Sue Taylor Parker

A developmental model for the evolution of language and intelligence in early hominids

This paper presents a model for the nature and adaptive significance of intelligence and language in early hominids based on comparative developmental, ecological, and neurological data. We propose that the common ancestor of the great apes and man displayed rudimentary forms of late sensorimotor and early preoperational intelligence similar to that of one- to four-year-old children. These abilities arose as adaptations for extractive foraging with tools, which requires a long postweaning apprenticeship. They were elaborated in the first hominids with the shift to primary dependence on this feeding strategy. These first hominids evolved a protolanguage, similar to that of two-year-old human children, with which they could describe the nature and location of food and request help in obtaining it. The descendents of the first hominids displayed intuitive intelligence, similar to that of four- to seven-year-old children, which arose as an adaptation for complex hunting involving aimed-missile throwing, stone-tool manufacture, animal butchery, food division, and shelter construction. The comparative developmental and paleontological data are consistent with the hypothesis that the stages of development of intelligence and language and their neural substrates in our species recapitulate the stages of their evolution.

Object manipulation, tool use and sensorimotor intelligence as feeding adaptations in cebus monkeys and great apes

In this paper we propose a typology for classifying object manipulation and tool use. We then classify tool use as context specific or intelligent tool use on the basis of criteria drawn from Piagets Sensorimotor Intelligence Series in human infants. In an extension of Hamiltons hypothesis we argue that intelligent tool use and tertiary sensorimotor intelligence in cebus monkeys and great apes is an adaptation for feeding on a variety of seasonally limited embedded food sources, while context specific tool use is an adaptation for feeding on one class of embedded food sources. We also argue that the evolution of specific object manipulation schemata must be considered separately from the evolution of intelligence.

A sexual selection model for hominid evolution

The following paper develops a sexual selection model for the evolution of bipedal locomotion, canine reduction, brain enlargement, language and higher intelligence. The model involves an expansion of Darwin’s ideas about human evolution based on recent elaborations of sexual selection theory. Modern notions about intrasexual competition and female and male choice and their ecological correlates are summarized along with a new model for the role of sexual selection in speciation. Rapid evolution of bipedal locomotion as a male adaptation for nuptial feeding of females is proposed as a model for ape-hominid divergence through sexual selection; canine reduction is attributed to selection for associated epigamic displays. The analogy with male specialization through sexual selection speciation in hamadryas baboons is noted. Subsequent changes in female reproductive physiology are attributed to female competition for increased male parental investment during the time of early Homo andHomo erectus. The origin of higher intellectual and language abilities inHomo sapiens is attributed to male competition through technology and rule production to control resources and females; intellectual abilities involved in social manipulation are attributed to female competition for male parental investment and maintenance of polyandry. The course of hominid evolution is characterized as involving a trend from a promiscuous mating system toward increasing intensity of adaptations for male control of females, and by increasing intensity of female adaptation to maintain male parental investment while circumventing male control.

A Social-Technological Model for the Evolution of Language [and Comments and Reply]

This paper develops a model for the evolution of language that is consistent with semanticist and pragmaticist interpretations of the forms and functions of language and the processes of language acquisition and language change. The proximate aspect of the model emphasizes the social contexts of language acquisition and language change; its adaptive aspect emphasizes the sociobiological concept of communication as social manipulation. Both aspects emphasize the relationship between subsistence technology and social behavior. Specifically, the model suggests that the stages of evolution of the lexical and syntactical systems roughly parallel the stages of their acquisition; that primitive lexical forms of reference and request first arose among the earliest hominids for food location and food sharing in relation to extractive foraging on embedded foods; that simple syntax first arose among Homo erectus for encoding regulatory rules and procedures concerning recruitment, aggregation, and coordination of workers at resource sites in relation to big-game hunting; and that complex syntax arose among H. sapiens for encoding procedures for predicting resource distributions and constitutive rules for classifying relationships and performing ritual transformations of statuses and relationships, e.g., kinship terminological systems and rules of exogamy in relation to subsistence specialization.

The comparative and developmental study of self-recognition and imitation: The importance of social factors

Both mirror self-recognition (MSR) and “true” or “representational” imitation are among a host of different abilities that emerge in human infants between 18 and 24 months of age, when mental representation develops (Piaget, 1952). Mental representation is the highest cognitive achievement of the sensorimotor period. We believe that this is the basis for the expression of both self-recognition and imitation; by considering comparative and developmental evidence we shall discuss some of the cognitive conditions for each. Several researchers have suggested that the ability to imitate is a necessary condition for the development of self-recognition in human infants (e.g., Baldwin, 1903; Kaye, 1982; Lewis & Brooks-Gunn, 1979; see also Gopnik & Meltzoff, SAAH 10; Hart & Fegley, SAAH 9). However, contrary to this position, one hypothesis of this chapter is that imitation is not necessary for the development of self-recognition. We believe that the developmental and comparative approaches must be used together in order to specify cognitive conditions for self-recognition and imitation (Mitchell, 1987; Parker, 1990, 1991). It is particularly difficult to determine the cognitive prerequisites by studying children alone, because many complex behaviors appear concurrently within a very narrow time frame. Developmental study of closely related primate species may be required to isolate the factors that are important in the development of cognitively complex behaviors such as self-recognition and imitation (Antinucci, 1989; Parker, 1991). Therefore, we shall utilize developmental data collected from our closest genetic relatives, chimpanzees, to compare with developmental data from human primates.

A developmental approach to the origins of self-recognition in great apes

In this paper I present an hypothesis to explain the presence of mirror self-recognition (MSR) in great apes and human infants, and the absence of MSR in monkeys. This hypothesis is based on the following elements: 1) review of Gallupian studies of MSR in monkeys and apes; 2) review of Lewis & Brooks-Gunns study for self-recognition in human infants; 3) application of the human model to comparative data on MSR in nonhuman primates; 4) discussion of cognitive correlates of MSR in human infants; 5) analysis of the cognitive correlates of MSR absence in monkeys, and MSR presence in apes; 6) comparative analysis of the modalities of occurrence of imitation and understanding of causality in monkeys and apes; and 7) a cladistic reconstruction of the evolution of MSR.

A general model for the adaptive function of self-knowledge in animals and humans

This article offers a general definition of self-knowledge that embraces all forms and levels of self-knowledge in animals and humans. It is hypothesized that various levels of self-knowledge constitute an ordinal scale such that each species in a lineage displays the forms of self-knowledge found in related species as well as new forms it and its sister species may have evolved. Likewise, it is hypothesized that these various forms of levels of self-knowledge develop in the sequence in which they evolved. Finally, a general hypothesis for the functional significance of self-knowledge is proposed along with subhypotheses regarding the adaptive significance of various levels of self-knowledge in mammals including human and nonhuman primates. The general hypothesis is that self-knowledge serves as a standard for assessing the qualities of conspecifics compared to those of the self. Such assessment is crucial to deciding among alternative reproductive and subsistence strategies. The qualities that are assessed, which vary across taxa, range from the size and strength of the self to its mathematical or musical abilities. This so-called assessment model of self-knowledge is based on evolutionary biological models for social selection and the role of assessment in animal communication.

Imitation and Circular Reactions as Evolved Mechanisms for Cognitive Construction.

The purpose of this article is to elaborate and extend some of Baldwin’s and Piaget’s ideas concerning the self-teaching functions of imitation and circular reactions. It is argued that circular reactions are evolved means for self-induced cognitive construction and that imitation is an evolved means for self-and other-induced cognitive construction. Comparative data on the taxonomic distribution of imitation and circular reactions in monkeys and apes suggest that these means for cognitive construction are rare among primates and must have evolved first in the common ancestor of great apes and humans.