160054 SE Seminar in Psycho-, Patho- or Neurolinguistics (2012S)

Topic 1: Non-Verbal Generics

Non-verbal demonstratives, like pointing to something or showing something up, pick out their referents as particular objects or sets of objects individuated by spatial means. Despite of this, we have repeatedly found in studies with human infants, children, and adults that, when such gestures are used ostensively and the context does not suggest otherwise, they are taken to refer to the object kind that the referent represents rather than to the particular object present in the context. This paradoxical phenomenon of non-verbal demonstrative reference to kinds parallels some core properties of generic linguistic expressions. In particular, generic constructions are unmarked, there is a 'default' bias towards generic interpretation of ambiguous sentences, and the predicates of generic expressions are expected to reflect essential, kind-relevant properties that are tolerant to counterexamples. We argue that non-verbal demonstrative reference shares these properties, which reflect fundamental design features of the cognitive mechanisms subserving human ostensive communication.

Topic 2: Opaque Knowledge

Instrumental actions performed by non-human primate species pursue a restricted range of goals that directly satisfy basic biological needs of the actor, and employ means that are transparently related to the physical properties of the goal object and the visible situational constraints on action. In contrast, several properties of human goal-directed actions and culturally transmitted instrumental skills render them causally or teleologically opaque for a nave observational learner. Human actions may be teleologically opaque because they are directed to goals that are far detached from their immediate biological needs and because they involve multiple outcomes.
Humans also frequently perform hierarchically organized sequences of goal-directed actions where local sub-goals can be identified only in terms of their relation to the final goal. Actions can also be causally opaque because the means they adopt or the manner in which they are performed leaves it unclear to the observer how (or whether) they are causally connected to the ends they achieve. The causal and teleological opacity of human instrumental actions represents a non-trivial learnability problem for purely observational social learning mechanisms. We propose that this learnability problem led to the evolutionary selection of a new type of social learning mechanism provided by communicative action demonstrations, which highlight and actively guide the learners attention to the relevant aspects of the cognitively opaque instrumental actions to be acquired. We argue that both producing and interpreting such communicative knowledge demonstrations rely on specific adaptations. Evidence on observational learning of novel instrumental actions by human infants versus non-human primates supports our proposal for a human-specific system of cultural knowledge transfer based on ostensive communicative demonstrations.