The standardized path coefficient and t-value for hypothesis H2a showed a negative sign for the relationship between extrinsic instrumentality and work motivation (b ¼ _.14, po.01), not supporting our hypothesis. Basi-cally, the negative sign was opposite to our expectation. The unexpected result may be explained by a suppressor effect ( Cohen and Cohen, 1983). A suppressor variable is basically defined as a variable that increases the predictive validity of another variable (or set of variables) by its inclusion in a regression equation ( Conger, 1974; Cohen