Motivational Modulation of On-Line Attention Control Processes

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Motivational Modulation of On-Line Attention Control Processes

Catherine Poulsen, Ph.D.
Concordia University, 2000

This thesis brings together two broad subdisciplines of psychology --
cognition and motivation -- in order to explore how motivational processes
interact on-line with cognitive mechanisms in directing human behaviour and
performance. A series of five experiments were conducted in which the Rogers
and MonseU(1995) task switching paradigm was combined with motivational
manipulations involving earned point incentives (Derryberry, 1993) to
investigate the effects of prior and current motivation on task execution,
attention switching, and inhibition. Using a leftlright button press, participants
alternated every second trial between vowel/consonant (letter task) and
evedodd (digit task) judgments in response to target-foil stimulus pairs (e-g.,
A3, G#, ?6) presented on a computer monitor. Participants responded to the
letter or ciigit target while inhibiting the competing (letter or digit) or neutral
(spbo!) foil. Task motivation was =lar+xdatec! by assigri~g p2rrfucipmts
equal or differential incentives for letter and digit task performance during an
initial training phase or during the switch task itself. Motivational incentives
were found to have a large and selective influence on attention switching,
evidenced by faster switching to the high-valued than low-valued task, but had
no effect on either simple task execution processes or the inhibition of task-set
cuing by a competing foil. In addition, prior motivational experience with
differential task incentives during training had a greater and more reliable
impact on attention switching than did current differential incentives applied
during the switch task itself. These results reveal that motivation does not
simply have a global facilitating influence on performance, but rather operates
through highly specific mechanisms to bias goal-directed behaviour. Results
are interpreted in terms of the apparent differential sensitivity to motivational
input exhibited by attention control mechanisms versus automatic, stimulustriggered processes. A finther distinction is made between implicit
motivational modulation of executive control mechanisms versus the
engagement of an optional, incentive-based performance strategy. Also
discussed are speculations regarding underlying neural mechanisms mediating
these motivational influences on attention and the potential implications of
these results for skill development and performance.