The Empathy Hierarchy: Unique Associations of Childhood Callous Unemotional Traits and Autism Spectrum Disorder Symptoms

• Conduct problems (CP): Persistent aggressive, defiant, or rule-breaking behaviour in children (diagnoses such as oppositional defiant disorder and conduct disorder).

• Callous-unemotional (CU) traits: A lack of guilt or remorse, low empathy, little concern about performance, and shallow emotions.

• Autism spectrum disorder (ASD): A developmental condition involving differences in social communication and interaction, plus restricted or repetitive behaviours and interests.

• Typically developing (TD): Children without clinically significant psychological problems, used as a comparison group.

• Comorbid / co-occurring: Present at the same time as another condition.

• Empathy (cognitive vs. affective): Cognitive empathy is understanding what others feel (e.g., recognising emotions, theory of mind). Affective empathy is sharing or resonating emotionally with others.

• Theory of mind: The ability to understand that others have their own thoughts and feelings.

• Empathic responding / prosocial behaviour: Acting on another’s distress, such as comforting or helping.

• Hierarchical model of empathy: The idea that empathy builds in steps: noticing emotional cues, recognising the emotion, understanding the person’s state, then responding.

• Attention to distress cues: How quickly a child’s attention goes to signs of others’ distress. It was measured with a computer “dot probe” task.

• Hierarchical regression: A statistical method that tests whether a variable explains an outcome after other variables are accounted for.

• Effect size (d, ηp²): Numbers showing how large an effect is, beyond whether it is statistically significant.

1. Aim 1: Are ASD symptoms and CU traits each uniquely associated with four components of empathy, once their overlap is accounted for? (The components were attention to distress cues, emotion recognition, understanding emotional states, and empathic responding. These follow Nuske and colleagues’ hierarchical model.)

2. Aim 2: Do clinic-referred children grouped as CP-only, CP+CU, CP+ASD, or CP+CU+ASD differ from each other and from TD children on these components?

The authors hypothesised that both ASD and CU traits would relate to reduced attention to distress. They expected ASD alone to relate to poorer emotion recognition and understanding of emotional states, and CU traits alone to relate to reduced prosocial behaviour. They also expected the CP+CU+ASD group to show the greatest deficits.

Method in brief: The sample was 408 children from the Sydney area (aged 1–8 years, mean age 4.28). Of these, 317 were referred to a university-based research clinic (n = 200) or a community clinic (n = 117) for conduct problems, and 91 were TD. Parents completed questionnaires on conduct problems, ASD symptoms, CU traits, and empathy. Children completed laboratory tasks for attention, emotion recognition (dynamic faces), and understanding of emotional states (scenes from The Lion King). Analyses controlled for child age, gender, and study site. Not every child completed every task, so sample sizes varied across analyses.

Overlap among measures: CP severity was strongly correlated with CU traits (r = .67) but not with ASD symptoms (r = .08). ASD symptoms and CU traits were moderately correlated (r = .32).

Unique associations (Aim 1):

• Attention to distress cues: Neither ASD symptoms nor CU traits were uniquely associated with it. Extra analyses that considered aggression or anxiety also found no association.

• Emotion recognition: Higher ASD symptoms, but not CU traits, were uniquely associated with poorer recognition (small-to-moderate effect, d = 0.315). By emotion, the association held for anger, fear, and pain, but not for happy or sad expressions.

• Understanding emotional states: Neither ASD symptoms nor CU traits were uniquely associated with it.

• Empathic responding: Higher CU traits were only marginally associated with reduced responding in the main model (p = .059, d = 0.421), while ASD symptoms were not (p = .149). When understanding of emotional states was left out of the model, because that task had a smaller sample, the CU association became significant (p = .009, d = 0.429).

Group differences (Aim 2):

• Attention to distress cues: There were no group differences.

• Understanding emotional states: There were no significant group differences (p = .067).

• Emotion recognition: Groups differed (moderate effect). The CP+ASD and CP+CU+ASD groups were significantly less accurate than the CP+CU group. The CP+CU group did not differ from the TD or CP-only groups.

• Empathic responding: Groups differed (moderate effect). The CP+CU+ASD group had the lowest responding. It was significantly lower than the CP+CU group, which was in turn lower than the CP-only group. The CP-only group did not differ from the CP+ASD or TD groups.

Overall pattern: ASD symptoms were linked to difficulties at an earlier step of the empathy hierarchy (emotion recognition). CU traits were tentatively linked to difficulties at the later step (empathic responding). Having both appeared to worsen the empathic-responding deficit.

Interpretation

• The emotion recognition finding fits the meta-analyses on ASD. It also fits the only other study to examine ASD and CU traits together in young children, which found that CU-related recognition problems were explained by co-occurring ASD symptoms. This challenges the view that CU traits are underpinned by emotion recognition deficits.

• The authors suggest the recognition difficulties in ASD may stem from social information processing differences, such as less attention to faces and people.

• The empathic responding finding matches earlier evidence that autistic children show prosocial behaviour at similar levels to TD children, while CU traits are negatively linked to prosociality even after accounting for ASD. This study reports it for the first time in a clinic-referred sample of young children.

• The finding is consistent with how CU traits are defined diagnostically (limited prosocial emotions). The extra deficit in children with both ASD and CU traits may reflect the flow-on effect of emotion recognition difficulties in ASD.

• The authors suggest children with ASD may show differences rather than deficits in emotion processing. Some may be hypersensitive to others’ emotions, which could increase prosocial behaviour in some situations and cause overwhelm in others.

• The expected links with attention to distress and with understanding emotional states were not found. This contradicts earlier research. The authors suggest the tasks may have been too difficult for such young children, and that the understanding task was validated only from age 5. The attention measure showed no correlation with the other measures, and low task accuracy supported this explanation.

Limitations

• Laboratory data were missing for many children, and some analyses, especially those on understanding emotional states, were underpowered.

• Every child with ASD symptoms also had conduct problems, so the findings may not apply to autistic children without them.

• The tasks depended on young children understanding instructions, and the main symptom measures were parent-reported.

• The authors describe the compounding effect of ASD as unexpected and recommend replication.

Recommendations

• Future research:

  • Replicate the findings in larger samples.

  • Use developmentally appropriate measures, such as mobile eye tracking, which does not require an active response.

  • Develop a measure of understanding emotional states suited to preschoolers.

  • Test whether the ASD–emotion recognition link holds in children without conduct problems.

• Clinical practice:

  • For children with CP and ASD, treatment should consider adding an emotion recognition module. Under the hierarchical model, better recognition should flow on to better understanding and empathic responding.

  • For children with CP and CU traits, treatment should directly target empathic responding. One example is the CARES module in Parent–Child Interaction Therapy adapted for CU traits (PCIT-CU), which uses parent modelling and token rewards, and has been shown to improve child empathy.

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