1. " Brain activities during Go/No-Go Association Task " Kouichi Hioki 1, Katsunori Matsuoka 2, Hiroshi Watanabe 2, Hiroyuki Umemura 2 1 Kobe University Graduate school of letters, Kobe, Japan. 2 National Institute of Advanced Industrial Science and Technology, Human Stress Signal Research Center, Japan. E-mail:kohioki@lit.kobe-u.ac.jp

2. Plan of presentation  What is Go/No-Go Association Task(GNAT)  Our Opinion  Neurophysiological knowledge  Method and result  Conclusion

3. What is Go/No-Go Association Task (Dilemma of social psychology)  Although discrimination still exists, White Americans tend to answer that they don’t have prejudice to African Americans(Wittenbrink, Judd, Park., 1997.). ↓  Some distortion is included in measurement in question papers.

4. 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.

5. What is GNAT BugsGood FleaCockroach Spider Lily RoseSunflowerHoner PoisonLuckyHappy Evil Sad

6. What is GNAT FlowerBad FleaCockroach Spider Lily RoseSunflowerHoner PoisonLuckyHappyEvilSad

7. 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.

8. 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.

9. Neurophysiological knowledge Conflict state:  The characteristic which a stimulus has crosses (“Bug”=bad ⇔ “Good” = good) and the amount of information which should be processed increases. ・ When a conflict state occurs, Anterior Cingulate Cortex(ACC) will also be activatedAnterior Cingulate Cortex(ACC) （ Fan, Flombaum, McCandliss, Thomas, & Posner, 2003 ）.

10. ACC (Anterior cingulate cortex) Veen ＆ Carter （ 2002 ） showed that negative brain waves were checked, when ACC was activated.

11. 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 wouldn’t be checked

12. Method  Participants:4 male p articipants  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

13. Data Sampling  Sampling late: 1000Hz.  Base line: left earlobe  Filter: Below 0.5Hz. Above 30Hz.  Fz/Cz/C3/C4/Pz （ The10 ‐ 20system ）

15. Results  All the participants showed short reaction time in Congruent Trials.

16. Waveforms(Congruent Trial) μV

17. Waveforms(Incongruent Trial) μV

18. Waveforms(FZ) μV

19. 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.