Jensen's model of intelligence is contrasted with a cognitive-developmental model in which accurate self-representation of cognitive processes is a basic characteristic of human thinking and intelligence. This is ignored in Jensen's model. However, there is evidence that content-free processes pertinent to g, such as speed of processing, are directly recorded in one's self-image. This, in turn, influences one's thinking style, the disposition to be open to experience, and thus intellectual functioning itself. Hence g is a psychological construct, despite its strong dependence on biological processes.
2. The environment-oriented level of knowing and the general-purpose level of processing potentials may be taken to correspond, by and large, to Jensen's second-order (that is, the various broad abilities) and third-order factors (that is, g), respectively. However, the psychometric model does not involve a self-knowing and self-regulation system as such. Positing this system has some important implications for the nature and operation of the two other levels of the mind. Here we will focus only on the implications of this model for Jensen's conception of g as a primarily biological rather than a psychological construct.
3. In Jensen's words, "g cannot be described in terms of knowledge content of mental test items, or in terms of skills, or even in terms of theoretical cognitive processes. It is not fundamentally a psychological or behavioral variable, but a biological one." (p. 578). I suggest, based on the evidence to be summarized below, that this interpretation of g may be valid only insofar as the relation of g to the environment-oriented systems is concerned. It is invalid for the relations of g to the self-oriented level of the mind. Epistemologically speaking, this implies that Jensen's claim that g cannot be defined psychologically cannot be accepted.
4. Specifically, if g is "thought of as a distillate of the common source of individual differences in all mental tests, completely stripped of their distinctive features of information content, skill, strategy, and the like" (p.74) then, by definition, g becomes a construct that can not be defined in reference to the actual computational, processing, or procedural characteristics that define each of the various domains of cognitive activity (or ability), such as spatial or numerical ability that are built onto it. Naturally, under these conditions g must be conceived of as something like the central processing unit of a computer and defined accordingly (in reference to its speed of operation, probably the RAM or ROM that it is available for its operation).
5. Moreover, it might be the case that g is without content even from the point of view of the thinking person himself. In a study that attempted to specify the relationships between actual cognitive abilities (domain-specific abilities, such as mathematical, causal, spatial, and social thought, and general abilities, such as memory, speed of processing, inference, self-monitoring, and self-regulation) and their self-representation, we have shown that all but one of these abilities stand out in both actual performance and self-representation as distinct abilities. It is only speed of processing that is not recorded as an autonomous dimension of the mind by the self-monitoring system. Instead, it seems to be recorded in its relationships to the domain-specific systems it supports. That is, the more effort required in the functioning of a domain-specific system the more this system requires the various functions of the processing system, such as speed of processing. Mathematical thought is a particularly important example of these privileged relationships to processing speed and other parameters of g, such as efficiency for inhibition. This is of course consistent with the claim that general processing ability is "empty" or without content (Demetriou & Kazi, 2000).
6. This is only half of the story, however. If the actual computational or operating processes of g are associated with the various domain-specific abilities then g cannot be specified psychologically. However, g does acquire psychological and subjective meaning once (and to the degree that) it is recorded by the self-awareness system and comes under the control of self-regulation processes. Specifically, we have also shown that g is directly and in an almost linear fashion related to self-representation of logicality. This evidence suggests that the faster individuals are in processing, and the more able in analogical reasoning, the more logical (and, to a lesser extent, the better able to learn) they think they are (Demetriou & Kazi, 2000). In fact, we have also shown that fast processing and high analogical reasoning with ensuing self-representations are positively and systematically related to the dimension of openness to experience, one of the Big Five factors of personality (Demetriou, in press). These findings suggest that the projection of processing power (or g) into one/s self-image of cognitive efficiency shapes general mental self-worth and self-esteem. Through this g shapes decisions about what tasks one is to work on and how. In turn, this grafting of g into the self-representation system influences the person's problem-solving strategies and thinking styles. This is obviously a psychological marking of g by any definition. Even more: in the long run, it contributes to the formation of g because the more one has of it the more one works to augment and differentiate it.
7. In conclusion, g is recorded in the thinker's self-representations. This, in turn, influences the thinking and personality dispositions of the individual to relate to the environment in particular ways. Thus, g, from this point of view, is a psychological construct. This does not imply that g is not primarily determined by biological factors. It only means that those factors acquire psychological meaning and effects through self-representation. Hence a g nexus suggested by Jensen himself, namely, the study of the relationships between g and personality in order to understand how g contributes to shaping the person's everyday life, leads to an interpretation of the nature of g that deviates from Jensen's preferred one.
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Jensen, A. (1999) Precis of: "The G Factor: The Science of Mental Ability" PSYCOLOQUY 10(23). ftp://ftp.princeton.edu/pub/harnad/Psycoloquy/1999.volume.10/ psyc.99.10.023.intelligence-g-factor.1.jensen http://www.cogsci.soton.ac.uk/cgi/psyc/newpsy?10.023