The brain is not alone


After a long break, now I am back with the blog: Happy New Year! INSOSCI is looking forward to holding our final book symposium on February 12 and 13 at Witten/Herdecke University, with renowned international researchers in the field joining the INSOSCI team and contributing chapters to a book devoted to the ‘social brain’, mainly in the context of behavioural science and economics. This reflects a trend that has been emerging in the blog entries over the past years: When philosophically trying to approach the role of neuroeconomics in understanding economic phenomena, a core issue is the potential role of externalism, that is, the question how far the brain is systematically connected to external phenomena in constituting ‘mind’. This differs fundamentally from the treatment of external phenomena just as external causal impacts on brain activity. This also differs from how mechanistic philosophy is commonly applied on the neurosciences: Mechanisms are always seen as being confined ‘within’ the brain, triggered by external impacts and resulting in behavioural outputs. The social brain hypothesis, understood in terms of philosophical conceptions like the extended mind, would instead claim that mechanisms transcend the boundary of the body and are constituted by both somatic entities and external entities.

Interestingly, these ideas are attracting the curiosity of science writers and journalists. At the end of 2018, the Christmas double issue of the renowned weekly newspaper ‘The Economist’ has a report on ‘Team Ethan’ entitled “The network Within, the Network Without”. This is about a 11-year-old boy who was borne without cerebellum. Sounds fantastic: A human can not only survive without an essential part of the brain, but even conduct an almost normal life, going to school, playing with Lego toys, and so on. How can this work? One surprising observation is that it might be better to have no cerebellum than a damaged one, especially if the damage comes later in life. With no cerebellum, the other parts of the brain can gradually step in and help to realize functions that normally are realized by the cerebellum.

The cerebellum is crucial for motor coordination and all kinds of learning that involve complex motor performance. But recently researchers argue that the cerebellum also plays a role in emotions and cognition. To a certain extent, this is only plausible if one adopts a view, as ventilated by theorists of grounded cognition, that even abstract concepts are rooted in the internalization of sensorimotor loops. For example, the meaning of words would involve internalized action patterns, and thus the cerebellum, tightly integrated with many other parts of the brain, would also play a role in human speech.

How could Ethan grow up without a cerebellum? The solution is the ‘Team Ethan’, i.e. his family, mostly. Ethan does not really move like a boy with cerebellum, because his movements are trained via other mechanisms, mostly like stereotyped habits, trained over a long time via the interaction with the family members who would always help and interfere with his movements (compare it to learning a musical instrument, which focused on a highly artificial and stable narrow environment). The scientists who study Ethan treat this as a case of externalized mechanisms of body movement. The journalist makes an interesting point regarding Lego. Normal kids would learn to put Lego together based on acquiring a whole range of automated movements of their hands, mediated by the cerebellum. In Ethan’s case, much of these movements are channelled via higher-level cognitive functions which can piggyback on the logic of Lego, which is embodied in the design of the Lego pieces. This is more onerous, but eventually also results in a functionally equivalent pattern of motor control that is no longer conscious but proceed in an automatic way.

Ethan’s case reveals three insights. Firstly, the brain is a highly flexible and adaptive organ, where functions are deeply embedded in vast networks that cross many parts of the brain; exclusive assignment of function to single and narrow parts is certainly misleading. Secondly, by implication, great care is needed in analytically dividing the brain into ‘higher’ and ‘lower’ level functions. And thirdly, brain functions are scaffolded on a wide range of external entities: The brain is not alone.


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