Effects of social norm types on pro-environmental behavior: The moderating role of moral identity and fNIRS evidence

doi:10.3724/SP.J.1041.2026.1197

Abstract

Abstract:

Against the backdrop of increasingly severe ecological and environmental challenges, promoting individuals’ pro-environmental behavior is critical. Although social norms constitute a key external determinant, their effectiveness varies by type; in particular, injunctive norms tend to be less effective than descriptive norms, and their underlying psychological and neural mechanisms remain unclear. The present study employed the Greater Good Game paradigm in conjunction with functional near-infrared spectroscopy (fNIRS) to examine the moderating role of moral identity in the effects of different types of social norms on pro-environmental behavior, as well as the associated neural mechanisms. The results showed that, under the moral identity priming condition, injunctive norms significantly enhanced both pro-environmental behavior and behavioral tendencies compared with descriptive norms. In the non-priming condition, descriptive norms did not produce a statistically significant difference in behavioral choices relative to injunctive norms but exhibited a greater tendency toward pro-environmental behavior. Neuroimaging results indicated that moral identity was associated with increased activation in the dorsolateral prefrontal cortex (DLPFC). Further analyses revealed that the combination of injunctive norms and moral identity primarily activated the orbitofrontal cortex (OFC) and medial prefrontal cortex (mPFC), whereas the combination of descriptive norms and moral identity mainly activated the right temporoparietal junction (rTPJ). These findings elucidate a dual-pathway mechanism through which social norms influence pro-environmental behavior and highlight the critical moderating role of moral identity. The study provides implications for policy and practice: enhancing the effectiveness of injunctive norms by activating moral identity, while leveraging the stabilizing effect of descriptive norms, offers empirical support for behavior interventions grounded in neural mechanisms.

Key words: pro-environmental behavior, social norm types, moral identity, Greater Good Game, fNIRS

REN Mengmeng, LI Jin, ZHONG Yiping, YANG Lijun. (2026). Effects of social norm types on pro-environmental behavior: The moderating role of moral identity and fNIRS evidence. Acta Psychologica Sinica, 58(6), 1197-1212.

Figures/Tables 8

Figure 1. Background Information for Injunctive Norms (A) and Descriptive Norms (B).

Figure 2. Experimental Procedure.
Note. The figure illustrates the overall structure of the experimental procedure and the timing sequence within a single trial. The example trial shown corresponds to a representative trial from the moral identity priming block under the descriptive norm condition.

Figure 3. MPT Model of the Greater Good Game.
Note. s represents the probability of choosing the individual account (self-interested decision path); e represents the probability of choosing the environmental account within the non-self-interested path (see Section 2.4.1 for model specification).

Figure 4. Sagittal View of fNIRS Channel Layout.
Note. Red circles denote emitters; blue circles denote detectors; the numbers between them indicate channels. Color figures are available in the electronic version; the same applies hereafter.

Figure 5. Proportion of Environmental Account Choices Under Different Experimental Conditions (Error bars represent the standard error of the mean).

Figure 6. Brain Activation Maps of the Main Effects and Interaction Between Social Norm Types and Moral Identity Priming.
Note. Colors in the figure represent F-values from the ANOVA (range: 0-11); warmer (redder) colors indicate larger F-values for the corresponding main effects or interaction in those brain regions.

Figure 7. Activation of OFC, mPFC, and rTPJ During the Decision Phase Across Different Groups.
Note. * p < 0.05, ** p < 0.01, *** p < 0.001

Appendix Table 1 Scores of the 10 Environmental Organizations on Two Manipulation Check Items

Environmental organizations	This environmental organization has made outstanding contributions to environmental protection (M ± SD)	This environmental organization has far-reaching influence in the field of environmental protection (M ± SD)
World Wide Fund for Nature	4.73 ± 0.47	4.65 ± 0.58
International Union for Conservation of Nature	4.56 ± 0.54	4.49 ± 0.63
China Environmental Protection Foundation	4.42 ± 0.58	4.34 ± 0.52
The Nature Conservancy	4.69 ± 0.43	4.53 ± 0.55
Global Environment Facility	4.22 ± 0.66	4.17 ± 0.63
Greenpeace	4.01 ± 0.74	3.93 ± 0.84
Friends of the Earth	3.83 ± 0.65	3.74 ± 0.79
Alibaba Foundation	3.57 ± 0.72	3.46 ± 0.75
China Association of Environmental Protection	3.64 ± 0.62	3.51 ± 0.62
All-China Environment Federation	3.75 ± 0.65	3.64 ± 0.78

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