The benefit of symbols: monkeys show linear, human-like, accuracy when using symbols to represent scalar value

When humans and animals estimate numbers of items, their error rate is proportional to the number. To date, however, only humans show the capacity to represent large numbers symbolically, which endows them with increased precision, especially for large numbers, and with tools for manipulating numbers. This ability depends critically on our capacity to acquire and represent explicit symbols. Here we show that when rhesus monkeys are trained to use an explicit symbol system, they too show more precise, and linear, scaling than they do using a one-to-one corresponding numerosity representation. We also found that when taught two different types of representations for reward amount, the monkeys systematically undervalued the less precise representation. The results indicate that monkeys, like humans, can learn alternative mechanisms for representing a single value scale and that performance variability and relative value depend on the distinguishability of each representation

Towards a resolution of some outstanding issues in transitive research: an empirical test on middle childhood

Transitive Inference (deduce B > D from B > C and C > D) can help us to understand other areas of sociocognitive development. Across three experiments, learning, memory, and the validity of two transitive paradigms were investigated. In Experiment 1 (N = 121), 7-year-olds completed a three-term nontraining task or a five-term task requiring extensive-training. Performance was superior on the three-term task. Experiment 2 presented 5–10-year-olds with a new five-term task, increasing learning opportunities without lengthening training (N = 71). Inferences improved, suggesting children can learn five-term series rapidly. Regarding memory, the minor (CD) premise was the best predictor of BD-inferential performance in both task-types. However, tasks exhibited different profiles according to associations between the major (BC) premise and BD inference, correlations between the premises, and the role of age. Experiment 3 (N = 227) helped rule out the possible objection that the above findings simply stemmed from three-term tasks with real objects being easier to solve than computer-tasks. It also confirmed that, unlike for five-term task (Experiments 1 & 2), inferences on three-term tasks improve with age, whether the age range is wide (Experiment 3) or narrow (Experiment 2). I conclude that the tasks indexed different routes within a dual-process conception of transitive reasoning: The five-term tasks indexes Type 1 (associative) processing, and the three-term task indexes Type 2 (analytic) processing. As well as demonstrating that both tasks are perfectly valid, these findings open up opportunities to use transitive tasks for educability, to investigate the role of transitivity in other domains of reasoning, and potentially to benefit the lived experiences of persons with developmental issues

Scio Ergo Sum: Knowledge of the Self in a Nonhuman Primate

The pressures of developing and maintaining intricate social relationships may have led to the evolution of enhanced cognitive abilities in many social nonhuman species, particularly primates. Knowledge of the dominance ranks and social relationships of other individuals, for example, is important in evaluating one’s position in the prevailing affiliative and dominance networks within a primate society and could be acquired through direct or perceived experience. Our analysis of allogrooming supplants among wild bonnet macaques had revealed that individual females successfully evaluate social relationships among other group females and possess egotistical knowledge of their own positions, relative to those of others, in the social hierarchy. These individuals, therefore, appeared to have abstracted and mentally represented their own personal attributes as well as those of other members of the group. Bonnet macaques also seem to recognise that other individuals have beliefs that may be different from their own, manipulate another individual’s actions and beliefs in a variety of social situations, and selectively reveal or withhold information from others—capabilities displayed by certain individuals that became evident in the course of our earlier studies on tactical deception in the species. In conclusion, the ability to develop belief systems and form mental representations, generated by direct personal experience, suggests a rather early evolutionary origin for fairly sophisticated cognitive capabilities, characterised by an objectified self with limited regulatory control over more subjective levels of self-awareness, in cercopithecine primates, pre-dating those of the great apes. We, therefore, argue, in this review, that bonnet macaques might represent an intermediate stage in the evolution of self-awareness, a process which began with the subjective awareness that characterises most, if not all, higher animal species and culminates in the most sophisticated form of symbolic self-awareness, apparently the hallmark of the human species alone

Horse sense: social status of horses (Equus caballus) affects their likelihood of copying other horses’ behavior

Animals that live in stable social groups need to gather information on their own relative position in the group’s social hierarchy, by either directly threatening or by challenging others, or indirectly and in a less perilous manner, by observing interactions among others. Indirect inference of dominance relationships has previously been reported from primates, rats, birds, and fish. Here, we show that domestic horses, Equus caballus, are similarly capable of social cognition. Taking advantage of a specific ‘‘following behavior’’ that horses show towards humans in a riding arena, we investigated whether bystander horses adjust their response to an experimenter according to the observed interaction and their own dominance relationship with the horse whose reaction to the experimenter they had observed before. Horses copied the ‘‘following behavior’’ towards an experimenter after watching a dominant horse following but did not follow after observing a subordinate horse or a horse from another social group doing so. The ‘‘following behavior,’’ which horses show towards an experimenter, therefore appears to be affected by the demonstrator’s behavior and social status relative to the observer