ASYMMETRIC INTERFERENCE BETWEEN CONCURRENT TASKS - AN EVALUATION OF COMPETING EXPLANATORY MODELS

According to Kinsbourne's functional cerebral distance model, asymmetr ic interference between concurrent cognitive and manual tasks reflects the functional specialization of the cerebral hemispheres. However, a lternative explanations include initial-values artifact (statistical b ias model), motor asymmetry (manual dominance model), and a combinatio n of functional cerebral distance and manual dominance (two-factor mod el). We evaluated the competing models in four experiments with right- and left-handed university students for whom manual dominance was in effect reversed by requiring the dominant hand to perform the more dif ficult manual task. The cognitive load of the nonmanual task was varie d within each experiment. The results did not support any of the model s but, instead, reflected only tradeoffs between manual and nonmanual performance. The primary implications for future research are that per formance on both tasks must be measured, and each task must be sensiti ve to interference from the other task, if observed asymmetries are to be interpretable. (C) 1997 Elsevier Science Ltd.