Abstract:

Prosocial behaviors—actions intended to bene?t others—are critical indicators of adolescents’ moral character and social competencies, and form the basis for societal harmony and cooperation. Adolescence is a critical period for facilitating prosocial behavior and internalizing prosocial values attributing to the ecological and biological transitions in this stage. Research on youth prosocial behavior in the past decades consistently implicated peers as important and unique socializing agents. Particularly, peer group changes and the increasing importance of peer relationships during adolescence provide both risks and opportunities for the development of prosocial behaviors. In addition, adolescents may exhibit differences in the degree to which they are affected by peer experiences, which are often rooted in their genetic predispositions. Recent evidence indicated that the genes involved in dopamine neurotransmission and metabolism act in an additive manner to influence sensitivity to the environment. However, exploration regarding the dynamic trajectory of the relationship between peer experience and prosocial behavior and whether the dynamic relationship is moderated by dopaminergic genes in a longitudinal framework is still lacking. With the adoption of the multilocus genetic profile score (MGPS) approach, the present study aimed to explore the dynamic trajectory of the relationship between peer rejection and prosocial behavior, and whether the dynamic association was moderated by dopaminergic genes.

One thousand and forty-four Chinese Han adolescents (aged 13~15 years with a mean of 13.32 ± 0.48 years old at Time 1; 50.1% girls) were followed up for three years. Peer-rated prosocial behavior and peer-nominated peer rejection were collected at each time point. All measures presented good reliability. Real-time genotyping was performed for each participant using MassARRAY RT software version 3.0.0.4 and analyzed using the MassARRAY Typer software version 3.4 (Sequenom). The relationship between the developmental trajectories of peer rejection and prosocial behavior and the moderating role of dopaminergic genes was examined via the parallel latent growth model and multiple group comparison analyses.

The means, standard deviations, and bivariate correlations among all studied variables were presented in Table 1. The MGPS was uncorrelated with peer rejection at each time point, indicating the absence of correlation between genes and environment (rGE). Peer rejection was negatively correlated with prosocial behavior, concurrently and prospectively. Prosocial behavior and peer rejection showed moderate annual consecutive stability across time. The LGCMs suggested that adolescents’ prosocial behavior and peer rejection increased linearly during the follow-up period (See Table 2). The parallel process LGCM (χ²(20) = 113.31, CFI = 0.97, TLI = 0.95, RMSEA = 0.07, SRMR = 0.06) showed that higher initial levels of peer rejection were associated with lower initial levels and slower growth of prosocial behavior. The change rates of peer rejection were associated with the developmental change of prosocial behavior, that is, the slower increase in peer rejection was associated with a greater increase in prosocial behavior over time (See Figure 1). More importantly, the effects of the initial level of peer rejection on the initial level and growth in prosocial behavior were moderated by MGPS, with lower MGPS being more sensitive to the initial level of peer rejection (See Table 3, Figure 2 and Figure 3).

These findings support the dynamic relationship between peer relationships and prosocial behavior and shed light on the complex polygenic underpinnings of the latter.

Key words: prosocial behavior, peer rejection, dopaminergic genes × environment, developmental trajectories, parallel latent growth modeling