Autistic skill or social deficit?
Research from the Yale University Child Study Center provides further evidence that autistic children view the world in markedly different ways than their non autistic peers. They were specifically looking at differences in attention to biological movement. According to the announcement by the National Institute of Health, who helped fund the study:
The researchers borrowed a technique from the video game industry, called motion capture. They then reduced the movements to only points of light at each joint in the body, like animated constellations. These cartoons played normally — upright and forward — on one half of the screen, but upside-down and in reverse on the other half. The inverted presentation engages different brain circuits and is known to disrupt perception of biological motion in young children. The normal soundtrack of the actor’s voice, recorded when the animations were made, accompanied the presentations.
You can view some of these animations in the New Scientist report on line
Yale recruited a sample of autistic toddlers and two control groups - normally developing toddlers matched for age and non-verbal intelligence and developmentally delayed toddlers matched for age and verbal intelligence. Then they showed them the animations and measured their attention to the biological and non biological animations.
Virginia Hughes, writing for the Simons Foundation Autism Research Initiative, tell us that
the toddlers with autism showed no preference for the upright figure when watching the peek-a-boo animations, looking at it 50.7 percent of the time, compared with 58.9 percent of the time for the developmentally delayed group and 62.7 percent for typical controls.
When watching the pat-a-cake animations, however, the autism group looked at the upright figure 65.9 percent of the time, significantly more than at the inverted figure. The pattern for the two control groups remained the same.
Not surprisingly non-autistic children showed a preference for cartoons played normally. Autistic children seemed not to have a preference, except for the pat-a-cake animation. The study team realized that this was because the movement of the dots of light synchronized with the clapping sound in the sound track. So they looked for less obvious audiovisual synchronies (AVS) in the other four animations. The AVS was less powerful in these other four animations than in the pat-a-cake example but still they found
“Audio-visual synchronies accounted for about 90 percent of the preferred viewing patterns of toddlers with ASD and none of unaffected toddlers,” said Jones. “Typically-developing children focused instead on the most socially relevant information.”
To test if the autistic toddlers were attending to AVS in preference to biological movement they recruited a fresh set of autistic toddlers and devised two more animations whose AVS was stronger than the unintended AVS in the four animations but less than the powerful AVS of the pat-a-cake animaton. If autistic attention was related to the strength of AVS they should be able to predict the new cohort’s preferred viewing patterns. And they did.
The study provides strong evidence that autistic toddlers do not have a preference for biological movement but are drawn to AVS that are ignored by non autistic peers and are not immediately apparent to research scientists without the assistance of computer analysis. This is potentially both a benefit and a deficit. Elizabeth Moon has written a novel, The Speed of Dark, about autistic adults whose ability to detect patterns and synchronies was valued while their need for accommodations in order to exercise this ability was decried. The novel’s strength derives in part from the author’s ability to exploit the dramatic tension between these two conflicting positions.
In contrast the present study does not even begin to acknowledge the potential strengths of this talent for detecting synchronies. Instead it focuses entirely on the negative aspects. The authors suggest that because attention to biological movement is such a robust feature, occurring across species and persisting in humans who are blind or cognitively impaired, its apparent absence in autism is enough to explain all the familiar impairments.
The authors explain it thus
Typically developing human infants preferentially attend to biological motion within the first days of life1. This ability is highly conserved across species2, 3 and is believed to be critical for filial attachment and for detection of predators4. The neural underpinnings of biological motion perception are overlapping with brain regions involved in perception of basic social signals such as facial expression and gaze direction5, and preferential attention to biological motion is seen as a precursor to the capacity for attributing intentions to others6.
There is a problem here. Klin et al argue that autistic subjects do not exhibit preferential attention to biological motion. Then they up the stakes dramatically with their reference to the ability to attend to biological motion. Ability and preference are not the same thing. Then comes another giant leap, suggesting that because of neural overlap with brain areas associated with facial expression and gaze direction, a preference for biological motion is somehow responsible for theory of mind.
So, rather than being an ability, enhanced awareness of audio-visual synchronies is a disability because it comes at the expense of attending to biological motion, which is believed to be critical for bonding with a caregiver, recognizing danger , developing social cognition and acquiring theory of mind. It may be that Klin et al are right and this skill is critical. But it is a bit of a leap to suggest that this is what their experiment tested for and that it is lacking in autistic children. If it is so highly conserved across species, the fact that it is not evident in autistic subjects in this experiment suggests not that it is absent or weak, rather that it is being overridden by higher brain functions. If it is so basic to survival that snails have it, its lack should present as a catastrophic deficit in humans. It would be interesting to devise an experiment to discover in what circumstances autistic children (and adults for that matter) do exercise a preference for biological movement. If it is so important we should be looking for ways to encourage it that do not diminish the achievements of autistic children in attending to patterns and synchronies in their environment.
Klin’s research is valuable. It is a pity that the commentary on the results overstated its importance and sought to overplay the potential disabling effects for autistic people while failing to acknowledge any potential strengths that might derive from synchronous thinking. Research that adds to our understanding should not need to be dramatized in this way.
Footnote
Morton Ann Gernsbacher has written some trenchant pieces about how preconceptions can influence the interpretation of research results. For example
Using the Deese-Roediger-McDermott “false memory” paradigm, two groups of participants were presented auditorily with lists of semantically related words (e.g., bed, rest, awake, tired, and dream), and later asked to discriminate between words they’d heard and words they hadn’t heard, including words that were semantically associated to words they’d heard (e.g., sleep). As shown in Figure 2, the green group demonstrated significantly better memory discrimination than the purple group; the green group was less likely to falsely recognize words they hadn’t heard, despite the false words’ semantic association with words they’d heard.
The green group’s better memory discrimination was attributed to their mentally representing words “in an aberrant manner,” even though a concurrent — and direct — test of semantic clustering found no differences between the green and purple groups. The green group’s aberrant semantic mental representations was hypothesized to stem from “anatomic abnormalities … or as a result of an as-yet unknown pathology.”
When another research team reported no difference between green- and purple-type participants in either false recall or false recognition, the authors of the study that had observed the green group’s better discrimination interpreted the other study’s lack of a between-group difference to the green group also having “frontal-executive impairment.”
No prizes for guessing that the green group were autistic. In another article she points out that if you are autistic:
having a thicker cortex than someone who is not autistic is considered bad (Hardan et al., 2006) — and having a thinner cortex than someone who is not autistic is also considered bad (Chung et al., 2005; Hadjikhani et al., 2006a, 2006b). Your thicker cortex might be a function of higher fluid intelligence (Dawson et al., 2006; Fjell et al., 2006); your thinner cortex might be a function of better memory retrieval (Sowell et al., 2001). It doesn’t matter: If you’re autistic, having either a thicker or thinner cortex is just considered bad.
