Ethnicity as a social context for the development of African-American adolescents

Does anticipated future racial discrimination undermine African-American adolescents' academic motivation and performance? Do face-to-face experiences with racial discrimination at school undermine African-American adolescents' academic functioning? Does African-American ethnic identity buffer these relations? This paper addresses these questions using two waves of data from a longitudinal study of an economically diverse sample of African-American adolescents living near Washington D.C. The data were collected at the beginning of the 7th grade and after the completion of the 8th grade. As expected, the experiences of day-to-day racial discrimination at school from one's teachers and peers predicted declines in grades, academic ability self-concepts, and academic task values. A strong, positive connection to one's ethnic group (our measure of ethnic identity) reduced the magnitude of the association of racial discrimination experiences with declines in both academic self-concepts and school achievement. Most youth responded to anticipated future discrimination with increased academic motivation.     

The chronometry of mental ability: An event-related potential analysis of an auditory oddball discrimination task

The relation between intelligence and speed of auditory discrimination was investigated during an auditory oddball task with backward masking. In target discrimination conditions that varied in the interval between the target and the masking stimuli and in the tonal frequency of the target and masking stimuli, higher ability participants (HA) displayed more accurate discriminations, faster response time, larger P300 amplitude, and shorter P300 and mismatch negativity (MMN) latency than lower ability participants (LA). Task difficulty effects demonstrated with variation in mask type indicate that the mask does not interfere with the detection of the deviant target stimulus, but rather that the target and mask are integrated as a single compound stimulus. The temporal effects suggest that the speed of accessing short-term memory is faster for HA than LA and, on the basis of the MMN latency, the effect is accomplished automatically, without focused attention. Moreover, the pattern of results obtained with these data support the view that the accuracy effects are determined by processing speed rather than discrimination ability. Comparator models that accommodate these effects are discussed.     

Titrating-delay matching-to-sample in the pigeon

The titrating-delay matching-to-sample (TDMTS) procedure offers researchers an additional behavioral task thought to capture some important features of remembering. In this procedure, the delay between sample offset and comparison onset adjusts as a function of the subject's performance. Specifically, correct matches increase the delay and incorrect matches decrease the delay, and steady-state titrated delays serve as the primary dependent measure. The present series of experiments investigated the effects of several procedural variables on performance in TDMTS procedures in an effort to elucidate better its features to allow for more precision in future use. Experiment 1 reports results from a parametric analysis of fixed-ratio response requirements on the sample key that indicated improved remembering in the form of higher daily titrated delay values as the requirement was increased. Experiment 2 investigated the extent to which the initial delay value in each session affected session-wide delay values. Results indicated that regardless of value of the initial delay, the subjects' performances adjusted the delay values in the direction of the known baseline delay-value levels. Experiment 3 manipulated the step size by which delay values were adjusted and the results indicated that larger step sizes increased both session-to-session variability and within-session range of titrated delay values, although the average values remained approximately the same. These results suggest that the TDMTS task serves as a promising procedure to study what many refer to as memory.     

Psychosocial Correlates of Medical Mistrust Among African American Men

The current study proposed and tested a conceptual model of medical mistrust in a sample of African American men (N = 216) recruited primarily from barbershops in the Midwest and Southeast regions of the United States. Potential psychosocial correlates were grouped into background factors, masculine role identity/socialization factors, recent healthcare experiences, recent socioenvironmental experiences (e.g., discrimination), and healthcare system outcome expectations (e.g., perceived racism in healthcare). Direct and mediated relationships were assessed. Results from the hierarchical regression analyses suggest that perceived racism in healthcare was the most powerful correlate of medical mistrust even after controlling for other factors. Direct effects were found for age, masculine role identity, recent patient–physician interaction quality, and discrimination experiences. Also, perceived racism in healthcare mediated the relationship between discrimination experiences and medical mistrust. These findings suggest that African American men’s mistrust of healthcare organizations is related to personal characteristics, previous negative social/healthcare experiences, and expectations of disparate treatment on the basis of race. These findings also imply that aspects of masculine role identity shape the tone of patient–physician interactions in ways that impede trust building processes.     

感知/亲历医疗暴力医生的内向和外向反应——基于浙江调研数据的分析

自行设计量表并收集浙江省36家医院671名医生有效问卷,使用方差分析方法探讨感知/亲历医疗暴力的医生群体的内向和外向反应特征。研究发现,三级医院医生亲历医疗暴力比重显著高于基层医院。高医疗暴力发生率产生削弱医生工作积极性和子女学医支持度,并提升其高风险患者识别意愿的内向反应(P<0.05)。亲历医疗暴力医生感知的医疗暴力发生率高于未亲历暴力医生,且有更消极的内向反应和对于医疗暴力法律环境及医疗卫生改革政策更负面的外向反应(P<0.05)。接受反医疗暴力培训、了解暴力防控流程医生的内外向反应较为正面。     

Cerebellar contributions to tactile perception in people with varying sensorimotor experiences: Examining the sensory acquisition hypothesis

The sensory acquisition hypothesis states that the sensory demand of a task is the most crucial factor in determining the level of cerebellar activity. The present study was conducted to examine whether the prediction of sensory demand holds when participants have different sensorimotor training experiences. Archery athletes and non-athletic control participants were asked to perform tactile discrimination tasks during fMRI scanning. In archery athletes, a pattern of reduced cerebellar activation accompanying higher sensory cortical activity was observed, whereas in non-athletic control participants the visual network was found to be in concert with extensive cerebellar activation. These findings are in accordance with the prediction that the cerebellum plays a supportive role for the cerebral cortex in sensory data acquisition.     

不合规任务与工作拖延行为的关系：自我损耗和主动性人格的作用

工作拖延行为是当今职场人士面临的普遍困扰之一。基于资源保存理论,本研究从不合规任务视角探究工作拖延行为的成因。对196位员工的两时点调查数据进行层次回归分析,结果表明：不合规任务正向预测员工工作拖延行为,自我损耗在不合规任务与工作拖延行为之间起着中介作用,主动性人格负向调节不合规任务与自我损耗的正向关系以及自我损耗的中介效应。以上结果对预防或降低工作拖延行为具有启发意义。     

Ontogeny of early event memory: II. Encoding and retrieval by 2- and 3-month-olds

The ability of 2-month-old infants to discriminate changes in a 5-object crib mobile following a retention interval of 24 hr was assessed using the mobile conjugate reinforcement paradigm. Infants were trained in 3 daily 15-min sessions to produce mobile movement by footkicking. Twenty-four hr later, independent groups received generalization tests with mobiles containing 1–5 novel objects substituted into their original training mobile. A control group was tested with the original training mobile. These findings were compared with findings of 2 previous studies involving identical procedures with 3-month-olds, reanalyzed for measures of individual performance over successive test minutes. Although, in absolute terms, 2-month-olds had a flat generalization gradient relative to 3-month-olds, when each infant's kick rate during the generalization test was expressed relative to that infant's kick rate before, and at the end of, training, it was found that the generalization gradients of 2- and 3-month-olds were indistinguishable. The relative response measures indicated a surprising degree of specificity by both age groups: Test mobiles containing more than 1 novel object did not cue retrieval, but test mobiles containing no more than 1 new object yielded perfect retention and complete generalization. These data indicate that infants as young as 2 months are capable of encoding and maintaining a representation of the specific details of their training context for at least 24 hr and, after that delay, can perform fine discriminations based on the discrepancy between their test context and that representation.     

Effects of morphine, clonidine, and intensity change on electric-shock discrimination.

The effects of morphine, clonidine, and changes in stimulus intensity were examined in squirrel monkeys responding on one of two levers following brief presentations of one of two electric-shock intensities (0.1 and 0.5 mA). Responses were designated as correct or incorrect depending on which shock intensity had been presented and which lever was pressed. Morphine (0.42 to 1.80 mg/kg) and clonidine (0.075 to 0.18 mg/kg) decreased percentage correct responding. Morphine and clonidine also increased response latency and the number of shock presentations that were not followed by responses. Changes in shock intensity also decreased percentage correct responding but had no effect on response latency or on the number of shock presentations not followed by responses.     

Attention in the pigeon: testing for excitatory and inhibitory control by the weak elements.

In two experiments, pigeons were trained on a successive discrimination between a color and either a compound S+ or a compound S- consisting of a form superimposed on a second color. Two stimulus control tests followed discrimination training: an attention test in which the form and colors used in training were presented singly and in combination, and then a resistance-to-reinforcement test using the form element of S+ or S- and a novel form. In the attention test, the birds trained with a compound S+ responded most to the S+ compound, less to the S+ color alone, and still less to the S+ form on a dark key. Few responses were made to the negative stimulus, either alone or with the S+ form added. The birds trained with a compound S- pecked most at the S+ color and to a compound of the S+ color with the S- form added. The resistance-to-reinforcement test showed that the birds trained with a compound S+ responded more to the S+ form than to a novel form. However, the birds trained with a compound S- did not reliably respond more to a novel form than to the S- form. These findings suggested that the form element of a compound S+ gains some excitatory control, but the form element of a compound S- does not acquire inhibitory control. The possibility existed that low levels of responding to the S+ form on a dark background in the first experiment were due to use of a darkened key to separate S+ and S- periods during discrimination training. However, the essential findings were the same in a second experiment in which darkening of the chamber separated S+ and S- periods.