Cjep 60-4

In the present study, the relationship between performance on temporal and pitch discrimination and psychometric intelligence was investigated in a sample of 164 participants by means of an experimental dissociation paradigm. Performance on both temporal and pitch discrimination was substantially related to psychometric intelligence (r = .43 and r =.39). Regression analysis and structural equation modeling suggested that both psychophysical domains can be considered as valid predictors of psychometric intelligence. Both predictor variables contributed substantial portions of both shared and unique variance to the prediction of individual differences in psychometric intelligence. Thus, the present study yielded further evidence for a functional relationship between psychometric intelligence and temporal as well as pitch discrimination acuity. Eventually, findings are consistent with the notion that temporal discrimination – in addition to general aspects of sensory discrimination shared with pitch discrimination – reflects specific intelligence-related aspects of neural information processing. Résume Dans la présente étude, la relation entre l’intelligence psychométrique et les rendements à la discrimination temporelle et à la discrimination des hauteurs tonales a été étudiée auprès de 164 participants à l’aide d’un paradigme de dissociation expérimentale. Les rendements à la discrimination temporelle et à la discrimination des hauteurs tonales ont pu être liés de façon substantielle à l’intelligence psychométrique (r = ,43 et r = ,39). L’analyse de régression et la modélisation de l’équation structurelle suggèrent que les deux domaines psychophysiques peuvent être considérés comme des prédicteurs valides de l’intelligence psychométrique. Les deux variables psychophysiques contribue de manière importante à la variance partagée et unique dans la prédiction des différences individuelles de l’intelligence psychométrique. Ainsi, l’étude soutient l’idée qu’il existe une relation fonctionnelle entre l’intelligence psychométrique et l’acuité de la discrimination temporelle et de la hauteur tonale. Les conclusions concordent avec la notion que la discrimination temporelle en plus des aspects généraux de la discrimination sensorielle partagée avec la discrimination de la hauteur tonale reflète des aspects du traitement de l’information neurale qui sont liés à l’intelligence spécifique. During the last three decades, the mental speed approach to human intelligence has produced converging evidence for a linear relationship between efficiency and speed of information processing in so-called “elementary cognitive tasks” (ECTs) and psychometric intelligence (see Deary, 2000; Neubauer, 1995, 1997; Schweizer, 2005; Vernon, 1987). Various measures of speed of information processing, such as simple and choice reaction time following the rationale of Hick (1952; for reviews see Jensen, 1987, 1998), inspection time (Brand & Deary, 1982; Vickers, Nettelbeck, & Wilson, 1972), short-term memory scanning (Sternberg, 1966, 1969), or long-term memory retrieval (Posner & Mitchell, 1967), have been found to be associated with higher psychometric intelligence. Several attempts have been made to describe the physiological basis of individual differences in speed and efficiency of the information processing system and its association to psychometric intelligence. Biological approaches to human intelligence usually refer to the concept of “neural efficiency” in the brain as a basic determinant of individual differences in cognitive abilities (Bates, Stough, Mangan, & Pellett, 1995; Neubauer, 2000; Sternberg & Kaufmann, 1998; Vernon, 1993). Against the background of this concept, the relationship between intelligence and speed of information processing has been explained by different approaches such as reliability of neuronal transmission (Hendrickson, 1982; Hendrickson & Hendrickson, 1980), specific cortical activation (Neubauer, Freudenthaler, & Pfurtscheller, 1995; Neubauer, Schrausser, & Freudenthaler, 2000), neural pruning (Haier, 1993), myelination of neurons (Miller, 1994), neural adaptability (Schafer, 1979, 1982, 1985), or differences in neural plasticity (Garlick, 2002). In his model of neuronal oscillations, Jensen (1982) proposed that individual differences in processing speed and psychometric intelligence can be attributed to differences in the rate of oscillation between refractory and excitatory states of neurons or groups of neurons. A high oscillation rate is supposed to allow a faster and more efficient transmission of neurally encoded information, since it will take less time for a neuron to enter the excitatory phase of its cycle when Nadine Helmbold, Stefan Troche, and Thomas Rammsayer Georg Elias Müller Institute for Psychology University of Göttingen Canadian Journal of Experimental Psychology, 2006, 60-4, 294-306 Canadian Journal of Experimental Psychology Copyright 2006 by the Canadian Psychological Association 2006, Vol. 60, No. 4, 294-306 DOI: 10.1037/cjep2006027 CJEP 60-4 12/4/06 9:05 PM Page 294