Visual nesting of stimuli affects rhesus monkeys’ (Macaca mulatta) quantity judgments in a bisection task

Nonhuman animals are highly proficient at judging relative quantities presented in a variety of formats, including visual, auditory, and even cross-modal formats. Performance typically is constrained by the ratio between sets, as would be expected under Weber’s law and as is described in the approximate number system (ANS) hypothesis. In most cases, tests are designed to avoid any perceptual confusion for animals regarding the stimulus sets, but despite this, animals show some of the perceptual biases that humans show based on organization of stimuli. Here, we demonstrate an additional perceptual bias that emerges from the illusion of nested sets. When arrays of circles were presented on a computer screen and were to be classified as larger than or smaller than an established central value, rhesus monkeys (Macaca mulatta) underestimated quantities when circles were nested within each other. This matched a previous report with adult humans (Chesney & Gelman, Attention, Perception, & Psychophysics 24:1104–1113, 2012), indicating that macaques, like humans, show the pattern of biased perception predicted by ANS estimation. Although some macaques overcame this perceptual bias, demonstrating that they could come to view nested stimuli as individual elements to be included in the estimates of quantity used for classifying arrays, the majority of the monkeys showed the bias of underestimating nested arrays throughout the experiment.     

Music and Language Skills of Children with Williams Syndrome

We examined music and language abilities in a group of children with Williams syndrome (WS, n = 19) and a comparison group of normal children (n = 19) equivalent for receptive vocabulary. Consistent with previous reports and the model of Nonverbal Learning Disabilities (Rourke, 1989), the children with WS scored better on verbal than performance measures of the WISC-III, and performance on simpler verbal tasks (e.g., receptive vocabulary) was superior to performance on more complex verbal tasks (e.g., comprehension). Performance on music tests was relatively good, being comparable to mental age based on receptive vocabulary and similar to that of the comparison group. Music and language abilities were moderately correlated for both groups of children. Compared to normal children, the WS group expressed greater liking of music and a greater range of emotional responses to music.     

Longitudinal study of perception of structured optic flow and random visual motion in infants using high‐density EEG

Electroencephalogram (EEG) was used in infants at 3–4 months and 11–12 months to longitudinally study brain electrical activity as the infants were exposed to structured forwards and reversed optic flow, and non‐structured random visual motion. Analyses of visual evoked potential (VEP) and temporal spectral evolution (TSE, time‐dependent amplitude changes) were performed on EEG data recorded with a 128‐channel sensor array. VEP results showed infants to significantly differentiate between the radial motion conditions, but only at 11–12 months where they showed shortest latency for forwards optic flow and longest latency for random visual motion. When the TSE results of the motion conditions were compared with those of a static non‐flow dot pattern, infants at 3–4 and 11–12 months both showed significant differences in induced activity. A decrease in amplitudes at 5–7 Hz was observed as desynchronized theta‐band activity at both 3–4 and 11–12 months, while an increase in amplitudes at 9–13 Hz was observed as synchronized alpha‐band activity only at 11–12 months. It was concluded that brain electrical activities related to visual motion perception change during the first year of life, and these changes can be observed both in the VEP and induced activities of EEG. With adequate neurobiological development and locomotor experience infants around 1 year of age rely, more so than when they were younger, on structured optic flow and show a more adult‐like specialization for motion where faster oscillating cell assemblies have fewer but more specialized neurons, resulting in improved visual motion perception.     

Medial prefrontal cortex supports source memory for self-referenced materials in young and older adults

Behavioral evidence suggests that young and older adults show a benefit in source memory accuracy when processing materials in reference to the self. In the young, activity within the medial prefrontal cortex supports this source memory benefit at study. In this investigation, we examined whether the same neural regions support this memory benefit in both age groups. Using fMRI, we scanned participants while they studied and retrieved pictures of objects paired with one of three scenes (source) under self-reference and other-reference conditions. At the time of study, half of the items were presented once and half twice, allowing us to match behavioral performance between the groups. Both groups showed equivalent source accuracy benefits for objects encoded self-referentially. Activity in the left dorsal medial prefrontal cortex supported subsequent source memory in both age groups for the self-referenced relative to the other-referenced items. At the time of test, source accuracy for both the self- and other-referenced items was supported by a network of regions including the precuneus in both age groups. At both study and test, little in the way of age differences emerged, suggesting that when they are matched on behavioral performance, young and older adults engage similar regions in support of source memory when processing materials in reference to the self; however, when we did not match performance, age differences in functional recruitment were prevalent. These results suggest that by capitalizing on preserved processes (self-referential encoding), older adults can show improvement in memory for source details that they would typically not remember well, relative to the young.     

The Influence of Clinical Experience and Assessment Method on the Evaluation of Child Behavior Change

This research examined how people’s ability to detect behavior change in simulated child targets is affected by their clinical experience and the assessment method they use. When using summary assessment methods that are widely employed in research and clinical practice, both inexperienced and experienced clinical staff detected changes in the overall frequency of targets’ aggressive behavior, but were not uniquely influenced by changes in targets’ reactions to social events. When using contextualized assessment methods that focused on conditional reactions, experienced staff showed greater sensitivity than novices to context-specific changes in targets’ aggressive and prosocial reactions to aversive events. Experienced staff also showed greater sensitivity to context-specific changes in their overall impressions of change, but only for aggression. The findings show how clinically experienced judges become more attuned to if…then… contingencies in children’s social behavior, and how summary assessment methods may hamper the detection of change processes.     

On individual differences in person perception: raters' personality traits relate to their psychopathy checklist-revised scoring tendencies

This study investigated raters' personality traits in relation to scores they assigned to offenders using the Psychopathy Checklist-Revised (PCL-R). A total of 22 participants, including graduate students and faculty members in clinical psychology programs, completed a PCL-R training session, independently scored four criminal offenders using the PCL-R, and completed a comprehensive measure of their own personality traits. A priori hypotheses specified that raters' personality traits, and their similarity to psychopathy characteristics, would relate to raters' PCL-R scoring tendencies. As hypothesized, some raters assigned consistently higher scores on the PCL-R than others, especially on PCL-R Facets 1 and 2. Also as hypothesized, raters' scoring tendencies related to their own personality traits (e.g., higher rater Agreeableness was associated with lower PCL-R Interpersonal facet scoring). Overall, findings underscore the need for future research to examine the role of evaluator characteristics on evaluation results and the need for clinical training to address evaluators' personality influences on their ostensibly objective evaluations.     

Self-disclosure in Latinos' intercultural and intracultural friendships and acquaintanceships: Links with collectivism, ethnic identity, and acculturation

Relationships among collectivism, ethnic identity, acculturation, and self-disclosure rates in Latinos' intercultural and intracultural friendships and acquaintanceships were examined. An online survey collected data from 59 international Latinos and 73 Latino American nationals. Results revealed that relationship type (friend vs. acquaintance) and relationship partner ethnicity (Latino vs. White American) had significant relationships with self-disclosure. Participants disclosed more personal information to friends than acquaintances, and they disclosed more to Latino than to White American persons. Higher collectivism was related to increased self-disclosure across all relationship types. Acculturation exerted a significant main effect only in the context of friendships but interacted significantly with ethnicity in both friendships and acquaintanceships. Ethnic identity did not display any significant direct or interaction effects.     

Suicide methods in singapore (2000-2004): types and associations

The choice of suicide methods varies between countries. Common methods used in Singapore between 2000 and 2004 were jumping (72.4%), hanging (16.6%), and poisoning (5.9%). Those who jumped were more likely to be young, single, female, and to have had a major mental illness. By comparison, those who hung themselves were more likely to be older (OR 2.68), Indian (OR 2.32), and to leave a suicide note (OR 1.53). Those who used poison were more likely to be married (OR 2.33), to be on antidepressants (OR 2.40), to have previously attempted suicide (OR 2.13), and to leave a letter (OR 2.30). The choice was determined by accessibility, acceptability, generational, gender, and racial factors.