Section 1


Outline of Human Phylogeny

Evolutionary Trees
and DNA

Brain Evolution

Hand and Bipedality

Section 2
Social and socio-
cultural systems

Primate societies

Social relations and the evolution of culture

Social relations, communication and cognition

Human socio-cultural patterns

Tools and symbolic behaviour

Palaeolithic Art

Contemporary hunter-gatherer art

Section 3
Ontogeny and symbolism

Editorial Introduction: Ontogeny & Phylogeny

The role of ontogenesis

Brain, cognition, and language

Early interaction and cognitive skills

Language and thought

Theories of symbolization
and development

Children's drawings and the evolution of art

Section 4
Language systems

Spoken language and
sign language

The gestural primacy hypothesis

Comparative cognition

Animal language and cognition

Language acquisition


The prehistory of grammar

Writing systems


Links Policy

Relevant Links

Cognitive abilities in a comparative perspective

Andrew Lock and Michael Colombo

Recent studies of non-human animals indicate that cognitive processes mediate many areas of their behaviour. A number of human cognitive systems, and their properties for example memorial processes, categorical auditory and visual perception appear to have quite deep phylogenetic roots. It is not yet possible, however, to provide a precise evolutionary classification of these systems, for ecological factors play as large a role in the elaboration of an animal's cognitive abilities as does its phylogenetic status. Thus, many 'indices' that have been proposed as differentiating phylogenetic groups in terms of their 'learning abilities' or 'intelligence' have not been substantiated: initially promising proposals have been confounded by animals from 'lower' taxa showing 'unexpected' levels of ability in sensory domains relevant to their ecological niches. A restricted focus on primates, however, does tend to show an improvement in levels of performance from prosimians to Great Apes on tasks such as reversal learning; and it seems likely that these changes are based in differences in the underlying cognitive abilities and strategies these species employ.

The ability to form concepts has been shown for a number of non-human species. Most of these concepts have physical instantiations. Conflicting claims are made regarding the possession of the concepts of 'same' and 'different'. These appear to be absent in pigeons and goldfish; their status in monkeys is subject to dispute; they are quite well elaborated in the Great Apes, especially in chimpanzees, where most of the experimental effort has been focused. In this last-mentioned species, 'same-different' judgements extend into areas of analogy and transitive inference, which are perhaps closer to reasoning abilities than merely conceptual ones.

Observational learning (or imitation) has been divided into the categories of social facilitation, stimulus enhancement, and imitative copying. The last of these is largely confined to the Great Apes; whereas the other two occur across all the primate groups. Imitative copying is less developed in the Great Apes than in humans, and 'teaching' plays little or no role in the transfer of skills. Chimpanzees are capable of adaptive novel responses in a problem-solving context; but these are more possible for them in some situations than in others. Chimpanzees and orang-utans show self-recognition when confronted with a mirror; but all other primates tested tend to react to mirrors socially, as if they were confronting another conspecific.

Monkeys and apes occasionally act as though they recognize that other individuals have beliefs, but even the most compelling naturalistic and experimentally-induced observations can usually be explained in terms of learned behavioural contingencies, without invoking a higher-order 'understanding' of intentionality. What little evidence there is at this time does point towards chimpanzees (and possibly the other Great Apes) having some 'theory of other minds', although its precise nature is not yet clear.

There are some Piagetian-inspired investigations of comparative cognitive abilities. The Great Apes appear to reach sensorimotor Stage 6 in object permanence, spatial concepts, imitation, and the understanding of causality. Piagetian investigations of possible representational intelligence have proved disappointing to date.

Two oversimplified but none the less useful generalizations would characterize monkeys as possessing the ability to form conceptual representations, and apes as able to manipulate representations; and monkeys as more dominated by immediate perceptual experience than apes. In both cases, abilities are often restricted to particular domains of action. The elaboration of cross-modal and cross-situational abilities appears a major factor in the evolution of primate cognitive skills towards those possessed by modern humans.