Abstract: Recent studies showed that humans, regardless of age, education, and culture, can extract the linear trend of a noisy scatterplot. Although this capacity looks sophisticated, it may simply reflect the extraction of the principal trend of the graph, as if the cloud of dots was processed as an oriented object. To test this idea, we trained Guinea baboons to associate arbitrary shapes with the increasing or decreasing trends of noiseless and noisy scatterplots, while varying the number of points, the noise level, and the regression slope. Many baboons successfully learned this conditional match-to-sample task, and their accuracy varied as a sigmoid function of the t-value of the regression, the same statistical index upon which humans also base their answers. The perceptual component of human graphics abilities seems thus to be based on the recycling of a phylogenetically older competence of the primate visual system for extracting the principal axes of visual displays.
Category: Comparative cognition
Age effect in expert cognitive flexibility in Guinea baboons (Papio papio)
Cognitive flexibility in non-human primates is traditionally measured with the conceptual set shifting task (CSST). In our laboratory, Guinea baboons (N = 24) were continuously tested with a CSST task during approximately 10 years. Our task involved the presentation of three stimuli on a touch screen all made from 3 possible colours and 3 shapes. The subjects had to touch the stimulus containing the stimulus dimension (e.g., green) that was constantly rewarded until the stimulus dimension changed. Analysis of perseveration responses, scores and response times collected during the last two years of testing (approximately 1.6 million trials) indicate (1) that the baboons have developed an “expert” form of cognitive flexibility and (2) that their performance was age-dependent, it was at a developing stage in juveniles, optimal in adults, declining in middle-aged, and strongly impaired in the oldest age group. A direct comparison with the data collected by Bonté , Flemming & Fagot (2011) on some of the same baboons and same task as in the current study indicates that (3) the performance of all age groups has improved after 10 years of training, even for the now old individuals. All these data validate the use of non-human primates as models of human cognitive flexibility and suggest that cognitive flexibility in humans has a long evolutionary history.
Are monkeys sensitive to informativeness: An experimental study with baboons (Papio papio)
Informativeness (defined as reduction of uncertainty) is central in human communication. In the present study, we investigate baboons’ sensitivity to informativeness by manipulating the informativity of a cue relative to a response display and by allowing participants to anticipate their answers or to wait for a revealed answer (with variable delays). Our hypotheses were that anticipations would increase with informativity, while response times to revealed trials would decrease with informativity. These predictions were verified in Experiment 1. In Experiments 2 and 3, we manipulated rewards (rewarding anticipation responses at 70% only) to see whether reward tracking alone could account for the results in Experiment 1. We observed that the link between anticipations and informativeness disappeared, but not the link between informativeness and decreased RTs for revealed trials. Additionally, in all three experiments, the number of correct answers in revealed trials with fast reaction times (< 250ms) increased with informativeness. We conclude that baboons are sensitive to informativeness as an ecologically sound means to tracking reward.