Two languages, one brain and theory of mind

Blogging on Peer-Reviewed ResearchAt first, when I read this journal article in Social, Cognitive and Affective Neuroscience, I thought, ‘Stop the presses; this one’s a barn burner.’ Since then, I’ve backed off my enthusiasm a bit, but I still think it’s fascinating. Chiyoko Kobayashi, Gary H. Glover, and Elise Tem have a really intriguing piece on brain-imaging studies done on bilingual Japanese-English speakers, when the subjects worked on false belief questions that tested their ability to solve ‘theory of mind’ problems. The piece, entitled ‘Switching language switches mind: linguistic effects on developmental neural bases of “Theory of Mind”‘ (abstract available here), comes to a number of conclusions, some of them needing to be confirmed by other research, but they’re worth mulling over at Neuroanthropology.

I discussed “false belief” (FB) tests and how they indicate developmental changes in children’s ability to perceive the thoughts of others in my post, Sapir-Whorf hypothesis is right… sort of? Kobayashi and colleagues asked bilingual subjects to solve FB problems in either Japanese or English, and they compared both younger and older subjects, who had learned their second language later in life than the younger subjects.

Different theorists disagree about how important language is to the development of ‘Theory of Mind’ (ToM) ability, affecting how children solve (or fail to solve) FB problems. For this reason, different experiments have sought to distinguish whether language ability supports the development of ToM or vice versa, but, as Kobayashi and colleagues summarize, ‘the evidence is mixed on this issue’ (62). Children improve on FB tests when given language training and yet pre-verbal children seem to be able to solve some ToM problems that are not based on language. I feel that the authors’ conclusion is warranted, that the evidence seems ‘to support a conjecture that some aspects of language affect ToM throughout development and adults may process ToM more verbally than children’ (63).


With some ToM perception being shaped by language, researchers have wondered whether or not the ability to deal with FB problems might vary across cultures. Analyses of research done in a range of places show that children seem to acquire ToM abilities around the same time, but, as Kobayashi and colleagues write, ‘these results do not necessarily rule out that there may be linguistic influence on “how” ToM is understood.’ Do people who speak different languages use the same sorts of mental processes to solve the same problems? It’s a great question, and exactly the kind of thing I would eventually like to do in my own sports research: Do players from different ‘traditions’ or with different sorts of skills solve the same perceptual-motor problems in identical or distinctive fashion? But I digress… back to Kobayashi, Glover and Tem.

In the case of ToM, there do seem to be some linguistic effects. As Kobayashi and colleagues describe:

Several cross-linguistic studies on ToM have found some linguistic effects on the FB task performance. For example, Mandarin Chinese speaking children performed significantly better when yiwei and dang, which connote that the belief referred to may be false, were used then when xiang (the more neutral verb) was used (Lee et al., 1999). Similarly, Turkish or Puerto Rican Spanish (PR Spanish) speaking children who have either a specific verb (Turkish) or a case marker (PR Spanish) available to make the FB mental state more explicit, performed better in the FB task than Brazillian Portuguese or English speaking children who do not have those lexicons (Shatz et al., 2003). These qualitative differences in ToM may not easily be detected by the forced-choice style FB tasks used in the majority of the cross-cultural studies of ToM. (63) (I’m leaving in the citations although I won’t provide a bibliography — you’ll have to read the original.)

These prior studies open the door to really thinking about how language might affect a person’s ability to solve certain kinds of social perception problems, but I think the authors are correct that the way in which FB tasks are designed makes it more difficult to see these differences. That is, the forced-choice style of FB testing may artificially ‘tighten’ the constraints on the way that the brain deals with ToM challenges; in more naturalistic social interaction, the differences might be exacerbated, but we don’t really know.

But to get to the results of the research by Kobayashi, Glover and Tem, there are a number of interesting outcomes:
1) Their research confirms prior experiments that show, over time, we get better and better at ‘mind reading’ and recognizing irony, so our brains don’t have to get as active to deal with them; in children, ToM problems and irony activate the brain more broadly than in adults. This isn’t terribly surprising as we find that most skills become more specific and tightly localized in the brain as they improve.

2) The study added additional support to earlier research that shows the age at which we acquire a second language affects how we process that language in relation to our first language; the younger we learn the second language, the closer it is in our brain (literally) to our first language. For those who learn a second language later, the areas of the brain which are most active when dealing with each language are more widely separated, perhaps because languages learned later are learned more through declarative memory (rather than being as dependent on procedural memory).

3) The area of the brain activated during ToM questions suggest that these tasks are more language dependent in adults than children, again, confirming earlier research.

But the result that initially piqued my interest most is summarized in the following: ‘These results may indicate that people recruit different linguistic and cognitive resources depending upon the language used to process ToM, and that this difference may become greater as people age’ (69).

To examine the brain network specific to processing ToM in each language in each group, we compared the activity during the L1 (Japanese) ToM condition with that during the L2 (English) ToM condition within each age group. In adults, the L1 ToM condition elicited more brain activity in the ventral ACC and bilateral mPFC than the L2 task. In contrast, the L2 task demonstrated greater activity than the L1 task in other brain regions such as the left precuneus and right temporal pole (TP) that have been suggested to be involved in ToM related processing but have not been considered to be core ToM processing regions … (66)

When I first read through this, I was confused; the title of the article had suggested something much more than this: “Switching language switches mind: linguistic effects on developmental neural bases of ‘Theory of Mind.’” In fact, it was studies of Japanese-English bilingual individuals, and all of the adults had learned English as the second language, and later in life than the child subjects.

As much as I want this research to demonstrate that cultural differences lead to differences in the way that the brain accomplished a common task (FB problems and ToM, in this case), I just can’t get behind this study as showing the effect convincingly. This is why, although it’s suggestive, I think that the research needs to be confirmed with some different experiments, perhaps not using bilingual subjects. It is fascinating to use bilingual individuals as they provide their own controls, in some sense, but it also means that it’s very hard to separate the cultural difference in ToM from the simple fact of English being the second language.

But I also have reservations about what the authors think that they are testing. Kobayashi and colleagues continually use ‘language’ as the operative variable, but they are aware that this glosses other sorts of differences that might be affecting ToM. I want to quote the entire paragraph where they discuss these limitations so that I can discuss, again, why I take issue with certain uses of ‘cultural differences’ in psychology explanations, even though I am very much in the business of studying ‘cultural differences.’ Here’s the passage from the original article (again, I’ll leave in the references even though I’m not reproducing the bibliographic information):

There are limitations in the present study. One limitation involves the effect of culture. Although throughout this article the results have been interpreted in terms of linguistic effects on neural bases of ToM, these results could equally be attributed to cultural effects since our participants were bicultural as well as bilingual. Behavioral experiments on biculturalism have found consistently significant difference between Americans/Westerns and Japanese/Asians in how the different cultural groups interpret everyday events and phenomena. Westerners have been shown to view the world more analytically, while Easterners tend to view the world more holistically (Nisbett, 2003). These differences in the world view seem to affect one’s self construal (Markus and Kitayama, 1991) and other social cognition and perception including ToM and perspective-taking (Lehman et al., 2004; Wu and Keysar, 2007). According to a cultural explanation, the results presented here in age differences in ToM specific activity could be attributed to early biculturalism in children (therefore, a greater overlap of the L1 and L2 ToM in the mPFC region) and late biculturalism in adults (therefore, a greater separation of the L1 and L2 ToM). However, since no measure of the participants’ cultural identity or experience [e.g. cultural priming (as in Hong et al., 2001)] was included, this study was unable to differentiate between cultural and linguistic effects. Future work, which includes measures of participants’ cultural identity, would help address these questions. (Kobayashi, Glover and Tem 2008:68)

Alright, where do I begin? First, Americans/’Westerns’ and Japanese/Asians are dangerous simplifications. First of all, the ‘Americans’ and ‘Japanese’ involved are usually college students, so some difference may arise from the differences between American and Japanese college students. Second, using these two groups as surrogates to represent all ‘Westerns’ and ‘Asians,’ as we’ve already discussed, is fraught with problems. The desire to generalize from basic psychology experiments, such as the contrast between ‘analytic’ and ‘holistic’ thought, is also a kind of stereotype that I doubt very much captures the real differences between forms of thought. For example, something tells me that Japanese college students are as capable of ‘analytical’ thought as Western college students are. But that’s just the surface of the problems.

The bigger problem, for me, is the whole explanatory thrust. Instead of thinking about plausible low level, dynamic explanations — such as intellectual training, patterns of stress in individuals at certain stages of life differing between societies, styles of social interaction and communication, or social pressures to perceive more or less subtle signals of other people’s emotional states — we deal in blanket assumptions about cultural, nay ‘civilization’ differences, between Asians and Westerners — Westerners view the world analytically, Asians holistically. While I applaud so much about this research, the ‘two cultures’ model of difference between Asia and the West cannot be redeemed, not just because the stereotypes are too broad, but also because it assumes a kind of ‘shared mind’ or culture-wide mental structure that is wildly improbable at best. That is, we are likely to get differences between groups of people in the way that their minds work, but the odds of this being Asians compared to Westerners are just too long given what we know about how the brain takes to training.

In this case, I’m more comfortable, actually, with suggesting that the difference is caused by language than an essential difference between Asians and Westerners. Differences in grammatical structure are an entirely plausible root for differences in the way that we think about other individual’s perceptions — although I think there are other possible factors — much more likely than the ‘Asian’ or ‘Western’ mind.

Normally, I try to be really good about giving credit where it’s due, but I can’t remember who put me onto this article. It may be one of the usual suspects in our blogroll, but I admit that I simply got so damn excited when I read the article that I lost track of where I had run across the reference. The ‘History’ in my browser is so full of neuroscience that there’s no way I can figure it out from there. And when I tried to figure it out through Google, I discovered that the first author shares a name with the ‘Japanese eating machine,’ world record-holder in eating hotdogs or something like that. Apologies, then, to the other science bloggers turning people on to this article; I’d be happy to put in a link if you know someone who posted on this piece.

References

Kobayashi, Chiyoko, Gary H. Glover, and Elise Temple. 2008. Switching language switches mind: linguisticeffects on developmental neural bases of ’Theory of Mind.’ Social, Cognitive and Affective Neuroscience (SCAN [nice…]) 3(1): 62-70. doi:10.1093/scan/nsm039

5 thoughts on “Two languages, one brain and theory of mind

  1. Pingback: Dave’s Whiteboard » Blog Archive » Of two minds about false belief

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