The EPDA alerted me to a scientific paper that described advanced Theory of Mind in Young Onset Parkinson’s. The paper, which is by R-L Yu et al from the National Taiwan University, and is published in the journal Parkinsonism and Related Disorders, is available in full online.
I didn’t know what Theory of Mind was (let alone the advanced version), but the abstract helpfully explains:
Advanced Theory of Mind (ToM) refers to the sophisticated ability to infer other people’s thoughts, intentions, or emotions in social situations. With appropriate advanced ToM, one can behave well in social interactions and can understand the intention of others’ behavior.
Wikipedia has further information about Theory of Mind, which it describes as:
the ability to attribute mental states—beliefs, intents, desires, pretending, knowledge, etc.—to oneself and others and to understand that others have beliefs, desires and intentions that are different from one’s own.
and notes that:
ToM deficits have been observed in people with autism spectrum disorders, schizophrenics, persons under the influence of alcohol and narcotics, sleep-deprived persons, and persons who are experiencing severe emotional or physical pain.
[Around this point, I began to wonder if the results were a cause or an effect of Parkinson’s: could it be possible that people with minor social disorders – small enough for them not to register on the autistic scale, say – were, somehow, more susceptible to Parkinson’s? Of course, this idea was based upon a sample of one – me. I function reasonably well socially, but have been known to completely miss social cues, to be bamboozled by social phenomena (I never did quite get the point of sport, soap operas or the cult of celebrity), and to be very quiet indeed at parties. I also have something approaching a negative bar presence. But none of this is new; I’ve been shy since I was small.]
According to the Taiwanese researchers, there is an indication that advanced Theory of Mind is affected by Parkinson’s in the early stages. This runs counter to another research paper that I found (by J. Péron et al in Rennes, France; published in Neuropsychologia in 2009), which found that advanced Parkinson’s patients showed a loss of ToM, but that those in the earlier stages did not. That article came to the conclusion that “the nigrostriatal and mesolimbic dopaminergic pathways do not contribute to ToM abilities” (i.e. that loss of dopamine in early stage Parkinson’s did not affect an individual’s social or ToM abilities); instead, the French researchers suggested that “impairment of ToM abilities [occurred when the] degenerative process [had] spread beyond the dopaminergic pathways”.
However, other research has found that early stage Parkinson’s may affect ToM abilities. It seems to be a controversial area: depending, I suspect, on the people drafted as subjects, on their relative cultural backgrounds, on the tests used, and on the administration of these tests.
From the two papers mentioned in this post, it seems that the standard way of testing ToM is via a sort of comprehension test in which a short story (that includes inappropriate social behaviour) is relayed to the subject, and the subject is subsequently quizzed on the social aspects of the tale. Images – in the form of cartoons – were used in a similar way in the Taiwanese research. The French study also included a test in which emotions were to be “read” from images of people’s faces. This latter is described as an “affective” test (ie related to the emotions), while the stories constitute “cognitive” tests (ie based on mental processes).
It seems to me – whose scientific experience, such as it is, is exclusively within the natural sciences (physics, chemistry and biology) – that these tests are inherently subjective and, consequently, difficult to analyse consistently. Of course, I have no doubt that the people engaged in this type of research can draw upon a collective experience that facilitates the understanding of such results. Nonetheless, I am not surprised that the conclusions vary so much.
PDFs of the full texts of the articles mentioned are available as follows:
- R.-L. Yu et al. (National Taiwan University, Taiwan) / Parkinsonism and Related Disorders 18 (2012)
- J. Péron et al. (Universite Rennes, France) / Neuropsychologia 47 (2009)