Abstract: Observational learning in chimpanzees and young children was investigated using an artificial fruit designed as an analog of natural foraging problems faced by primates. Each of 3 principal components could be removed in 2 alternative ways, demonstration of only one of which was watched by each subject. This permitted subsequent imitation by subjects to be distinguished from stimulus enhancement. Children aged 2-4 years evidenced imitation for 2 components, but also achieved demonstrated outcomes through their own techniques. Chimpanzees relied even more on their own techniques, but they did imitate elements of 1 component of the task. To our knowledge, this is the first experimental evidence of chimpanzee imitation in a functional task designed to simulate foraging behavior hypothesized to be transmitted culturally in the wild.

Abstract: Soiled bedding influences cleanliness and disease levels in dairy cows and there is no evidence of an inherent latrine behaviour in cattle. If cows were trained to use a concrete area of the housing system as a latrine, a cleaner bed could be maintained. Thirteen group-housed, 14-16-month-old Holstein-Friesian heifers, were clicker trained with heifer-rearing concentrate pellets as a reward. Training was carried out in four phases. (Phase 1) Association of feed reward with clicker, criterion: 34/40 correct responses. (Phase 2) Simple task (nose-butting a disc) to reinforce phase 1 association, criterion: 17/20 correct responses. (Phase 3) Association of eliminative behaviour with reward where criterion was four sessions with only one incorrect response: criteria for each heifer in phases 1-3 were set using binomial tests. (Phase 4) Shaping eliminative behaviour to occur on concrete. Possible responses were, eliminating on concrete (C) or straw (S), or moving from one substrate to another immediately before eliminating: C --> S, S --> C. Heifers were rewarded for the desired behaviours C and S --> C and ignored when S and C --> S occurred. If learning was achieved, C should increase as C --> S decreased and S --> C should increase as S decreased: tested with Spearman rank correlations. All heifers achieved criterion by day 4 of phase 1 (P = 0.001); day 1 of phase 2 (P = 0.001) and day 10 of phase 3 (P < 0.009). Responses changed throughout phase 3 beginning with (i) looking at the trainer whilst voiding then moving to trainer after the click, and later including (ii) moving to trainer immediately before- or (iii) during voiding. No relationship was found between S and S --> C (rs = -0.14; P = 0.63) or C and C --> S (rs = -0.33; P = 0.25). All group members eliminated more often on concrete (580) than on straw (141) but four heifers with consistently longer lying bouts also showed more C --> S before lying down (Mann-Whitney, P = 0.007). The present study is believed to be the first reported work to show that cattle can be trained to show an awareness of their own eliminative behaviour. This was not successfully shaped to latrine behaviour, however, and it is suggested that floor type may not have been a sufficiently salient cue. Voiding on straw occurred largely with response C --> S (0.73) and general behaviour suggested that this was strongly linked to lying patterns of individual heifers.

Abstract: This research examined exchange and value attribution in tufted capuchin monkeys ( Cebus apella). We presented subjects with opportunities to obtain various foods and a tool from an experimenter in exchange for the foods or tool in the subjects' possession. The times elapsed before the first chow biscuits were expelled and/or an exchange took place were recorded as the dependent measures. Laboratory chow biscuits, grapes, apples, and a metal bolt (a tool used to probe for syrup) were used as experimental stimuli. The subjects demonstrated the ability to recognize that exchanges could occur when an experimenter was present with a desirable food. Results indicate that subjects exhibited significant variation in their willingness to barter based upon the types of foods that were both in their possession and presented by the experimenter. Subjects more readily traded chow biscuits for fruit, and more readily traded apples for grapes than grapes for apples. During the exchange of tools and food, the subjects preferred the following in descending order when the probing apparatus was baited with sweet syrup: grapes, metal bolts, and chow biscuits. However when the apparatus was not baited, the values changed to the following in descending order: grapes, chow, and metal bolts. These results indicate that tufted capuchins recognize opportunities to exchange and engage in a simple barter system whereby low-valued foods are readily traded for more highly valued food. Furthermore, these capuchins demonstrate that their value for a tool changes depending upon its utility.

Abstract: Three experiments were conducted to test whether a pair of tufted capuchin monkeys (Cebus apella) could generalize their ability to exchange tokens and tool objects with a human experimenter to similar exchanges with a conspecific partner. Monkeys were tested in side-by-side enclosures, one enclosure containing a tool-use apparatus and one or more token(s), and the other enclosure containing one or more tool object(s). The monkeys willingly transferred tokens and tools to a conspecific with little practice. Following a small amount of training, we also found that the monkeys would select situation-appropriate tokens to exchange for specific tools, but did not select appropriate tool objects in response to another monkey's token transfers. Implications regarding role reversal are discussed.

Abstract: To investigate whether learning to discriminate between visual compound stimuli depends on decomposing them into constituting features, hens were first trained to discriminate four features (red, green, horizontal, vertical) from two dimensions (colour, line orientation). After acquisition, hens were trained with compound stimuli made up from these dimensions in two ways: a separable (line on a coloured background) stimulus and an integral one (coloured line). This compound training included a reversal of reinforcement of only one of the two dimensions (half-reversal). After having achieved the compound stimulus discrimination, a second dimensional training identical to the first was performed. Finally, in the second compound training the other dimension was reversed. Two major results were found: (1) an interaction between the dimension reversed and the type of compound stimulus: in compound training with colour reversal, separable compound stimuli were discriminated worse than integral compounds and vice versa in compound training with line orientation reversed. (2) Performance in the second compound training was worse than in the first one. The first result points to a similar mode of processing for separable and integral compounds, whereas the second result shows that the whole stimulus is psychologically superior to its constituting features. Experiment 2 repeated experiment 1 using line orientation stimuli of reversed line and background brightness. Nevertheless, the results were similar to experiment 1. Results are discussed in the framework of a configural exemplar theory of discrimination that assumes the representation of the whole stimulus situation combined with transfer based on a measure of overall similarity.