a similar approach by Schurz and Wiengartner show certain advantages of this new approach.     

Perceptual learning in monocular pattern masking: experiments and explanations by the twin summation gain control model of contrast processing

We investigated practice effects on contrast thresholds for target patterns. Results showed that practice decreased contrast thresholds when targets were presented on maskers. Thresholds tended to decrease more at the higher end of the masker contrast range. At least partially, learning transferred to stimuli of the untrained phase. We simulated changes in threshold versus contrast functions using a contrast-processing model and then fit the model to pre- and posttraining data. The simulation results and model fit suggest that learning in pattern masking can be accounted for by changes in nonlinear transducer functions for divisive inhibitory signals.     

Trustworthiness,friendships and self‐control: factors that contribute to young children's school adjustment

The aim of present study was to examine the relationship between young children's peer‐reported trustworthiness and their school adjustment. Two hundred and eleven (103 male and 108 female) children in the United Kingdom (mean age = 6 years 2 months) took part in this study. Measures of peer‐reported trustworthiness, child‐rated school adjustment, and teacher‐rated school adjustment were administered twice across a one‐year period. Also, children's number of friendships, peer acceptance, and self‐control were assessed at Time 2. Multisample path analyses were conducted separately by sex. For both samples there were direct longitudinal paths between peer‐reported trustworthiness and changes in teacher‐rated school adjustment. For boys, the longitudinal path between peer‐reported trustworthiness and changes in child‐rated loneliness was mediated by peer acceptance, and peer‐reported trustworthiness mediated the relationship between self‐control and teacher‐rated school adjustment. Sex differences in peer‐reported trustworthiness also emerged: girls were rated as more trustworthy by their peers than were boys. The findings support the hypothesis that young children's trustworthiness contributes to school adjustment, which is due in part to peer acceptance. Copyright © 2007 John Wiley & Sons, Ltd.     

The relationship between loneliness and interpersonal trust during middle childhood

The authors administered measures of loneliness, generalized trust beliefs in peers, and trust beliefs in specific familiar peers (i.e., opposite-gender peers, same-gender peers, close same-gender peers) to a sample of 63 children (33 girls, 30 boys) from 4th and 5th grades (M age = 10 years, 6 months). They assessed children's trusting behavior by engaging them in a Prisoner's Dilemma game (reciprocal trusting) and by evaluating teachers' ratings. The authors found that, across gender, loneliness was negatively correlated with each measure of trust beliefs and trusting behavior. As expected, the relationship between children's loneliness and trust, specifically trust beliefs in same-gender peers, was stronger for girls than for boys. In support of an additive risk model, the authors found low trust beliefs in same-gender peers and low reciprocal trusting behavior with peers each statistically contributed to loneliness in girls.     

Temporal and spatial factors reflecting performance improvement during learning three-ball cascade juggling

Beek and van Santvoord [Beek, P. J., & van Santvoord, A. A. M. (1992). Journal of Motor Behavior, 24, 85-94] proposed a three-stage model of learning to juggle based on group analyses of temporal measures. Here, we examined in detail how the temporal and spatial features of juggling evolved in eight individual participants progressing from the second to the third stage of learning. During the second stage, the dwell ratio, defined as the ratio of the time that the juggler holds a ball between catch and toss and the hand cycle time (HCT), was stable when it was about 0.83. The subjects with a dwell ratio near this value and controlled throws exhibited stable juggling, whereas the subjects with a dwell ratio of 0.80 or smaller exhibited unstable juggling. Compared to the former group, the latter group had a longer time from the throw of a ball to the arrival at its zenith (TZ), and a shorter time between the arrival of an airborne ball at its zenith and the subsequent throw (IZR). The latter group also exhibited larger variability in the dwell ratio and IZR. With practice, the subjects appropriated, on average, the duration of TZ and IZR to the dwell ratio and improved the ability to accurately throw balls by changing the motions of the limb segments involved. Although these changes helped to stabilize the performance during the second stage, the variability problem was not sufficiently resolved. Only two out of eight subjects passed on to the third stage by the last (10th) Session. They achieved small variability in IZR, dwell ratio, and flight paths of the ball while juggling with short HCTs and small dwell ratios. These results suggest that the reduction of variability in these variables was essential to pass on to the third stage.     

Neural evidence that vivid imagining can lead to false remembering

The imperfect nature of memory is highlighted by the regularity with which people fail to remember, or worse, remember something that never happened. We investigated the formation of a particular type of erroneous memory by monitoring brain activity using functional magnetic resonance imaging during the presentation of words and photos. Participants generated a visual image of a common object in response to each word. Subsequently, they sometimes claimed to have seen photos of specific objects they had imagined but not actually seen. In precuneus and inferior parietal regions of the cerebral cortex, activations in response to words were greater when participants subsequently claimed to have seen the corresponding object than when a false memory for that object was not subsequently produced. These findings indicate that brain activity reflecting the engagement of visual imagery can lead to falsely remembering something that was only imagined.