Do the global advantage and interference effects covary?

The global precedence hypothesis has been operationally defined as a faster or earlier processing of the global than of the local properties of an image (global advantage) and as interference by processing at the global level with processing at the local level (global interference). Navon (1977) proposed an association between the global advantage and interference effects. Other studies have shown a dissociation between the two effects (e.g., Lamb & Robertson, 1988). It seems that the controversy in previous research resulted from not equalizing the eccentricities of global and local properties. In the present study, the eccentricities of the two levels were equalized by using stimuli with all their elements located along their perimeters. The results of the first experiment demonstrated that although the global level was identified faster than the local level in both the central and the peripheral locations of the visual field (global advantage), the pattern of global interference varied across the visual field. Consistency of global and local levels increased the speed of processing of the local level displayed at the center of the visual field but slowed down the processing of that level at peripheral locations. The results of Experiment 2 demonstrated that it was most likely that the variation in the pattern of global interference was determined by the variable of eccentricity, rather than by the sizes of the global and local levels.