Minimum rank and minimum trace of covariance matrices

This paper considers some mathematical aspects of minimum trace factor analysis (MTFA). The uniqueness of an optimal point of MTFA is proved and necessary and sufficient conditions for a point x to be optimal are established. Finally, some results about the connection between MTFA and the classical minimum rank factor analysis will be presented.     

Life change and the sensation seeking motive

College undergraduates were administered the Life Experiences Survey, the Discomfort scale of the Psychological Screening Inventory, and the most recent version of the Sensation Seeking Scale. The findings did not replicate Smith et al.'s results concerning the role that sensation seeking plays in the relationship between negative life change and psychological distress. However, the data suggest that the sensation seeking motive is a causal variable that is predictive of recent life events that college students have experienced, and that future life-stress research should examine the occurence of controllable life events as a function of subjects' personality traits.     

Toward understanding sex differences in pay allocation: Agency,communion, and reward distribution behavior

This research examined the extent to which the personality characteristics of agency and communion are sex linked, and the extent to which differences in these orientations can account for sex differences in reward distribution behavior. In two studies, the agency and communion level of large samples of male and female undergraduates were assessed. As expected, males were more agentic and females were more communal. Moreover, when subjects who scored high or low on agency and high or low on communion were asked to allocate rewards between themselves and a co-worker, these personality differences were related to their allocation decisions. These results were used as the basis for discussing the role that sex-linked personality differences might play in distributive justice judgments.This article is an adaptation of a colloquium presentation at the meeting of the American Psychological Association, Los Angeles, August 1981. The research reported here was supported by NIMH grant MH29987-1, Goals, Motives, and Norms of Reward Distribution, and by NIMH Biomedical Research Support Grant from the College of Social Science, Michigan State University. The authors wish to thank Andrea Doughty for her valuable advice, and to gratefully acknowledge the help of Mark Teicher, Julie B. Klein, Sue Schnelbach, Pat Loepp, Barb Allen, Gavin Goodrich, Bob O'Hara, Kelly Bowen, Rod Hollenstein, Steve Schultz, and Mary Hurst.     

Is Implicit Personality Theory illusory? Armchair criticism versus replicated empirical research

The Tzeng and Tzeng (1982) criticisms of the assumptions underlying the Jackson, Chan, and Stricker (1979) study of Implicit Personality Theory fail to take account of the relevant empirical data. For example, the key contention of Tzeng and Tzeng–that the measures of judged and empirical trait-co-occurrence used by Jackson et al. were not comparable–is contradicted by replicated findings which establish that the two are substantially and consistently related, results for which Tzeng and Tzeng offer no alternative explanation. In short, Tzeng and Tzeng have not demonstrated that their criticisms have any real substance. Hence, none of the Jackson et al. results and conclusions, including those questioning the conditional probability index as a measure of empirical co-occurrence and those supporting the validity of Implicit Personality Theory, are affected or changed.     

Perceptual cues used in reproduction of inspired volume

Man is capable of reproducing an inspired lung volume (IV) with relative precision (±3 %–8 %). To investigate the importance of cues which may be used to determine IV, we performed two experiments. In each, the subject inspired a “standard” breath (from resting end~xpired lung volume) corresponding to 25%, 50%, or 75% of inspiratory capacity (IC) and then expired nearly completely. From this expired volume, the subject either tried to reproduce the tidal volume (i.e., volume of air inspired) of the first breath (volume reproduction) or to reproduce the previous end-inspired lung volume (position reproduction). The constant error indicated that subjects overestimated tidal volume by about 200 ml. Despite this overestimation, the variability of reproduction was less for volume reproduction than for position reproduction when IV was small. The JND for volume reproduction increased linearly with increasing IV, whereas the JND for position reproduction was similar at all IVs so that the Weber ratio decreased. These observations suggest that, in the perception of inspired volume, the sensation of end-inspired position is important when the inspired volume is large, but that subjects apparently rely on some other cue to reproduce small lung volumes accurately.     

Matching-to-sample and oddity-from-sample in goldfish.

Acquisition of three-alternative simultaneous matching-to-sample and oddity-from-sample was investigated. Five goldfish were trained on matching and five on oddity for a minimum of 70 days. Subsequently, six of the fish were trained for 70 days on the other task. Acquisition was similar for oddity and matching. Correct responding started at about chance level and slowly increased to about 75%, with some animals performing at levels of over 85%. Acquisition of oddity following matching and matching following oddity began below chance. Maximal level of performance on second-task oddity was comparable to that on first-task matching. By contrast, the maximal levels of performance when matching was the second task were not as high as that of the same subjects at the end of first-task oddity. All fish exhibited strong color preferences during matching acquisition but not during oddity acquisition. The data demonstrated that goldfish can acquire a discrimination in which the stimulus associated with reinforcement depends on the identity of a second stimulus.     

Oculomotor programming disturbances in the dementia syndrome

Three types of oculomotor programming disturbances are described in patients with the dementia syndrome. This report describes two of these abnormalities, poorly regulated gaze patterns and a programming type of gaze perseveration. All patients showed poorly regulated gaze patterns in contrast to the normal controls, whereas on the whole only the moderately affected patients showed the programming type of gaze perseveration. The third type of oculomotor programming disturbance is efferent perseveration of gaze (a hypokinetic, "staring" type of gaze pattern) and can be seen with severe dementia. The possible significance of these findings is discussed.     

Personality patterns of adolescent poor and good sleepers

To determine whether poor sleepers have a unique personality constellation significantly different from that of good sleepers, a sample of 162 emotionally disturbed adolescent poor sleepers was compared to a sample of 153 emotionally disturbed adolescent good sleepers on standardized personality instruments. Poor sleepers were found to have a high incidence of neurotic psychopathology with personality patterns characterized by depression, fearfulness, inhibition, anxiety, and rumination. In contrast, good sleepers showed quasi healthy and/or characterological patterns. While this study does not resolve cause and effect relationships, it does establish a highly significant relationship between neuroticism and sleep disturbance for adolescent boys and girls, and also demonstrates a similarity of personality dynamics and patterns between adult and adolescent samples of patients with sleep disturbances.