Cognitive Science Colloquium

Fall 2008

All meetings take place on Thursdays, 3.30-5.30 pm in Bioscience Research Building 1103.

September 11 — Randy Gallistel (Department of Psychology and Rutgers Center for Cognitive Science, Rutgers University)

Title: Risk assessment in man and mouse.
Abstract: Subjects decided when to switch from one target to another as time elapsed in a trial. Human subjects were asked to “catch” a target that appeared either at Location A after a short duration (i.e. 2 seconds) or at Location B after a longer. Mouse subjects harvested pellets whose release was triggered either from interrupting an infrared beam in either the “short” hopper or the “long” hopper. The trial type (short or long) was not signaled; subjects relied on their sense of the time elapsed since trial onset to decide when to switch. The relative frequency of the two types varied between blocks. Choosing an appropriate target switch time requires accurate assessment of the risk of premature departure from the short target and late arrival at the long target. The risk has two components: intrinsic (due to variability in the subject’s estimates of elapsed time) and extrinsic (the relative frequency). Both human and mouse subjects track the optimal switch point fairly closely. Thus, under these circumstances risk assessment is accurate and decision-making optimal in both man and mouse. The mouse results open up the possibility of a genetic approach to the neural mechanisms of risk assessment.

September 25 — Daniel Fessler (Anthropology, UCLA)

Title: The evolved psychology underlying culture acquisition: some tentative suggestions
Our species' ability to thrive in virtually every ecosystem on the face of the planet is principally due to our capacity to acquire, exploit, and further develop information that we obtain from other people. Anthropologists have long pondered the question of the evolution of what has been termed "the capacity for culture." However, until recently, most attempts to address this issue have relied on informationally and evolutionarily implausible generalized learning mechanisms. Evolutionary psychologists have achieved considerable success in identifying domain-specific mental mechanisms. However, with only a few exceptions, they have largely overlooked the problem of culture acquisition. This talk explores the emerging perspective that our species' use of culture depends on the workings of an assortment of special-purpose psychological mechanisms that evolved in order to exploit the enormous adaptive potential of socially transmitted information.

October 9 — Robert Seyfarth (Psychology, Penn)

Title: Baboon Metaphysics
Abstract: What can studies of nonhuman primates tell us about the evolution of human cognition? Long-term research on baboons suggests that natural selection has favored in baboons – and, by extension, other monkeys and apes – a mind that is specialized for observing social life, computing social relations, and predicting other animals’ behavior. This knowledge is based on discrete-valued traits (identity, rank, kinship) that are combined to create a representation of social relations that is hierarchically structured, open-ended, and rule-governed, and that embodies a recognition of other individuals’ motives and the causal relations that link one individual’s actions with another’s. Long before the evolution of language, the demands of social life created minds that were preadapted to evolve it.

October 23 — Brian Scholl (Psychology, Yale)

Title: Perceiving persisting objects
Visual experience consists of more than discrete snapshots of the world: we must bind individual views over time into a coherent dynamic experience. Not only must we perceive discrete objects, but we must see them as the *same* objects through time, motion, featural change, and interruptions such as occlusion. While a tremendous amount of research has explored static object representations, surprisingly little has focused on the factors which underlie the representation of persisting objects, beyond low-level motion mechanisms. I will describe and demonstrate several projects from our laboratory which explore three primary aspects of object persistence: (1) Surprising demonstrations of failures of visual awareness (involving 'motion-induced blindness' and 'inattentional blindness'), highlighting the extent to which we can completely fail to be consciously aware of salient persisting objects in the first place; (2) Studies of visual tracking (using psychophysics and fMRI) which begin to reveal the underlying 'rules' by which the visual system determines when objects do and do not persist; and (3) Studies of ambiguous motion displays (including examples of causal perception) which reveal the additional rules that help to determine 'which went where', in situations involving multiple moving objects. Each of these research strands will involve perceptually salient demonstrations of various types, with subject populations including adults, infants, and nonhuman primates. Collectively, this work begins to reveal how the mind weaves coherent persisting visual representations out of fragmented snapshots of the world.

November 6 — Alison Gopnik (Psychology, UC Berkeley)

Title: Figuring out what we think and why: causal inference and theory of mind
Abstract: In the past ten years theory theorists have begun to make the idea of theories and theory formation more precise. This research has applied work in the philosophy of science and computer science on causal graphical models or Bayes nets to cognitive development. Most of this work, however, has concerned physical causality. I will present new work applying these ideas to children's understanding of psychological causation, including analyses of false belief, trait attribution and free will.

November 20 — Sian Beilock (Psychology, University of Chicago)

Title: Expert performance: from action to perception to understanding
What makes a highly skilled performer different from his or her novice counterpart? At first glance, one might suggest that the answer is simple. It is the quality of overt behavior that separates exceptional performers from those less skilled. We can all point to many ‘real world’ examples of such performance differences – just try comparing any professional athlete to his or her recreational counterpart. Although actual performance is one component that differentiates skilled individuals from novices, my research program suggests that these overt performance distinctions are only part of the picture. In this talk, I will present a series of studies exploring differences in the attentional substrates and memory structures governing novice and expert motor skill performance as it unfolds in real time. I will also cover work exploring the role of motor experience in the representation and understanding of skill-relevant information in situations where there is no intention to act. Specifically, I will show that activities as diverse as language comprehension, memory judgments, and preferences for objects/events in one’s environment are modulated by one’s motor skill expertise. Together, this work highlights differences in the cognitive and neural operations supporting novice and skilled performance on the playing field and beyond. Implications for learning, training, and performance breakdowns under stress will be discussed.

December 11 — Barbara Landau (Cognitive Science, Johns Hopkins)

Title: Language and (New) Thought
Abstract: Does language change thought?  This classical question has recently received renewed attention, as new lines of evidence have been offered, either supporting or arguing against the idea that speaking a particular language -- or having a language at all -- affects our non-linguistic organization. The domain of space has provided particularly fertile territory for this debate.  In this talk, I will present a new hypothesis about the way in which language interacts with spatial representations, arguing that this occurs on a momentary basis, with no repercussions for permanent changes in our spatial representation.  This hypothesis not only accounts for new data I will discuss; it also accounts for much of the existing data on both sides of the aisle, in domains as different as spatial cognition and the representation of color.  Having a language undoubtedly changes human cognition -- but it does not change human concepts.