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Human analog tests of object permanence were administered to various breeds of adult dogs (Canis familiaris). Experiment 1 showed that the performance of terriers, sporting, and working dogs did not differ. Dogs succeeded in solving invisible displacement problems, but performance was lower than in visible displacement tests. Familiarity with the task had(More)
This article addresses the issue of the communication of emotion by actors. In Study 1, the facial behavior of 6 actors portraying emotions as felt or unfelt were analyzed with the Facial Action Coding System. Results indicated that the portrayals of felt emotions were closer to the expression of genuine emotion than the portrayals of unfelt emotions for 3(More)
Visual accommodation and object permanence tests were administered to 70 puppies (Canis familiaris), aged 4 weeks to 9 months. The results showed that understanding of visible displacement problems emerged at the 5th weeks and developed rapidly until the 8th week. Although the search behaviors of older puppies were more flexible, no further significant(More)
Four experiments were performed to identify the spatial information that cats used to encode the position of an object they saw move and disappear. In Experiment 1 and 2, several sources of allocentric spatial information were manipulated. Results indicated that the cats used none of these sources and instead relied primarily on their own spatial(More)
The aim of the experiment was to study the relation between accuracy of judgment of facial expressions of emotions and time for judgment. The results for 34 college students confirmed previous data showing high performance in identification of all emotions, although there were some important differences between emotions. Also, times for judgment were longer(More)
This study explored the duration of cats' working memory for hidden objects. Twenty-four cats were equally divided into four groups, which differed according to the type of visual cues displayed on and/or around the hiding boxes. During eight sessions, the four groups of cats were trained to locate a desirable object hidden behind one of the four boxes(More)
Pregnant C57BL/6 mice were chronically treated with 0, 4, 6, or 8 ppm of methylmercury chloride (MeHg) in drinking water during fetal and early postnatal development. Four behavioral functions were analyzed in female and male offspring between the age of 6 and 12 weeks: motor coordination learning on the rotarod; training to spatial alternation in the(More)
Phencyclidine (PCP) treatment induces social withdrawal in the rat model of schizophrenia but little is known about the qualitative adequacy of behaviors displayed during interactions. Affiliative, avoidance, and aggressive behaviors were examined in rats 20 h after the 1st, the 8th, and the 15th injection of 10 mg/kg of PCP or of a saline vehicle. PCP(More)
In macaque monkeys, aspiration but not excitotoxic lesions of the medial temporal lobe limbic structures, the amygdala and hippocampus, produce a severe impairment in visual recognition memory. Furthermore, certain ventromedial cortical regions, namely the rhinal (i.e., entorhinal and perirhinal) cortex, are now known to be critical for visual recognition(More)
The cognitive effects of subchronic phencyclidine administration in rats are still unsettled in the literature. Possible causes of discrepancies are different drug treatment regimens and task parameters. The current experiment tested whether variations in procedures of the delayed T-maze alternation task result in performance differences following identical(More)