Brain activities during Go/No-Go Association Task

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" Brain activities during Go/No-Go Association
Task "

• Kouichi Hioki1,
• Katsunori Matsuoka2, Hiroshi Watanabe2, Hiroyuki
  Umemura2
• 1Kobe University Graduate school of letters,
  Kobe, Japan.
• 2National Institute of Advanced Industrial
  Science and Technology, Human Stress Signal
  Research Center, Japan.
• E-mailkohioki_at_lit.kobe-u.ac.jp

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Plan of presentation

• What is Go/No-Go Association Task(GNAT)
• Our Opinion
• Neurophysiological knowledge
• Method and result
• Conclusion

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What is Go/No-Go Association Task(Dilemma of
social psychology)

• Although discrimination still exists, White
  Americans tend to answer that they dont have
  prejudice to African Americans(Wittenbrink, Judd,
  Park., 1997.).
• ?
• Some distortion is included in measurement in
  question papers.

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What is GNAT

• Greenwald, McGhee, Schwartz, (1998) noted that
  there are some differences in reaction time to
  stereotype words between high and low prejudice
  person.
• And they created Implicit Association Test(IAT)
  as a measure for implicit prejudiced degree.
• Then, Nosek Banaji(2001) created Go/No-Go
  Association Task(GNAT) as an improved version of
  IAT.

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What is GNAT
Bugs
Good
Rose
Sunflower
Honer
Flea
Cockroach
Lily
Poison
Lucky
Happy
Sad
Spider
Evil
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What is GNAT
Flower
Bad
Rose
Sunflower
Honer
Flea
Cockroach
Lily
Poison
Lucky
Happy
Evil
Sad
Spider
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What is GNAT

• GNAT is considered to be the tool which measures
  the strength of the implicit association between
  a concept and an attribute category.
• However, it remains an unsettled question whether
  the GNAT score is a score which reflected
  "Association" truly.

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Our Opinion

• While performing the incongruent trials (e.g.,
  discriminating Flower and Bad from
  distracters), we should be making the conflict
  state occur.
• And while performing the congruent
  trials(Flower and Good) , a conflict state
  will not occur.
• They can be checked on Neurophysiologcally.

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Neurophysiological knowledge

• Conflict state
• The characteristic which a stimulus has crosses
• (Bugbad ? Good good)
• and the amount of information which should be
  processed increases.
• When a conflict state occurs, Anterior
  Cingulate Cortex(ACC) will also be activated
• (Fan, Flombaum, McCandliss, Thomas, Posner,
  2003).

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ACC (Anterior cingulate cortex)
VeenCarter(2002)showed that negative brain waves
were checked, when ACC was activated.
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Hypothesis

• While performing the incongruent trials (e.g.,
  discriminating Flower and Bad from
  distracters), we should be making the conflict
  state occur.
• While performing the congruent trials(Flower
  and Good) , a conflict state will not occur.
• In Incongruent trials.
• ?Negative brain waves would be checked
• In Congruent trials.
• ?Negative brain waves wouldnt be checked

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Method

• Participants4 male participants
• Recorded Event Related Potentials(ERP) with 5 tin
  electrodes during GNAT trials .
• Trial
• Congruent Trial(72trials)
• Discriminating Flower and Good from
  distracters
• Incongruent Trial (72trials)
• Discriminating Flower and Bad from
  distracters

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Data Sampling

• Sampling late 1000Hz.
• Base line left earlobe
• Filter Below 0.5Hz. Above 30Hz.
• Fz/Cz/C3/C4/Pz(The10-20system)

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Results

• All the participants showed short reaction time
  in Congruent Trials.

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Waveforms(Congruent Trial)
µV
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Waveforms(Incongruent Trial)
µV
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Waveforms(FZ)
µV
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Conclusion

• All the participants showed short reaction time
  in Congruent Trials.
• Only in Incongruent trials, the negative waveform
  has been checked at after about 200ms from the
  reaction .
• The ACC activated only in GNAT Incongruent
  trials.
• Therefore, we can say the GNAT time lag may
  reflect cognitive conflict.