TASK FEEDBACK EFFECTS ON CONFLICT MONITORING AND EXECUTIVE CONTROL: RELATIONSHIP TO SUBCLINICAL MEAS

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TASK FEEDBACK EFFECTS ON CONFLICT MONITORING AND
EXECUTIVE CONTROL RELATIONSHIP TO SUBCLINICAL
MEASURES OF DEPRESSION
Avram J. Holmes, Diego A. Pizzagalli
Harvard University Department of Psychology
Feedback
Behavioral Results
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• Pseudo-randomized and fully counterbalanced
  feedback was presented prior to each behavioral
  block (excluding practice blocks).
• Positive Feedback Compared to subjects who have
  already participated in the study your
  performance in the last block was ABOVE AVERAGE.
  Please remember to respond as quickly as possible
  to the stimuli while remaining accurate.
• Negative feedback Compared to subjects who have
  already participated in the study your
  performance in the last block was significantly
  BELOW AVERAGE. Please remember to respond as
  quickly as possible to the stimuli while
  remaining accurate.

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Participants
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• 57 Harvard University undergraduate students and
  community subjects (63 Caucasian 68 female
  mean age 23.46, SD 7.93, mean ed. 14.83, SD
  1.99).
• For a portion of the analyses participants were
  placed into groups based on their Beck depression
  inventory scores8.
• Simon task, the low BDI (mean BDI 3.50, S.D.
  0.88) and high BDI (16.573.34) included 21 and
  13 subjects, respectively.
• Stroop task, the low BDI (3.430.87) and high BDI
  (16.383.40) included 20 and 14 subjects.

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• Stroop Task ANOVAs
• The Group x Condition interaction for Gratton RT
  scores suggested that high and low BDI subjects
  differed in their Gratton effects irrespective of
  feedback (F1,32 5.14, p lt 0.04 (Fig 4). Low (p
  lt 0.001) but not high (p gt 0.5) BDI subjects were
  significantly faster for the incongruent
  following incongruent trials.
• Simon Task regression analysis
• The regression indicated that even after
  controlling for positive feedback effects BDI
  scores explained unique variance in post-conflict
  adjustment scores ?R2 0.119, ? F(1,54) 7.32,
  p 0.009 (Fig. 5).
• Stroop Task regression analysis
• As with the Simon task the regression indicated
  that, after controlling for positive feedback
  effects, BDI scores explained unique variance in
  post-conflict adjustment scores ? R2 0.092, ?
  F(1,54) 5.60, p lt 0.03 (Fig 6).

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Laming/Rabbit Effect
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RT
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Tasks
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• A series of probes appeared one at a time
  separated by a fixation cross.
• Probes were presented for 200ms. Following the
  probe an inter-trial interval was jittered
  (2300,2800,3300ms).
• 98 congruent trials and 54 incongruent trials in
  each block (37.5 incongruent trials per 736 min
  block).
• Simon Task trials consisted of one congruent
  probe (green circle) and three incongruent probes
  (red circle, red square, and green square).
• Probes were presented to the left or right of a
  fixation cross, and participants were instructed
  to make spatial responses with either their left
  or their right index fingers.

Conclusions

• The present findings confirm that individuals
  utilize errors and negative feedback to monitor
  their performance and adjust behavior
  accordingly, consistent with the theory that
  response conflict and errors act as a signal to
  allocate increased levels of cognitive control on
  subsequent trials.
• Participants with elevated depressive symptoms
  showed decreased post-error and post-conflict
  performance, emerging mainly within the context
  of emotionally negative feedback relating to task
  performance.
• Whether these behavioral impairments are due to
  dysfunctions within frontocingulate pathways
  subserving conflict monitoring, error processing,
  and feedback evaluation should be tested in
  future neuroimaging studies.

• Stroop Task stimuli consisted of three words
  (RED, GREEN, and BLUE) printed in three different
  colors of ink (red, green, and blue).