DC Shifts and Event-related Potentials Associated with Workload in a Dual Task Situation

  • W. C. McCallum
Part of the Brain Dynamics book series (BD)


McCallum et al. (1988) reported the appearance of negative DC shifts associated with involvement in a manual tracking task. Subjects tracked a moving letter across a screen under conditions in which tracking difficulty was systematically manipulated and various decisions and responses were demanded. Each tracking trial lasted approximately 28 sec during which a progressive negative shift of cortical potential was observed as the level of task involvement increased. In the more difficult trials, these negative shifts were of significantly greater amplitude than in easier trials. Toward the beginning of each trial transient positive-going shifts were associated with the visual presentation and memorization of sets of letters that had to be utilized in target decisions during the course of tracking. Letter-set size was varied from 1 to 6 to create a memory paradigm of the type described by Sternberg (1969). McCallum et al. found that the level of positivity was directly related to set size.


Tracking Error Primary Task Secondary Task Negative Shift Tracking Task 
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  1. McCallum WC (1991): DC shifts in the human brain: Their relationship to the CNV and Bereitshaftspotential. In: From Neuron to Action, Deecke L, Eccles JC, Mountcastle VB, eds. Heidelberg: SpringerGoogle Scholar
  2. McCallum WC, Cooper R, Pocock PV (1988): Brain slow potential and ERP changes associated with operator load in a visual tracking task. Electroencephalogr Clin Neurophysiol 69: 453–468CrossRefGoogle Scholar
  3. Sternberg S (1969): The discovery of processing stages: Extensions of Donder’s method. In: Attention and Performance, Koster WG, ed. Acta Psychol 30:276315Google Scholar
  4. Wickens C, Kramer A, Vanasse L, Donchin E (1983): Performance of concurrent tasks: A psychophysiological analysis of the reciprocity of information processing resources. Science 221: 1080–1082CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1993

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  • W. C. McCallum

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