Memory and Theory of Mind

Theory of Mind is essentially a label for the research area that investigates the conceptual system that underlies our ability to impute mental states (i.e., what we know, think, want, feel, etc.) to others and ourselves.

The study of these concepts is essential for our understanding of memory insofar as memory is not just storage of information, but is also dependent on knowledge of our own information-storage processes.

What Is Our Theory of Mind?

Our theory of mind is constituted by our everyday mental concepts. The analysis of these concepts is influenced by traditions in analytical philosophy of mind. They are characterized as propositional attitudes (Russell, 1919)—that is, they describe a relation between an organism (person) and a proposition.

Since cognitive science Opens in new window has taken on board this commonsense view of the mind, an important question is how such a relationship to a proposition can be implemented.

The representation theory of mind (RTM; Field, 1978; Fodor, 1978) assumes that a propositional attitude consists in holding a representation of the proposition and that this representation plays a certain functional role in the economy of mental states. This can be best illustrated with the two core concepts: belief and desire.

These are core concepts, since knowing what someone believes (thinks) to be the case (e.g., Max thinking the chocolate is in the cupboard and thinking that going there will get the chocolate into his possession) and what that person desires (wants) (e.g., Max wanting the chocolate to be in his possession) allows us to make a behavioral prediction that Max will approach the cupboard. This kind of inference is known since Aristotle as the practical syllogism.

Searle (1983, after Anscombe, 1957) points out that these two states are mirror images in terms of causal direction and direction of fit. The function of a belief is to be caused by reality and the believed proposition should match reality.

The function of desire (want) is to cause a change in the world (mind to world causation) so that the world conforms to the desired proposition (world should fit mind)—for example, if Max wants the chocolate to be in the cupboard, then this desire should cause action leading to a change of the chocolate’s location such that it conforms to what Max desires.

This trivial-sounding example does highlight the important distinctions.

Three Important Distinctions

1. First vs. Third Person

One important distinction is between first-person and third-person attribution of mental states. A third-person attribution is an attribution to another person and a first-person attribution is one to myself.

The observer can capture this difference between her own and Max’s subjective view by the second-order attribution that Max thinks he knows where the chocolate is. This is useful to keep in mind when it comes to false memories. Since a memory can only be a recollection of something that actually occurred, a false memory is not a memory by third-person attribution, although it is by first-person attribution.

2. Sense and Reference

A related second point has to do with Frege’s (1892/1960) distinction between sense and reference. Since mental states involve representations, they connect us to objects and events in the real (or a possible) world.

Famously, Oedipus knew and married Iocaste (referent: a particular person), but he did not know or marry her as his mother but as an unrelated queen (sense: how Iocaste was presented to Oedipus’ mind).

Thus, in third-person parlance we can say that Oedipus married his mother if we use the expression “his mother” to pick out (refer to) the individual whom he married without implying that he knew Iocaste under that description. In first-person description of the event Oedipus would not have used the descriptor “my mother.”

These distinctions are useful to keep in mind when discussing infants’ ability to remember particular events: Whenever a memory trace of a unique event can be demonstrated then one can conclude (in first-person parlance) as a particular event—that is, that the infant makes cognitive distinctions that represent that event as a particular event.

3. Having vs. Representing a Mental State

The third important distinction is that between being in a mental state (or having an attitude) and representing that mental state.

For understanding or knowing that a person is in a mental state, or to reflect on one’s own mental states, one has to be able to represent that state. In order to be able to represent a state, one needs a concept of that state—that is, a rich enough theory of mind.

The study of how children acquire the requisite theory of mind is therefore essential for our understanding of how children come to understand memory. Furthermore, since some memorial states are reflective or self-referential, children need a theory of mind for being in such states or having such memories.

Why We Need a Theory of Mind for Memory

We probably do not need a theory of mind for implicit (nondeclarative Opens in new window) memory, but for explicit (declarative Opens in new window) memory we do, since “explicit memory is revealed when performance on a task requires conscious recollection of previous experiences.” (Schacter, 1987).

To be conscious of a fact one requires to be also aware of the state with which one beholds that fact. The higher-order-thought theories of consciousness make this their core claim (Armstrong, 1980; Rosenthal, 1986).

To be conscious of this state of affairs means, according to theory, that one entertains a second-order thought about the seeing—that is, the second-order thought represents the first-order seeing.

A weaker version does not require that one has to entertain the second-order thought, but only that one has to have the potential for having the second-order thought (Carruthers, 1996). That some such condition must be true can be seen from the following consideration:

The important point of these conceptual analyses is that to be conscious of some fact requires some minimal concept of knowledge or of some perceptual state like seeing.

Unfortunately, there is no clear evidence when children understand a minimal state of this sort. There is some evidence of understanding (mother’s) emotional reactions and seeing (direction of gaze) in the first year of life (see Perner, 1991, chap. 6; Baldwin & Moses, 1996; Gopnik & Meltzoff, 1997, for summaries and discussion of problems of interpretation).

There is also some recent evidence that between 8 and 12 months children might be inferring people’s intentions to grasp an object from where that person looks (Spelke, Philips, & Woodward, 1995) and even between 5 to 9 months from how a person touches an object (seemingly intentional or accidentally).

And by 18 months (where children’s understanding of mental phenomena seems to flourish in general) children imitate people’s intended actions even when they observe a failed attempt (Meltzoff, 1955a) and they understand differences in preferences (e.g., that someone else can prefer cauliflower over biscuits, Repacholi & Gopnik, 1997).

Evidence that children distinguish their knowledge from ignorance is available at a relatively late age. Povinelli, Perilloux, and Bierschwale (1993) asked children to look for a sticker under one of three cups.

Children were first trained to look under the cup at which the experimenter had pointed. After some training even the youngest were able to do this.

When asked to look without the experimenter pointing, an interesting developmental difference emerged. Children older than 2 years and 4 months acted without hesitation when they knew which the cup the sticker was under, but hesitated noticeably when—in the absence of the experimenter’s poining—they had to guess where it was.

Interestingly this is also the age at which children start using the phrase “I don’t know” (Shatz, Wellman, & Silber, 1983). In contrast, children younger than that showed no comparable difference in reaction time. This may indicate that young 2-year-olds do not yet reflect on what they do and do not know.

So, theory of mind research is not yet able to give a guideline for when infants might develop explicit, conscious memories. Memory development may help out on this point.

Meltzoff (1985, 1995b) demonstrated that 14-month-old infants can reenact a past event (e.g., they imitate the experimenter leaning forward to touch a panel with forehead so that panel lights up) after several months. Recently this has been demonstrated in 11-month-olds with a delay of 3 months.

Since this is achieved from a brief observational period and does not require prolonged learning, and since patients with amnesia cannot do this (McDonough, Mandler, KcKee, & Squire, 1995), it is tempting to conclude that such enactment demonstrates explicit, conscious memory.

One should, though, keep in mind that delayed imitation that is based on a single event (third-person view) is not to be equated with a memory (knowledge) of that event as a single, past event (first-person view).