Mental Rotational Ability Is Correlated with Spatial but Not Verbal Working Memory Performance and P300 Amplitude in Males

Gregory J Christie,Deborah M Saucier,Janice Sutherland,Brian J Ward,Matthew S Tata,Robert J Sutherland,Charles M Cook,Corrado Sinigaglia

doi:10.1371/journal.pone.0057390

Gregory J Christie, Deborah M Saucier + Show 6 more

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https://doi.org/10.1371/journal.pone.0057390

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Abstract

This study investigated how both sex and individual differences in a mental rotation test (MRT) influence performance on working memory (WM). To identify the neural substrate supporting these differences, brain electrical activity was measured using the event-related potential technique. No significant sex differences were observed in a test of verbal WM, however males were significantly faster than females to respond to probe stimuli in a test of spatial WM. This difference was no longer significant after controlling for differences in MRT score, suggesting that rotational ability mediates performance in the spatial memory task for both sexes. A posterior P300 was observed in both tasks as participants encoded information into memory, however the amplitude of the P300 correlated with RT in the spatial task but not in the verbal task. Individual differences in the MRT also correlated with RT and with the amplitude of the P300, but again only in the spatial task. After splitting the analysis by sex, partial correlations controlling for MRT revealed that for males, individual differences in rotational ability completely mediated the correlation between the P300 and RT in the spatial task. This mediating effect was not observed for the female participants. The results therefore suggest a relatively stronger association in males between innate mental rotational ability, spatial memory performance, and brain electrophysiological processes supporting spatial memory.

Highlights

There are no systematic differences in intelligence between adult males and females [1], certain tasks may elicit relatively differential performance including a male advantage for several tests of spatial reasoning and the manipulation of mental imagery [2]
To elucidate the neural origins of these differences, scalp-recorded event-related potentials (ERPs) were obtained both when participants initially encoded information into working memory (WM) and when they subsequently compared a probe item against the information retained in WM
When the analysis was restricted to the sample of randomly recruited participants, we replicate the male advantage in the spatial task first reported in our pilot study: males were faster at the spatial task than their own performance on the verbal task, and they were

Summary

Introduction

There are no systematic differences in intelligence between adult males and females [1], certain tasks may elicit relatively differential performance including a male advantage for several tests of spatial reasoning and the manipulation of mental imagery [2]. The MRT yields one of the largest [7,8] cognitive sex differences between adult males and females, with a male advantage of approximately 0.8 – 1.0 d [9,10,11,12,13]. Whereas female performance on other tests of spatial cognition (e.g. spatial visualization) have improved substantially through the period from 1945–1995 [7], the magnitude of the sex difference in the MRT has remained largely unchanged [14]. The male advantage for covert rotation is evident for the rotation of simple two-dimensional shapes [15] and real-world objects such as animals, tools, and persons, effect sizes are smaller [16]

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