veille

Searching for nothing: placing zero on the temporal continuum

Abstract

Generalization allows responses acquired in one situation to be transferred to similar situations. For temporal stimuli, a discontinuity has been found between zero and non-zero durations: responses in trials with no (or 0-s) stimuli and in trials with very short stimuli differ more than what would be expected by generalization. This discontinuity may happen because 0-s durations do not belong to the same continuum as non-zero durations. Alternatively, the discontinuity may be due to generalization decrement effects: a 0-s stimulus differs from a short stimulus not only in duration, but also in its presence, thus leading to greater differences in performance. Aiming to reduce differences between trials with and without a stimulus, we used two procedures to test whether a potential reduction in generalization decrement would bring performance following zero and non-zero durations closer. In both procedures, there was a reduction in the discontinuity between 0-s and short durations, supporting the hypothesis that 0-s durations are integrated in the temporal subjective continuum.

veille

Unique spatial behavior of the Japanese serow (Capricornis crispus) in the open mountains of Mt. Fuji

Abstract

The Japanese serow (Capricornis crispus) exhibits spatial behavior adapted to forest habitats with relatively stable food supply and climatic conditions, such as sedentary habits, small home ranges, and little seasonal variation in habitat selection. However, investigations have not previously been conducted in open mountainous habitats with high seasonal variability. Therefore, I examined spatial behavior of the Japanese serow in an open mountainous region of Mt. Fuji, central Japan, based on GPS location data. These mountain-dwelling serows had much larger annual home ranges (female: 316.5 ha, male: 373.1 ha) compared with forest-dwelling populations. Spring and summer home range sizes were the largest, and winter home range size was the smallest, ranging from 20.3%–56.1% of maximum. Limited forage and harsh climatic conditions in winter seemed to drive such energy-minimizing behavioral strategies. Selection of vegetation types and elevation varied seasonally, likely because of changes in forage availability and climate conditions. These spatial behaviors in mountain-dwelling serows resemble those of several related mountain ungulates, implying that these behaviors are adaptations to highly seasonal open mountainous habitats. My findings suggest that the main factors affecting spatial behavior are habitat characteristics, such as climate, forage abundance, and seasonality. These findings provide support for an ecological pattern in ungulate spatial behavior whereby closed habitats promote small and stable home ranges, whereas open habitats promote large and seasonally fluctuating home ranges.