Eye contact and vocal responsiveness in squirrel monkey infants and their caregivers

Seventeen newborn squirrel monkeys, housed socially with their mothers and other adult females, were observed during their first 10 days of life. As early as day 1, infants began responding, vocally as well as by eye contact, to vocalizations and gaze directed to them by mothers and allomothers (aunts). Visual contact appeared always to be initiated by the adults. Infants spent less than 4% of awake time in eye contact with adults, but most infant-directed vocalizing occurred during these episodes, when both mothers and allomothers greatly increased their rate of calling. Infants were more likely to respond to vocalizations directed to them while in eye contact; 72% of infants' responsive vocalizing occurred then. These data are compared to those for human mothers and infants, where eye contact has also been shown to stimulate vocal exchange. A functional explanation of the involvement of allomothers, based on the infant's clinging position, is discussed.     

Micro-position effects in visual short term memory

Short-term memory for visually presented eight-digit numbers was tested in a forced recall, read-and-dial task. The digits were presented non-grouped or grouped in 2+2+2+2 or 2+3+3 digit formats. Spatial grouping enhanced memory performance and produced local discontinuities in the serial position curves related to grouping format. These micro-position effects are explained in terms of the relative spatial distinctiveness of individual digits.     

换位棋问题规则的表征与解题正确率间关系的研究

本研究通过对被试求解换位棋过程的记录与分析,重点研究了问题表征在换位棋求解过程中的作用。实验结果表明：（1）正确表征问题规则是解题的必要前提.对问题规则信息的误解和遗漏,是影响解题正确率的重要因素。其中对非隐含问题规则的错误表征也占全部错误表征的很大比率。（2）“关键结构”的发现是解决换位棋的必要条件,对问题规则的错误表征影响“关键结构”的发现.（3）前置问题的解决经验对目标问题的正确表征无显著的影响作用。     

自我报告测量中项目前后关系效应的研究

本文指出了自我报告法中项目前后关系效应的普遍存在性及其危害性。讨论了用信息加工的观点对项目前后关系效应所作的认知上的理论解释,以及测量工具中促使产生这种项目前后关系效应的关键特征。同时也讨论了项目序列位置的作用。     

非常短暂呈现时间过程中的系列位置效应

以中国汉字为材料,考察不同系列项目呈现时间范式中的系列位置效应,并验证Ｎｅａｔｈ提出的区辨理论公式对中文材料的适用性。结果表明,在非常短暂的系列项目呈现时间,并且项目之间的时间间隔按不同中数比率变化的实验条件中．均存在明显的系列位置效应;但是Ｎｅａｔｈ提出的区辨理论的公式,不能预测本实验结果,从另一个方面说明汉字不同于拼音文字的特点。     

Component analysis in cross-sectional and longitudinal data

An extension of component analysis to longitudinal or cross-sectional data is presented. In this method, components are derived under the restriction of invariant and/or stationary compositing weights. Optimal compositing weights are found numerically. The method can be generalized to allow differential weighting of the observed variables in deriving the component solution. Some choices of weightings are discussed. An illustration of the method using real data is presented.Preparation of this article was supported in part by PSC-CUNY Grant #665365 to Roger E. Millsap and by National Institute of Aging Grant NIA-AG03164-03 to William Meredith. The authors thank John Nesselroade for permitting the use of the data presented in the article.     

Reinforcement probability and ordinal position of response in fixed-interval schedules

Four rats pressed levers and received food pellets under fixed-interval reinforcement schedules of 20, 60, and 180 seconds. The number of responses in each interval was recorded. From these data, the probability of reinforcement was determined as a function of response count. These functions were generally increasing. This finding is consistent with previous suggestions that increasing response rates within fixed intervals may be a function of response count in addition to or instead of elapsed or remaining time.     

A new estimator of the uniqueness in factor analysis

A closed form estimator of the uniqueness (unique variance) in factor analysis is proposed. It has analytically desirable properties—consistency, asymptotic normality and scale invariance. The estimation procedure is given through the application to the two sets of Emmett's data and Holzinger and Swineford's data. The new estimator is shown to lead to values rather close to the maximum likelihood estimator.     

The effects of interval duration on temporal tracking and alternation learning

On cyclic-interval reinforcement schedules, animals typically show a postreinforcement pause that is a function of the immediately preceding time interval (temporal tracking). Animals, however, do not track single-alternation schedules-when two different intervals are presented in strict alternation on successive trials. In this experiment, pigeons were first trained with a cyclic schedule consisting of alternating blocks of 12 short intervals (5 s or 30 s) and 12 long intervals (180 s), followed by three different single-alternation interval schedules: (a) 30 s and 180 s, (b) 5 s and 180 s, and (c) 5 s and 30 s. Pigeons tracked both schedules with alternating blocks of 12 intervals. With the single-alternation schedules, when the short interval duration was 5 s, regardless of the duration of the longer interval, pigeons learned the alternation pattern, and their pause anticipated the upcoming interval. When the shorter interval was 30 s, even when the ratio of short to long intervals was kept at 6:1, pigeons did not initially show anticipatory pausing-a violation of the principle of timescale invariance.