Simplifying the Implication-Realization Model of Melodic Expectancy

Results from previous investigations indicate that the implication-realization (I-R) model (Narmour, 1990) of expectancy in melody may be overspecified and more complex than necessary. Indeed, Schellenberg's (1996) revised model, with two fewer predictor variables, improved predictive accuracy compared with the original model. A reanalysis of data reported by Cuddy and Lunney (1995) provided similar results. When the principles of the I-R model were submitted to a principal- components analysis, a solution containing three orthogonal (uncorrelated) factors retained the accuracy of the model but was inferior to the revised model. A separate principal-components analysis of the predictors of the revised model yielded a two-factor solution that did not compromise the revised model's predictive power. Consequently, an even simpler model of melodic expectancy was derived. These results provide further evidence that redundancy in the I-R model can be eliminated without loss of predictive accuracy.