关键词: 社会性框架效应, 静息态功能磁共振, 功能连接, 右侧颞顶联合区, 道德脑网络

Abstract:

As an important cognitive bias, the framing effect shows that individuals' decision preferences are sensitive to the verbal description (i.e., frame) of options. The social framing effect could be distinguished from the non-social one according to whether the decision would influence others. The psychological mechanisms of the non-social framing effect (e.g., Gain/Loss framing effect) and that of the social one are essentially different. When making non-social decisions, frames affect people’s judgment of which option is more beneficial or less risky. When making social decisions, frames affect people’s preferences through the influence of other-regarding concerns and social norms.
In the present study, a new paradigm was developed to induce the social framing effect. We asked participants to make a tradeoff between economic benefits and the feelings of others; when participants showed a stronger preference for income maximization, the probability for their partners to receive a painful electrical shock would increase proportionally. This decision was described as either a “harm” to, or simply “not helping” other persons in two frame conditions. 30 participants (age: 20.58 ± 1.91 years old) were enrolled in the experiment and 24 of them were included in the final analysis. The resting-state functional magnetic resonance (rs-fMRI) data was acquired using the Echo Planar Imaging (EPI) sequence from a 3-T Siemens scanner. This scanning acquired 180 volumes with TR = 2 s (lasting 6 min). Rs-fMRI data were processed and analyzed using the DPABI and RESTplus toolbox to calculate the amplitude of low-Frequency Fluctuation (ALFF) and Functional Connectivity (FC).
On the behavioral level, we found that participants made more prosocial decisions in the Harm frame compared to the Help frame condition, resulting in a significant social framing effect. For the resting fMRI analysis, we first run a whole-brain correlation analysis between ALFF and the behavioral index and found the ALFF of the right temporoparietal junction (rTPJ) could significantly predict the behavioral index of the social framing effect. Considering the observed social framing effect would result from different levels of moral conflict between Harm and Help frames, we predicted that it would be closely related to the moral network. Therefore, we further localized 12 seeds from a new, meta-analysis of functional MRI studies for moral processing. Seed-based FC analysis showed that the functional connectivity between the medial prefrontal cortex and the caudate was significantly associated with the behavioral index of the social framing effect. Multivariate machine learning-based regression analysis further confirmed these results, suggesting the importance of rTPJ and moral network for the observed social framing effect.
The present study is based on a novel experimental paradigm, using resting functional imaging techniques to explore the brain mechanism of the social framing effect. We found that the ALFF value of the right TPJ and the strength of the functional connectivity value between the medial prefrontal lobe and the caudate within a moral network can effectively predict the social framing effect. This study is the very first one to explore the extent to which individual social decision-making can be influenced by verbal description and its underlying neural mechanisms, which shed light on the further exploration of individual differences in social decision-making.

Key words: social framing effect, resting-state fMRI, functional connectivity, right temporoparietal junction, moral network