The effect on performance of hemispheric attentional load in function of two modalities of afference-efference

Abstract

The effects of the hemispheric attentional load on performance was investigated while manipulating two modalities of afference-efference. Twenty-one male subjects participated in this study. Two main tasks were selected. The verbal task consisted of repeating words heard monaurally during a period of ten seconds. The motor task was an index finger tapping task of ten second duration. Eight blocks of four trials were presented. Eight experimental conditions were identified: (1) right hand alone; (2) left hand alone; (3) right ear alone; (4) left ear alone; (5) right hand and right ear; (6) right hand and left ear; (7) left hand and right ear; (8) left hand and left ear. Number of correctly pronounced syllables, number of taps on the key, and standard deviation of time of intertap intervals (ITI) were used as measures of performance. The analysis of verbal performance and the variability of intertap intervals did not reveal any significant difference between the experimental conditions. The motor speed results indicated that only the right hand and right hand ⇔ left ear conditions were significantly faster than all other conditions; F(5,415) = 7.42, p < 0.001. Moreover, the second phase trials (from 5 to 10 sec) were significantly slower than the first (from 0 to 5 sec); F(1,83) = 46.97; p < 0.001. The conclusions were that (1) the increase of hemispheric attentional load had a negative effect on performance above a critical load level, (2) two modalities of afference/efference, when utilized in the same perceptual hemifield, had opposite effects on performance according to the hemispheric location, (3) two afference-efference modalities, each used in a different perceptual hemifield, had similar effects on performance, according to their hemispheric location.