Discrimination learning of rotated faces: a Markov analysis of coding and association processes]

30 subjects participated in a discrimination experiment learning face-letter associations under four rotation conditions (45 degrees, 90 degrees, 135 degrees, 180 degrees). Under each condition two thirds of the faces were presented twice, upright and rotated away from the vertical; the remaining faces were presented once, upright or rotated. Learning is described by a joint Markov model: For faces that are presented twice it assumes a separate association and encoding process (two-stage-model), for faces that are presented once it assumes an association process (all-or-none-model). The Markov model fits the data for all four rotation conditions. The angle of rotation does not affect learning for faces that are presented once. For faces that are presented twice it influences both the association and the encoding process. For the angles employed, the effect of rotation can be approximated linearly. The results suggest that the encoding of a rotated face differs increasingly from an upright face as a function of these angles of rotation. This confirms analogous conclusions from mental rotation experiments.     

Reflections upon charitable giving: A comparison of individuals from business, ‘manual’ and professional backgrounds

This paper compares three groups of individuals in their beliefs about charitable giving. Focusing upon their preferences for different kinds of needy recipients, the paper compares the views of 49 people from (a) business, (b) professional and (c) ‘manual’ backgrounds. Their justifications of need provided the basis for comparisons on the basic themes of emotional response to requests for funds, to local versus overseas aid and to the relative roles of charity and state provision. It is argued that distinctions between the groups show the need to examine specific beliefs as well as generally held ideologies about charity. In addition, a further comparison of the groups is used to argue that they exemplify differences in the actual form of the gift relationship. These differences in form show the importance of examining charitable giving within specific social contexts, as well as with reference to the various ways of raising funds.     

The epidemiology of suicide and attempted suicide

Since more than one century suicides have been registered in national statistics of death causes. They thus furnish one of the few parameters of psychiatrically relevant behaviour by means of which trends, cohort, age-group and period effects can be studied over longer periods. Since the second half of last century, the suicide rates for Swiss males--similar to those found in England and Wales--show a decrease in consecutive birth cohorts up to males born in the decade 1930-1940, and a continued decline in the total trend until about World War II. From then on the suicide rates of males in consecutive birth cohorts have been slowly increasing in the majority of European and North American countries--but not so in Sweden. Opposite to this, the predominantly low rates for females display little change. Further to the considerable differences between nations and the predominance of suicides committed by females in some Asian countries and Cuba, the changes indicate the significance of cultural and economic environmental factors. Typical period effects are mainly the result of changes in conception and conditions of life. In attempted suicide they proceed in a more sensitive and more rapid way and are about ten times higher. Such a period effect showing increases by about 300% in younger age-groups followed by a decline, attaining its peak about 1976, was ascertained in large cities of the Federal Republic of Germany. By the example of the effects of a television serial, the study of causal processes turning collective environmental factors into individual suicidal behaviour, proved that regularities are effective in learning by a process of modelling. Besides, the epidemiological data give essential hints how to treat suicidal behaviour.     

HIV infection: trauma and coping with trauma

The initial results of a German-Swedish research project demonstrate the at times active-resistant and at times passive-resigned approaches of AIDS patients toward their illness.     

Threshold tracking for assessment of long-term adaptation and sensitization in pain perception

To assess temporal variations in the perception of "phasic" heat pain stimuli a psychophysical tracking procedure was developed that enables repeated assessment of the pain threshold at short intervals. This "double-tracking" procedure produces two tracking curves simultaneously, one that approaches the pain threshold gradually from above, the other from below. The threshold for phasic heat pain was measured in 80 tracking trials with stimuli at temperatures near the pain threshold. Concurrently, the threshold for "tonic" heat pain was determined after every 20 tracking trials with a stimulus adjustment procedure. Eleven healthy subjects (age: 26.4 yr. +/- 6.0) participated in 2 sessions each. Phasic stimulation near the pain threshold did not produce any trends in either of the two threshold measures. Hence there was no long-term adaptation or sensitization. However, there were random variations (random walks) in the tracking curves, which we interpret as resulting from a stochastic relationship between stimulus and sensation. In agreement with other reports, discrimination seemed to be better at painful than at nonpainful temperatures.     

Decision time and movement time in depression: differential effects of practice before and after clinical improvement

Choice reaction time involves, at least two components of response latency, decision time and movement time. Studies of choice reaction time usually provide values of these two components averaged over a given number of trials. The aim of the present study of depressed subjects was to investigate changes across practice on Decision Time (DT) and Movement Time (MT) before and after clinical improvement. 19 depressed subjects were given two sessions of 50 trials each, one before treatment (Di) and one after recovery (Df). Decision time and movement time exhibited quite different patterns. Decision time significantly decreased with clinical improvement. No significant variation across trials was found, in either session. Movement time values varied across trials but the variations observed on Di and Df were significantly different, whereas before treatment latencies recorded at the end of the session were greater than those scored at the start, the contrary was observed after clinical recovery. No significant difference was found between values of movement time scored at the start of the two sessions.     

Telescoping is not time compression: A model

A model of telescoping is proposed that assumes no systematic errors in dating. Rather, the overestimation of recent occurrences of events is based on the combination of three factors: (1) Retention is greater for recent events; (2) errors in dating, though unbiased, increase linearly with the time since the dated event; and (3) intrusions often occur from events outside the period being asked about, but such intrusions do not come from events that have not yet occurred. In Experiment 1, we found that recall for colloquia fell markedly over a 2-year interval, the magnitude of errors in psychologists' dating of the colloquia increased at a rate of .4 days per day of delay, and the direction of the dating error was toward the middle of the interval. In Experiment 2, the model used the retention function and dating errors from the first study to predict the distribution of the actual dates of colloquia recalled as being within a 5-month period. In Experiment 3, the findings of the first study were replicated with colloquia given by, instead of for, the subjects.     

On the logic of causally necessary and sufficient conditions: Towards a theory of motive-explanations of human actions

Research carried out under the auspices of the Bank of Sweden. Tercentenary Foundation project RJ 86/183: Basic Concepts of Procedural Law in the Light of Present-Day Philosophy of Language and Linguistics.