Published in

Dittrich WH (1992) Behavioral and Brain Sciences 15, 152

W.H.Dittrich

University of Exeter, Department of Psychology, Washington Singer Labs, Exeter EX4 4QG, England

--------------------------------------------------------------

BBS Commentary on

Cheney, D.L. & Seyfarth, R.M. (1990): How monkeys see the world. University of Chicago Press.

Evolution of intelligence: The starting point for most modern theories of intelligence in primates is the assumed discrepancy between their performance on learning tests in the laboratory and their 'greater intelligence when dealing with each other'(p.256; cf. 'social intelligence hypotheses'). C&S emphasize this discrepancy while supporting a more general version such as Rozin's (1976) inaccessibility model of intelligence within different domains. They characterize their approach as a practical, functional perspective, but in the end it seems to be more a utilitarian, than an evolutionary functional approach. I would argue that their approach to intelligence is in fact a version of the 'sufficiency argument ' first introduced by Simon (1981) in the context of AI. The essence of this approach is that intelligent creatures must be able to represent the important aspects of their environments in their knowledge of the world. Within a functioning monkey society the representational requirements of this knowledge are probably so severe that only a few modes of knowledge can meet them. Therefore a demonstration that a particular mode of intelligence can support the wide range of representations monkeys obviously do use is powerful evidence for that mode as the appropriate model of monkeys' intelligence. What C&S arguing, in effect is due to the dominance of social affairs that the social mode of intelligence has the required representational power. Nevertheless, it should be stated that the notion of intelligence is in fact too vague to be the core of an evolutionary approach to cognitive behaviour or cognition. Even human intelligence is not a homogenous scientific concept (Howe 1988). Primate intelligence can be divided into several relatively autonomous abilities, e.g. perceptual or motor skills, communicative or social competence, foraging knowledge, categorization or classification performance. Intelligence has evolved independently in different taxonomic groups and is neither a cognitively homogeneous nor a phylogenetically homologous behavioural function. Intelligent behaviour evolved because animals had to cope with the increasing environmental complexity resulted from evolutionary diversification. The increasing instability of animal/environment interactions could only be handled by reducing this complexity internally, that is to say cognitively (duplicate complexity hypotheses). On this basis, the critical evolutionary pressure could be social, but it could be any other relevant ecological factor. In the Cercopithecidae, as opposed to birds or other primate groups, it may have been mainly a social factor. But it seems to be of little value to stress one factor of intelligence (e.g. social knowledge) against others (e.g. nonsocial knowledge). Instead, we should take a functional systemanalytic approach (Dittrich 1988; 1990), that is we should take all relevant, both proximate and ultimate, factors into account to understand behavioural processes. Such a view implies that intelligence did not evolve domain-specific. On the contrary, domain-specificity seems to be the result of particular adaptation processes and not the starting point. In practice, the different selection pressures tending to produce intelligence are linked, so any claim that the evolution of intelligence can be explained on the basis of a single factor is highly implausible.

Concept formation: Surprisingly, C&S don't mention any of the important studies of the structural basis of the assumed mentalistic processes called intelligence. Admittedly, though it has proved extremely difficult to isolate the comparatively simple but measurable mental processes which are assumed to form the building blocks of more general knowledge. But some causal investigations have been done (cf. Griffin 1982; Mackintosh 1983; Weiskrantz 1985; Baddeley 1986). C&S gave no attention to key areas such as vision or memory and they are highly critical of experimental laboratory tests e.g. in the area of animal 'concepts'. Certainly, the results of experiments on concept formation are controversial, but that is typical in areas under intensive research. There is a strong body of positive and reliable results highlighting different parts of the cognitive process of concept formation (e.g. Rosch & Lloyd 1978; Smith & Medin 1981; Herrnstein 1985; Lea & Ryan 1990; Perrett et al. in press). C&S correctly emphasize the point that sometimes the ecological context in these studies is missing. This is an essential point not because ecology is en vogue but because it is a precondition for understanding the idea of 'concepts' to grasp functional relations between external objects and internal cognitions. To understand the mind of monkeys C&S look at the monkeys' immediate environment, but ignore the organization of cognitive components as the basis for conceptual order. Laboratory experiments on concept formation, perhaps, do the reverse. But, ecological factors are ultimatively insufficient to understand the diversity of monkeys' ability to categorize and classify (Dittrich 1988). Cognitive factors such as hypotheses (Gregory 1980) or schemata (Lorenz 1975) are operating in perception and memory, and they play an important role in goal-achieving behaviour. However, the reference points of mental representations are not necessarily the goals to which behaviour is oriented or which it is intended to reach (McFarland 1989). According to the 'connection principle' formulated by Searle (1990), intention and its communication is bound to consciousness, which monkeys probably lack. Thus, is the monkey's lack of what Searle calls aspectual shape the reason why mind-reading between monkeys will finally remain in the realms of science fiction?

Philosophy of science: Different approaches to primate ethology give different perspectives and different perspectives lead to different observations. But different does not imply better. Does the utilitarian cognitive viewpoint proposed by C&S offer a broader or more realistic perspective for observation and data collection than the more cautious classical approach? The intentional perspective may be more convenient for describing primate behaviour, but it does not necessarily lead to a better understanding of what is happening in the monkey's mind. The reality of the monkey's mind or the 'how to be like a monkey' is forever inaccessible but this is not, as C&S claim, an empirical matter, but a logical one. The achievable aim is to understand the effects and causes of monkeys' behaviour, including the roles played by their cognitions and the underlying physiological structures. The concept of intelligence is purely descriptive; it has not been established as a valid explanatory concept in scientific psychology (Howe 1988). The same holds for the concepts of mind, belief and intention. The founders of ethology were acutely aware of the trap of believing that by describing animals' behaviour they were providing reasons for the behaviour; a necessary distinction which is often lost in cognitive science when we account for behaviour in such terms as belief, desire, goal-orientation or intention. Can we transfer traditional ethologists' wisdom to modern primatology? Or will it turn out that human, scientific intelligence is domain-specific?

Acknowledgments

I am grateful Ian Gordon, Michael Howe, Catriona Ryan and especially Stephen Lea for helpful discussions. Preparation was supported by the Alexander von Humboldt-Foundation through a Feodor Lynen Fellowship held by the author.

References

BADDELEY, A. (1986) Working memory. Oxford Univ.Press

DITTRICH, W. (1988) Wie klassifizieren Javaneraffen (Macaca fascicularis) natürliche Muster? Ethology 77, 187-208.

DITTRICH, W. (1990) Das Erkennen von Ausdrucksbewegungen aus den Bewegungen des Gesichts. Psychologische Beiträge 3/4, in press.

GREGORY, R.L. (1980) Perceptions as hypotheses. Philosophical Transactions of the Royal Society of London, Series B 290, 181-197.

GRIFFIN, D.R.(Ed.) (1982) Animal Mind - Human Mind. Springer.

HERRNSTEIN, R.J. (1985) Riddles of natural categorization. In: Animal intelligence, ed. L.Weiskrantz, Clarendon Press

HOWE, M.J.A. (1988) Intelligence as an explanation. Brit.J.Psychol. 79, 349-360.

LEA, S.E.G.,& RYAN, C.M.E. (1990) Unnatural concepts and the theory of concept discrimination in birds. In: Quantitative analyses of behavior, Vol.8: Behavioral approaches to pattern recognition and concept formation, eds. M.L.Commons, R.J.Herrnstein, S.Kosslyn, S.,& D.Mumford, Erlbaum.

LORENZ, K. (1975) Evolution and modification of behavior. Univ.Chicago Press

MACKINTOSH, N.J. (1983) Conditioning and associative learning. Oxford Univ.Press

McFARLAND, D. (1989) Problems in animal behaviour. Longman.

PERRETT, D.I.P., BENSON, P.J., HIETANEN, J.K., ORAM, M.W.,& DITTRICH, W.H. (in press) When is a face not a face? Correlations between perception and single neurons. In: Anomalies of space, form, colour in perception and art: Links with normal and abnormal brain function, eds. R.Gregory & J.Harris.

ROSCH, E.,& LLOYD, B.B.(eds.) (1978) Cognition and categorization. Erlbaum.

ROZIN, P. (1976) The evolution of intelligence and access to the cognitive unconscious. In: Progress in psychology, vol.6, eds. In: eds. J.N. SPRAGUE & A.N.EPSTEIN, Academic.

SEARLE, J.R. (1990) Consciousness, explanatory inversion and cognitive science. Behav.Brain Sci. 13, 585-595.

SIMON, H.A. (1981) The sciences of the artificial. MIT Press 2nd ed.

SMITH, E.E.,& MEDIN, D.L. (1981) Categories and Concepts. Harvard Univ.Press

WEISKRANTZ, L.(ed.) (1985) Animal intelligence. Clarendon Press