Effects of Isometric Hand-Grip Muscle Contraction on Young Adults' Free Recall and Recognition Memory

Abstract

Purpose: The purpose of this study was to determine if physical arousal produced by isometric hand-dynamometer contraction performed during word-list learning affects young adults' free recall or recognition memory. Method: Twenty-four young adults (12 female; Mage = 22 years) were presented with 4 20-item word lists. Moderate arousal was induced in 12 adults by an initial 30-s maximal hand-dynamometer squeeze with force productions of 50% maximum; low arousal was induced in 12 adults by an initial 1-s maximal dynamometer squeeze with force production of 10% maximum during learning. Memory performances following dual-task conditions experienced during the encoding, consolidation, and recall phases of learning were compared to a single-task control condition during which words were learned in the absence of isometric exercise. Results: Planned contrasts revealed that arousal coinciding with word encoding led to significantly poorer immediate recall, F(1, 23) = 10.13, p < .05, = .31, delayed free recall, F(1, 23) = 15.81, p < .05, = .41, and recognition memory, F(1, 23) = 6.07, p < .05, = .21, compared with when there was no arousal. Neither arousal condition facilitated participants' memory performance. Conclusion: The reduction in long-term memory performance specific to the encoding phase of learning is explained in terms of the dual-task attentional demands placed on participants.