Sex differences in object location memory.

The ability to remember where objects were is thought to require multiple separate processes. One has to encode the precise positions occupied, assign the various objects to the correct (relative) locations, and achieve an integration of both types of spatial information. This study examined whether sex differences exist for these selective components of object location memory. Twenty males and 20 females participated in the following task. On a PC screen, they were shown a square with 10 different objects for 30 s. Subsequently, the objects disappeared from the screen, reappeared in a row above the square, and subjects were asked to relocate them in three different conditions. In the object-to-position-assignment condition, the original positions were premarked in the square, so subjects needed only to assign the correct object to the correct position. In the positions-only condition, all objects assumed the same identity. Therefore, subjects had only to reproduce the precise positions. Finally, in the combined condition, subjects were required to replace all the different objects in the square without any of object positions premarked. The absolute displacements between an object's original and its relocated position reflect the integration mechanism. Females did as well as males in the object-to-position-assignment condition and on the absolute displacements in the combined condition, but they were less efficient than males in positional reconstruction per se. Thus, it seems that the male advantage in spatial memory is not a general effect but applies only to certain specific processing components. Moreover, the employment of a dual task during encoding, concurrent articulatory suppression, yielded no significant interactions with sex. This suggests that females' weaker positional encoding does not derive from the use of an inefficient verbal strategy.