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Research Focus
Theory of mind, language and the temporoparietal
junction mystery
Josef Perner and Markus Aichhorn
University of Salzburg and Center for Neurocognitive Research, Hellbrunnerstraße 34, 5020 Salzburg, Austria
Brain imaging of adults during false-belief story
tasks consistently shows activation of the temporoparietal junction in English-speaking Americans and
German-speaking Europeans. Kobayashi et al. find this
observation in adult English speakers but not in English-speaking children or in English–Japanese bilingual
persons. This finding suggests a cultural or linguistic
influence on location of brain function and argues
against maturation of innately specified neural substrates. It is reminiscent of effects of linguistic development, bilingualism and cultural differences on
theory of mind development.
Introduction
The paper by Kobayashi et al. [1] caught our attention for
about as many reasons as there are words in its title:
neural basis, theory of mind (ToM), linguistic/cultural
effects, children. A central aspect of ToM is that the mind
takes a perspective on the world. Children’s appreciation of
this fact has been assessed by their understanding of false
beliefs, for example to understand that a person who does
not witness an unexpected transfer of an object will then
look for the object in its original, but now empty, place.
Saxe and Kanwisher [2] adopted this paradigm in the form
of short story vignettes for brain imaging with adults to
explore the neural correlates of ToM reasoning (Studies 1–
6, M, P and A in Figure 1). For contrast, they used structurally very similar photo vignettes, also adopted from
work with normally developing children and children with
autism. Because of the structural similarity between the
false-belief and photo task, this contrast is considered to
be a good way to filter out the specific mental aspects of
false beliefs. Most earlier studies used Happé’s Strange
Stories [3], in which a burglar mistakenly thinks that a
policeman has caught him when the policeman merely
wants to return the burglar’s lost glove, in contrast to
physical event stories – a cat triggering the burglar alarm
(F, G, H and V in Figure 1). One recent study contrasted
false beliefs with true beliefs (S).
Brain imaging of false-belief reasoning shows
remarkable consistency
Activation differences were consistently reported [2,4]
within the anterior cingulate/paracingulate area in the
medial prefrontal cortex (mPFC), the temporoparietal
junction (TPJ)/posterior superior temporal sulcus (pSTS)
area, areas along the middle temporal gyrus down to the
Corresponding author: Perner, J. ([email protected]).
temporal pole (TP) and the posterior cingulate cortex/precuneus region (PC). In particular, bilateral activation in
the TPJ was found across all 15 studies (with only three
exceptions in Figure 1: H only left, M only right, and V
neither). The importance of the TPJ for reasoning about
beliefs is also highlighted by lesion studies showing that a
patient with extensive bilateral damage to the mPFC
(including an area activated by most ToM studies [4]) could
still solve false-belief tasks [5], and patients with damage
in the left TPJ showed specific impairment on false-belief
tasks, whereas damage to the mPFC resulted in a wider
impairment including executive problems [6]. Figure 1
illustrates the consistency of imaging results for the right
hemisphere showing the peak voxels reported in these
studies on adults from Western cultures speaking IndoGermanic languages: English-speaking Americans (Studies 1–6 and M in Figure 1) or British (F, G) or German-speaking Europeans (A, P, S and V).
Surprising results from brain images of bilingual
children
Kobayashi et al. [1] tested 12 bilingual Japanese–Englishspeaking and 12 monolingual 9-year-old children from the
New York Metropolitan area on second-order belief stories
(what one person thinks another person thinks) presented
verbally (either in English or Japanese) or as nonverbal
cartoons. Non-ToM control stories were modelled after
physical-event stories used in earlier studies [3]. Only
bilingual children tested with Japanese stories showed
activation in one of the typical four areas (mPFC). Most
surprisingly, even monolingual English children (‘ ’ in
Figure 1) did not show any activation in the TPJ. Why
did this study produce different findings from those of
previous studies?
The investigation by Kobayashi et al. differs from
earlier studies
In the study by Kobayashi et al. [1] children rather than
adults and second-order beliefs instead of first-order beliefs
were tested, and some children were bilingual and had,
therefore, a somewhat different linguistic/cultural background. Any effect of materials can be checked by looking
at the earlier study by Kobayashi et al. [7] on adults.
Reassuringly, here there was activation in or near three
of the typical areas in the right hemisphere: TPJ, PC and
mPFC. This finding suggests that the lack of activation
reported for children is not due to different story materials
but to the age and background of the participants.
In particular, the hitherto unanimously reported activation of the TPJ in (presumably) monolingual adults
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Figure 1. Location of peak voxels in y- and z-space coordinates (outlines of cerebral structures are only approximate) in three lateral and medial areas reported in imaging
studies of false-belief (FB) processing in comparison with data reported by Kobayashi et al. [1,7] for monolingual English speakers. Abbreviations: mPFC, medial prefrontal
cortex; MTG, middle temporal gyrus; PC, precuneus; TP, temporal pole; TPJ, temporoparietal junction.
seems to be absent in Japanese–English bilingual children
as well as in 9-year-old monolingual children. This is
potentially an important finding.
The difference in findings has potentially important
implications
We focus on TPJ-R (TPJ in the right hemisphere), which
Saxe and Kanwisher [2] suggested was specifically associated with ToM and false-belief understanding. There are
signs in the data by Kobayashi et al. [1] that activation in
the TPJ when dealing with false beliefs might be modulated by development and environmental factors, such as
cultural or linguistic background or bilingualism – which of
these factors accounts for the observed differences is not
known. Nevertheless, the data of Kobayashi et al. suggest
that the cerebral location for ToM cannot be prespecified in
a genetic code awaiting maturation (as assumed by modularity theorists [8]).
The specificity claim of Saxe and Kanwisher is still
highly contested
Mitchell [9] pointed out that basic attentional processes (as
tested by invalid cueing and flanker paradigm) activate the
same region of the TPJ-R as does the false-belief–photo
contrast, as well as other processes [10]. Mitchell argues
that it is more plausible that TPJ-R activation is due to such
basic attention-shifting processes rather than to ToM, but
2
the author does not identify any relevant attentional aspect
that distinguishes the false-belief from the photo task.
Nevertheless, if the TPJ activation does reflect such basic
attention-shifting processes, the findings by Kobayashi et al.
would suggest something even more remarkable, namely,
that even the brain location of very basic attentional processes is subject to linguistic/cultural variation or bilingualism.
Methodological reservations
The reported activation differences are unusually small
and there is remarkably little coherence in regions
reported for the different groups (bilinguals–monolinguals adults–children) studied and contrasts analysed.
Hence the lack of activation of the TPJ in children and
in bilingual adults might be due to a lack of power rather
than a systematic difference between the groups. For
instance, a direct contrast between monolingual English
speakers and bilingual persons (Table 3 in Ref. [1]) was
barely significant for cartoons but not for verbal stories.
Moreover, a third study by Kobayashi et al. [11] with
English-speaking monolingual children and adults showed
only a main effect for condition (ToM versus non-ToM) in
the TPJ bilaterally but no clear age difference apart from a
difficult to interpret triple interaction among age, story
type (cartoon, verbal) and condition. The reason for the
weak results and lack of coherence might lie in the design
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of treating the monolingual and bilingual group differently
in the number of conditions (bilingual persons were given
an additional story block for the second language) and in
the choice of control task (e.g. opponents fighting), which
might itself have elicited a non-negligible amount of ToM
thoughts about emotions – and more than a photo task
would have elicited. Moreover, from the text it seems that
the ToM stories in the cartoons were quite different (e.g.
thinking that the other ate one’s food – a moral issue) from
those in the language conditions (e.g. thinking that the
other missed a news item). Although there are potential
problems with the studies by Kobayashi et al. [1,7,11], their
findings are nevertheless suggestive.
Data indicate potential parallels between cultural–
linguistic effects on brain function and on
development of ToM
Cultural differences
In recent years many reports appeared to show cognitive
style differences between Eastern and Western cultures.
Chinese adults show stronger perspective-taking abilities
than do Americans in communication games [12]. However, Chinese children seem to have no advantage over
Americans in ToM tasks even though they perform considerably better on executive tasks [13].
Language development
There are persistent reports that performance on falsebelief tests relates to verbal intelligence [14] and, perhaps, specifically to a child’s ability to process tensed
that-complements (e.g. ‘‘he said that the chocolate is in
the cupboard’’) [15]. This link with language is most
impressively underlined by orally taught deaf children
who learn sign language belatedly. They not only have a
language delay of some years but also are equally delayed
on passing the false-belief test [16]. Moreover, first-generation adult signers of Nicaraguan sign language, who
developed the language from scratch to a moderate level
of grammatical sophistication, have serious problems
with the false-belief test – problems not seen in second-generation signers, for whom that language has
reached a more advanced level of complexity (J. E. Pyers,
PhD Thesis, University of California, 2004). An interesting counterpoint to these developmental dependencies is
the fact that ToM performance can persist in the face of
even severe impairment of grammar due to neurological
insult [17].
Bilingualism
Goetz [18] and A. Kovacs (unpublished) report superior
performance by bilingual children on false-belief tasks.
Considering that understanding false beliefs has been
found to relate especially strongly to children’s ability to
admit alternative names for things [19], the greater familiarity of bilingual children with alternative common names
might be responsible for their ToM advantage. Bialystok
[20] explains performance differences on the ToM-related
appearance–reality task as a result of better attentional
inhibition processes. This is an intriguing idea considering
the involvement of TPJ-R in false-belief processing and in
attentional refocusing as mentioned above.
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Concluding remarks
The findings of Kobayashi et al. do not solve the problem of
assigning a specific functional role to the TPJ. If anything,
they deepen the mystery of what the TPJ might be responsible for. However, their data raise the possibility that the
brain physiology of this mysterious function might be liable
to cultural and linguistic variation with intriguing links to
similar developmental variation. This is a provocative
suggestion that awaits confirmation.
Acknowledgements
We thank the anonymous reviewers for their helpful comments and
Benjamin Weiss for his help with the meta-analysis chart and the
European and Austrian Science Funds (ESF/FWF project I93-G15
‘‘Metacognition of Perspective Differences’’) for financial support.
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