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Core Knowledge vs Object Indexes

Consider the conjecture that infants’ abilities concerning physical objects are characterised by the Principles of Object Perception because infants’ abilities are a consequence of the operations of a system of object indexes. If this conjecture is true, should we reject the claim that infants have a core system for physical objects? Or does having a system of object indexes whose operations are characterised by the Principles of Object Perception amount to having core knowledge of those principles?
\emph{Outstanding problem} Since having core knowledge of objects does not imply having knowledge knowledge of objects, how can the emergence in development of knowledge of simple facts about particular physical objects be explained? What is the role of core knowledge of objects, and what other factors might be involved?
Let’s consider some consequences of the CLSTX conjecture.
\emph{The CLSTX conjecture} Infants’ abilities concerning physical objects are characterised by the Principles of Object Perception because infants’ abilities are a consequence of the operations of a system of object indexes \citep{Leslie:1998zk,Scholl:1999mi,Carey:2001ue,scholl:2007_objecta}.

The CLSTX conjecture:

The principles of object perception

are not things believed or known:


they characterise the operation of

object indexes.

Leslie et al (1989); Scholl and Leslie (1999); Carey and Xu (2001)

(‘CLSTX’ stands for Carey-Leslie-Scholl-Tremoulet-Xu \citep[see][]{Leslie:1998zk,Scholl:1999mi,Carey:2001ue,scholl:2007_objecta})
We saw this quote in the first lecture ...

‘if you want to describe what is going on in the head of the child when it has a few words which it utters in appropriate situations, you will fail for lack of the right sort of words of your own.

‘We have many vocabularies for describing nature when we regard it as mindless, and we have a mentalistic vocabulary for describing thought and intentional action; what we lack is a way of describing what is in between

(Davidson 1999, p. 11)

Actually we don’t lack a way of describing what is in between. We already have it. We were simply not aware of it because we hadn’t thought carefully enough about the representations and processes involved in perception and action.
The discovery that the principles of object perception characterise the operation of object-indexes doesn't mean we have met the challenge exactly. We haven't found a way of describing the processes and representations that underpin infants' abilities to deal with objects and causes. However, we have reduced the problem of doing this to the problem of characterising how some perceptual mechanisms work. And this shows, importantly, that understanding infants' minds is not something different from understanding adults' minds, contrary to what Davidson assumes. The problem is not that their cognition is half-formed or in an intermediate state. The problem is just that understanding perception requires science and not just intuition.
What is the relation between infants' competencies with objects and adults'? Is it that infants' competencies grow into more sophisticated adult competencies? Or is it that they remain constant throught development, and are supplemented by quite separate abilities?








social interaction




time --->

The identification of the Principles of Object Perception with object-indexes suggests that infants' abilities are constant throughout development. They do not become adult conceptual abilities; rather they remain as perceptual systems that somehow underlie later-developing abilities to acquire knowledge.
Confirmation for this view comes from considering that there are discrepancies in adults' performances which resemble the discrepancies in infants between looking and action-based measures of competence ... [This links to unit 271 on perceptual expectations ...]

The Core Knowledge View?

‘Just as humans are endowed with multiple, specialized perceptual systems, so we are endowed with multiple systems for representing and reasoning about entities of different kinds.’

Carey and Spelke, 1996 p. 517

‘core systems are

  1. largely innate
  2. encapsulated
  3. unchanging
  4. arising from phylogenetically old systems
  5. built upon the output of innate perceptual analyzers’

(Carey and Spelke 1996: 520)

representational format: iconic (Carey 2009)

Which of these features are features of a system of object indexes?
Left half:

The Core Knowledge View

Infants, like most adults, do not know the principles of object perception; but they have core knowledege of them.


The CLSTX conjecture

The principles of object perception characterise how a system of object indexes should work.

Infants’ (and adults’) object indexes track objects through occlusion.

Five-month-olds do not know the location of an occluded object.

Five-month-olds do have perceptual expectations concerning its location.

‘CLSTX’ stands for Carey-Leslie-Scholl-Tremoulet-Xu \citep[see][]{Leslie:1998zk,Scholl:1999mi,Carey:2001ue,scholl:2007_objecta}
Are these two views compatible? I think we had better characterise core knowledge in such a way that they turn out to be true!

Next Big Problem

Our Next Big Problem is this. We've said that infants' competence with causes and objects is not knowledge but something more primitive than knowledge, something which exists in adults too and can carry information discrepant with what they know. So, if at all, how does appealing to these early capacities enable us to explain the origins of knowledge?

Core Knowledge Isn’t Knowledge

... so how can we explain the developmental origins of knowledge?

Berthier et al, Where’s the ball reaching study
Further issue ... we now have a more complicated story about the emergence of knowledge
Broadly, my suggestion will be that the competence which appears in the first months of development leads to knowledge of objects and causes only in conjunction with various additional things, like social interaction, perhaps language and abilities to use tools.
The picture I want to offer differs from those of researchers like Vygotsky and Tomasello in that there is an essential role for early-developing forms of representation that are more primitive that concepts or thoughts and do not appear to have any kind of social origin.
But the picture also differs from those of researchers like Spelke and Carey in that these early developing forms of representation are only one of several components that are needed to understand the origins of knowledge.
To explore this idea I want to switch to a completely different domain, colour.
[*Aside on tool use:] Basic forms of tool use may not require understanding how objects interact (Barrett, Davis, & Needham; Lockman, 2000), and may depend on core cognition of contact-mechanics (Goldenberg & Hagmann, 1998; Johnson-Frey, 2004). Experience of tool use may in turn assist children in understanding notions of manipulation, a key causal notion (Menzies & Price, 1993; Woodward, 2003). Perhaps non-core capacities for causal representation are not innate but originate with experiences of tool use.