Neural basis of cultural influence on self-representation

INTRODUCTION

Self-representation determines the relationship between ourselves and others in social behaviors (Zhu, Zhang, Fan & Han, 2007)

Westerners

EAST ASIANS

How is cultural influence on self-representation accomplished in the human brain?
(Zhu et al., 2007)

Neural Substrates of Self-Representation

Self-descriptive traits vs. other-descriptive traits

MPFC ACTIVATION LINKED TO SELF-JUDGMENTS
(Craik et al., 1999; Kelley et al., 2002; Liebermann et al., 2004; Zhang et al., 2006)

MPFC engaged in representation of self-knowledge, like one's own personality traits (Zhang et al., 2007)

Self-referential effect influenced by culture

Does the Chinese self include intimate others while the Western self excludes any others?

Stronger MPFC activation linked to self- than best-friend-judgments in Americans (Heatherton et al., 2006)

HYPOTHESIS:
Is MPFC activation unique to representations of the individual's self for Westerners but not for Chinese?

METHODS

N = 26
(13 Chinese, 13 Western)

Mean age (Western) = 21.5, SD =1.13
Mean age (Chinese) = 23.1, SD =2.33

METHODS

• Placed in fMRI
• Shown one of four cue words
• Referenced either self, mother, or public other
• Font discrimination task as control
• Asked if adjective matched cue word

METHODS

• 384 adjectives
• 32 lists of 12 words each

METHODS

• Given surprise recognition test
• Remember "self" vs. "others" words
• Tested for conscious remembrance
• Extraneous brain activity controlled for

RESULTS

MPFC showed increased activity to self- than other-judgments for both Chinese and Western

Contrast between mother- and other-judgments showed stronger activation in MPFC and left prefrontal cortex in Chinese subjects

However, contrast between mother- and other-judgments showed activation ONLY in ACC for Westerners

Self-judgment increased MPFC activity

Other-judgment decreased MPFC activity

MPFC activity associated with mother-judgment increase in Chinese
and
decreased in Westerners

The interaction between culture and judgement was reliable and significant (F(2,48) =3.58, p

Paired t-tests confirmed fMRI signals were larger in self- than mother-judgment tasks for Westerners (t(12) = 2.624, p 0.05).

Culture x Reference x Activation Foci was significant (F(1,24) = 5.90, p

Culture (Western vs. Chinese)
Reference (Self vs. mother)
Activation Foci (MPFC vs. ACC)

This indicates cultural effects on neural substrates of self-representation was mainly evident in MPFC activity (Zhu et al., 2007)

DISCUSSION

Reinforced Heatherton et al.'s (2006) evidence for neural distinction between self and intimate persons evident for Westerners but not Chinese

Replicated previous work (Zhu & Zhang, 2002), showing personal traits related to self-judgments better remembered than mother-judgments for Westerners but not Chinese

Found stronger MPFC activation in self-relative vs. other-judgments, consistent with previous studies of Westerners (Kelley et al., 2002; Lieberman et al., 2004)

MPFC found to be specific to self for Westerners, indicated by decrease in activity for mother-judgments (Zhu et al., 2007)

Despite these differences between Westerners and Chinese, the locus of activity in the MPFC was similar between groups for self-representation

However, there was no distinction between the self-judgment and the mother-judgment in Chinese individuals, indicating usage of MPFC for self and mother

These results indicate that habitual ways of processing information correspond with detectible parallel neural processes (Zhu et al., 2007)

Limitations

• Small sample size
• Different types of Westerners
• All Westerners had spent time in China