When IQ is controlled, does motivation still predict achievement? ** (Intelligence).(Statistical Data Included)

1. Introduction

In his famous book "Hereditary Genius," Francis Galton (1869/1962) circumscribed the roots of eminence in the following way:

 
   By natural ability, I mean those qualities of intellect and disposition, 
   which urge and qualify a man to perform acts that lead to reputation. I do 
   not mean capacity without zeal, nor zeal without capacity, nor even a 
   combination of both of them, without an adequate power of doing a great 
   deal of very laborious work. (p. 77) 

In Galton's terms, reputation (talent, eminence) will emerge from proper qualifications (high capacities, gifts), urges and zeal (needs, passions), as well as the power for laborious work (will power, persistence). These "ingredients" of exceptional performance identified by Sir Francis Galton more than a century ago have reappeared again and again (a) in general models of school learning (e.g., Bloom, 1976; Carroll, 1963; Walberg, 1984), (b) in more specific models of talent emergence (e.g., Feldhusen, 1992; Gagne, 1993; Renzulli, 1986; Tannenbaum, 1983), (c) in models of skill growth proposed by industrial psychologists (e.g., Atkinson, 1964; Kanfer & Ackerman, 1989; Vroom, 1964), and (d) in biographical analyses of eminent historical figures (e.g., Simonton, 1994). Cognitive aptitudes and motivational factors are probably the two most commonly mentioned determinants of academic achievement. Not only are they included in theoretical models, but they have appeared as independent variables in thousands of empirical studies of school learning, skill training in work settings, talent development in arts and sports, as well as longitudinal studies of occupational achievement. The most common belief within the general population is that both factors exert approximately equal causal influences on talent development (Gagne & Blanchard, submitted for publication). Attribution studies also show that both effort and ability are by far the two major causal attributions for both success and failure, not only in academics (Good & Brophy, 1990), but also in music (Austin & Vispoel, 1998) and sports (Biddle, 1993).

To what extent does empirical research support these "equalitarian" beliefs? First, the very strong relationship between cognitive aptitudes, usually measured by some type of IQ test, and academic achievement is well-documented. In a survey of close to 3000 empirical studies of school learning, Walberg and his colleagues (see Walberg, 1984) computed an average correlation of .71 between various IQ measures and academic achievement. It emerged as the most powerful determinant, by far, among dozens of factors examined. Similarly, in her synthesis of many meta-analytic surveys of the predictive validity of IQ tests in work settings, Gottfredson (1997) argued (a) that the validity of intelligence measures applied to most occupations, (b) that it rose with job complexity, and (c) that "g can be said to be the most powerful single predictor of overall job performance" (p. 83). Recently, Schmidt and Hunter (1998) published for the field of personnel psychology a synthesis similar to that of Walberg's. They analyzed the predictive validity of 19 distinct constructs and selection methods, including general mental ability (GMA) tests, work samples, interviews, assessment centers, job knowledge, job tryout, job experience, peer ratings, even graphology! In the case of GMA tests, they computed validity coefficients of .51 and .56 with job performance and job training, respectively. The relationship between motivation and achievement is also well-documented. In the above-mentioned review, Walberg (1984) and his colleagues found an average correlation of .34 between various indices of motivation and school learning. In terms of explained variance, this contribution is about one-fourth of the predictive power of IQ ([r.sup.2] = .50 for IQ, and .12 for motivation). And it is probably a generous estimate since the text does not specify if the correlations used for the motivation component were independent contributions, that is after controlling for the predictive power of intelligence. In the Schmidt and Hunter synthesis, 2 of the 19 predictors analyzed belong to the general area of motivation, namely conscientiousness and vocational interests; their average validities with regard to job performance are .31 and .10, respectively. Again, these are zero-order correlations.

If cognitive abilities and motivation are both significant determinants of achievement, to what extent are they related to each other? Schmidt and Hunter (1998) cited Ones, Viswesvaran, and Schimdt (1993) to support their premise of a zero correlation between conscientiousness and IQ; they also cited Holland (1986) to justify a similar lack of correlation between interests and cognitive abilities. On the other hand, the gifted education literature is replete with statements to the effect that gifted children are more motivated; most checklists of "gifted" characteristics include curiosity, incessant questioning, and similar indices of intrinsic motivation (IM) to learn (e.g., Clark, 1996; Davis & Rimm, 1989; Gallagher, 1985). Some research also supports that relationship, showing significant differences between gifted children or adolescents and peers of average abilities on a variety of measures of motivation: intellectual curiosity, IM, achievement motivation, task orientation, and so forth (Gottfried & Gottfried, 1996; Janos & Robinson, 1985; Lloyd & Barenblatt, 1984; Vallerand, Gagne, Senecal, & Pelletier, 1994). But, other studies report no correlation whatsoever between measures of these two constructs (e.g., Aspinwall & Taylor, 1992; Joswig, 1994; Spence, Pred, & Helmreich, 1989; Wong & Csikszentmihalyi, 1991). These contradictory results brought Shore, Cornell, Robinson, and Ward (1991) to express the following doubts: "There is insufficient explanation of how attention to intrinsic motivation might be different for the gifted compared with others. The implication in much of the literature that gifted children have more of it, or a superior kind, is not supported" (p. 215).

The prediction problem is compounded by a major terminological ambiguity, since there is no agreed upon definition of the term gifted (Gagne, 1995). Consequently, the gifted subjects in comparative studies are selected with a variety of procedures. Gagne argued that two types of measures are used more regularly: IQ tests (group or individual) and academic achievement scores (grades or standardized tests). In the framework of Gagne's Differentiated Model of Giftedness and Talent, IQ tests pinpoint intellectually gifted (IG) students, whereas grades identify academically talented (AT) students, or, in Gagne's (1995) words, IGAT students. These two groups overlap only partially. Consequently, many studies that compare "gifted" children with peers of average abilities are often comparing achieving gifted children. It follows that many of the significant differences observed between the two groups could be attributable as much to the superior cognitive abilities of these gifted children as to their academic talent. This methodological problem speaks eloquently in favor of efforts to disentangle the respective causal contributions of cognitive aptitudes (A) and motivation (M) to achievement.