Abstract: In this research, we asked whether 2 chimpanzee (Pan troglodytes) subjects could reliably sum across pairs of quantities to select the greater total. Subjects were allowed to choose between two trays of chocolates. Each tray contained two food wells. To select the tray containing the greater number of chocolates, it was necessary to sum the contents of the food wells on each tray. In experiments where food wells contained from zero to four chocolates, the chimpanzees chose the greater value of the summed wells on more than 90% of the trials. In the final experiment, the maximum number of chocolates assigned to a food well was increased to five. Choice of the tray containing the greater sum still remained above 90%. In all experiments, subjects reliably chose the greater sum, even though on many trials a food well on the “incorrect” tray held more chocolates than either single well on the “correct” tray. It was concluded that without any known ability to count, these chimpanzees used some process of summation to combine spatially separated quantities. Speculation regarding the basis for summation includes consideration of perceptual fusion of pairs of quantities and subitization.

Abstract: Seventeen African dwarf goats (adult females) were trained on oddity tasks using an automated learning device. One odd stimulus and three identical nonodd stimuli were presented on a screen divided into four sectors; the sector for the odd stimulus was varied pseudorandomly. Responses to the odd stimulus were deemed to be correct and were reinforced with food. In phase 1, the goats were trained on eight stimulus configurations. From trial to trial the odd discriminandum was either a + symbol or the letter S, and the nonodd discriminandum was the symbol not used as the odd one. In phase 2, the animals were similarly trained using an unfilled triangle or a filled (i.e., solid black) circle. In phase 3, three new discriminanda were used, an unfilled, small circle with radiating lines, an unfilled heart-shaped symbol, and an unfilled oval; which of the three discriminanda was odd and nonodd was varied from trial to trial. Following these training phases, a transfer test was given, which involved 24 new discriminanda sets. These were presented twice for a total of 48 transfer test trials. Results early in training showed approximately 25% correct, which might be expected by chance in a four-choice task. After 500-2,000 trials, results improved to approximately 40-44% correct. The best-performing subject reached 60-80% correct during training. On the transfer test, this subject had 47.9% correct and that significantly exceeded 25% expected by chance. This finding suggests that some exceptional individuals of African dwarf goats are capable of learning the oddity concept.

Abstract: Investigation of tool use is an effective way to determine cognitive abilities of animals. This approach raises hypotheses, which delineate limits of animal's competence in understanding of objects properties and interrelations and the influence of individual and social experience on their behaviour. On the basis of brief review of different models of manipulation with objects and tools manufacturing (detaching, subtracting and reshaping) by various animals (from elephants to ants) in natural conditions the experimental data concerning tool usage was considered. Tool behaviour of anumals could be observed rarely and its distribution among different taxons is rather odd. Recent studies have revealed that some species (for instance, bonobos and tamarins) which didn't manipulate tools in wild life appears to be an advanced tool users and even manufacturers in laboratory. Experimental studies of animals tool use include investigation of their ability to use objects physical properties, to categorize objects involved in tool activity by its functional properties, to take forces affecting objects into account, as well as their capacity of planning their actions. The crucial question is whether animals can abstract general principles of relations between objects regardless of the exact circumstances, or they develop specific associations between concerete things and situations. Effectiveness of laboratory methods is estimated in the review basing on comparative studies of tool behaviour, such as “support problem”, “stick problem”, “tube- and tube-trap problem”, and “reserve tube problem”. Levels of social learning, the role of imprinting, and species-specific predisposition to formation of specific domains are discussed. Experimental investigation of tool use allows estimation of the individuals' intelligence in populations. A hypothesis suggesting that strong predisposition to formation of specific associations can serve as a driving force and at the same time as obstacle to animals' activity is discussed. In several “technically gifted” species (such as woodpecker finches, New Caledonian crows, and chimpanzees) tool use seems to be guided by a rapid process of trial and error learning. Individuals that are predisposed to learn specific connections do this too quickly and thus become enslaved by stereotypic solutions of raising problems.

Abstract: Dogs are more skilful than a host of other species at tasks which require they respond to human communicative gestures in order to locate hidden food. Four basic interpretations for this proficiency surface from distilling the research findings. One possibility is that dogs simply have more opportunity than other species to learn to be responsive to human social cues. A different analysis suggests that the domestication process provided an opening for dogs to apply general cognitive problem-solving skills to a novel social niche. Some researchers go beyond this account and propose that dogs' co-evolution with humans equipped them with a theory of mind for social exchanges. Finally, a more prudent approach suggests that sensitivity to the behaviours of both humans and conspecifics would be particularly advantageous for a social scavenger like the dog. A predisposition to attend to human actions allows for rapid early learning of the association between gestures and the availability of food.