Introduction: explaining the brain (Chapter 1) (& Craver on Canvas facultative)
Lecture 1
The mind-body problem
One of the main questions of cognitive neuroscience is, how the body can have a causal influence on
the mind.
Descartes (16th-17th century) -> dualism.
• The body and mind are separate realms.
• There is an interaction between the two inside the pineal gland.
• The soul causes thought.
According to Descartes, animals have no mental life, while people do (mechanistic/reductionist
thinking).
Physicalism is the idea that the mind comes from matter.
Idealism is the idea that the mind causes matter. The world comes into existence by the act of
observing the world.
Neutral monism is the idea that a third substance influences both the body and the mind.
If the physical stuff produces the mind, it is not clear what the reason is for the mind existing: it is an
epiphenomenon. There are electronics that can sense things: does this mean they have experiences?
It is possible that conscious life is not required for the complex actions to happen.
Physicalism is the general consensus (the mind is what the brain does). It stems from early
neuroscience (phrenology (Gall)-> bumps on the head).
Phineas P. Gage (19th century): had personality changes after severe brain injury.
This case and other evidence points to modularity of the brain.
The modularity of the brain debate: specified modules vs general purpose device?
Modularity of the brain refers to the degree to which the brain has separate components.
➔ To what extent is the brain a homogenous general-purpose machine, that does everything at
once?
➔ Or does it have specified modules that cause separate functions?
Chomsky
• The brain is organized into different modules, each with a different function
• There is an innate language model
Fodor – the features of a module
1. Modules are domain-specific: they operate in a certain field (language, vision, etc.)
2. Their operation is mandatory: when it goes into action, this cannot be changed.
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Example: People will perceive the top line as longer than the bottom one, even when knowing
they are the same length.
3. They are informationally encapsulated: related to second characteristic. Other information
that one has, cannot change the module.
Modularity helps researchers to study the brain. The organization of the brain might reveal something
about the architecture of the mind. The interesting notion of research is how modules operate rather
than where they are.
David Hume: the mind at birth is a blank slate.
What is an explanation of a function or mental phenomenon?
Box-arrow cognition models became prominently used from the 1950s on (cognitive revolution).
Computers were used as an analogy for thinking about the brain. The downside of these models is
that there are mental events in between, which are not explained in detail. Box models only give us a
functional analysis and are often underdetermined: meaning there can be different box models that
can explain the same phenomenon.
In a reductionist explanation, one field can be reduced to another field. To cross from one field to
another you need a bridge law. At the bottom fields (physics, biochemistry), bridge laws seem very
prominent, making it easy to cross over. This is harder in the higher fields (sociology, psychology).
When we try to explain psychology through neuroscience, it seems impossible to find a bridge law.
For this field, reductionism might not work.
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A mechanistic explanation seems similar to a reductionist explanation. In a mechanistic explanation,
you find no direct mapping from one level to another. Something has to happen.
Carl Craver said that there doesn’t seem to be a way to define what an explanation, a mechanism, or
part of a mechanism is.
According to him, the whole is more than the sum of its parts (non-reductive). An example of this is
the following visual:
The perception of the triangle is there even when one realizes that it consists of three pacmans. In a
reductive explanation, the whole is the same as the sum of its parts (f.e. a pile of sand).
The non-reductive approach can be applied to the mind: the LTP, hippocampus, grid cells, etc. cause
the emergent property memory. The process works on several levels (f.e. with oxygen metabolism,
organs -> muscles -> molecules)
Phenomena may not have a fundamental level of explanation but require a multi-level
understanding. Some levels can be so far away from the phenomenon, that there does not seem to
be a relationship, even though it is still there.
How to identify mechanisms?
Etiological causal relevance is the idea that one thing causes another thing.
Constitutive relevance is the idea that all the parts that interact produce the phenomenon as a
whole. For something to be relevant for the phenomenon, you need to show that:
• You can manipulate parts of the mechanism -> phenomenon changes
• You can manipulate the phenomenon as a whole -> parts change
➔ Mutual manipulability
How to investigate brain mechanisms
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(see lecture 4)
Not all mental phenomena may be explained by a mechanistic process in the brain.
Two types of errors that occur in research are:
• Lumping errors: assuming that several distinct phenomena are actually one.
• Splitting errors: treating singular phenomena as distinct.
• Filler terms often hide failures of real understanding (f.e. recognize, represent, generate,
filter).