Demographics of the final sample are summarized in Table 1. There were no significant differences in age between groups. However, disparities emerged in educational attainment, with autistic males exhibiting lower levels than both non-autistic males (p < 0.001) and females (p = 0.03). As anticipated, significant differences were found in AQ scores, with autistic individuals scoring higher than non-autistic counterparts (all p < 0.001). Furthermore, non-autistic males had higher AQ scores than non-autistic females (p = 0.03). Autistic males received their diagnosis at a younger age than autistic females (p < 0.001). Lastly, autistic participants presented with a greater number of comorbid diagnoses than non-autistic participants (all p < 0.001).

An analysis of accuracy based on rated valence of the picture with context, following a correct answer on the picture without context, revealed lower odds of correct responses in the shift than in the non-shift condition (\(\:\beta\:\) = -2.9, 95% CI [-3.45, -2.34], p < 0.001), and in the social than in the non-social condition (\(\:\beta\:\) = -0.66, 95% CI [-1.2, -0.13], p = 0.016). In addition, autistic participants had lower odds of making a correct response (\(\:\beta\:\) = 0.3, 95% CI [0.06, 0.54], p = 0.013) than non-autistic participants.

Interaction between group, sex, and social content for correct responses. The box plots represent the observed median correct response rates for emotion recognition with context, with the interquartile range and individual data points for each condition. The red crosses represent the observed means. In addition, the colored points represent the estimated marginal means with their 95% CI

These main effects were further qualified by an interaction effect between group, sex and the social nature of the stimuli on the odds of correct responses (\(\:\beta\:\) = 0.61, 95% CI [0.06, 1.15], p = 0.029). Post-hoc comparisons revealed a significantly higher odds of correct responses in autistic females than autistic males in the non-social condition (\(\:\beta\:\) = -0.52, 95% CI [-1.02, -0.03], p = 0.035), not observed in the social condition (\(\:\beta\:\) = 0.01, 95% CI [-0.42, 0.44], p = 1) and not observed in the non autistic group (non-autistic females vs. non autistic males in the non-social condition: \(\:\beta\:\) = -0.03, 95% CI [-0.52, 0.47], p = 0.999; in the social condition: \(\:\beta\:\) = -0.1, 95% CI [-0.55, 0.35], p = 0.943). Post-hoc comparisons also revealed a lower odds of correct responses in autistic females than non-autistic females in the social condition (\(\:\beta\:\) = -0.52, 95% CI [-0.98, -0.06], p = 0.02), not observed in the non-social condition (\(\:\beta\:\) = 0.11, 95% CI [-0.42, 0.64], p = 0.955). This was not observed in males (autistic vs. non-autistic males in the non-social condition: \(\:\beta\:\) = -0.39, 95% CI [-0.9, 0.12], p = 0.196; in the social condition: \(\:\beta\:\) = -0.41, 95% CI [-0.88, 0.06], p = 0.116). This interaction is depicted in Fig. 2.

Analyses showed longer RT in the shift than in the non-shift condition (\(\:\beta\:\) = 158, 95% CI [137, 178], p < 0.001) and in the social than in the non-social condition (\(\:\beta\:\) = 61, 95% CI [12, 111], p = 0.016). Autistic participants were slower than non-autistic participants (\(\:\beta\:\) = -90, 95% CI [-110, -69], p < 0.001). Additionally, RT were longer for negative than positive stimuli (\(\:\beta\:\) = -66, 95% CI [-85, -47], p < 0.001) and for females than males (\(\:\beta\:\) = 19, 95% CI [2, 37], p = 0.031).

The main effects on RT were qualified by significant two-way and three-way interaction effects, which are presented both here and in Fig. 3. First, the interaction effect between group and shift (\(\:\beta\:\) = -27, 95% CI [-43, -10], p = 0.001) revealed that the difference between the shift and non-shift condition was larger in autism (\(\:\beta\:\) = -171, 95% CI [-199, -144], p < 0.001) than in non-autistic individuals (\(\:\beta\:\) = -144, 95% CI [-174, -114], p < 0.001). In addition, the interaction effect between the group and the social nature of the stimuli (\(\:\beta\:\) = -55, 95% CI [-74, -36], p < 0.001) indicated that the difference in RT between social and non-social stimuli was also larger in autism (\(\:\beta\:\) = -89, 95% CI [-153, -24], p = 0.002) than in non-autistic participants (\(\:\beta\:\) = -34, 95% CI [-102, 34], p = 0.579). Finally, the interaction between the shift and the social nature of the stimuli (\(\:\beta\:\) = 103, 95% CI [85, 121], p < 0.001) revealed that the RT difference between social and non-social stimuli was larger in the shift (\(\:\beta\:\) = -113, 95% CI [-181, -44], p < 0.001) than in the non-shift condition (\(\:\beta\:\) = -10, 95% CI [-73, 54], p = 0.979). However, these three interactions were qualified by a three-way interaction between group, shift and the social nature of the stimuli (\(\:\beta\:\) = -42, 95% CI [-59, -25], p < 0.001) indicating that while the difference between the shift and non-shift conditions was larger in the autistic than in the non-autistic individuals, this difference was more pronounced in the social than in the non-social condition (shift vs. no shift in autism and non-social condition: \(\:\beta\:\) = -109, 95% CI [-147, -72], p < 0.001; in autism and social condition: \(\:\beta\:\) = -233, 95% CI [-267, -199], p < 0.001; in no-autim and non-social condition: \(\:\beta\:\) = -103, 95% CI [-145, -62], p < 0.001; in no-autism and social condition: \(\:\beta\:\) = -185, 95% CI [-221, -150], p < 0.001).

In addition, a significant interaction between group and emotion (\(\:\beta\:\) = -28, 95% CI [-50, -6], 95% CI [-50, -6], p = 0.012) showed that the difference in RT between negative and positive stimuli was more pronounced in non-autistic (\(\:\beta\:\) = 80, 95% CI [50, 110], p < 0.001) than in autistic individuals (\(\:\beta\:\) = 52, 95% CI [25, 79], p < 0.001). This interaction was qualified by a three-way interaction between group, sex and emotion (\(\:\beta\:\) = 24, 95% CI [0, 49], p = 0.05), indicating that this slower response time for negative than positive stimuli in non-autistic individuals was more pronounced in males (positive vs. negative stimuli in non-autistic males: \(\:\beta\:\) = 95, 95% CI [58, 133], p < 0.001, autistic males: \(\:\beta\:\) = 55, 95% CI [18, 93], p < 0.001, non-autistic females: \(\:\beta\:\) = 65, 95% CI [22, 108], p < 0.001, autistic females: \(\:\beta\:\) = 49, 95% CI [14, 84], p = 0.001).

Finally, there was an interaction between shift and sex (\(\:\beta\:\) = 34, 95% CI [13, 55], p = 0.002), indicating that the difference in RT between the shift and non-shift conditions was smaller in males (\(\:\beta\:\) = -141, 95% CI [-171, -111], p < 0.001) than females (\(\:\beta\:\) = -175, 95% CI [-204, -145], p < 0.001). However, this interaction, along with the aforementioned interaction between group and shift, was further qualified by a three-way interaction involving group, shift, and sex (\(\:\beta\:\) = 56, 95% CI [39, 73], p < 0.001). This revealed that the reduced difference in RT between the shift and the non-shift conditions in males compared to females was more pronounced in the non-autistic group than it was in the autistic group (shift vs. no shift in ASD Females: \(\:\beta\:\) = -174, 95% CI [-212, -136], p < 0.001; ASD Males: \(\:\beta\:\) = -168, 95% CI [-206, -131], p < 0.001; non-autistic females: \(\:\beta\:\) = -175, 95% CI [-213, -137], p < 0.001; non-autistic males: \(\:\beta\:\) = -113, 95% CI [-153, -74], p < 0.001).

Significant interactions on RT. The box plots represent the observed median response time (RT) for emotion recognition with context, with the interquartile range and individual data points for each condition. The red crosses represent the observed means. In addition, the colored points represent the estimated marginal means with their 95% CI. The first line (A) represents the significant two-way interactions and the second line (B) represents the significant three-way interactions (relative to the corresponding two-way interactions). M = Males; F = Females; Neg = Negative stimuli (with context); Pos = Positive stimuli (with context); Soc = Social stimuli, NonSoc = Non-social stimuli