Colloquia

Fall 2009

Paul Glimcher
Title: "An Informal Discussion of Intertemporal Choice"
Abstract:Standard models of inter-temporal choice suggest that the value of future gains declines as a hyperbolic function of delay. The longer one has to wait for a reward the less that reward is subjectively valued, but the rate of decline is not constant. Initially, goods decline in value quite quickly but that rate of decline slows as delays increase. Recent neurobiological and behavioral work, however, has begun to challenge this conclusion. Growing evidence suggests an alternative model in which the subjective values of rewards declines at a constant rate and the process of choosing between two or more options enforces a subtle change in the valuation process which makes rewards appear as if they declined hyperbolically in value, but only with regard to the soonest available option. While highly speculative, this alternative proposal both accounts for the bulk of the available data in the literature and makes novel behavioral predictions.

Mark Steyvers
Title: "Wisdom of Crowds in Human Memory: Reconstructing Events by Aggregating Retrieved Memories Across Individuals"
Abstract: When individuals independently recollect events or retrieve facts from memory, how can we average these retrieved memories to best reconstruct the actual set of events or facts? We analyze the collective performance of individuals in a series of episodic and declarative memory tasks involving the ordering of events and items. For example, in our declarative memory tasks, we ask individuals to chronologically order events, such as the order of all 44 US presidents or order US cities according to size. In our episodic ordering tasks, we ask individuals to reconstruct the order of events as observed in a video sequence. We introduce Bayesian models for aggregating order information across individuals. The models assume that each individual's reconstruction is a perturbed version of the unobserved ground truth and that there is variability across individuals in the perturbation noise. The models demonstrate a wisdom of crowds effect, where the aggregated orderings are closer to the true ordering than the orderings of the best performing individual. The models also demonstrate that the degree of knowledge of each individual, and general problem difficulty can be estimated accurately in the absence of any explicit feedback or access to ground truth. We will discuss generalizations of these findings to other combinatorially complex problems such as matching problems (e.g., remembering which flag goes with what country), traveling salesman problems.
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Klaus Oberauer
Title: "Modelling Working Memory"
Abstract: The limited capacity of working memory plays a central role in determining individual differences and age-related changes in cognitive abilities. Our understanding of working memory rests on theories describing components and mechanisms verbally, often lacking the precision necessary to make testable predictions. This state contrasts with the related literature of short-term memory, which has generated a number of computational models of how people recall short lists in order (e.g., Burgess & Hitch, 1999). My colleagues and I have started to build on the insights gained from modelling short-term memory tasks to develop computational models of working memory. Our initial focus is on the complex-span paradigm, in which people are asked to recall a short list in order, and to complete an unrelated processing task in between presentation of the list items (e.g., reading span, operation span). I will present two computational models that both reproduce key data with the complex-span paradigm. One model extends the SOB model of Farrell and Lewandowsky (Farrell & Lewandowsky, 2002), the other is a computational implementation of the time-based resource-sharing model (Barrouillet, Bernardin, & Camos, 2004). I will show where the models make different predictions, and if time allows, present some data helping to distinguish them.
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Lisa Feldman Barrett
Title: "Of Mice and Men: The Nature of Emotion"
Abstract: The science of emotion requires is a model that can account for both specific-general and species-specific aspects of emotion within one unifying framework. I will suggest one possible systems-level framework, called the Conceptual Act Model. In this model, fear, sadness, happiness, and in fact all the mental events that people name with emotion words are not basic building blocks in the mind or in the brain. Instead, I propose that these mental events result from the interplay of more basic psychological ingredients. Individual and cultural differences in emotion can be understood in terms of variation in these ingredients or their interaction. This model parsimoniously incorporates neuroscience findings from rats, primates, and humans, as well as the psychological findings, and outlines the mechanisms that produce the range and variety of behavioral and introspective instances that people call “emotion.” It also provides a general framework for mapping mind to brain.

Lynn Hasher
Title: "Attention Regulation and Aging"
Abstract: Why do older adults (and others, as well) have difficulty remembering? Our research has focused on this question with the general hypothesis that attention regulation, at both encoding and retrieval, differs across the adult lifespan. I'll present evidence supporting this broad view of memory, with particular focus on evidence suggesting that older adults have difficulty remembering because they encode too much information and cannot select among that information at retrieval. I'll also present evidence suggesting that the same phenomenon holds for young adults operating at off peak times of day.

Robert Emery
Title: "Children's Pain and Parents' Anger in Divorce: Research and Alternative Dispute Resolution"
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Scott Lilienfeld
Title: "Rediscovering the Mask: The Search for Successful Psychopathy"
Abstract: Although psychopathic personality has long been recognized as a risk factor for antisocial and criminal behavior, clinical lore has frequently raised the possibility that some features of psychopathy, such as physical fearlessness and social dominance, are associated with social success. In this talk, Dr. Lilienfeld will discuss the controversial construct of successful psychopathy and present recent findings suggesting that components of psychopathy assessing fearless dominance predispose to interpersonal success across several domains, including heroism, leadership, and dating success.

Richard Lucas
Title: "Do Life Circumstances Matter for Subjective Well-Being?"
Abstract: Past research has shown surprisingly small associations between happiness and objective life circumstances. This evidence, combined with the stability and heritability of well-being and the moderate to strong correlations with personality traits, has led some to suggest that life circumstances do not play much of a role in determining subjective well-being. I will present a reinterpretation of some existing evidence, along with some new evidence from nationally representative panel studies, which shows that life circumstances can be linked with happiness in some very powerful ways.