Reconciliation

Matched

1. Responsibility for a social choice that yields a low (negative) outcome for a partner produces interpersonal guilt, experienced by the decision-maker as a larger decrease in momentary happiness than when the partner made the same choice.

   hypothesis —

   Responsibility for a social choice that yields a low (negative) outcome for a partner produces interpersonal guilt, experienced by the decision-maker as a larger decrease in momentary happiness than when the partner made the same choice.

   hypothesis —

2. The anterior insula is the neural substrate of the guilt effect, increasing its BOLD response when participants are responsible for low outcomes affecting their partner.

   hypothesis —

   The anterior insula is the neural substrate of the guilt effect, increasing its BOLD response when participants are responsible for low outcomes affecting their partner.

   hypothesis —

3. Functional connectivity between guilt- and responsibility-related outcome-phase regions and prefrontal cortex changes depending on whether participants decide for themselves alone or also for their partner, and on the type of choice (Safe or Risky).

   hypothesis —

   Functional connectivity between guilt- and responsibility-related outcome-phase regions and prefrontal cortex changes depending on whether participants decide for themselves alone or also for their partner, and on the type of choice (Safe or Risky).

   hypothesis —

4. If responsibility for outcomes generates guilt, then participant happiness should decrease more after low lottery outcomes for the partner when the participant rather than the partner chose the lottery.

   prediction —

   If responsibility for outcomes generates guilt, then participant happiness should decrease more after low lottery outcomes for the partner when the participant rather than the partner chose the lottery.

   prediction —

5. If the anterior insula tracks guilt, then insula BOLD should be higher in the Social than the Partner condition and show a significant Social-by-low-outcome interaction.

   prediction —

   If the anterior insula tracks guilt, then insula BOLD should be higher in the Social than the Partner condition and show a significant Social-by-low-outcome interaction.

   prediction —

6. Participants’ probability of choosing the risky option (lottery) increased with the difference between the expected value of the lottery and the value of the safe option (Study 1: t(4796) = 9.26, p < 3.1e–20, β = 0.074; Study 2: t(3829) = 10.62, p < 5.3e–26, β = 0.093).

   control fig2a,fig2d

   Participants’ probability of choosing the risky option (lottery) increased with the difference between the expected value of the lottery and the value of the safe option (Study 1: t(4796) = 9.26, p < 3.1e–20, β = 0.074; Study 2: t(3829) = 10.62, p < 5.3e–26, β = 0.093).

   control fig2a,fig2d

7. Participants chose the lottery more often in the Solo condition than in the Social condition in Study 1 (t(4796) = 2.54, p = 0.011, β = 0.164) but not in Study 2 (t(3829) = 0.23, p = 0.82, β = 0.015).

   empirical fig2a,fig2d

   Participants chose the lottery more often in the Solo condition than in the Social condition in Study 1 (t(4796) = 2.54, p = 0.011, β = 0.164) but not in Study 2 (t(3829) = 0.23, p = 0.82, β = 0.015).

   empirical fig2a,fig2d

8. There was no significant interaction between the difference in expected values and experimental conditions in either study (p > 0.52).

   control —

   There was no significant interaction between the difference in expected values and experimental conditions in either study (p > 0.52).

   control —

9. Risk premiums did not differ between Social and Solo conditions in either study (Study 1: t(39) = 1.53, p = 0.134, d = 0.24, BF10 = 0.49; Study 2: t(43) = –0.21, p = 0.84, d = –0.03, BF10 = 0.17).

   control fig2b,fig2e

   Risk premiums did not differ between Social and Solo conditions in either study (Study 1: t(39) = 1.53, p = 0.134, d = 0.24, BF10 = 0.49; Study 2: t(43) = –0.21, p = 0.84, d = –0.03, BF10 = 0.17).

   control fig2b,fig2e

10. The risk-aversion parameter ρ did not differ between gain and loss trials (Study 1: t(17) = 0.21, p = 0.84, d = 0.05; Study 2: t(15) = –0.61, p = 0.55, d = 0.15).

    control —

    The risk-aversion parameter ρ did not differ between gain and loss trials (Study 1: t(17) = 0.21, p = 0.84, d = 0.05; Study 2: t(15) = –0.61, p = 0.55, d = 0.15).

    control —

11. Participants were slightly more risk averse (higher ρ) in the Social than the Solo condition in Study 1 (t(39) = 2.27, p = 0.03, d = 0.36, BF10 = 1.69) but not in Study 2 (t(43) = 1.40, p = 0.17, d = 0.21, BF10 = 0.41).

    empirical fig2c,fig2f

    Participants were slightly more risk averse (higher ρ) in the Social than the Solo condition in Study 1 (t(39) = 2.27, p = 0.03, d = 0.36, BF10 = 1.69) but not in Study 2 (t(43) = 1.40, p = 0.17, d = 0.21, BF10 = 0.41).

    empirical fig2c,fig2f

12. Participants showed very similar risk preferences whether deciding only for themselves (Solo) or for themselves and their partner (Social), with only a tendency toward higher risk aversion in the Social condition in Study 1.

    synthesis —

    Participants showed very similar risk preferences whether deciding only for themselves (Solo) or for themselves and their partner (Social), with only a tendency toward higher risk aversion in the Social condition in Study 1.

    synthesis —

13. In both studies, participant momentary happiness correlated with the rewards obtained in the current trial by both the participant and the partner.

    empirical fig3a,fig3b,fig3e,fig3f

    In both studies, participant momentary happiness correlated with the rewards obtained in the current trial by both the participant and the partner.

    empirical fig3a,fig3b,fig3e,fig3f

14. Rutledge and colleagues established that changes in momentary happiness during a probabilistic reward task are explained by recent reward expectations and the prediction errors arising from them.

    literature-context —

    Rutledge and colleagues established that changes in momentary happiness during a probabilistic reward task are explained by recent reward expectations and the prediction errors arising from them.

    literature-context —

15. A likelihood ratio test showed the Responsibility model fitted the happiness data better than all other models, including the Responsibility Redux model (Study 1: all LR ≥ 47.36, p < 0.0001; Study 2: all LR ≥ 77.83, p < 0.0001).

    empirical table1

    A likelihood ratio test showed the Responsibility model fitted the happiness data better than all other models, including the Responsibility Redux model (Study 1: all LR ≥ 47.36, p < 0.0001; Study 2: all LR ≥ 77.83, p < 0.0001).

    empirical table1

16. The Responsibility model yielded higher R2 values than all other models (Study 1: all t > 3.6, p < 0.007; Study 2: all t > 2.9, p < 0.034), except the Guilt-envy model in Study 1 (t = 2.19, p = 0.17).

    empirical table1

    The Responsibility model yielded higher R2 values than all other models (Study 1: all t > 3.6, p < 0.007; Study 2: all t > 2.9, p < 0.034), except the Guilt-envy model in Study 1 (t = 2.19, p = 0.17).

    empirical table1

17. Participants’ own reward prediction errors (sRPE) influenced happiness more than the partner’s reward prediction errors (social_pRPE and partner_pRPE) (Study 1: all Z > 6.0, p < 0.001; Study 2: all Z > 3.7, p < 0.003).

    empirical —

    Participants’ own reward prediction errors (sRPE) influenced happiness more than the partner’s reward prediction errors (social_pRPE and partner_pRPE) (Study 1: all Z > 6.0, p < 0.001; Study 2: all Z > 3.7, p < 0.003).

    empirical —

18. The partner’s reward prediction errors resulting from the participants’ own choices (social_pRPE) had weights greater than 0 (Responsibility model: Study 1: Z = 2.85, p = 0.004; Study 2: Z = 3.26, p = 0.001), contributing to explaining participants’ momentary happiness.

    empirical —

    The partner’s reward prediction errors resulting from the participants’ own choices (social_pRPE) had weights greater than 0 (Responsibility model: Study 1: Z = 2.85, p = 0.004; Study 2: Z = 3.26, p = 0.001), contributing to explaining participants’ momentary happiness.

    empirical —

19. The stability of the estimated computational-model parameters was verified with a parameter recovery procedure.

    methodological fig3s1

    The stability of the estimated computational-model parameters was verified with a parameter recovery procedure.

    methodological fig3s1

20. The ‘Responsibility’ computational model was used to generate expected BOLD responses per participant for the model-based fMRI analysis.

    methodological —

    The ‘Responsibility’ computational model was used to generate expected BOLD responses per participant for the model-based fMRI analysis.

    methodological —

21. The Responsibility Redux model, taking into account expected, previous and current rewards, reward prediction errors for both participant and partner, and decision-maker, predicted the variations in participants' momentary happiness well.

    empirical fig3c, fig3g

    The Responsibility Redux model, taking into account expected, previous and current rewards, reward prediction errors for both participant and partner, and decision-maker, predicted the variations in participants' momentary happiness well.

    empirical fig3c, fig3g

22. Participant happiness was lower when the participant was the decision-maker (Social + Solo vs. Partner), independent of outcome (Study 1: t(3600) = –3.92, p < 0.0001, β = –0.14; Study 2: t(2870) = –6.07, p < 0.0001, β = –0.24).

    empirical —

    Participant happiness was lower when the participant was the decision-maker (Social + Solo vs. Partner), independent of outcome (Study 1: t(3600) = –3.92, p < 0.0001, β = –0.14; Study 2: t(2870) = –6.07, p < 0.0001, β = –0.24).

    empirical —

23. The lower happiness when the participant is the decision-maker may reflect responsibility aversion, a cost of the ‘weight of the responsibility’.

    interpretation —

    The lower happiness when the participant is the decision-maker may reflect responsibility aversion, a cost of the ‘weight of the responsibility’.

    interpretation —

24. The interaction between partner outcome and decision-maker was significant (Study 1: t(1180) = 3.52, p = 0.0004, β = 0.37; Study 2: t(937) = 2.85, p = 0.0045, β = 0.33): when the partner received the low outcome, participant happiness was lower when the participant rather than the partner had chosen the lottery.

    empirical fig3d,fig3h

    The interaction between partner outcome and decision-maker was significant (Study 1: t(1180) = 3.52, p = 0.0004, β = 0.37; Study 2: t(937) = 2.85, p = 0.0045, β = 0.33): when the partner received the low outcome, participant happiness was lower when the participant rather than the partner had chosen the lottery.

    empirical fig3d,fig3h

25. The linear mixed model containing all three two-way interaction terms (Model 5) best explained the happiness data in both studies, and its crucial partnerHigh:participantDecided (guilt) interaction was significant.

    empirical app1table2

    The linear mixed model containing all three two-way interaction terms (Model 5) best explained the happiness data in both studies, and its crucial partnerHigh:participantDecided (guilt) interaction was significant.

    empirical app1table2

26. The behavioural guilt effect (larger happiness decrease after low partner outcomes following participant rather than partner choices) is compatible with ‘simple guilt’.

    interpretation —

    The behavioural guilt effect (larger happiness decrease after low partner outcomes following participant rather than partner choices) is compatible with ‘simple guilt’.

    interpretation —

27. The guilt effect occurred whether the participant received the high lottery outcome (Study 1: t(39) = –3.58, p < 0.001, d = 0.56; Study 2: t(43) = –2.68, p = 0.01, d = 0.4) or the low outcome (Study 1: t(39) = –3.39, p = 0.002, d = 0.54; Study 2: t(43) = –3.58, p < 0.001, d = 0.54).

    control —

    The guilt effect occurred whether the participant received the high lottery outcome (Study 1: t(39) = –3.58, p < 0.001, d = 0.56; Study 2: t(43) = –2.68, p = 0.01, d = 0.4) or the low outcome (Study 1: t(39) = –3.39, p = 0.002, d = 0.54; Study 2: t(43) = –3.58, p < 0.001, d = 0.54).

    control —

28. Responsibility for choices did not influence happiness following positive (high) lottery outcomes for the partner (both studies, all |t| < 1.3, p > 0.2, BF10 < 0.2).

    control —

    Responsibility for choices did not influence happiness following positive (high) lottery outcomes for the partner (both studies, all |t| < 1.3, p > 0.2, BF10 < 0.2).

    control —

29. All BOLD/fMRI results derive from Study 2 (the fMRI study), whereas the behavioural results come from both Study 1 and Study 2.

    scope —

    All BOLD/fMRI results derive from Study 2 (the fMRI study), whereas the behavioural results come from both Study 1 and Study 2.

    scope —

30. The bilateral ventral striatum was more active when participants chose the risky rather than the safe option (Cohen’s d = 0.72 left, 0.85 right), replicating previous findings.

    control fig4a

    The bilateral ventral striatum was more active when participants chose the risky rather than the safe option (Cohen’s d = 0.72 left, 0.85 right), replicating previous findings.

    control fig4a

31. Decisions in the Social compared with the Solo condition engaged three clusters — the precuneus (d = 0.79), left temporo-parietal junction (d = 0.59), and medial prefrontal cortex (d = 0.54).

    empirical fig4b

    Decisions in the Social compared with the Solo condition engaged three clusters — the precuneus (d = 0.79), left temporo-parietal junction (d = 0.59), and medial prefrontal cortex (d = 0.54).

    empirical fig4b

32. Only the precuneus and TPJ showed positive Risky–Safe differences in both the Social>Solo and Social>Partner comparisons, being most active when participants chose the lottery in the Social condition.

    empirical fig4c

    Only the precuneus and TPJ showed positive Risky–Safe differences in both the Social>Solo and Social>Partner comparisons, being most active when participants chose the lottery in the Social condition.

    empirical fig4c

33. During receipt of lottery versus safe outcomes, clusters were more active in the bilateral anterior insula, dmPFC, right STS, bilateral ventral striatum, right dorsolateral prefrontal cortex, and bilateral inferior parietal lobe.

    empirical fig4d

    During receipt of lottery versus safe outcomes, clusters were more active in the bilateral anterior insula, dmPFC, right STS, bilateral ventral striatum, right dorsolateral prefrontal cortex, and bilateral inferior parietal lobe.

    empirical fig4d

34. The insula ROIs responded more to low lottery outcomes for the partner in the Social than the Partner condition (even after subtracting responses to high outcomes), mirroring the behavioural guilt effect.

    empirical fig4e

    The insula ROIs responded more to low lottery outcomes for the partner in the Social than the Partner condition (even after subtracting responses to high outcomes), mirroring the behavioural guilt effect.

    empirical fig4e

35. A mass-univariate voxel-wise analysis found a small left anterior insula cluster (peak T = 3.95, d = 0.59, 22 voxels) responding more to low partner outcomes following participant than partner choices, which survived small-volume family-wise-error correction (p = 0.024).

    empirical fig4f

    A mass-univariate voxel-wise analysis found a small left anterior insula cluster (peak T = 3.95, d = 0.59, 22 voxels) responding more to low partner outcomes following participant than partner choices, which survived small-volume family-wise-error correction (p = 0.024).

    empirical fig4f

36. Prior literature documents an association between the anterior insula and guilt.

    literature-context —

    Prior literature documents an association between the anterior insula and guilt.

    literature-context —

37. As a manipulation check, bilateral ventral striatum activation increased with expected certain rewards and the expected values of chosen lotteries (left: pFWE = 0.002, T = 5.63, d = 0.75; right: pFWE = 0.005, T = 5.46, d = 0.70).

    control fig4g

    As a manipulation check, bilateral ventral striatum activation increased with expected certain rewards and the expected values of chosen lotteries (left: pFWE = 0.002, T = 5.63, d = 0.75; right: pFWE = 0.005, T = 5.46, d = 0.70).

    control fig4g

38. One cluster in the left STS responded more to partner reward prediction errors resulting from participant rather than partner choices (pFWE = 0.022, T = 4.70, d = 0.53, 100 voxels, peak MNI [−52 –32 0]).

    empirical fig4h

    One cluster in the left STS responded more to partner reward prediction errors resulting from participant rather than partner choices (pFWE = 0.022, T = 4.70, d = 0.53, 100 voxels, peak MNI [−52 –32 0]).

    empirical fig4h

39. The left superior temporal sulcus cluster responded to model-based regressors coding participant reward prediction resulting from participant and partner choices across both sessions of the experiment.

    empirical fig4i

    The left superior temporal sulcus cluster responded to model-based regressors coding participant reward prediction resulting from participant and partner choices across both sessions of the experiment.

    empirical fig4i

40. The authors suggest this left STS region tracks a partner’s unexpected outcomes less when they do not follow from the participant’s decisions.

    interpretation —

    The authors suggest this left STS region tracks a partner’s unexpected outcomes less when they do not follow from the participant’s decisions.

    interpretation —

41. Prior functional connectivity work has shown network differences between social and self-only choices, midbrain–anterior cingulate interactions during guilt compensation, and links between insula connectivity and responsibility aversion.

    literature-context —

    Prior functional connectivity work has shown network differences between social and self-only choices, midbrain–anterior cingulate interactions during guilt compensation, and links between insula connectivity and responsibility aversion.

    literature-context —

42. Left anterior insula connectivity with a right IFG cluster was highest when participants made Risky choices for themselves and Safe choices for both players (pFWE = 0.020, T = 4.34, d = 0.80, 115 voxels, peak MNI [46 16 22]).

    empirical fig5

    Left anterior insula connectivity with a right IFG cluster was highest when participants made Risky choices for themselves and Safe choices for both players (pFWE = 0.020, T = 4.34, d = 0.80, 115 voxels, peak MNI [46 16 22]).

    empirical fig5

43. A left IFG cluster showed the opposite pattern of connectivity with the left STS seed — highest for Safe-self / Risky-both-players choices — but did not survive correction for multiple comparisons (p uncorrected = 0.001, T = 4.44, 35 voxels).

    empirical fig5s1

    A left IFG cluster showed the opposite pattern of connectivity with the left STS seed — highest for Safe-self / Risky-both-players choices — but did not survive correction for multiple comparisons (p uncorrected = 0.001, T = 4.44, 35 voxels).

    empirical fig5s1

44. Dot products between individual neural guilt responses and the Yu et al. (2020) guilt-related brain signature (GRBS) were overall positive (mean = 5.22, median = 6.97, sign test p = 0.017, Cliff’s Delta = 0.4).

    empirical —

    Dot products between individual neural guilt responses and the Yu et al. (2020) guilt-related brain signature (GRBS) were overall positive (mean = 5.22, median = 6.97, sign test p = 0.017, Cliff’s Delta = 0.4).

    empirical —

45. Individual GRBS dot-product values did not correlate with the behavioural guilt responses (Spearman’s Rho = –0.058, p = 0.725).

    control —

    Individual GRBS dot-product values did not correlate with the behavioural guilt responses (Spearman’s Rho = –0.058, p = 0.725).

    control —

46. Among the computational models fitted to momentary happiness data, the Responsibility Redux model achieved the best (lowest) AIC in both studies (Study 1 AIC –1499; Study 2 AIC –1195).

    methodological table1

    Among the computational models fitted to momentary happiness data, the Responsibility Redux model achieved the best (lowest) AIC in both studies (Study 1 AIC –1499; Study 2 AIC –1195).

    methodological table1

47. In mixed-effects regressions on choices, the Social condition significantly increased choice of the risky option in Study 1 but not in Study 2.

    empirical app1table1

    In mixed-effects regressions on choices, the Social condition significantly increased choice of the risky option in Study 1 but not in Study 2.

    empirical app1table1

48. During the outcome phase, responses to low lottery outcomes were higher in the Social than the Partner condition in both left and right insula and lower in the right middle temporal cortex.

    empirical app1table9

    During the outcome phase, responses to low lottery outcomes were higher in the Social than the Partner condition in both left and right insula and lower in the right middle temporal cortex.

    empirical app1table9

49. The difference in response between low and high lottery outcomes was greater in the Social than the Partner condition in left insula, right insula, and right middle temporal cortex.

    empirical app1table10

    The difference in response between low and high lottery outcomes was greater in the Social than the Partner condition in left insula, right insula, and right middle temporal cortex.

    empirical app1table10

50. Participants rated their partners highly on sympathy, cooperation, honesty, openness, and sociability in both studies.

    control app1table11

    Participants rated their partners highly on sympathy, cooperation, honesty, openness, and sociability in both studies.

    control app1table11

51. On each trial participants chose between a safe monetary option and a risky lottery, under three conditions: deciding for themselves (Solo), for themselves and the partner (Social), and for the partner deciding for both (Partner).

    scope —

    On each trial participants chose between a safe monetary option and a risky lottery, under three conditions: deciding for themselves (Solo), for themselves and the partner (Social), and for the partner deciding for both (Partner).

    scope —

52. Study 2 reproduced the Study 1 design inside the fMRI scanner with otherwise identical parameters, except for longer inter-stimulus intervals (3–11 s) and a fixed experimenter partner.

    scope —

    Study 2 reproduced the Study 1 design inside the fMRI scanner with otherwise identical parameters, except for longer inter-stimulus intervals (3–11 s) and a fixed experimenter partner.

    scope —

53. To hold the partner's behaviour constant across participants, the partner's decisions were simulated by an algorithm that always chose the option with the highest expected value.

    methodological —

    To hold the partner's behaviour constant across participants, the partner's decisions were simulated by an algorithm that always chose the option with the highest expected value.

    methodological —

54. Momentary happiness was modelled with five computational models (Basic, Inequality, Guilt-envy, Responsibility, and Responsibility Redux) sharing separate, exponentially decaying terms for certain rewards, expected value, and reward prediction errors.

    methodological —

    Momentary happiness was modelled with five computational models (Basic, Inequality, Guilt-envy, Responsibility, and Responsibility Redux) sharing separate, exponentially decaying terms for certain rewards, expected value, and reward prediction errors.

    methodological —

55. Model selection among the happiness models used likelihood ratio tests comparing the Responsibility model pairwise against each of the other models.

    methodological —

    Model selection among the happiness models used likelihood ratio tests comparing the Responsibility model pairwise against each of the other models.

    methodological —