Depression,self-focus,and social interaction

The accuracy of depressed and nondepressed subjects' perceptions of their own and a social interactional partner's performance was investigated. Twenty depressed and twenty nondepressed college students participated in dyadic interactions and then rated their own and their partner's social behavior. The interactions were also rated by objective coders. Depressed subjects were differentiated from nondepressed subjects on several measures by both the coders and the subjects. Depressed subjects' self-ratings were correlated with the coders' ratings more often than were the nondepressives' ratings, suggesting depressives provided more accurate self-observations. Contrary to prediction, depressives were also more accurate in judging their partner's behavior. Depressives experienced heightened levels of self-focused attention, but this attentional focus did not mediate the relationship between depression level and self-accuracy. Finally, an analysis of the verbal statements suggests that performance differences between depressives and nondepressives may be a function of the quantity, rather than the quality, of the verbal production.     

Cognitive components in risk perception: Natural versus manmade risks

In a questionnaire study 106 Norwegian students rated natural and manmade hazards according to risk magnitude and public versus private responsibility for risk management. Another group of 50 subjects judged 36 natural hazards on nine risk dimensions used in previous psychometric studies of ‘manmade risks’. When ratings on nine risk characteristics for natural hazards were factor analyzed a three-dimensional solution was found, with one active/passive dimension, one potency dimension, and one novelty dimension. This contrasts with the two-dimensional solution found for manmade hazards. Responsibility for risk management was found to be related to the type of risk in focus, and different risk characteristics seem to play different roles for manmade and natural hazards.     

Memory for two stimulus-response items in pigeons

Six pigeons served in a discrete-trial experiment on short-term memory. Combinations of three key positions and two ordinal positions, yielding six possible sequences of stimulus-response pairs, were used as lists of items. A retention interval separated list presentation from the test phase in which two (for Group 1) or three (for Group 2) keys were illuminated with either red or green light. A reinforcer was delivered if a subject pecked the key of the first item on a red trial and the key of the second item on a green trial. When the retention interval was lengthened from one to five or nine seconds, a systematic loss of stimulus control resulted. Lengthening the interval between items from one to eight seconds had a much smaller effect for the birds in Group 1, whereas a systematic loss of stimulus control was found in red trials for the birds in Group 2. The functional relations between choice accuracy and delay provided an empirical basis for analysis of what relations among temporal events can become discriminative stimuli.     

Evaluating performance in continuous experiments with feedback to subjects

Consider an experiment in which a subject guesses repeatedly at a randomly chosen target on a continuum. To guarantee a positive probability of success, the continuum is partitioned into a finite but large number of segments. The subject is given directional feedback. General guessing strategies are characterized, and an optimal strategy is identified. The hypothesis that the subject's performance can be explained by chance alone is of interest in such experiments. A test is developed based on comparing the subject's performance to expected performance using the optimal strategy. A skill-scoring procedure is developed for assessing a subject's performance in light of the strategy used, and a test based on skill-scoring is advanced.Research by the first author is supported in part by the Air Force Office of Scientific Research under grant AFOSR 77-3180.The authors wish to thank the referees for remarks that led to improvements in both content and clarity.     

Nonmetric maximum likelihood multidimensional scaling from directional rankings of similarities

A maximum likelihood estimation procedure is developed for multidimensional scaling when (dis)similarity measures are taken by ranking procedures such as the method of conditional rank orders or the method of triadic combinations. The central feature of these procedures may be termed directionality of ranking processes. That is, rank orderings are performed in a prescribed order by successive first choices. Those data have conventionally been analyzed by Shepard-Kruskal type of nonmetric multidimensional scaling procedures. We propose, as a more appropriate alternative, a maximum likelihood method specifically designed for this type of data. A broader perspective on the present approach is given, which encompasses a wide variety of experimental methods for collecting dissimilarity data including pair comparison methods (such as the method of tetrads) and the pick-M method of similarities. An example is given to illustrate various advantages of nonmetric maximum likelihood multidimensional scaling as a statistical method. At the moment the approach is limited to the case of one-mode two-way proximity data, but could be extended in a relatively straightforward way to two-mode two-way, two-mode three-way or even three-mode three-way data, under the assumption of such models as INDSCAL or the two or three-way unfolding models.The first author's work was supported partly by the Natural Sciences and Engineering Research Council of Canada, grant number A6394. Portions of this research were done while the first author was at Bell Laboratories. MAXSCAL-4.1, a program to perform the computations described in this paper can be obtained by writing to: Computing Information Service, Attention: Ms. Carole Scheiderman, Bell Laboratories, 600 Mountain Ave., Murray Hill, N.J. 07974. Thanks are due to Yukio Inukai, who generously let us use his stimuli in our experiment, and to Jim Ramsay for his helpful comments on an earlier draft of this paper. Confidence regions in Figures 2 and 3 were drawn by the program written by Jim Ramsay. We are also indebted to anonymous reviewers for their suggestions.     

Auditorily elicited EEG desynchronization and synchronization: A review of Christina M. Krause's doctoral thesis

The present paper reviews the doctoral dissertation of Christina M. Krause, in which auditorily elicited EEG desynchronization (ERD) and synchronization (ERS) was studied in five experiments. These experiments which were conducted by Krause and co-workers are the first in which the ERD-method was systematically applied to the analysis of the perception and processing of complex auditory stimuli. The main conclusion is that listening to sounds elicits ERS, whereas cognitive and/or memory processes elicit ERD.     

Reactions following the sudden death of a classmate

Findings from a study of adolescents grief reactions following the sudden death of a friend and a classmate are presented. The group (26 classmates) was followed up after one and nine months. Interviews and a questionnaire including the Imapact of Event Scale and the Hogan Grief Inventory were used. The general grief scores on the Hogan Grief Inventory indicated that the grief level was similar to that of adolescents who had lost siblings. The scores on the Impact of Event Scale showed a descline in distress level from 1 to 9 months. However, after 9 months about 1/5 of the students still scored above a clinical cut-off point indicating post-traumatic stress levels. Recommendations for improving help following such events are presented.