The formation of reference systems in visual motion perception

Summary In visual perception complex movements are usually split up into components — e.g., in such a way that a moving reference system is applied, to which partial movements can be related. In the following experiment a perceptual vector analysis of this kind was investigated. It was shown that 1) a radial translatory movement (relative component) can be isolated perceptually from a rotatory movement (global component) and that 2) the precision of this decomposition of the complex movement is dependent on the strength at which the rotating reference system is anchored perceptually.The authors wish to thank M. Rauterberg for collecting the experimental data     

A machine-level software program for the generation of aversive conditioning schedules using the KIM-1 microprocessor

A microprocessor system can be used both to control aversive conditioning (classical, signaled and Sidman avoidance, and conflict) experiments and to acquire behavioral data in multiple subjects at a fraction of the cost of solid state systems. The software described in this paper can be used to program tones and shocks and count responses, independently, in up to 12 animals simultaneously.     

A three-component analysis of the modality effect in single-trial free recall

Johann-Wolfgang-Goethe Unversität, Frankfurt am Main, West-Germany In single-trial free recall a superiority of acoustical over visual presentation has been observed in the recency part of the serial position curve. The rehearsal-buffer model by Atkinson and Shiffrin (1968) was modified to distinguish between three different explanations that are discussed in the literature. The application of the model allowed some of the parameters to vary across modes of presentation while other parameters were held constant. A model assuming either a precategorical acoustical storage or additional processing for visually presented items gives a better account of the results than does a model derived from a two-store hypothesis.     

Balancing the ledger: An application of Nagy's theories to the study of continuity and change among generations

This study uses an interpretive interview method to examine the micro-processes of generational continuity and change among a group of social activists. Boszormenyi-Nagy's theory of responsibility between generations, alternative models outside the family, and choice are used to explain the instances of change. Implications for research and practice are addressed.     

Suicidal Behaviors in Surviving Monozygotic and Dizygotic Co‐Twins: Is the Nature of the Co‐Twin's Cause of Death a Factor?

Genetically informative samples can address hereditary and experiential influences on suicide‐related behaviors. The frequency of suicide‐related behaviors was compared in twins from two survivor groups: (1) those whose co‐twins' deaths were suicides (monozygotic [MZ]: n = 47; dizygotic [DZ]: n = 31), and (2) those whose co‐twins' deaths were nonsuicides (MZ: n = 347; DZ: n = 170). The frequency of suicide attempts among suicide survivors was significantly higher in MZ than DZ twins, while the frequency of suicide attempts among nonsuicide twin survivors did not differ between MZ and DZ twins. Twin concordance for suicide attempts more likely reflects a genetic predisposition than a behavioral reaction to the loss.