Abstract: The common practice of ranking a group of animals in the closest possible order to a linear dominance hierarchy assumes that dominance among those animals is generally transitive. In fact, analysis of groups in which dominance relationships are random shows that this method has a surprisingly high probability of producing an apparently linear or near-linear hierarchy by chance. As such, the existence of transitive dominance should be tested before it is used in ranking. A suitable statistical test is described here. Chance may also contribute to the linear appearance of hierarchies based on other factors.

Abstract: Hearst and Jenkins proposed in 1974 that elicited responding accounts for the feature-positive effect. To test this position, pigeons were exposed to a feature-positive or feature-negative discrimination between successively presented displays--one consisted of a red and a green response key and the other consisted of two green response keys. There were four main conditions: 5-5 (5-sec trials, 5-sec intertrial intervals), 5-30, 30-30, and 30-180. Conditions 5-30 and 30-180 should produce the largest amount of elicited responding, and therefore the largest feature-positive effects. A response-independent bird was yoked to each response-dependent bird to allow direct assessment of the amount of elicited responding generated by each condition. Contrary to the predictions by Hearst and Jenkins's theory, response-dependent birds showed large feature-positive effects in each condition. The largest feature-positive effect was obtained in condition 5-5. Response-independent birds produced similar results, but manifested low response rates.

Abstract: Five cases with so-called “Dermato- und Enterozoenwahn” are reported, and the following themes are analysed from the “multidimensional” point of view: 1) process to build the shape of the intruder which is bothering the patients, 2) behavior against the intruding small animal and attitude towards the therapeutist; their characteristic manner to make complaints, 3) premorbid personality and 4) physical findings. In regard to one of the formation types of this disease, we have postulated through the neuropsychological analysis of case 5 (somatoparaphrenic patient) that patients of the typical cases 1, 2 and 3 suffer from a special kind of agnosia (perturbation of recognition; disturbance of aperception) in which they take their abnormal body sensations for causing by the small imaginary animals. Our cases showed the importance of a premorbid personality and present life-situations in combination with physical dissolution taking part in the pathoplastic process of this particular disease.