Minimal Mindreading in Great Apes and Young Children

The project will test the two-system mindreading hypothesis which holds that the mindreading ability (attributing mental states to others) of nonhuman animals and infants is subject to signature limits which set it apart from a more sophisticated system displayed by older children and adults. A cognitively more sophisticated system may process 'beliefs as such' whilst the limited system processes registrations - belief-like states that are limited in that they cannot process propositions about identity (which is required for 'beliefs as such'). Registrations resemble beliefs and either could be used to pass the benchmark test of belief-reasoning - the change-of-location false belief task.

The change-of-location false belief task consists of a subject viewing an actor put a desired object in one of two containers. Subsequently, the actor leaves the scene and, unbeknownst to actor but not the subject, another actor changes the location of the object to a different location. When the first actor returns, the subject should indicate where it expects the actor to look for the object. Crucially, the subject is not necessarily representing a propositional belief of the actor (i.e. 'they believe the object to be hidden there') but could also solve the task by tracking the relation of the actor and an object; in other words, by registering the actor's relation to the object.
In order to reveal which of the systems is being deployed in a false belief test, the test needs to require representing also under which aspect is an object represented in another's mind - an object needs change identities. This change-of-identity task would tease apart the successful performance of the limited mindreaders from the sophisticated ones: a limited mindreader would pass the change-of-location task but fail the change-of-identity task; the sophisticated mindreader would pass both.

According to some authors, children under the age of four and nonhuman animals have a limited system and cannot represent others' aspectual representations (which requires a sophisticated system). Given that apes and young children have been reported to pass an implicit change-of-location false belief task in which their looking behaviour was recorded (in lieu of explicit predictions such as pointing or verbalising), the same eye-tracking methodology can be used with an aspectual false belief task. The two-system hypothesis predicts that, while successful in the change-of-location task, apes and children should fail at a change-of-identity task. The overall aim of this project is to test this hypothesis and further illuminate the way great apes and young children represent the mental states of others, which in turn informs the nature of their social cognition more broadly.