Preliminary Analyses
Group Differences in Autistic Traits
As expected, formally diagnosed autistic people (M = 29.33, SD = 8.89) were higher in autistic traits than non-autistic people (M = 20.25, SD = 7.21; mean difference = 9.08, BCa 95% CI [6.84, 11.35], t[586] = 9.02, p < 0.001, d = 1.23).
Group Differences in Control Variables
As shown in Table
1, on average, the autistic group was younger than the non-autistic group (mean difference = − 9.18, BCa 95% CI [− 11.91, − 6.36],
t[586] = 5.40,
p < 0.001,
d = 0.74). There was no difference in gender distribution between the autistic and the non-autistic group (Φ = − 0.001,
p = 0.99, BCa 95% CI [− 0.09, 0.08]). Moreover, reasoning ability was not different between autistic (
M = 32.77,
SD = 14.61) and non-autistic people (
M = 34.13,
SD = 14.36; mean difference = − 1.36, BCa 95% CI [− 4.97, 2.84],
t[586] = 0.70,
p = 0.49,
d = 0.10).
Relationships with Control Variables
The general belief in a just world did not correlate with age (r[586] = 0.07, BCa 95% CI [− 0.01, 0.16], p = 0.09). Women had a lower general belief in a just world (r[583] = − 0.13, BCa 95% CI [− 0.21, − 0.05], p = 0.002). A higher reasoning ability was associated with a lower general belief in a just world (r[586] = − 0.23, BCa 95% CI [− 0.31, − 0.16], p < 0.001).
Higher autistic traits correlated with lower age in the sample (r[586] = − 0.09, BCa 95% CI [− 0.17, − 0.01], p = 0.03). Autistic traits did not correlate with gender (r[583] = 0.001, BCa 95% CI [− 0.08, 0.09], p = 0.98). The higher the autistic traits, the higher was the reasoning ability (r[586] = 0.08, BCa 95% CI [0.002, 0.16], p = 0.04).
Autistic Compared to Non-autistic People’s General Belief in a Just World (Hypothesis 1)
The formally diagnosed autistic individuals (M = 20.40, SD = 7.97) had a lower general belief in a just world than the non-autistic individuals (M = 27.37, SD = 9.70). The mean difference of − 6.97, BCa 95% CI [− 8.91, − 4.96], was significant (t[586] = 5.37, p < 0.001, d = 0.73).
Including Control Variables
Given that the autistic and the non-autistic groups did differ in age, and gender and reasoning ability were correlated with the general belief in a just world, the analysis was repeated with these variables as covariates. Again, autistic (Madj = 20.85, SEadj = 1.22) compared to non-autistic (Madj = 27.36, SEadj = 0.40) people’s general belief in a just world was significantly lower (mean difference = − 6.51, BCa 95% CI [− 8.68, − 4.32], F[1, 580] = 25.41, p < 0.001, η2part = 0.04).
The covariate age was not significant (p = 0.13, η2part = 0.004); women had a lower general belief in a just world than men (p = 0.001, η2part = 0.02); and higher reasoning ability was related to a lower general belief in a just world (p < 0.001, η2part = 0.06).
Relationship Between Autistic Traits and General Belief in a Just World (Hypothesis 2)
As expected, higher autistic traits were associated with a lower general belief in a just world (r[586] = − 0.31, BCa 95% CI [− 0.38, − 0.24], p < 0.001). Both variables were also correlated in this way, separately, in the group of autistic people (r[58] = − 0.48, BCa 95% CI [− 0.67, − 0.26], p < 0.001) and the group of non-autistic people (r[526] = − 0.23, BCa 95% CI [− 0.31, − 0.15], p < 0.001).
Including Control Variables
Controlling for age, gender, and reasoning ability showed that autistic traits and the general belief in a just world were significantly negatively related beyond the control variables in the overall sample (B = − 0.34, BCa 95% CI [− 0.44, − 0.25], SE B = 0.05, β = − 0.28, p < 0.001), in the group of autistic people (B = − 0.37, BCa 95% CI [− 0.59, − 0.17], SE B = 0.10, β = − 0.42, p < 0.001), and in the group of non-autistic people (B = − 0.28, BCa 95% CI [− 0.39, − 0.18], SE B = 0.06, β = − 0.21, p < 0.001).
Age was positively related to the general belief in a just world in the overall sample (β = 0.08, p = .04), but not in the separated autistic and non-autistic groups (βs = 0.21 and 0.05, ps > 0.05). Gender and the general belief in a just world were related in the overall sample and in the non-autistic group (βs = − 0.13 and − 0.14, ps < 0.002 [with a lower general belief in a just world in women]), but not in the autistic group (β = − 0.06, p = 0.59). In all three regression analyses, a higher reasoning ability was related to a lower general belief in a just world (βs = − 0.21, − 0.29, and − 0.22, ps < 0.02). All overall regression models were significant (ps < 0.001).
Personal Belief in a Just World
Formally diagnosed autistic people (M = 27.53, SD = 8.45) had a lower personal belief in a just world than non-autistic people (M = 32.80, SD = 8.31; mean difference = − 5.27, BCa 95% CI [− 7.55, − 2.87], t[386] = 4.50, p < 0.001, d = 0.63). Moreover, the higher the autistic traits, the lower was the personal belief in a just world (r[386] = − 0.29, BCa 95% CI [− 0.39, − 0.19], p < 0.001). A lower personal belief in a just world was also associated with a lower general belief in a just world (r[386] = 0.69, BCa 95% CI [0.60, 0.76], p < 0.001).
Conforming the hypothesis, the personal belief in a just world significantly mediated the indirect effect (
ab) of the autism group (formally diagnosed autistic vs. non-autistic) on the general belief in a just world, indicated by the fact that the respective bootstrap interval did not include the null (Hayes
2013;
ab = − 3.80,
SE ab = 0.88, BCa 95% CI [− 5.41, − 2.05]). Controlling for age, gender, and reasoning ability did not change the result (
ab = − 3.16,
SE ab = 0.88, BCa 95% CI [− 5.03, − 1.54]).
The indirect effect between autistic traits and the general belief in a just world was also mediated by the personal belief in a just world (ab = − 0.23, SE ab = 0.05, BCa 95% CI [− 0.32, − 0.14]). This result held after statistically controlling for age, gender, and reasoning ability (ab = − 0.21, SE ab = 0.04, BCa 95% CI [− 0.30, − 0.13]).
External Locus of Control
Autistic people (M = 15.28, SD = 4.79) had a higher external locus of control than non-autistic people (M = 12.46, SD = 4.11; mean difference = 2.82, BCa 95% CI [1.55, 4.09], t[386] = 4.77, p < 0.001, d = 0.67). Higher autistic traits were correlated with a higher external locus of control (r[386] = 0.29, BCa 95% CI [0.18, 0.39], p < 0.001). Furthermore, the higher the external locus of control, the lower was the general belief in a just world (r[386] = − 0.51, BCa 95% CI [− 0.58, − 0.43], p < 0.001).
External locus of control mediated the indirect effect between autism group and the general belief in a just world (ab = − 2.82, SE ab = 0.68, BCa 95% CI [− 4.24, − 1.60]). This mediation was also significant when age, gender, and reasoning ability were controlled for (ab = − 2.25, SE ab = 0.68, BCa 95% CI [− 3.62, − 0.90]).
Having an external locus of control also mediated the indirect effect between autistic traits and the general belief in a just world (ab = − 0.16, SE ab = 0.03, BCa 95% CI [− 0.23, − 0.10]). The mediation remained significant after statistically controlling for age, gender, and reasoning ability (ab = − 0.14, SE ab = 0.03, BCa 95% CI [− 0.21, − 0.08]).
Self-deception
Self-deception was lower in formally diagnosed autistic people (M = 77.12, SD = 11.82) than in non-autistic people (M = 83.79, SD = 14.12; mean difference = − 6.67, BCa 95% CI [− 9.83, − 3.07], t[386] = 3.44, p < 0.001, d = 0.48). In addition, higher autistic traits were associated with lower self-deception (r[386] = − 0.36, BCa 95% CI [− 0.44, − 0.28], p < 0.001). When self-deception was higher, the general belief in a just world was also higher (r[386] = 0.40, BCa 95% CI [0.29, 0.51], p < 0.001).
Self-deception was a significant mediator of the relationship between autism (formally diagnosed autistic people vs. non-autistic people) and the general belief in a just world (ab = − 1.60, SE ab = 0.50, BCa 95% CI [− 2.75, − 0.79]). This result remained robust after controlling for age, gender, and reasoning ability (ab = − 1.17, SE ab = 0.41, BCa 95% CI [− 2.07, − 0.42]).
There was also a significant mediation of the relationship between autistic traits and the general belief in a just world via self-deception (ab = − 0.15, SE ab = 0.03, BCa 95% CI [− 0.22, − 0.09]). The mediation was significant even after controlling for age, gender, and reasoning ability (ab = − 0.12, SE ab = 0.03, BCa 95% CI [− 0.18, − 0.07]).