Cited by 297Neural and Behavioral Psychology StudiesExperimental Behavioral Economics StudiesNeuroendocrine regulation and behavior

Linking Brain Structure and Activation in Temporoparietal Junction to Explain the Neurobiology of Human Altruism

Open access
Morishima, Yosuke, Schunk, Daniel, Bruhin, Adrian, Ruff, Christian C., Fehr, Ernst·2012·Neuron

Abstract

Human altruism shaped our evolutionary history and pervades social and political life. There are, however, enormous individual differences in altruism. Some people are almost completely selfish, while others display strong altruism, and the factors behind this heterogeneity are only poorly understood. We examine the neuroanatomical basis of these differences with voxel-based morphometry and show that gray matter (GM) volume in the right temporoparietal junction (TPJ) is strongly associated with both individuals' altruism and the individual-specific conditions under which this brain region is recruited during altruistic decision making. Thus, individual differences in GM volume in TPJ not only translate into individual differences in the general propensity to behave altruistically, but they also create a link between brain structure and brain function by indicating the conditions under which individuals are likely to recruit this region when they face a conflict between altruistic and selfish acts.

AI snapshot

Written from the paper’s full text.

TL;DR

In 30 healthy adults, gray matter volume in the right temporoparietal junction (TPJ) was strongly associated with altruism specifically in the domain of advantageous inequality, not disadvantageous inequality or reciprocity. Functional TPJ activation followed an inverted U-shaped profile, peaking when the cost of an altruistic act was just below the individual’s maximum willingness to pay.

Key findings

  • Right TPJ gray matter volume positively correlated with the altruism parameter \(b\) for advantageous inequality: whole-brain VBM peak \(t = 5.94\), \(p < 0.05\) voxelwise whole-brain FWE corrected; a priori right TPJ ROI correlation \(r = 0.61\), \(p < 0.001\).
  • No significant TPJ gray matter correlation was found with altruism in disadvantageous inequality \(a\) (ROI \(r = -0.01\), \(p = 0.95\); whole-brain \(p > 0.05\), uncorrected) or with positive reciprocity \(q\) or negative reciprocity \(d\).
  • Behaviorally, mean altruism was positive for advantageous inequality (\(b\): mean 0.275, \(t(28) = 6.39\), \(p < 0.0001\)) and disadvantageous inequality (\(a\): mean 0.085, \(t(28) = 4.06\), \(p = 0.004\)); \(b\) was significantly higher than \(a\) (\(t(28) = 4.52\), \(p = 0.0001\)).
  • Functional TPJ activation showed an inverted U-shaped pattern around the individual-specific maximum willingness to pay \(w\), with peak activation at MNI [60, -44, 18], \(t = 4.12\), \(p = 0.003\) FWE corrected for the cluster; TPJ gray matter volume was associated with \(w\) (\(r = 0.79\), \(p < 10^{-5}\)).

Methods

  • Thirty healthy adults participated (17 females; 19–37 years; mean 23.36 years); one subject was excluded for very inconsistent behavior, though the results text reports \(n = 30\) and \(t(28)\).
  • Subjects completed dictator and reciprocity games involving binary monetary allocations between themselves and anonymous partners; a mathematical model of social preferences estimated individual parameters \(a\), \(b\), \(q\), and \(d\).
  • Voxel-based morphometry (VBM) tested correlations between local gray matter volume and preference parameters, including an a priori right TPJ ROI centered at [54, -54, 24]; fMRI BOLD data were analyzed for TPJ activation during the task, with SPM8 used for MRI preprocessing and analysis.

Limitations

  • The paper does not include a stated limitations section.
  • Evident from the text: the sample is small (30 participants, with one excluded for inconsistent behavior), and the design is correlational, so it cannot establish that TPJ structure causes altruistic preferences.
  • Evident from the text: findings are limited to a specific set of economic games with anonymous partners and to the right TPJ; the reported \(n = 30\) alongside one exclusion and \(t(28)\) is also internally inconsistent.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1016/j.neuron.2012.05.021

Cites

38 of 38 references verified0 citation errors · 0 not checkable

Statistics

3 tests recomputed · 0 with the reported and recomputed p on opposite sides of .05

Claims the paper makes

0 of 17 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Gray matter volume in the right temporoparietal junction (TPJ) is strongly positively correlated with altruism in the domain of advantageous inequality (parameter b).

    “We find that GM volume in the right TPJ displays a strong positive correlation with b, our preference measure of altruism in the domain of advantageous inequality (t = 5.94, p < 0.05, voxelwise whole-brain familywise error [FWE] corrected) (Figure 3A)”
    • Also stated in: § Gray Matter Volume in the Right TPJ Predicts the General Propensity for Altruistic Acts · boosted
      “we also obtain a high and significant correlation (Figure 3B, r = 0.61, p < 0.001)”
    • Also stated in: § DISCUSSION · boosted
      “GM volume in the right TPJ, an area that has been shown to be implicated in perspective-taking tasks, is strongly associated with individuals' behavioral altruism in situations of advantageous inequality.”
    Quote in the paperSubstantial claim
  • Findingown data

    No other brain region is significantly correlated with parameter b in a whole-brain analysis.

    “Moreover, a whole-brain analysis shows that no other brain region is (whole-brain FWE corrected) significantly correlated with b (Table S2).”
    Quote in the paperSubstantial claim
  • Findingown data

    Gray matter volume in the right TPJ is not correlated with altruism in the domain of disadvantageous inequality (parameter a).

    “while we observe no correlation with preferences for altruism in the domain of disadvantageous inequality a (p > 0.05, uncorrected).”
    • Also stated in: § Gray Matter Volume in the Right TPJ Predicts the General Propensity for Altruistic Acts · plain
      “preferences for altruism in the domain of disadvantageous inequality a are uncorrelated with GM volume (Figure 3C, r = À0.01,p = 0.95).”
    Quote in the paperSubstantial claim
  • Findingown data

    Altruism in the domain of advantageous inequality (parameter b) is significantly higher than altruism in the domain of disadvantageous inequality (parameter a) (t(28)=4.52, p=0.0001).

    “Interestingly, altruism in the domain of advantageous inequality (b) is significantly higher than altruism in the domain of disadvantageous inequality (a, t(28) = 4.52, p = 0.0001).”
    Quote in the paperSubstantial claim
  • Findingown data

    On average, the preference parameter b (altruism in advantageous inequality) is significantly positive (mean 0.275, t(28)=6.39, p<0.0001).

    “On average, a (mean 0.085, t(28) = 4.06, p = 0.004) and b (mean 0.275, t(28) = 6.39,p < 0.0001) are significantly positive”
    Quote in the paperSubstantial claim
  • May combine two claims. 7
  • Classified as probably not a substantial claim. 1
  • May combine two claims.

    Findingown data

    Gray matter volume in the TPJ is not significantly correlated with positive reciprocity (parameter q) or negative reciprocity (parameter d).

    “Interestingly, neither q nor d is significantly correlated with TPJ GM volume (Figures 3D and 3E) or with any other brain region (Table S2)”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    Parameters a and b are positively correlated, but the correlation falls just short of statistical significance (r=0.29, p=0.11).

    “Both parameters are positively correlated, albeit the correlation falls just short of statistical significance (r = 0.29, p = 0.11).”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationown data

    The right TPJ is important at the structural-anatomical level for subjects' baseline propensity to behave altruistically, while the concrete extent of an individual's functional TPJ activation depends on the relationship between the individual's maximum willingness to pay and the cost of the altruistic act.

    “Taken together, our data thus suggest that the right TPJ is important at the structural-anatomical level for subjects' baseline propensity to behave altruistically, while the concrete extent of an individual's functional TPJ activation is dependent on the context, i.e., on the relationship between the individual's maximum willingness to pay for an altruistic act and the cost of the altruistic act.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisecitation

    Previous research documented that individuals' propensity for altruism is relatively stable across time, but these studies did not provide a biological basis for this temporal stability.

    “Previous research has documented that individuals' propensity for altruism is relatively stable across time, but these studies did not provide any biological basis for this temporal stability (Benz and Meier, 2008;Van Lange, 1999).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Benz and Meier, 2008

      Not checked in the free run.

    • cites Van Lange, 1999 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Gray matter volume in the TPJ is associated with both baseline altruism (parameter b) and subject-specific functional activity profiles in the TPJ.

    “Our results thus indicate that GM volume in TPJ is associated with both subjects' baseline altruism as measured by b and subject-specific functional activity profiles in the TPJ.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisereasoning

    Prior studies on pSTC do not examine how individual differences in task-independent brain structure relate to behaviorally expressed preferences for altruism, and therefore do not establish a link between individual differences in brain structure and individual-specific conditions for functional activation of TPJ in the altruism task.

    “These studies, however, do not examine how individual differences in (task-independent) brain structure are related to subjects' behaviorally expressed preferences for altruism; therefore, they do not establish a link between individual differences in brain structure and the individual-specific conditions for the functional activation of TPJ in the altruism task.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisenone given

    There is enormous individual heterogeneity in human altruism, and the sources of individual variation are still very poorly understood.

    “However, there is also enormous individual heterogeneity in human altruism, and the sources of individual variation are still very poorly understood.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Premisecitation

    Recent applications of brain morphometry indicate that individual differences in brain structure can be useful in understanding individual differences in traits and skills.

    “Recent applications of brain morphometry indicate that individual differences in brain structure can be useful in understanding individual differences in traits and skills (Kanai and Rees, 2011).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Kanai and Rees, 2011

      Not checked in the free run.

8 of 8
  • The authors state this as an assumption.

    The utility function specified by the equation with parameters a, b, q, and d adequately captures subjects' social preferences.

    “We applied a model of social preferences in order to estimate each individual's preferences for altruistic acts.Formally, the model can be represented by the following equation:”
    “UAðPA; P B Þ = ð1 À br À as À qq + dvÞP A + ðbr + as + qq À dvÞP B”
  • The paper relies on this without support.

    Anatomical brain structure, including gray matter volume, does not change over short periods of time.

    “The present study shows that anatomical structure, which does not change over short periods of time, can account for the strong heterogeneity in individuals' preferences for altruistic acts.”
2 of 2

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Previous findings link prosocial decisions with several hubs in the social brain network, including the amygdala, ventral striatum and TPJ.

    “Moreover, we found evidence that social value distance is also encoded by neural responses in the ventral striatum and TPJ in prosocials, consistent with previous findings linking prosocial decisions with several hubs in the social brain network 7,36 , including the amygdala, ventral striatum and TPJ.”
  • Social value distance signals in prosocials may also relate to mentalizing about the needs of others, integrating social information into estimates of subjective value, and calculating altruistic values in the social brain network.

    “Social value distance signals in prosocials may also relate to mentalizing about the needs of others 36,37 , integrating social information into estimates of subjective value 40 , and calculating altruistic values 41 in the social brain network.”

Statistics that don’t add up

Each reported p-value recomputed from its test statistic and degrees of freedom.

  • Inconsistent p-value: t(28) = 4.06, p = .004

    Minor

    The paper reports p = .004 here; recomputing from the test statistic and its degrees of freedom gives p < .001 (two-tailed). The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .004 · recomputed p < .001

1 of 1

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Doesn’t add upt(28) = 4.06reported p = .004 · recomputed p < .001

    “t(28) = 4.06, p = .004”

  • Consistentt(28) = 6.39reported p < .0001 · recomputed p < .001

    “t(28) = 6.39,p < .0001”

  • Consistentt(28) = 4.52reported p = .0001 · recomputed p < .001

    “t(28) = 4.52, p = .0001”

3 of 3

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Self-check results appear here once an independent check has confirmed them.

Cites

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1 of the 39 references couldn’t be matched to a known paper.

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Authors
Morishima, Y., Schunk, D., Bruhin, A., Ruff, C. C., & Fehr, E.
Affiliations
University of Zurich (CH)
Corresponding author
  • Morishima, Yosuke
  • Fehr, Ernst
Venue
Neuron
Publisher
Elsevier BV
Published
2012-07
Volume
75
Issue
1
Pages
73-79
ISSN
0896-6273 (ISSN-L)
OpenAlex
W1989006812
Cited by
296
References
39
Citations by year
2026: 15 · 2025: 9 · 2024: 13 · 2023: 29 · 2022: 21 · 2021: 43 · 2020: 22 · 2019: 18 · 2018: 24 · 2017: 24 · 2016: 25 · 2015: 17 · 2014: 13 · 2013: 21 · 2012: 1
FWCI
8.51
Type
journal article
Language
en
Open access
Locations
  • Neuron (publishedVersion)
  • PubMed (publishedVersion)
  • Archive ouverte UNIGE (University of Geneva) (publishedVersion, other-oa)
  • Zurich Open Repository and Archive (University of Zurich) (acceptedVersion)
  • IRIS (submittedVersion)
  • SERVAL (Université de Lausanne) (submittedVersion)
  • Archive ouverte UNIGE (University of Geneva) (submittedVersion, cc-by)
  • Zurich Open Repository and Archive (University of Zurich) (submittedVersion)
  • Zurich Open Repository and Archive (University of Zurich)
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Neural and Behavioral Psychology Studies
  • Social Sciences › Safety Research › Experimental Behavioral Economics Studies
  • Social Sciences › Psychology › Social Psychology › Neuroendocrine regulation and behavior
Keywords
altruism, temporoparietal junction, gray matter volume, individual differences, brain structure-function relationship, voxel-based morphometry
MeSH terms
Adult, Altruism, Choice Behavior, Female, Humans, Male, Parietal Lobe, Temporal Lobe, Young Adult

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