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Adults of Microtus agrestis, M. arvalis and Clethrionomys glareolus were offered the opportunity to explore an experimental alley, a section of which contained male odours of either of the three species. Neither of the species explored one of the sections of the alley more than the other one if the choice was between a section with conspecific odour and a non-odorous section. Both M. agrestis and C. glareolus preferred the non-odorous section when the choice was between M. arvalis odour and a non-odorous section. If an encounter with another vole was arranged in the alley before the opportunity was given to explore the partly odorous alley, then some additional avoiding responses to odours were assessed. M. agrestis now avoided both alien male conspecific odours and its own home cage odours. M. arvalis now avoided both the odours of C. glareolus and M. agrestis. Other responses to odours were not affected by an encounter. An encounter per se did not lead a vole to avoid the place where it had taken place. The survival value and the possible role of the avoiding tendencies in intra- and interspecific competition for space are discussed. Probably, odour avoidance is only an additional way in the communication between voles.

The aim was to find empirically justified criteria for attention and activity. Patients with various disorders and controls were observed during psychiatric examinations. Measures of attention increased with age, were lower in patients than controls, were correlated with each other and related to the quality of task performance. Activity measures decreased with age, were higher in patients, were correlated among each other and concerned motility as well as talking initiatives. Criteria from other studies and the DSM-III were critically examined. Inattention was not associated with hyperactivity, except in mentally retarded children. Inattention was common in many diagnostic categories.

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