On the detection of a brief signal in the temporal center of a noise masker of varying duration

The threshold of a brief signal temporally centered in a noise masker first increases and then decreases as the masker is increased in duration. We discuss two explanations for this “over-shoot” phenomenon which consider the role of peaks of an exponentially weighted sliding integrator. One such explanation takes into account the finding that the steepness of the psychometric function continues to increase monotonically as its location moves first right and then left.     

中国儿童和青少年肤色色度的测定

采用色差测色计对548名3—17岁的中国儿童和青少年进行了脸颊部肤色色度测定,分别测出X、Y、Z三刺激值及x、y色度坐标。结果表明:中国儿童和青少年的平均肤色色度值为x=0,3828,y=0.3454;反射率为26.02%;主波长为590.2nm;刺激纯度(Pe)为27.4%。女性的反射率略高于男性,反射率有随着年龄增长而逐步下降的趋势。男性的肤色刺激纯度则略高于女性,饱和度随着年龄增长而有逐步增大的趋势。中国儿童和青少年的结果和成年人的比较,反射率较之成年人高3%左右,饱和度则低4%左右,主波长则较长约0.9nm。     

文昌鱼的光动反应

文昌鱼的中枢神经系统早在上个世纪就受到神经解剖学家们的注意。这是因为它代表着动物演化上的一个很典型的阶段。在这个阶段,动物身体的背侧开始有了神经管。这个神经管在外形上很象脊椎动物胚胎初期形成的神经管,其内部的神经组织也较简单。此外,正如神经管初成阶段的脊椎动物胚胎一样,文昌鱼还不具备发育的和特异     

A bayesian approach to confirmatory factor analysis

Confirmatory factor analysis is considered from a Bayesian viewpoint, in which prior information on parameter is incorporated in the analysis. An iterative algorithm is developed to obtain the Bayes estimates. A numerical example based on longitudinal data is presented. A simulation study is designed to compare the Bayesian approach with the maximum likelihood method.Computer facilities were provided by the Computer Services Center, The Chinese University of Hong Kong.     

Two logit models for external analysis of preferences

A logit vector model and a logit ideal point model are presented for external analysis of paired comparison preference judgments aggregated over a homogeneous group. The logit vector model is hierarchically nested within the logit ideal point model so that statistical tests are available to distinguish between these two models. Generalized least squares estimation procedures are developed to account for heteroscedastic sampling error variances and specification error variances. Two numerical illustrations deal with judgments concerning employee compensation plans and preferences for salt and sugar in the brine of canned green beans.     

FUNCTIONAL ASSESSMENT,CURRICULAR REVISION,AND SEVERE BEHAVIOR PROBLEMS

An adolescent female with multiple handicaps and a long history of severely disruptive behavior participated in a functional assessment linked directly to specific revisions in her school curriculum. During Phase 1, reversal designs were used to test hypotheses pertaining to antecedent and auricular influences on problem behavior. During Phase 2, a multiple baseline across afternoon and morning time periods demonstrated that the auricular revisions were effective in eliminating severely disruptive behavior and increasing on-task responding. Data also showed that inappropriate “psychotic” speech was reduced and appropriate social interactions were increased. Follow-up results showed that the changes were maintained throughout the school year. Questionnaire data provided social validation of the procedures and outcomes. The findings are discussed in relation to their implications for functional assessment, individualized curricula, and positive programming for students with disabilities and serious behavior problems.     

Rational Selective Exploitation Among Americans and Chinese: General Similarity, With One Surprise

A cross-cultural experiment tested predictions regarding reward allocation decisions among subjects in the United States and Taiwan. The experiment included five independent variables—two between-subject factors (American vs. Chinese; instrumental vs. unspecified vs. social-emotional allocator orientation) and three within-subject factors (high vs. low employee competence, social skill, and mobility). In general, Americans and Chinese distributed rewards quite similarly: In both cultures, allocators distributed greater rewards to employees who were more competent and possessed greater social skill. In both cultures, instrumental allocator orientation induced stronger tendencies to base allocations on competence; social-emotional allocator orientation induced stronger tendencies to base allocations on social skill. In both cultures, subjects engaged in competence-based "rational selective exploitation"—among highly competent employees, those with greater professional mobility received larger portions of the reward pool than did counterparts with constrained mobility. In both cultures, subjects also evidenced an unexpected social-skill-based rational selective exploitation—among employees with good social skill those with greater professional mobility received larger portions of the reward pool than did counterparts with constrained mobility. However, there were a number of interactions with culture that ran contrary to our a priori predictions: We hypothesized that Americans would exhibit greater individualism by focusing on competence in allocating outcomes, and that Chinese would exhibit greater collectivism by focusing on social skill. Although Americans did attend to employee competence more than Chinese, Americans also attended to employee social skill more than Chinese. These findings are discussed in terms of an expanded conceptualization of the nature of individualism and collectivism.     

Black Students' Reactions to Feedback Conveyed by White and Black Teachers1

The present investigation examined some processes mediating self-fulfilling prophecies among black students. Specifically, we hypothesized that feedback conveyed by black and white teachers would differentially influence black students' perceptions of how the teacher viewed their success/failure, effort, ability, luck and task difficulty. In addition, we hypothesized that negative feedback would affect perceptions of evaluations differently than positive feedback. Ninety black undergraduates participated in an experiment in which a black or white teacher (confederate) expressed one of five evaluative feedback responses to a student's score on an analogies test. The results provided partial support for the first hypothesis: black female students perceived white teachers as assessing their performance less positively: that is, they perceived them to underestimate their ability and the difficulty of the task. Negative feedback also led students to believe the teacher held an unfavorable but inaccurate impression of their ability and effort, and that the teacher underestimated the difficulty of the task. These findings suggest that black students—black females in particular—may assume that white teachers hold less favorable assessments of them than black teachers and all students may be sensitive to negative evaluations.