Influence of Task Complexity on Manual Asymmetries

Abstract

The degree of manual asymmetry is generally assumed to vary with task complexity. However, task complexity as a factor in manual asymmetries has rarely been examined directly. Further, the results of psychophysical studies indicate that manual asymmetry increases with task complexity, while physiological studies consistently report a reduction of manual asymmetries in more complex tasks. The use of different tasks (rather than different complexity levels within a given task) in many psychophysical studies might result in this inconsistency. This study investigated the influence of task complexity on manual asymmetries in 70 right-handed subjects. We used three complexity levels within a finger-tapping paradigm. A strong advantage of the preferred hand was particularly pronounced in the simple finger-tapping task. When the task was more complex, the advantage of the preferred hand, and thus, the manual asymmetry significantly decreased or disappeared. These results support previous suggestions that simple motor tasks involve localised neural networks confined to one cerebral hemisphere, while complex motor tasks are controlled by more widely distributed neuronal assemblies that involve both hemispheres. However, the influence of task complexity on manual asymmetry seems not to be monotonic.

Bimanual information processing and the impact of conflict during mirror drawing

“…This finding hints at regular realignment of the hand positions due to task complexity, herewith weakening betweenhand performance differences. The latter is in line with previous data that have demonstrated that the degree of manual asymmetry diminishes with task complexity [23].…”

Task complexity relates to activation of cortical motor areas during uni- and bimanual performance: A functional NIRS study

“…During all periods, subjects were reminded to avoid any movements not associated with the required tasks. Each subject performed finger-tapping tasks with increasing complexity as employed by previous studies (Hausmann et al, 2004, Lissek et al, 2007: two 'simple' unimanual (condition 1 and 2) and two 'complex' unimanual (condition 3 and 4) sequence finger-tapping tasks each first using the right and then the left hand. Each subject also performed one 'complex' bimanual (condition 5) sequence finger-tapping task using both hands.…”

Hora de balanço

“…Não obstante, apesar das diferenças não se revelarem significativas em relação à assimetria manual, Lissek et al (123) observaram diferenças na activação cerebral durante a realização da tarefa motora, sendo que o sexo feminino demonstrou uma activação cortical mais bilateral do que o sexo masculino. A natureza da tarefa bem como a organização cerebral distinta em ambos os sexos têm sido apontadas como os principais factores que contribuem para esta discrepância de resultados (112,124) .…”