Folk Psychology, Gender, and Autism

Our species’ survival and reproduction has long depended on our ability to understand and predict the behaviors of the elements of our environment, and the world we live in seems to contain two fundamentally different kinds of entities: On one side there are the ordinary objects that behave according to causal physical laws, like falling boulders or flowing bodies of water. On the other hand there are humans and animals which seem to get up and move by their own volition and act in accord with underlying intentions, beliefs, and desires. In order to negotiate this duality in our environment, it makes sense that we might have evolved two corresponding representational subsystems. Neurophilosphers refer to our intuitive, separate cognizing of things and people as "folk physics" and "folk psychology". Examining this distinction may shed light on observed gender differences in sociality, as well as the sexed nature of neurodevelopmental disorders like autism.

Neurological evidence has been found to support the theoretical distinction made between folk psychology and folk physics. There are a set of brain regions referred to as “the social brain” that have been found to increase in activity when we represent the appearances, actions, and thoughts of living things. These include the tempoparietal junction, thought to represent actions perceived to be goal directed, the amygdala, implicated in responding to emotionally charged stimuli, and the medial prefrontal cortex, which has a role in representing others’ mental states (Farah & Heberlein, 2006). Collectively, the structures of the social brain constitute our folk psychological sense: they enable us to recognize when we are dealing with other minds as distinct from mere objects, to understand their actions as motivated by intentions, emotions, and beliefs, and subsequently to act more rationally ourselves. When these structures are not as active we instead rely on folk physics—apprehending the objects of our perception more purely in terms of their bare sensory features, like Newtonian motion in space.

Current research suggests that women on average have more folk psychological aptitude than men, who excel in folk physics. That is, women develop a social theory of mind faster and to a higher proficiency than men, who instead show greater aptitudes in spatial and mechanical representation.  Specifically, studies have shown that men lag behind women in the acquisition of certain social skills and language abilities and perform worse on tests measuring “mindreading” abilities, or levels of empathetic cognition, but outperform women in tasks more oriented towards the physical, such as spatial reasoning, visuospatial acuity, and motor coordination (Baron-Cohen, 1999). A further study has also been able to explain differences in men and women’s career preferences in terms of differential psychological orientation to things vs. people (Beltz, Swanson, & Berenbaum, 2011), with women tending to occupy more people-oriented careers. Many hypothesize such gender differences to be the result of masculinization of the brain in response to prenatal exposure to androgens like testosterone in (typically) the male embryo.

Potentially, Autism Spectrum Disorder (ASD) may be reconceived along the lines of the preceding discussion on gender, folk psychology, and folk physics. 75% of all individuals with ASD are male, and differences in brain anatomy and social development which parallel those observed between the sexes are even more apparent between autistic and "neurotypical" individuals (Baron-Cohen, 1999). For example, while men typically have larger brain sizes but smaller corpus callosa than women, people with ASD have the largest mean brain sizes and smallest corpus callosa of all. Autistic individuals also show the greatest delays in language acquisition, yet often possess exceptional spatial and mathematical reasoning abilities.  Furthermore, functional activation of the social brain in autistic individuals is diminished relative to their neurotypical counterparts (Farah & Heberlein, 2006). As a consequence of autistic individuals' resultant diminished capacity to represent beliefs and intentions, they often have difficulty understanding why people act as they do, and may fail to act according to social expectations by treating people more bluntly and like objects than others might. Together, these findings suggest that typical masculinization of the brain may predispose one to develop ASD, explaining the 3:1 :: male:female ratio of autistic individuals.

The following video from a 1944 study by Heider & Simmel illustrates how when things move like living creatures rather than dumb, physically determined matter, we automatically find ourselves attributing to them goals and psychological states: 

When prompted to describe the video, individuals with ASD are less likely to use as deeply intentional language as neurotypical individuals, revealing a less developed folk psychological sense. Thus, we might view autism as a hyper-masculinization of the brain and a strong orientation to things rather than people. In this way, relative ability in folk physics and folk psychology may be taken as measures on a continuum of masculinization of the brain, with ASD being a part of the extreme male end.

References:

Baron-Cohen, S. (1999). The extreme male-brain theory of autism The MIT Press, Cambridge, MA. Retrieved from http://search.proquest.com/docview/619398505?accountid=7379

Beltz, A. M., Swanson, J. L., & Berenbaum, S. A. (2011). Gendered occupational interests: Prenatal androgen effects on psychological orientation to things versus people. Hormones and Behavior, 60(4), 313-317. doi:http://dx.doi.org/10.1016/j.yhbeh.2011.06.002

Farah, Martha J. & Heberlein, Andrea S. (2006). “Personhood” Farah 321-338.

What can Parkinson’s disease teach us about sex differences?

You probably have heard of Parkinson’s disease, a neurodegenerative disorder that affects motor ability, usually in older people. It is known for causing symptoms such as tremors, slowing of movement, and muscle stiffness. People with Parkinson’s can also have many other symptoms, such as  anxiety, trouble sleeping, dementia, trouble swallowing, constipation, and depression [1]. Parkinson’s is linked to losing neurons in the brain that produce dopamine, a neurotransmitter that your body uses to signal between neurons, especially in pathways that involve motivation and reward seeking. The area of the brain that loses dopamine during Parkinson's disease is called the substantia nigra, which, unsurprisingly, helps control movement.

As you can see in the graph below, Parkinson’s disease is much more common in men than in women. Interestingly, a study conducted by Haaxma et al. has found that there are also sex differences in symptom progression [2]. According to this study, women are more likely to develop a tremor as their initial symptom, while men are more likely to develop rigidity first. This is important because tremor dominant Parkinson's is usually characterized by a slower and milder progression of the disease. The study also found that on average, women are about two years older when they are diagnosed, and more dopamine was lost in women before symptoms developed. 

Figure 1: Age and gender of Parkinson’s diagnosis in the U.K. Fewer women are diagnosed with Parkinson's and they tend to be diagnosed at a later age (bathnes). 

The researchers explained that these differences could be caused by a neuroprotective effect of a female sex hormone, estrogen. This means that the presence of estrogen helps prevent, or at least delay, the development of Parkinson's disease. Supporting this, they found that among women with children, the more children they had, the older the average age of diagnosis. Estrogen levels are extremely high during pregnancy, so more children means more estrogen exposure during the women's life. Also, the age of diagnosis correlated with a longer fertile life span (amount of time between first period and menopause). A longer fertile life span indicates that the women were exposed to a higher level of estrogen for more years, because estrogen levels decrease during menopause. Both of these findings could mean that more estrogen means more protection against Parkinson’s disease.

The neuroprotection of estrogen against parkinson’s disease points to a possible link of estrogen and dopamine activity, possibly by estrogen preventing toxins from being transported to the dopamine nerve terminal [3]. In fact, dopamine levels have been shown to be higher in female than in male rats [4]. Because dopamine is involved in pathways of reward seeking, arousal, and attention, this trend has been used to explain many sex differences, such as the fact that males have higher rates of ADHD and alcohol dependence. It’s good to remember that anything to do with the brain is probably too complex to attribute just to one hormone or neurotransmitter. Sex differences in Parkinson’s disease are probably way more complicated than just an estrogen-dopamine connection. However, it is important to study potential causes, however partial, because these can be used as targets in developing treatments.

Fun fact: If you are male, and are feeling jealous of estrogen’s neuroprotective effects against Parkinson’s, try drinking coffee. Caffeine intake has shown to decrease the likelihood of developing Parkinson’s in men (but not in women).

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1. Gillies, G.E., Pienaar, I.S., Vohra, S., and Qamhawi, Z. 2014. Sex differences in parkinson's disease. Front Neuroendocrinol 35: 370-384.

2. Haaxma, C.A., Bloem, B.R., Borm, G.F., Oyen, W.J., Leenders, K.L., Eshuis, S., Booij, J., Dluzen, D.E., and Horstink, M.W. 2007. Gender differences in parkinson's disease. J Neurol Neurosurg Psychiatry 78: 819-824

3. Dluzen, D.E. 2000. Neuroprotective effects of estrogen upon the nigrostriatal dopaminergic system. J Neurocytol 29: 387-399

4. Walker, Q.D., Rooney, M.B., Wightman, R.M., and Kuhn, C.M. 2000. Dopamine release and uptake are greater in female than male rat striatum as measured by fast cyclic voltammetry. Neuroscience 95: 1061-1070