Sex differences in the Simon task help to interpret sex differences in selective attention

Abstract

In the last decade, a number of studies have reported sex differences in selective attention, but a unified explanation for these effects is still missing. This study aims to better understand these differences and put them in an evolutionary psychological context. 418 adult participants performed a computer-based Simon task, in which they responded to the direction of a left or right pointing arrow appearing left or right from a fixation point. Women were more strongly influenced by task-irrelevant spatial information than men (i.e., the Simon effect was larger in women, Cohen's d = 0.39). Further, the analysis of sex differences in behavioral adjustment to errors revealed that women slow down more than men following mistakes (d = 0.53). Based on the combined results of previous studies and the current data, it is proposed that sex differences in selective attention are caused by underlying sex differences in core abilities, such as spatial or verbal cognition.

Fig. 1

Population pyramid of the 236 male and 182 female participants. The average age of male participants (27 years) was slightly higher than that of women (25 years, p = .01). If participants under 23 years of age would be excluded, the difference would no longer be significantly different and conclusions drawn from the analyses would not differ, though

Fig. 2

Schematic representation of the four conditions in the Simon task. Each trial started with a fixation stimulus (plus), followed by an arrow on its left or right side. The task was to respond with the left (A) key to a left pointing arrow and the right (L) key to a right pointing arrow. In the two instances of the compatible condition, the arrow and position relative to the fixation point matched, whereas they were in conflict in the two instances of the incompatible condition. It is well established that people respond more slowly in the incompatible condition, a phenomenon also known as the Simon effect

Fig. 3

Response times as a function of sex and stimulus–response compatibility. Bars indicate mean + 1 SEM. The Simon effect was larger in the group of women (42 ± 2.4) than in the group of men (29 ± 2.1)