For decades, research on autism and emotion has focused on the same question. Do autistic people struggle to recognize facial expressions? But maybe that’s the wrong question.
Instead of framing emotion recognition (or a lack thereof) as a deficit, a team of researchers report that autistic and non-autistic adults might just express emotions differently. So differently, in fact, that their faces might be “speaking different languages.”
The paper, appearing in Autism Research, explores this phenomenon in detail. It reports the results of one of the most exhaustive analyses of facial expression dynamics to date, using high-resolution motion capture to map how emotions unfold across the face over time.
Methodology
Led by the University of Oxford’s Connor Keating – along with colleagues at the University of Birmingham – the researchers assessed the facial expressions produced by more than two dozen autistic and 26 non-autistic adults matched for age, sex, and IQ.
The university researchers asked participants to pose expressions of anger, happiness, and sadness in two ways: silently following auditory cues, and while speaking a standardized sentence.
Rather than relying on subjective ratings or still photographs, the researchers worked with facial motion capture technology to record thousands of expressions. The researchers retargeted each recording onto a standardized digital face, eliminating differences in facial shape or structure that might otherwise skew the results.
It’s that approach that allowed the team to look at two distinct aspects of expression. One was activation – which facial muscles moved, and how strongly. The other was kinematics, including how smoothly or abruptly those movements unfolded. All told, the analysis relied on more than 265 million data points.
Different Expressions. The Same Emotions.
A few clear patterns emerged.
When expressing anger, autistic participants relied more heavily on the mouth and less on the eyebrows than their non-autistic peers. Classic anger cues – lowered brows, for example – garnered less attention. Mouth movements, on the other hand, played a larger role.
For happiness, the differences seem to be even more stark. Autistic participants tended to show less exaggerated smiles, with reduced involvement of the muscles around the eyes. Simply put, their smiles appeared to be less likely to resemble the Duchenne smile.
Sadness followed a decidedly different path. Autistic participants were more likely to signal sadness by moving their upper lip, rather than relying on the jaw or brow changes typically emphasized in non-autistic expressions.
These differences persisted even after the researchers controlled for facial morphology and for alexithymia.
What About Alexithymia?
Alexithymia mattered, but not the way you might expect. The study’s authors uncovered a connection between higher alexithymia scores and less differentiated facial expressions, especially for anger and happiness. People with higher alexithymia tended to produce expressions that overlapped more across emotions. And it didn’t matter whether they were autistic.
But alexithymia failed to explain the core differences between autistic and non-autistic expression styles. Those differences persisted even when the team took alexithymia into account.
When Production, Perception Don’t Align
Participants also completed an emotion recognition task, identifying emotions from silent, point-light facial displays. Among non-autistic participants, the researchers found a meaningful link between expression and perception. Those who produced more precise and clearly differentiated expressions – especially while speaking – were better at recognizing emotions in others.
That link vanished when it came to the autistic group. None of the measured features of facial expression predicted how well autistic participants recognized emotions.
The mismatch, the authors suggest, could help explain why emotion recognition often breaks down across neurotypes. If autistic and non-autistic people express emotions using different facial “codes,” then judging one another’s expressions becomes a cross-cultural task. And it might be one that neither group is equipped to handle.
Rethinking Emotion ‘Deficits’
The results of this study challenge some long-standing beliefs that autistic people have a fundamental impairment when it comes to emotion recognition. Instead, they point toward a relational explanation. A lack of emotional understanding doesn’t drive these difficulties. It could be the result of differences in expressive norms.
“What have previously been thought of as intrinsic emotion recognition deficits for autistic people,” the authors write, “may be more accurately described as difficulties resulting from cross-neurotype interactions.”
The researchers aren’t claiming that autistic people struggle to recognize emotions. Instead, they’re suggesting that recognition depends on whose faces are being read – and whose expressive language is being used.
As researchers continue to unpack the social dynamics of autism, the message here is a subtle but consequential one. That misunderstanding might be a mutual one. And when faces speak different emotional languages, things can get lost in translation.
Further Reading
Management of Autism in Clinical Settings
