How do people integrate information about motivation and ability of a person when they predict his performance? As the dynamic motivation factor acts as an amplifier of the static capacity factor, a multiplying rule can be expected to apply to prediction of performance. A multiplying rule implies a linear fan pattern in the factorial plot of the Motivation x ability data. This linear fan prediction has been supported in the United States but not in India. The present paper presents findings from several studies by the author, and provides an explanation for the discrepancy in results obtained with American and Indian students. The position taken is that the integration rules underlying prediction of performance are culture-specific, and that American and Indian students differ in their cultural outlook on how motivation and ability determine performance. Americans follow a multiplying rule which implies that effort or trying will be more effective with persons of high than low ability. In contrast, Indians follow an equal-weight averaging which implies that effort or trying will be equally effective with persons of low and high ability. Cognitive algebra employed in the two cultures thus directly reflect the causal conceptions prevalent in the two countries.