I talked about the notion of core knowledge in the very first lecture, but since then I
have not appealed to the notion.
This is deliberate because the notion is tricky; so I thought it would be good to postpone
our discussion of it for as long as possible.
Now I can put it off no longer.
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The first, very minor thing is to realise that there are two closely related notions, core
knowledge and core system.
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These are related this: roughly, core knowledge states are the states of core systems. More
carefully:
For someone to have \textit{core knowledge of a particular principle or
fact} is for her to have a core system where
either the core system includes a representation of that principle or
else the principle plays a special role in describing the core system.
So we can define core knowlegde in terms of core system.
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What do people say core knowledge is?
There are two parts to a good definition. The first is an analogy that
helps us get a fix on what we is meant by 'system' generally. (The second
part tells us which systems are core systems by listing their
characteristic features.)
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So talk of core knowledge is somehow supposed to latch onto the idea of a system.
What do these authors mean by talking about 'specialized perceptual systems'?
They talk about things like perceiving colour, depth or melodies.
Now, as we saw when talking about categorical perception of colour, we can think of the 'system' underlying categorical perception as largely separate from other cognitive systems--- we saw that they could be knocked out by verbal interference, for example.
So the idea is that core knowledge somehow involves a system that is separable from other cognitive mechanisms.
As Carey rather grandly puts it, understanding core knowledge will involve understanding something about 'the architecture of the mind'.
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Illustration: edge detection.
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This, them is the two part definition. An analogy and a list of features.
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There is one more feature that I want to mention; this is important
although I won't disucss it here.
To say that a represenation is iconic means, roughly, that parts of the
representation represent parts of the thing represented.
Pictures are paradigm examples of representations with iconic formats.
For example, you might have a picture of a flower where some parts of the
picture represent the petals and others the stem.
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Why postulate core knowledge?
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The first problem we encountered was that the Simple View is false.
But maybe we can appeal to the Core Knowledge View.
According to the Core Knowledge View, the principles of object perception, and maybe also the
expectations they give rise to, are not knowledge.
But they are core knowledge.
This raises some issues. Is the Core Knowledge View consistent with the claims that
we have ended up with, e.g. about categorical perception and the Principles of Object
Perception characterising the way that object indexes work?
I think the answer is, basically, yes. Categorical perception involves a system that has
many of the features associated with core knowledge.
[*looking ahead (don’t say):]
Consider this hypothesis.
The principles of object perception, and maybe also the expectations they give rise to, are not knowledge.
But they are core knowledge.
The \emph{core knowledge view}: the principles of object perception are
not knowledge, but they are core knowledge.
But look at those features again --- innate, encapsulated, unchanging and the rest.
None of these straightforwardly enable us to predict that core knowledge
of objects will guide looking but not reaching.
So the \emph{first problem} is that (at this stage) it's unclear what we
gain by shifting from knowledge to core knowledge.
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The Core Knowledge view may also help us to resolve
Discrepant Findings in other domains too ...
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Why postulate core knowledge?