Contents
Section 1
Palaeoanthropology
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Photogallery Outline of Human Phylogeny Evolutionary Trees and DNA Brain Evolution Hand and Bipedality |
Section 2
Social and socio-
cultural systems
Section 3
Ontogeny and symbolism
Section 4
Language systems
Links
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Links Policy Relevant Links |
Cognitive abilities in a comparative perspective
Andrew Lock and Michael Colombo
Abstract
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 þ for example memorial processes, categorical auditory and visual perception þ 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.