Role of optical flow field asymmetry in the perception of heading during linear motion

During linear translation through a stationary environment, the pattern of optical flow generated on each retina is symmetrical when the head is aligned with the heading, but during lateral gaze the optical flow is asymmetric. We assessed whether human subjects could use the magnitude of this asymmetry to determine the direction of heading during passive translation through a 3-D environment. When allowed to move their heads in order to look in the direction of self-motion, subjects indicated their heading precisely and accurately. When the head was locked in alignment with the misaligned body, and gaze adjustments were not allowed, responses were quite precise, but showed a large bias which increased with increasing heading angle.     

The effect of serving as a model of self-control on subsequent resistance to deviation in children

The effect of having a child serve as a rule-following model for other children on the model's own subsequent rule-following was investigated in a resistance to deviation situation. First- and second-grade boys (age range 73 to 94 months) who were told they would serve as self-controlling models for others and who actually served in this capacity touched prohibited toys less than did boys who were not told they would serve as models. Boys told they were to serve as models but who were prevented from performing deviated at a level between the models and boys given no responsibility. Having children serve as rule-following models for others is suggested as an effective, non-punitive technique to increase their self-control.     

The extinction of within-compound flavor associations

Three experiments studied extinction of the associations which are formed between two flavors presented in a simultaneous compound. In Experiment 1 those associations were identified by a sensory preconditioning procedure in which the poisoning of one element of the compound led to the rejection of the other element. Separate presentation of either element between their joint occurence and the poisoning of one element sharply attenuated the rejection of the other element. That attenuation was interpreted in terms of the extinction of within-compound associations. Experiment 2 obtained similar results with an alternative extinction procedure in which the elements of the original compound were presented in other compounds. Experiment 3 obtained similar results when the existence of the within-compound associations was determined by an alternative assessment procedure in which one element of the compound was made more attractive by the induction of a specific hunger. These experiments suggest that within-compound associations can be extinguished when the elements are separately presented outside of the compound. Experiments 2 and 3 make less plausible an alternative interpretation of the effects of separate element presentation in terms of reduction of the novelty of the element. The findings may be taken as implying that the elements of a simultaneously presented compound are joined by a single symmetrical association which acts at various points during a sensory preconditioning experiment.     

Dr. John Rittmeister - neurologist and resistance fighter]

He was born in Hamburg on 21st August 1898 and beheaded in the Pl?tzensee penitentiary on 13th May 1943. Our colleague was a personality combining professional striving and political commitment into a dialectic unity. The more important biographic data are given, the co-operation in the Schulze-Boysen-Harnack organisation is described as far as it has become known, and Rittmeister's scientific works are mentioned.     

Components of the reaction time stroop-task

Summary The Stroop-phenomenon in its single-trial reaction-time version is analyzed in terms of Donders's additive-components approach. The complete set of component tasks forms an incomplete factorial design, and so, for resolving reaction times into their component parts multiple regression with dummy coding is used. The results of two independent experiments confirm the asymmetry of the incongruence effect in naming and reading, but contradict the redundancy hypothesis for congruent items. This finding is consistent with the linear approach which in Exp. 1 accounts for about 45%, and in Exp. 2 for about 30%, of total reaction-time variance. In a third experiment reaction times for the detection of colours/words and for congruence/incongruence are measured. These data confirm the estimation of both the basic constant and the assumed matching component in the first two experiments. Finally it is proposed that the data can be interpreted on the assumption that a matching process is responsible for the incongruence effect in naming. Reading interference does not normally occur because of faster processes or fewer stages in a parallel reading channel. Different strategies in coping with the Strooptask (reading vs inhibition) may explain differences between Exps. 1 and 2 and the absence of the redundancy effect from the data. The constraints on such assumptions in the context of reaction-time measurement are discussed.Parts of the data analyzed here were reported at the 18th Congress of Experimental Psychology in April 1976 at Bochum. K.P. Muthig, now at the Free University of Berlin, Dpt. 12, helped in the performance and analysis of the first and third experiments.I gratefully acknowledge the helpful comments of O. Neumann (Bochum) and of three anonymous reviewers of an earlier version of this paper.     

Cardiac autonomic reactivity and recovery in predicting carotid atherosclerosis: the cardiovascular risk in young Finns study.

The present study examined the association of cardiac autonomic task-induced reactivity and recovery to preclinical atherosclerosis. Thirty-three men and 33 women aged 24-39 years participated in the ongoing epidemiological Cardiovascular Risk in Young Finns study. The authors measured heart rate (HR), respiratory sinus arrhythmia (RSA), and preejection period (PEP) during the mental arithmetic and speech tasks in 1999. Carotid atherosclerosis was assessed by measuring the thickness of the common carotid artery intima-media complex (IMT) with ultrasound in 2001. Higher HR, RSA, and PEP reactivity were associated with lower IMT values even after adjusting for cardiovascular risk factors (lipid levels, obesity, and blood pressure). In addition, better HR recovery after the mental arithmetic task was associated with lower IMT values, and this association persisted after all adjustments. Thus, higher task-induced cardiac autonomic reactivity and better HR recovery were related to less preclinical atherosclerosis. The authors concluded that cardiac pattern of reactivity and quick recovery may be associated with better cardiovascular health, and therefore all reactivity occurring in challenging situations should not automatically be considered as potentially pathological.