Cognitive Science Colloquium
All meetings take place on Thursdays, 3.30-5.30 pm in Bioscience Research Building 1103, unless otherwise noted.
February 5 — Noah Goodman (Psychology, Stanford University).
Title: Uncertainty in language and thought
Abstract: Probabilistic models of human cognition have been widely successful at capturing the ways that people represent and reason with uncertain knowledge. In this talk I will explore the ways that this probabilistic approach can be applied to systematic and productive reasoning -- in particular, natural language pragmatics and semantics. I will first describe how probabilistic programming languages provide a formal tool encompassing probabilistic uncertainty and compositional structure. I'll illustrate with a examples from inductive reasoning and social cognition. I will then present a framework for language understanding that views literal sentence meaning through probabilistic conditioning and pragmatic enrichment as recursive social reasoning grounded out in literal meaning. I will consider how this framework provides a theory of the role of context in language understanding, focusing on examples from implicature, vague adjectives, and figurative speech (hyperbole and irony).
February 12 — Michael Platt (Cognitive Neuroscience, Duke).
The Biology of Strategic Social Behavior
Abstract: Most primates seem specialized for social life, yet how biology shapes complex social behaviors remains poorly understood. To address this gap, we study the biology and behavior of rhesus macaques in both the laboratory and the field. Recent work in the lab shows that monkeys favor giving rewards to another monkey, particularly if he is more familiar or subordinate, rather than give the rewards to no one. Oxytocin—a hormone implicated in social bonding—makes monkeys more giving. Finally, giving behavior selectively activates cells in medial frontal cortex, an area previously implicated in empathy in humans. In a separate study, we found inactivating this area impairs social learning. By contrast, when monkeys play a competitive game against each other, they rapidly develop unpredictable behaviors that serve to hide their intentions. Planning deceptive feints activates a population of neurons in the lateral frontal cortex, an area linked to deceptive planning in humans; inactivating these cells impairs deceptive planning. In the field, we find that intraspecific variation in social behavior and cognition has fitness consequences and emerges, in part, from genes that regulate neuromodulatory function. Together, our findings suggest deep homologies in the biological origins of complex social function in primates.
February 26 — Jesse Snedeker (Psychology, Harvard University).
Title: Clean Mapping: A sketchy story about how conceptual structure could shape language acquisition and some experiments suggesting that it just might be true
Abstract: To acquire syntax, children must map sentences to their meanings (structured conceptual representations). If these conceptual representations are available prior to language, have a similar structure to the syntax, and have the right degree of abstraction, then this learning process could be pretty painless.* I'll discuss an apparent counter-example (psych verbs, where meaning and form seem to diverge) and show how it actually supports the hypothesis. Then I’ll present some studies that explore the conceptual pieces that make up verb meanings and their connection to the cognitive capacities of young infants. The methods that are used include eye-tracking, novel word learning, training studies, large-scale internet based research, and an infant imitation paradigm.
* Many generative linguists work in a framework theory where what I call conceptual structure is construed as an early part of syntax and what I call syntax is, in whole or part, an interface with phonology. That’s fine, with careful translation we still ought to be able to communicate.
March 5 — Nancy Kanwisher (Psychology, MIT). Note: visit cancelled / deferred to next academic year.
March 12 — Jeffrey Lidz (Linguistics, Maryland).
Title: On the proper treatment of experience in language learning
Abstract: A common pivot in debates about the nature of human language concerns the role of experience in shaping language development. While many have found young learners to be prodigious statistical learners and to display clear effects of quantity and quality of input on their ultimate language outcomes, others have focused on cases where the input is impoverished relative to the ultimate acquired knowledge. In this talk, I examine the properties of the learner that make input informative, providing a bridge between these two research traditions.
Note: the talk by Giorgio Vallortigara (Mind/Brain Sciences, University of Trento, Italy) that was scheduled for this date is cancelled / deferred to next academic year.
April 9 — David Poeppel (Psychology, NYU).
Title: Specialization for speech and structure for language
Abstract: I will discuss two new studies from my lab that focus on general questions about the cognitive science and neural implementation of speech and language. I come to (currently) unpopular conclusions about both questions. Based on a first set of experiments, using fMRI and exploiting the temporal statistics of speech, I argue for the existence of a speech-specific processing stage that implicates a particular neuronal substrate (the superior temporal sulcus). In a second set of experiments, using MEG, I go on to develop how temporal encoding can form the basis for more abstract, structural processing. The results demonstrate that, during listening to connected speech, cortical activity of different time scales is entrained concurrently to track the time course of linguistic structures at different hierarchical levels. Critically, entrainment to hierarchical linguistic structures is dissociated from the neural encoding of acoustic cues and from processing the predictability of incoming words. These results demonstrate syntax-driven, internal construction of hierarchical linguistic structure via entrainment of hierarchical cortical dynamics. The conclusions — that speech is special and language syntactic-structure-driven — provide new neurobiological provocations to the prevailing view that speech is hearing and that language is statistics.
April 23 — Gerry Altmann (Psychology, University of Connecticut).
Representing objects across time: language-mediated event representation.
Abstract: Language is often used to describe the changes that occur around us – changes in either state (“I cracked the glass…”) or location (“I moved the glass onto the table…”). To fully comprehend such events requires that we represent the ‘before’ and ‘after’ states of the object. But how do we represent these mutually exclusive states of a single object at the same time? I shall summarise a series of studies, primarily from fMRI, which show that we do represent such alternative states, and that these alternative states compete with one another in much the same way as alternative interpretations of an ambiguous word might compete. These studies also show that whereas the representations of distinct but similar objects (e.g. a glass and a cup) interfere with one another in proportion to their similarity, representations of the distinct states of the same object interfere in proportion to their dissimilarity. This interference, or competition, manifests in a part of the brain that has been implicated in resolving competition. Furthermore, activity in this area is predicted by the dissimilarity, elsewhere in the brain, between sensorimotor instantiations of the described object’s distinct states. I shall end with new data (still too hot to touch) whose interpretation is a first step towards a brain mechanism for distinguishing between object types, tokens, and token-states. [Prior knowledge of the brain is neither presumed, required, nor advantageous].
April 30 — Simona Ghetti (Psychology, UC Davis).
Title: Remembering during childhood
Abstract: The capacity to remember the past in vivid detail develops considerably during childhood and emerges from the contribution of several psychological processes. I will highlight the contribution of two classes of these, relational binding processes and metacognitive processes. Relational binding processes support the integration of the various features of an event (e.g., what, when, where) into a memory representation that captures the most important aspects of an experience. Metacognitive processes confer the ability to reflect on memory quality, which might support decision making (e.g., decisions to act on the basis of the content of one’s memory). Behavioral and neuroimaging evidence will be discussed.