Laterality biases to chimeric faces in Asperger syndrome: what is 'right' about face-processing?

Ashwin et al. (2005) showed adults with Asperger syndrome split-face photos called chimeric faces. Each photo had one half smiling and one half neutral. The team asked which face looked happier. They also gave a non-social task with chimeric objects.

The goal was to see which side of space the adults used most. A left-side bias points to right-brain face work. A weak or flipped bias hints at different wiring.

Adults with Asperger syndrome picked the left-side smile less often than typical adults. Their left-visual-field bias for face identity was smaller. On the object task they showed an odd right-side bias, something controls did not do.

The pattern says face identity, not emotion, drives the lateral glitch in Asperger syndrome.

Griffith et al. (2012) saw the same missing left-field bias with eye tracking, giving a thumbs-up to the 2005 result. McCarron et al. (2013) moved the test into real photos and still found wonky gaze in social scenes, extending the idea into everyday pictures.

Van der Donck et al. (2023) seems to clash. They found typical brain responses to facial identity in broad autism. The gap is about method: Chris looked at Asperger adults and side bias; Stephanie used EEG across wider autism and saw normal identity signals. Both can be true—bias and brain wave are different rulers.

Mansell et al. (2002) set the stage by showing left-brain executive hiccups in high-functioning autism but not Asperger’s. Chris narrowed the lens to face identity and still found Asperger difference, updating the map.

If you test face skills in adults with Asperger syndrome, don’t expect the usual left-side advantage. Use centered or mirrored stimuli and check both halves of space. When social-cognition scores seem off, remember the issue may sit in how the brain sides share the job, not in raw vision or feeling.