ABSTRACT
For many years, it was assumed that spatial S-R compatibility effects would only arise when the stimulus and response sets shared the same spatial dimensions, or were spatially congruent. Because orthogonally oriented S-R sets, such as up and down stimulus positions mapped to left and right responses, provide no basis for spatial correspondence, there was little reason to think that one mapping might be preferred to another. For example, Bertelson (1963) included conditions in which subjects made left and right keypresses to two vertically aligned stimulus locations, but he averaged across the mappings for a single “perpendicular” condition that he compared with direct and crossed mappings of horizontally aligned stimulus locations. However, studies of direction-of-motion stereotypes provided some suggestion of preferred mappings for orthogonal stimulus and response sets (see Chapter 9). For instance, Vince and Mitchell (1946) found that subjects preferred a rightward movement of a lever to move an indicator up and a leftward movement to move the indicator down. Research beginning in the latter half of the 1970s has confirmed that systematic, sometimes quite strong, S-R compatibility effects occur when stimuli and responses vary along orthogonal dimensions. Considerable effort in recent years has been devoted to explaining why these orthogonal S-R compatibility effects occur and how they relate to the more typical spatial correspondence effects discussed in earlier chapters.
