Previous studies (e.g., Bouman et al.,
2012) have found robust associations between peer-reported and self-reported bullying. In the current study there was a significant positive association between self- and peer-reported bullying, total sample,
r(701) = 0.29,
p < 0.001, autistic adolescents
r(107) = 0.35,
p < 0.001, neurotypical adolescents
r(593) = 0.28,
p < 0.001. A total, multi-informant, continuous bullying score was therefore created by standardising and summing peer-reported and self-reported bullying scores.
Properties of the IGI-C Across Autistic and Neurotypical Groups
Comparing the internal consistency of the IGI-C for autistic and neurotypical groups (Diedenhofen & Musch,
2016) revealed a significant difference for agentic goals, autistic group Cronbach’s α = 0.56, neurotypical group Cronbach’s α = 0.80; χ
2(1) = 16.53,
p < 0.001, but no such difference for communal goals, autistic group Cronbach’s α = 0.63, neurotypical group Cronbach’s α = 0.72; χ
2(1) = 2.24,
p = 0.134. DIF analysis also demonstrated differences across the two groups, with a large DIF value for several of the IGI-C items across both the agentic and communal subscales (see Table
1). Specifically, for the agentic scale, autistic adolescents were more likely to endorse, ‘others agree to do what you suggest’ and less likely to endorse, ‘you get to decide what to play’ compared to neurotypical adolescents with similar total agentic goal scores. For communal goals, autistic adolescents were more likely to endorse, ‘you feel close to others’ and less likely to endorse, ‘real friendship develops between you’, compared to neurotypical adolescents with a similar overall total communal goal score. Examining differences in the means of IGI-C items and subscale scores shows that autistic adolescents were more likely to endorse agentic goals, and neurotypical adolescents were more likely to endorse communal goals.
Associations Between Interpersonal Goals and Bullying
Separate bivariate correlations for autistic and neurotypical adolescents (Table
2) show that agentic goals were positively associated and communal goals negatively associated with bullying for neurotypical adolescents. Neither agentic nor communal goals were associated with bullying for autistic adolescents. Notably, agentic and communal goals were significantly positively correlated for autistic adolescents only.
Table 2
Descriptive statistics by group and bivariate correlations for study variables (neurotypical above the diagonal, autistic below the diagonal)
1. Sex | 108 | _ | _ | _ | 592 | _ | _ | _ | - | − .09* | − .22** | .27** | − .24** |
2. Age (months) | 108 | 183.01 (19.80) | 137–213 | − 0.35 | 592 | 155.77 (5.72) | 133—179 | 0.14 | .11 | – | − .04 | − .04 | − .06 |
3. Agentic goals | 107 | 4.81 (2.00) | 0–9 | −0.08 | 547 | 2.97 (1.86) | 0—9 | 0.41 | .01 | − .19* | – | − .03 | .19** |
4. Communal goals | 107 | 3.97 (2.09) | 0–9 | 0.00 | 545 | 8.33 (2.10) | 0—12 | − 0.95 | − .08 | − .00 | .51** | – | − .11* |
5. Bullying | 108 | 0.23 (1.92) | − 2.08–5.47 | 0.88 | 592 | − 0.04 (1.54) | − 3.01 – 5.83 | 0.89 | − .02 | − .02 | − .02 | .16 | – |
A hierarchical multiple regression model was constructed to predict bullying. Sex and age were entered at the first step, followed by group (i.e., autistic vs. neurotypical) and interpersonal goals. Finally, interactions between group and interpersonal goals were examined on the third step (see Table
3). Variance inflation factors (VIF) were inspected to ensure that multicollinearity was not problematic. Across the three regression models, all VIF were below 2.90 (prior to the inclusion of the interaction terms at Step 3) suggesting that there were low levels of collinearity amongst the independent variables (Fox,
2015).
Table 3
Hierarchical multiple regression analyses predicting bullying
| .05** | | .01* | | .01* | |
Age | | .01 | | .03 | | .01 |
Sex | | − .22** | | − .19** | | − .17** |
Group: autistic vs. NT | | – | | .08 | | .20 |
Agentic | | – | | .12** | | .15** |
Communal | | – | | − .03 | | − .07 |
Group*Agentic | | – | | – | | − .15* |
Group*Communal | | – | | – | | .23* |
Total R2 | .05** | | .06** | | .07** | |
At Step 1, Sex made a significant independent contribution to the prediction of bullying, such that boys were more likely to engage in bullying compared to girls, F(2, 649) = 16.33, p < 0.001. The inclusion of group and interpersonal goals improved model fit, p = 0.039, and the overall model was still significant, F(5, 646) = 8.27, p < 0.001. Both sex and agentic goals were significant independent predictors at Step 2, such that higher agentic goal identification and boys compared to girls were both independently associated with greater bullying. At Step 3, the inclusion of the interaction terms further improved model fit, p = 0.013, and the overall model was significant, F(7, 644) = 7.21, p < 0.001. At this final step, in addition to sex and agentic goals, both interaction terms were significant.
To unpack these interaction effects, two further regression models were run to examine the role of agentic and communal roles for bullying behaviour separately for neurotypical and autistic adolescents. For neurotypical participants, only agentic, β = 0.14, p < 0.001, not communal goals, β = −0.05, p = 0.235, were a significant predictor of bullying behaviour. Conversely, for autistic participants only communal, β = 0.23, p = 0.043, not agentic goals, β = −0.14, p = 0.217, were predictive of bullying.
Given the relatively small number of girls in the autistic group, all analyses were re-run excluding both autistic and neurotypical female adolescents from the models. Notably, results remained unchanged, with the exception of the main effect for agentic goals which was no longer a significant independent predictor of bullying behaviour, although both interpersonal goal by group interaction effects remained significant.