Self-Referential Processing and Encoding in Bicultural Individuals. Master's Thesis. Presented to

Transcription

1 Self-Referential Processing and Encoding in Bicultural Individuals Master's Thesis Presented to The Faculty of the Graduate School of Arts and Sciences Brandeis University Department of Psychology Angela Gutchess, Advisor In Partial Fulfillment of the Requirements for Master's Degree by Sarah Huff August 2012

2 Copyright by Sarah E. Huff 2012

3 Acknowledgements I would like to thank my advisor, Angela Gutchess, for her incredible mentorship and support, and for her willingness to allow me to pursue the research that is most exciting to me. I would also like to thank my second reader, Malcolm Watson, for his thoughtful comments. This project would not be where it is without the endless data analysis assistance and comments from our Post-Doctoral Research Fellow, Eric Leshikar. I would also like to express gratitude to the students in The Aging, Culture, and Cognition Lab, especially my fellow graduate students, Brittany, Chad, Hyeon, Nicole, and Margeaux for their friendship and encouragement. Finally, I want to thank my family, especially my parents, for giving me the opportunities that allow me to be where I am and for always believing in me. iii

4 ABSTRACT Self-Referential Processing and Encoding in Bicultural Individuals A thesis presented to the Psychology Department Graduate School of Arts and Sciences Brandeis University Waltham, Massachusetts By Sarah Huff Previous research has shown that cultural effects modulate both cognitive processes, such as memory, and neural activation. Neuroimaging evidence suggests that the medial prefrontal cortex (dmpfc and vmpfc) and posterior cingulate cortex (PCC) are involved in self-referential processing and memory, and that the specific activations differ as a result of cultural effects. In the current fmri study we used an adjective trait judgment task and surprise recognition memory task to investigate how having a bicultural identity influences self-referential processing and memory as compared to both a close other (mother) and distant, familiar other (Gandhi). Contrary to our expectations, results indicate that the dmpfc is more engaged for mother-referential processing than self-referential processing in our sample of bicultural Asian Americans. In terms of subsequent memory, there was increased activation in the PCC for mother-relevant and other relevant (compared to self-relevant) information that supported subsequent memory. Finally, we observed reversals in the pattern of activity in the dmpfc for iv

5 subsequent memory in those high in bicultural identity integration and those low in bicultural identity integration. These findings suggest that cultural effects, specifically bicultural identity integration, modulate neural activity during judgment and encoding of information relevant to the self and others. v

6 Table of Contents I. List of Tables.vii II. III. List of Figures...viii Introduction..1 A. Cognitive Representation of the Self...3 B. Neural Representation of the Self 5 C. Considering Individual Differences in the Self...7 D. Neural Evidence for a Dynamic Self in Bicultural Individuals...8 IV. Methods..13 A. Participants...13 B. Procedure...14 C. Imaging Parameters...15 D. Data Analysis.16 V. Results A. Bicultural Identity Integration 18 B. Behavioral Recognition Performance...18 C. Functional Imaging Data...19 VI. VII. VIII. VII. Discussion..22 Appendix A: Tables...32 Appendix B: Figures..33 References..36 vi

7 List of Tables 1. Summary of corrected recognition (hits-false alarms) presented in two forms: collapsed across BII and split by BII scores. vii

8 List of Figures 1. Parameter estimates for the peak voxels (labeled above each graph) extracted from significant activations that emerged from the processing data. 2. Parameter estimates for the peak voxels (labeled above each graph) extracted from the significant activations that emerged from the subsequent memory data. Panel A represents the contrast [mother remembered-mother forgotten]-[self remembered-self forgotten]. Panel B is [other remembered-other forgotten]-[self remember-self forgotten]. 3. Parameter estimates for the peak voxels (labeled above each graph) extracted from the significant activations that emerged from the interaction between subsequent memory data and Bicultural Identity Integration (BII) scores. The contrast shown above is low BII-high BII:[self remembered-self forgotten]- [mother remembered-mother forgotten]. viii

9 Self-Referential Processing and Encoding in Bicultural Individuals Culture has a fundamental influence on the development of the self; psychologists have frequently described culture as a lens for understanding the environment (Gutchess & Indeck, 2009). It informs our experiences, our conception of self in relation to others, as well as our cognitive functions, such as memory. An important consideration in the study of culture is that as globalization increases, fewer people identify with a single culture, making culture no longer a unidimensional term. Of people living in the United States, one out of every four has lived in another culture before moving to the United States and likely identifies with both cultures (U.S. Census, 2002, as cited in Benet-Martinez & Haritatos, 2005). According to the 2010 U.S. Census, the racial group that has had the highest percentage increase in the last ten years is of Asian descent. The number of people of Asian descent in America grew by 46% since 2000, to a total of 17.3 million U.S. citizens (U.S. Census, 2010). As multiculturalism becomes more prevalent throughout the United States and the rest of the world, it will become even more important to understand how the self is constructed for individuals who identify with more than one culture. Development of the self has been researched extensively, and inconsistencies emerge between whether the self is a stable, enduring concept or a dynamic entity. Moran and colleagues (2006) argue that, a central feature of human existence is the 1

10 possession of a sense of self that persists across space and time (p. 1586), whereas others state that the self is dynamic, prone to influence, and inconsistent across environments (Ng, Han, Mao, & Lai, 2010; Sui, Zhu, & Chiu, 2007). Furthermore, evidence suggests that culture has an influence on the self. Markus and Kitayama (1991) propose that people possess either an independent or an interdependent self-concept. Those with an independent self-concept tend to focus on individual uniqueness and success. In contrast, those with an interdependent self-concept are motivated by belonging to the group and contributing to the collective wellbeing. The constructs of individualism and collectivism have been used to categorize cultural ideologies and tendencies (Hofstede, 1980), and people from individualistic cultures tend to have a more independent self-concept, while those from collectivist cultures more often identify with an interdependent self (Triandis, 1995). Many East Asian cultures value the interdependent self whereas American culture encourages development of the independent self (Markus & Kitayama, 1991), and therefore the distinction between independent and interdependent self may be especially relevant for people who are bicultural Asian American, because these individuals likely possess both an interdependent and an independent self-concept. Most East Asians have an integrated interdependent self and attend to close others (e.g. mother) as much as they do to the self, whereas Americans are highly independent and attend to the self above all others, including the mother (Sui, Zhu, & Chiu, 2007). Hong, Morris, Chiu, and Benet- Martinez (2000) found that bicultural Chinese participants in Hong Kong and America were able to activate both Chinese and American cultural meaning systems. Therefore, a person who is exposed to both Asian and American cultural values may possess both the 2

11 interdependent and the independent self-construal styles, which may create a multidimensional self-concept. The possession of a multidimensional self requires the ability to use environmental cues to adjust one s self-construal style, a process that is defined as bicultural frame switching (Benet-Martinez & Hariatos, 2005; Hong et al., 2000; Ng, Han, Mao, & Lai, 2010). The ability to alter behavior based on cultural cues is influenced by the level of integration one feels within their multiple cultural identities, also known as Bicultural Identity Integration (referred to from here on as BII). People with high levels of identity integration view their multiple cultural identities as compatible, whereas those who view their cultural identities as oppositional, or conflicting, experience lower levels of identity integration, and higher levels of identity integration predict more fluid cultural frame switching. For example, Benet-Martinez and colleagues (2002) used an animated fish task to demonstrate that following exposure to a cultural prime (American or Chinese), Chinese Americans high in identity integration exhibit behavior congruent with the prime, such that those exposed to the Chinese prime exhibit more external attributions to the fish. The American prime elicits American behavior, as demonstrated by making more internal attributions about the fish. Alternatively, low levels of cultural integration predict prime incongruent behavior, also described as reactance. Cognitive Representation of the Self Measuring the self and its relation to others can be a difficult task because the self is a complicated entity and difficult to access. One of the main challenges is that most researchers use explicit self-report questions, which are subject to demand characteristics 3

12 and directed self-presentation styles. Implicit measures of self-reflection, such as memory, are less susceptible to this challenge. Additionally, measures of memory have reliably reflected differences in the self versus other. Rogers, Kuiper, & Kirker (1977) demonstrated a self-reference effect in memory that differentiates self from others. Participants rated adjectives on four dimensions (structural, phonemic, semantic, selfreference) and in a surprise recognition task, they remembered self-reference items best. This self-reference effect has been replicated many times, and most recently in studies of neural activation (Kelley et al., 2002; Macrae, Moran, Heatherton, Banfield, & Kelley, 2004). In addition to assisting in understanding the self, studying memory can also illuminate cultural differences, and has previously provided strong evidence for differences in cognitive strategies among people of different cultural backgrounds (Gutchess, Schwartz, & Boduroglu, 2011). The self-reference effect has been measured across cultures and substantial differences have been found. A comparison of Chinese and American participants shows that both Westerners and Chinese participants exhibit the self-reference effect (Zhang et al., 2006; Zhu & Zhang, 2002; Zhu, Zhang, Fan, & Han, 2007). However, after viewing personality traits pertaining to the self, mother, an unfamiliar other, or making semantic judgments, both self and mother adjectives are remembered best and to a similar degree among Chinese participants, suggesting a link between self and mother. This effect is not present in American participants who generally only exhibit the self-reference effect, with less benefit from referencing one s mother (Zhang et al., 2006; Zhu & Zhang, 2002; Zhu, Zhang, Fan, & Han, 2007). 4

13 Sui, Zhu, and Chiu (2007) looked at the self-reference effect in participants exposed to cultural primes. Priming is intended to activate a certain cognitive style that stems from cultural ideology, and in this study it was independent or interdependent self. As reviewed in the discussion of bicultural frame switching, bicultural individuals use contextual cues to inform their self-construal style, and cultural priming provides participants with specific cues that guide them toward an independent or interdependent frame. In this study, Chinese students were exposed to one of three priming conditions (Chinese, American, or a Neutral control), followed by an encoding task of 40 adjectives (20 describing self and 20 describing mother). The results of a surprise recognition task demonstrated no differences across the primed groups in accuracy for the self-reference condition, however American primes resulted in worse memory for mother-referenced adjectives than the other conditions. Thus, attending to the Western cultural cues can lead to a dissociation of memory effects for self or mother relevant information, even in individuals from a culture that emphasizes interdependence. Individual differences should also be considered in this context. Some people may be more susceptible to cultural priming because of their personal adherence to individualism and the independent self or collectivism and the interdependent self (Chiu & Hong, 2006, as cited in Han & Northoff, 2009). Additionally in individuals identifying with two cultures, levels of bicultural identity integration may influence the effectiveness of cultural priming and the ability to shift self-construal styles. Neural Representation of the Self Measures of neural activation are beneficial in the investigation of the self because some evidence has shown that they can be more sensitive and demonstrate 5

14 cultural variations more clearly than behavioral measures (Chiao, 2009a; Gutchess, Hedden, Ketay, Aron, & Gabrieli, 2010; Kitayama & Uskul, 2011). Neural measures can be used to pinpoint specific brain regions involved in processing information relevant to the self or other, allowing researchers to focus on cultural and individual differences in neural activation. So far, research has consistently shown that the medial prefrontal cortex (mpfc) and the posterior cingulate cortex (PCC) are the most important regions for self-relevant processing and making judgments about self versus other (Heatherton, Macrae, & Kelley, 2004; Heatherton et al., 2006; Northoff, Heinzel, de Greck, Bermpohl, & Dobrowolny, 2006). Kelley and colleagues (2002) were among the first researchers to use fmri to identify the mpfc as a region relevant in self-processing, specifically the self-reference effect in memory. In a follow-up study by Macrae and colleagues (2004), participants were asked to make judgments about trait adjectives of self-relevance, other-relevance, or case judgment. Based on a surprise recognition task, they demonstrated that activation of the mpfc during encoding of self-relevant words predicted later memory for those selfreferenced words. By contrasting brain activation elicited by items that were remembered with those that were forgotten and contrasting activity for items that were self-relevant with items that were not relevant to the self, specific brain regions that predict recognition for self-relevant information were identified, namely the mpfc (Macrae et al., 2004). This analysis provided confirmation that the mpfc is a potential neural substrate for the self-reference effect. Recent evidence has shown differences in neural activation during self-relevant processing across cultures. In Chinese participants, both self-referential and mother- 6

15 referential encoding activates mpfc, providing a potential explanation for similar enhancements in memory for mother and self, and also suggests that the Chinese concept of self includes the mother (Han & Northoff, 2009; Zhang et al., 2006). A comparison of Western participants to Chinese participants demonstrates increased mpfc activity in Westerners during self-judgments and reduced mpfc activity for mother-judgments. For Westerners, mpfc activity is specific to the self, while self-representation in mpfc in Chinese participants cannot be differentiated from mother-representation (Zhu et al., 2007). Considering Individual Differences in the Self Group differences, such as those between Chinese and Westerners, have been demonstrated both in memory for self-relevant information (Zhang et al., 2006; Zhu & Zhang, 2002; Zhu et al., 2007) and in neural activation during encoding of self-relevant versus other-relevant information (Zhang et al., 2006; Han & Northoff, 2009; Zhu et al., 2007). Within a group, individual differences are present, however, and by focusing on broad group differences, individual variation is often ignored. Group differences only represent average behavior or neural activation within a group, and it is therefore valuable to consider variation within the group by looking at individual differences in memory, self-construal, neural activation, and identity integration. The Self-Construal Scale (Singelis, 1994) measures self-construal style using the constructs of independence and interdependence and assists in understanding variation in personal self-construal styles. In an fmri investigation, Ray and colleagues (2010) had American participants complete an adjective judgment task (self, mother, valence and font) and The Self- Construal Scale. Contrary to expectations, those with an interdependent self-construal 7

16 exhibited greater recruitment of mpfc and PCC during self-relevant judgments than mother-relevant judgments. Another study (Chiao et al., 2009b) used The Self-Construal Scale with Japanese and American participants and looked at mpfc activity during general versus contextual judgments. East Asians characteristically focus on contextual traits because of an interdependent self-construal, while the American tendency to see the self as independent encourages more focus on general and stable traits (Markus & Kitayama, 1991; Masuda & Nisbett, 2001; Oyserman et al., 2002; Triandis, 1995). Degree of independent or interdependent self-construal style in both Japanese and American participants is predictive of mpfc activity during general or contextual judgments (Chiao et al., 2009b). The findings from these two studies illustrate individual differences in self-concept as influenced by culture, and provide justification for investigation of individual differences, particularly in those individuals who identify with multiple cultures. In addition to measuring personal adherence to culturally congruent values, cultural priming has illuminated the flexibility of self-construal style both between cultures and within cultures (among individuals and in biculturals). Neural Evidence for a Dynamic Self in Bicultural Individuals Studying bicultural individuals allows for demonstration of the plasticity of selfconcept as measured by changes in activity in the mpfc and PCC. According to Han & Northoff (2009), the self-other relationship is highly flexible in its neural manifestation and dependent on the social context (p. 210). Priming different aspects of the selfconcept, such as individualism and collectivism, orients individuals to different aspects of information, influencing memory and neural activity during self-reference judgments (Gutchess & Indeck, 2009). Priming manipulates the cultural orientation that is made 8

17 salient, allowing researchers to assess whether cultural effects for one society can be present when primed in another society. For example, can an Asian in Asia be primed with an independent self-construal style so that behavior will reflect that of an American in America (Oyserman & Lee, 2008)? In bicultural participants the effect of priming is dependent on identity integration, and either leads to prime congruent or prime incongruent responses (Benet-Martinez, Leu, Lee, & Morris, 2002). Recently, many researchers have primed bicultural individuals towards either an American or Asian focus and measured changes in neural activity evoked by the priming. Chiao et al. (2009c) exposed bicultural individuals to either an individualistic or a collectivistic prime followed by a self-judgment task performed during scanning. In the task, they were asked to decide whether a trait applied to them in general, in a specific context, or simply to identify the font of the trait. Participants exposed to the individualism prime showed greater activation in mpfc for general relative to contextual judgments and those given the collectivism prime demonstrated greater mpfc activation for contextual relative to general self-descriptions. Activation in the PCC mirrored these findings (Chiao et al., 2009c). Another study used priming prior to a trait judgment task (self-relevant, fatherrelevant, unfamiliar other person-relevant) and using a within subject design in Asian Americans provided evidence for cultural priming modulating activity in the dorsal portion of the mpfc (Harada, Li, & Chiao, 2010). Other researchers in Hong Kong, an arguably bicultural location, primed students with either Chinese or Western cultural images prior to completion of a self-judgment, mother-judgment, and non-intimate person-judgment during a fmri scan (Ng et al., 2010). Those who received the Western prime showed increased activity in ventral 9

18 medial prefrontal cortex (vmpfc) during self-judgment relative to other-judgment, which supports the idea of self-other differentiation in this region. Following the Chinese prime, participants showed no activation in the contrast of self versus mother, self versus other, or self versus non-intimate person, providing strong evidence for self-inclusiveness after the Chinese prime and self-exclusiveness after the Western prime. The potential for locating the neural substrates for the self, other, and the interaction between the two across and within cultures encourages more research. Additionally, there are gaps in the literature that can be addressed by measuring memory and neural differences in bicultural individuals, controlling for individual variations in identity integration. The current study extends the current literature by focusing on individual identity integration, employing priming to measure dynamic self-construal, and measuring both memory and neural activation. Asian Americans were exposed to a cultural prime (Asian, American, or Neutral) to provide contextual cues for subsequent behavior. The Bicultural Identity Integration Scale (BII) (Benet-Martinez & Haritatos, 2005) was used to measure individual differences in level of acculturation, identity integration, and ability to engage in cultural frame-switching. Functional magnetic resonance imaging (fmri) was used to assess differences in neural activation as a function of identity integration. Neural activity was measured during a trait judgment task, where participants were asked to make judgments about the self, mother, and Gandhi, as a familiar other who was not personally known. Following the scan, memory for the traits was tested and existence of the self-reference effect or other memory enhancements was measured. We were primarily interested in how the level of acculturation affects both behavioral (memory) and neurological (fmri) measures and susceptibility to the prime. 10

19 Our first hypothesis for the proposed study was that participants in all conditions, regardless of bicultural identity integration scores and prime condition, would exhibit a self-reference effect in memory, but only those exposed to the Asian prime would exhibit a mother-reference effect (Sui, Zhu, & Chiu, 2007), such that memory for motherreferenced words would not differ significantly from memory for self-referenced words. In terms of neural activation in mpfc, we expected higher levels of activation for selfrelevant information that is subsequently remembered than later forgotten (Gutchess, Kensinger, & Schacter, 2010; Macrae et al., 2004). With regards to the effects of priming, the second hypothesis was that those exposed to the American prime would show greater differentiation of self from both mother and other, as measured by activation in the medial prefrontal cortex (dmpfc and vmpfc) and the posterior cingulate cortex (PCC) during processing. We did not have specific predictions about how bicultural identity integration (BII) would affect neural activation or memory since this is a novel approach to measuring cultural effects on the neural level. However, using comparisons of priming and/or BII groups, we expected to replicate the finding that culture modulates activity in the dorsal portion of the mpfc (Harada, Li, & Chiao, 2010). Finally, we expected a cross-over interaction, such that a high score on the Bicultural Identity Integration Scale (BII) would predict a prime congruent response, demonstrating more flexibility in self-construal style, and that a low score on the BII would predict a prime incongruent response, or reactance, indicative of a more rigid selfconstrual style (Benet-Martinez et al., 2002). By using memory and fmri, our measurements were novel for testing this idea. Prime congruent and prime incongruent responses were determined by both memory performance and neural activation in the 11

20 mpfc and the posterior cingulate cortex. We expected that participants who scored high on the BII would exhibit behavior consistent with their priming condition, such that those exposed to the American prime would show differential activity in mpfc and PCC for both self and mother, but would not exhibit a mother reference effect in memory. Alternatively, participants who scored low on BII and were exposed to the American prime would show no differentiation between self and mother in neural activation but would exhibit self-reference and mother-reference effects in memory. 12

21 Methods Participants Forty-eight Asian American participants were recruited from the area surrounding Temple University. Participants were randomly assigned to three priming conditions: Asian prime (16 participants), American Prime (16 participants), or Neutral Prime (16 participants). Two participants from the Asian Prime condition and one from the American condition were excluded from all analyses because of imaging data loss for one and excessive movement in the scanner for the other two (Total 45 participants, 14 Asian Prime, 15 American Prime, and 16 in the Neutral Prime condition). After preprocessing, 11 additional participants were excluded for excessive movement. An additional three participants were excluded because the mask used for analysis of fmri data was not providing good coverage of the brain. This left a total of 31 participants who were used for analysis of neural activity during trait judgment and encoding. The full sample consisted of 18 females and 13 males (M age = years, SD = 7.16 years). The majority of the sample was Chinese (51.6%), followed by Korean (32.3%), Taiwanese (12.9%), and Hong Kong (3.2%). The average number of years since US arrival was 7.16 years (SD = 4.49 years), with a range from two to twenty years. In order to analyze the memory data, it was necessary to exclude another 13 participants for having an insufficient number of trials (<6) in at least one condition (self remembered, self forgotten, mother remembered, mother forgotten, other remembered, 13

22 other forgotten). A total of 18 participants were used in the analysis of subsequent memory data. The restricted sample used for memory data consisted of 8 males and 10 females (M age = years, SD = 4.66 years). The most common ethnicity was Chinese (50%), followed by Korean (38.9%), Taiwanese (5.6%) and Hong Kong (5.6%). Average number of years since US arrival was 7.67 years (SD = 4.58 years), with a range of two years to twenty years. Written informed consent was obtained from all participants before beginning the experiment. Procedure Approximately two weeks prior to scanning, participants attended a behavioral session. First, they signed an Informed Consent document, Demographics form, and Health Questionnaire. They then completed the Bicultural Identity Inventory (BII) (Benet-Martinez & Haritatos, 2005), which includes eight items on a 5-point Likert-type scale rated from 1 (completely disagree) to 5 (completely agree). Sample items include: I am simply an Asian who lives in North America (i.e., I am an Asian who happens to live in the U.S.) (reverse scored) and I feel part of a combined culture. For the scanning session, participants were randomly assigned to one of three priming conditions (Asian, American, or Neutral). After confirming the participant s eligibility to participate in fmri research, the scanning began. All cognitive tasks and primes were presented on E-prime (Psychology Software Tools, Pittsburgh, PA) and participants responded during scanning. Priming occurred immediately prior to each cognitive task. Participants were asked to make judgments about pictures of individuals from the primed culture (e.g. Indicate whether or not you like or dislike each face. Press the LEFT mouse button if you LIKE the face. Press the RIGHT mouse button if you 14

23 DISLIKE the face ). Primes immediately preceded two sets of adjective trait judgment tasks. The following instructions appeared on the screen, Now, you ll decide whether the adjective describes you ( Self ), your Mother, or other ( Mahatma Gandhi ). Please press the left (YES) or the right (NO) key for each trial. The prompt corresponding to the condition appeared on the screen with the adjective for each trial, followed by a fixation cross prompting a judgment before the next word appeared. There were a total of 144 words presented in two sets: self (48 words), mother (48 words), and Gandhi (48 words) judgments. Between the two sets of words, participants were exposed to another eight photos from the primed culture, and then completed another adjective trait judgment task. After completion of the adjective judgment task, participants saw an adapted version of the BII to be completed in the scanner, and then scanning was complete. The adjective task of interest in the current study was completed after two other priming sessions and two other tasks in the scanner often used for measuring cultural differences in cognition (The Framed Line Test and The Fish Task), which are not the focus of the present investigation and will be analyzed and reported separately. Outside of the scanner, participants were asked to complete a surprise recognition task for the words from the adjective trait judgment task. This was executed using E- prime software. There were 288 words presented, 144 old, and 144 new lures, which were counterbalanced within participants. They were asked to identity whether they had seen the word in the previous task. Finally, participants were debriefed and excused. Imaging Parameters The fmri scanner was a 3 Tesla Siemens Verio whole-body scanner with a standard CP head coil. Subjects were scanned with contiguous (no gap) 5 mm axial high- 15

24 resolution and T1-weighted structural slices (matrix size= ;TR=2000ms; TE=30 ms; FOV=210 mm; NEX=1; slice thickness=4.0 mm) were collected for spatial normalization procedures, and overlay of functional data. Precise localization based on standard anatomic markers (AC-PC Line) was used for all subjects (Talairach & Tournoux, 1988). Functional scans were acquired with a gradient-echo planar free induction decay (EPI-FID) sequence (T2*weighted: matrix; FOV=210 mm; slice thickness = 4.0 mm; TR=2000 ms; and TE=30 ms, slices = 30) in the same plane as the structural images. Voxel size was 3.33 mm 3.33 mm 5 mm. Data Analysis Preprocessing and analysis of the imaging data was done using SPM8 (Wellcome Trust Centre for Neuroimaging, London, UK). Preprocessing included slice-time correction, realignment to correct for movement, normalization to the Montreal Neurological Institute (MNI) template, coregistration of each participant s structural scan to their mean functional image derived from previous preprocessing steps, and spatial smoothing to a 6-mm full-width half maximum isotropic Gaussian kernel. For the analysis of subsequent memory, encoding trials of the adjective judgment task were sorted based on whether the word was later remembered or forgotten in the post-scan memory test (Brewer et al., 1999, Wagner et al., 1998, Gutchess, Kensinger, & Schacter, 2010). In order to analyze the effect of bicultural identity integration (BII), we performed a median split on these scores in order to create a high BII group and a low BII group. BII was measured on a 5-point scale and the median was Based on previous research on self-referential memory, we created four spheres from a priori ROIs using the SPM toolbox, MarsBar. Spheres of 10mm were created 16

25 from the peak voxel coordinates for the dorsomedial prefrontal cortex (dmpfc) (-2, 32, 50) and posterior cingulate cortex (PCC) (6, 36, 50) that were obtained from previous self-referential encoding research in our lab (Gutchess et al., 2010). The coordinates for ventral medial prefrontal cortex (mpfc) (-8, 60, 4) were obtained from a separate selfreference paper (Gutchess, Kensinger, & Schacter, 2007) because while vmpfc often emerges as a region activated for subsequent memory (Macrae et al., 2004), it did not emerge in our lab s previous self-referencing encoding study (Gutchess et al., 2010). We analyzed neural activity in the following three stages: trait judgment and encoding, subsequent memory, and cultural effects on subsequent memory. Trait judgment and encoding refers to the period during which participants were determining whether traits were relevant to the self, mother, and other. We analyzed this stage with the full sample (n=31) in order to determine whether the medial prefrontal cortex and posterior cingulate cortex were involved self-referential judgments and whether cultural effects influenced the engagement of these regions. Memory was analyzed by coding trials from processing as either subsequently remembered or subsequently forgotten. In this stage in the analysis, we used a restricted sample based on memory performance (n=18) and we were interested in whether cultural identification would modulate the engagement of medial prefrontal cortex during subsequent memory formation for words judged relative to the self, as opposed to mother and distant other Results report activations significant at the threshold of p FWE <.05 and were measured using small volume correction. 17

26 Results Bicultural Identity Integration As mentioned in the methods section, bicultural identity integration was measured using a five-point scale. Overall, our participants had scores that were about at the midpoint on the scale (M = 3.13, SD = 0.58). The scores fell along a fairly normal distribution, with the median at Behavioral Recognition Performance In order to analyze memory performance, we calculated corrected recognition scores using a measure of signal detection (hits minus false alarms) (Snodgrass & Corwin, 1988). We submitted the corrected recognition scores from the restricted sample used for the fmri analyses (n = 18) to a 3 (Condition: Self, Mother, Other) x 3 (Prime: American, Asian, Neutral) x 2 (BII Score: High, Low) Mixed ANOVA with condition as the within-subjects factor and prime and BII score as the between-subjects factors. There was a significant main effect of condition, F(2, 24) = 7.04, p <.01, η 2 =.37, driven by significantly better memory for self-relevant adjectives (M = 0.36, SD = 0.22) than mother-relevant adjectives (M =0.25, SD = 0.18), t(17) = 3.85, p <.01, and other-relevant adjectives (M = 0.38, SD = 0.22), t(17) = 3.57, p <.01 (see Table 1). No significant differences were seen between memory for mother-relevant and other-relevant adjectives. There were no significant interactions or main effects involving prime or BII score. 18

27 Functional MRI Data Trait Judgment and Encoding. In order to test our prediction that neural activation when making judgments about the self would be distinct from making judgments about mother or other, collapsing across both prime and BII, the following contrasts were created: self - mother, self - other, mother - other and the reverse of each. These contrasts were tested in the three ROIs mentioned in the methods section. Contrary to our expectation, activation was greater for the mother than the self and other in two distinct regions in the dorsomedial prefrontal cortex (dmpfc), as seen in Figure 1 (note we have only plotted one significant activation for each contrast). These activations demonstrate relatively more engagement of a dmpfc regions typically considered to be engaged by self-relevant processing when judging stimuli relevant to the mother, as compared to the self or other in the current sample. Also in contrast to much of the prior literature, the contrast of mother minus other revealed significant deactivation of the vmpfc, which was stronger for mother relative to both self and mother judgments. In the contrast of other minus self, there was greater deactivation in the posterior cingulate (PCC) for the self than for others, which, like the vmpfc finding, is surprising based on prior literature. There were no significant effects for the aforementioned contrasts by prime or BII. Beta values were extracted and significant activations were plotted, and can be seen in Figure 1. Subsequent Memory Analysis. In a similar manner to the analysis of the trait judgment and encoding data, the first step was to look at the contrasts collapsing across prime and BII. We were interested in the engagement of medial prefrontal cortex (dmpfc and vmpfc) and posterior cingulate cortex (PCC) during trials that were either 19

28 subsequently remembered or forgotten. In order to address this question our contrasts of interest were interactions for remembered/forgotten x self/mother and remembered/forgotten x self/other. The specific contrasts were: [self remembered-self forgotten]-[mother remembered-mother forgotten], and [self remembered-self forgotten]- [other remembered-other forgotten], and the reverse contrasts. We expected to see a selfreference effect in memory, such that activation in the mpfc and PCC would be greater for items relevant to the self (versus mother or other) that were later remembered compared to those later forgotten. However, the only significant activation was in the PCC in both the [mother remembered-mother forgotten]-[self remembered-self forgotten] and [other remembered-other forgotten]-[self remembered-self forgotten] contrasts. As can be seen in Figure 2, these activations indicate that there is increased engagement of the PCC for mother and other items later remembered, rather than forgotten, as compared to the self condition. Cultural Effects on Subsequent Memory. Cultural effects were tested by prime and BII. However, there were no significant interactions by prime, so we will only discuss the interactions with BII. In order to measure cultural effects on subsequent memory, we measured effects in the selected ROIs (i.e., vmpfc, dmpfc, and PCC). We tested for effects of BII in the following contrasts: high-low:[self remembered-self forgotten]-[mother remembered-mother forgotten] and high-low:[self remembered-self forgotten]-[other remembered-other forgotten] and the reverse of each [i.e., low-high]. A significant interaction emerged in the dmpfc. Among those participants with high BII there was greater activation in the dmpfc for mother-relevant information that was later remembered (versus forgotten), as compared to self-relevant information. The pattern 20

29 was reversed for participants with low BII scores, such that they engaged the region more for self-relevant items that were later remembered (versus forgotten), as compared to mother-relevant information (see Figure 3). These findings partially support our hypothesis that cultural effects would modulate neural activation in self-referential regions dmpfc, vmpfc, and PCC. 21

30 Discussion In the current study, we sought to investigate the cultural effects on selfreferential processing and memory as it relates to both close and distant others. We employed both memory tasks and measures of neural activation. Our study provided evidence for a self-reference effect in memory (Rogers, Kuiper, & Kirker, 1977) across primes and level of bicultural identity integration. Self-relevant adjectives were remembered better than both mother and other adjectives, and there was no difference in memory for adjectives referencing mother or other. Based on past research, we would have expected to see a mother-reference effect, with higher memory performance for words judged about the mother compared to another person, in all participants since they are all originally from East Asian countries, and that exposure to the American prime would attenuate the mother-reference effect (Sui et al., 2007). However, we did not see this effect of prime. The lack of a mother-reference effect in the current sample may be due to large individual differences in cultural identification. We did not see an interaction between memory performance and prime or identity integration. This may have been because our data were collected in the United States and previous research was done in China (Sui et al., 2007). We observed increased activation in self-referential regions (vmpfc and dmpfc) when viewing adjectives relative to the mother but not the self or other, collapsed across prime and BII. Additionally, we observed deactivation in the PCC for all conditions 22

31 (self, mother, Gandhi), but the relative deactivation was greater for the self condition. In previous research, these regions have shown heightened activation during self-relevant trials for European American participants (Craik et al., 1998; Heatherton et al., 2004; Heatherton et al., 2006; Northoff et al., 2006). In East Asians, these self-relevant regions show heightened activation for both self and mother (Han & Northoff, 2009; Zhang et al., 2006; Zhu, 2007). Therefore, it is surprising that the current sample is showing a unique pattern of preferential activation for the mother. It is possible that the distant, familiar other (Gandhi) is not viewed in the same way across cultures and varies within our sample. This may also be affected by the amount of time our participants have spent in the United States. Additionally, there is evidence for the mpfc activating when participants are making judgments about close others, and in our sample the mother is a close other (Ochsner et al., 2005). Also surprisingly, this finding is inconsistent with our behavioral data that suggests heightened processing during encoding of the self over the mother or other. While the mpfc is widely accepted as a region implicated in self-relevant processing, it is also engaged during mentalizing, or thinking about the mental states of another person. When prompted to think about the mental states of similar others, both dorsal and ventral regions of mpfc are activated (Mitchell, Banaji, & Macrae, 2005). However, when thinking about dissimilar others the dorsal region of the mpfc is more engaged (Mitchell, Macrae, & Banaji, 2006). It is possible that in the current study, participants are engaging these regions more for mother-relevant information because they are employing mentalizing during trait judgments and encoding, rather than more traditional self-referential processing. In this case, there may be dissociation from the 23

32 self, leading to a focus on others. In the other-self contrast, there was stronger deactivation of PCC for self than for the other, providing further evidence that this region may assist in the dissociation from self. Alternatively, these findings may be influenced by the fact that these participants are all bicultural East Asians living in the United States, outside of their native countries. In order to address whether the participants being bicultural East Asians living abroad influence the findings, we need to investigate other cultural effects, besides prime and BII, since we did not find any significant influence of cultural identity during trait judgment and encoding in our current sample. In the analysis of neural activity related to subsequent memory, we expected to see increased dmpfc activity for self-relevant items that were subsequently remembered than forgotten (Macrae et al., 2004). We also expected PCC activation because previous research has shown that the PCC is engaged in memory-related processes (Wagner, Shannon, Kahn, & Buckner, 2005), for information judged as self-referential, and for episodic memory (Sajonz et al., 2010). We saw that for both mother and other (as compared to self) judgments, there was heightened activation in only the PCC (not mpfc) for remembered than forgotten trials. Engagement of the PCC seems to be related to effective encoding for other and mother conditions but reflects impaired encoding in the self condition. This effect is likely due to the distinct engagement of the PCC that is separable from engagement of the mpfc. Johnson and colleagues (2006; Johnson, Nolen-Hoeksema, Mitchell, & Levin, 2009) have suggested that there is a dissociation between medial frontal and posterior cingulate activity in self-reflective processing based on two distinct agendas hopes and aspirations (promotion focus), and duties and obligations (prevention focus). Hopes and 24

33 aspirations require a more inward focused perspective, while duties and obligation require more social, outward focus. During promotion focused self-reflection there is relatively greater activity in the medial prefrontal and anterior cingulate and relatively greater activity in the posterior cingulate during prevention focused self-reflection. East Asians tend to be more prevention-focused, emphasizing duties and obligations, whereas Americans are more promotion-focused, concentrating on hopes and aspirations (Heine, 2005). The current results support the idea that East Asians are more prevention-focused, because there was activation in the PCC for effective encoding of other-relevant information and no activation in the mpfc for self-relevant information. Our results indicate that the posterior cingulate is engaged more for memory for information involving others in East Asian participants, perhaps because of a tendency towards prevention-focused processing. In the current sample, this region supports memory for information relevant to others (both close and distant) and inhibits memory for information related to the self. In other research, the PCC has been linked with not only thinking about others, but taking the perspective of others, also known as theory of mind (Jackson, Brunet, Meltzoff, & Decety, 2006). Prevention-focused processing requires taking the perspective of another person. We would argue that our participants are engaging more in outward focused perspective taking, and thus engaging the PCC, while making judgments about another person. This selectively improves subsequent memory for the information, relative to trials later forgotten. In the current study, participants do not seem to be engaging typical self-referential or promotion focus regions, such as mpfc. While surprising, it is consistent with our findings for trait judgment and encoding that show heightened activation in self-referential regions 25

34 (dmpfc) for the mother and not for the self. As previously mentioned, cultural effects, specifically a tendency to be more prevention-focused may have a role in modulating our findings. The primary aim of the current study was to investigate cultural effects on neural activation during a self-reference task and to measure which regions predict subsequent memory for information relevant to the self or close and distant others. We found evidence for cultural identity integration influencing activation in the dorsomedial prefrontal cortex, such that there was an interaction between BII (high versus low) and subsequent memory for items relevant to the mother versus self and other versus self. We saw dorsal mpfc activation for subsequent memory for mother judgments in those high in BII, but for self judgments for those low in BII. Among those high in BII, this finding is consistent with the trait judgment and encoding data, which shows greater dmpfc activation for the mother than the self. However, the pattern is reversed for those low in BII, such that, there is increased activation in the dmpfc for self-relevant items (as compared to mother-relevant) that are subsequently remembered (vs. forgotten). Based on these findings, it appears as though the participants in the high BII group are driving the increase in activity in the self-referential regions (dmpfc) for the mother that was seen in the results from the trait judgment and encoding data. Gutchess and colleagues (2010) saw similar reversals in a study comparing aging effects on memory. Those high in BII showed the same pattern as young adults in their study and those low in BII showed a pattern similar to older adults. These authors speculated that the reversals reflected differences in what older and younger adults attend to and indicate a qualitative difference in information processing, which also seems evident in our data. 26

35 High BII and low BII participants are engaging the same region (dmpfc) for successful encoding, but there is a distinction in the type of encoding, as influenced by bicultural identity integration. The reversal of dmpfc activity across high and low BII groups for the self and mother conditions supports the claim that cultural identification has an effect on the neural mechanisms underlying self-relevant memory. Evidence from the current sample suggests that there is a difference in the encoding of information relevant to the self versus mother between those high in BII and those low in BII. It should be noted that this effect is largely driven by subsequent forgetting of self-relevant information among those high in BII. There was relatively greater activation in the dorsal mpfc for selfrelevant trials that were subsequently forgotten, suggesting that the memory processes supported by the dorsal region of the mpfc are being impaired for the self-relevant items in those high in BII. Activation in the dmpfc may support enhanced memory for the self in those low in BII but hurt memory for the self in those high in BII. The engagement of the dorsal mpfc during self-evaluation and especially the interaction with cultural identity is consistent with Chiao and colleagues (2010) finding that culture modulates dorsal, but not ventral, regions of the mpfc. Activation in the dorsal region of the mpfc increases in self-referential tasks or tasks that involve selffocused attention and decreases in tasks that require other-focused attention (Gusnard & Raichle, 2001). Additionally, ventral portions of the mpfc are activated during explicit self-evaluation, such as determining whether information is self-relevant, and dorsal regions of the mpfc are activated when evaluating self-relevant information, as occurs in implicit self-evaluation (Moran, Heatherton, & Kelley, 2009). The task in the current 27

36 study is explicit self-evaluation and should therefore be activating ventral portion of the mpfc. Additionally, D Argembeau and colleagues (2007) found evidence that both dorsal and ventral portions of the mpfc are activated during self-referential processing, but dorsal regions are more activated during perspective taking. This suggests that our participants should be engaging both ventral and dorsal portions of mpfc, since the task is self-referential processing. However, the activation in only the dorsal regions may be due to cultural effects, namely bicultural identity integration, which only modulates the dorsal portion of the mpfc. In the current sample, activation of the dorsal mpfc provides support for processes that benefit memory for mother, and hurt memory for self in the participants that are high in bicultural identity integration. This suggests that these participants may be engaging in more perspective taking or mentalizing, as supported by activation in the dorsal mpfc for subsequently remembered information relevant to their mother, as compared to the self. Those participants that are low in bicultural identity integration seem to be using this region for self-relevant processing, as seen in the increased activation for subsequently remembered self-relevant items, as compared to the mother. This distinction in dmpfc activation between those high in BII and those low in BII suggests that cultural effects, specifically identity integration, may be modulating the activity in this region. Touryan and colleagues (2007) suggest that information about others and our understanding of them may be framed by a regulatory focus that is determined by social interactions. Social interactions are largely influenced by cultural norms, and therefore our participants may have different regulatory focus based on their cultural background, which may influence encoding of, and memory for self or other 28

37 relevant words. Those high in BII may show have closer relationships with their mothers, which has directed their regulatory focus and facilitated bicultural identity integration. Those low in BII may have a more self-directed regulatory focus, which hinders their ability to integrate both cultural identities. In trying to understand the results of the current study, it must be noted that most previous research on self-referential processing and memory has used European American participants. The canonical regions that underlie self-relevant processing and successful encoding are largely based on studies done with the European American population. In future research, it would be preferable to use regions of interest that are based on an East Asian population. Additionally, it will be important in future research to determine whether the regions are different or whether the processing of information is different, or both. Another important caveat to the findings discussed in this study is that we were forced to drop prime as a factor. Our hypotheses concerning the effects of bicultural identity integration were dependent on the interaction with prime. Since the participants in the current study were exposed to a prime, it would be important to replicate our findings without exposure to a prime in order to determine whether the effects are due to bicultural identity integration without any contribution from primes, as we had speculated based on previous research showing an effect of prime (Chiao et al., 2009c; Harada et al., 2010; Ng et al. 2010). It would also be important to replicate the current study with more participants so that we could analyze prime and determine whether BII would affect susceptibility to the prime. We expected to replicate previous findings that those high in BII would act consistent with the prime and those low in BII would exhibit reactance, 29

38 which is behavior that is incongruent with the prime (Benet-Martinez et al., 2002; Benet- Martinez et al., 2010). Though we were unable to measure the interaction between BII and prime, the current study makes a unique contribution to the literature by showing that an individual s level of bicultural identity integration modulates neural activity. Another limitation in the current study was in the data acquisition in mpfc. We believe that high levels of signal dropout in ventral regions of mpfc limited our ability to investigate the role of this region. While we excluded participants with the largest amount of drop out, we were still limited in the ability to look at ventral regions of mpfc. The most substantial limitation to the current study was lack of power. We were forced to exclude many participants because of memory performance and excessive movement in the scanner. This did not allow us to look at the effect of BII on susceptibility to prime because we had too few participants per condition. Additionally, participants had very good memory, which resulted in very few trials in the forgotten conditions. In future studies, it would be beneficial to include more trials or lower memory performance so that there would be more likelihood of forgotten items. As previously mentioned, we were forced to exclude 13 of 48 participants because of movement. The scanning session consisted of two separate tasks administered before the self-reference task discussed here. It is possible that participants were fatigued from being in the scanner, which caused them to be more restless. For future studies, it would be very important to better control movement in the scanner and may be beneficial to shorten the duration of time spent in the scanner. While the current study has limitations, it makes some unique contributions to the literature. In terms of neural activation, this particular sample shows preferential 30

39 engagement of self-referential regions for the mother during the adjective judgment task. This finding informs future research that could further investigate the cultural or individual effects underlying this pattern. In terms of subsequent memory, our data show greater involvement of areas implicated in memory processes for the mother and other as compared to the self. Both of these findings contrast prior findings on self-referencing, suggesting a substantial role for cultural background in the engagement of neural regions during self and other processing. Our results indicate a relationship between cultural effects and subsequent memory, suggesting that levels of acculturation, as assessed by BII scores, modulate neural activation during successful encoding of information relevant to the self and other. The current study provides preliminary evidence that self and other differentially engage mechanisms related to mentalizing and memory across people of different cultures, especially bicultural individuals. 31

40 Table 1 Appendix A: Tables Summary of corrected recognition (hits-false alarms) presented in two forms: collapsed by BII and split by BII scores. Self Mother Other All 0.36 (0.05) 0.25 (0.04) 0.28 (0.04) BII Score Low 0.32 (0.07) 0.20 (0.06) 0.23 (0.06) High 0.41 (0.08) 0.31 (0.06) 0.33 (0.06) Note. n =18 32

41 Appendix B: Figures Figure 1. Parameter estimates for the peak voxels (labeled above each graph) extracted from significant activations that emerged from the processing data. 33

42 Figure 2. Parameter estimates for the peak voxels (labeled above each graph) extracted from the significant activations that emerged from the subsequent memory data. Panel A represents the contrast [mother remembered-mother forgotten]-[self remembered-self forgotten]. Panel B is [other remembered-other forgotten]-[self remember-self forgotten]. 34

43 Figure 3. Parameter estimates for the peak voxels (labeled above each graph) extracted from the significant activations that emerged from the interaction between subsequent memory data and Bicultural Identity Integration (BII) scores. The contrast shown above is low BII-high BII:[self remembered-self forgotten]-[mother remembered-mother forgotten]. 35