• 01/19 Jim Townsend - abstract
• 01/26 Open
• 02/02 Open
• 02/09 Jerry Busemeyer - abstract
• 02/16 Ji Son - abstract
• 02/23 Hong Jiang - University of Maryland - abstract
• 03/02 Ido Erev - Israel Institute of Technology - abstract
• 03/09 Olaf Sporns - abstract
• 03/16 Spring Break
• 03/23 Open
• 03/30 Eldad Yechiam - abstract
• 04/06 Leslie Blaha - abstract
• 04/13 Chris Honey - abstract
• 04/20 Colin Allen - abstract
• 04/27 Angela Nelson
• 05/04 Damir Cavar

Abstracts

01/24: Jim Townsend The Geometry of Ways in which Perceptual Dimensions and Features can Interact (Or Not)

It has become increasingly evident since the pioneering work of Shepard and Garner and colleagues that the perceptual independence vs. dependence of dimensions or features is not a simple matter. In fact, there are many modes of interaction. Several of these did not become clear until general kinds of perceptual spaces were investigated. Ultimately, it will be critical to bring together both the geometric as well as the process and dynamic aspects of these issues. In addition, although separability and integrality (e.g., gestalt objects) are typically viewed as opposites, their theories and methodologies can be rather distinct. Patently, this subject can be germane to a number of important avenues of investigation in cognitive, perceptual, and motor domains of research, and in both basic as well as applied settings. This presentation will provide an informal discussion of some of these issues, emphasizing geometric considerations. Later talks will focus on dynamics and process models of perceptual independence.

02/09: Jerry Busemeyer
Explaining the importance weights used in decision making by attentional processing mechanisms

During the past 50 years, a number of paradoxes of decision making have been discovered, which have led to the downfall of expected utility theory as a viable description of human decision making. Recently a new theory of decision making has arisen to take its place called rank dependent utility theory. A key idea of this new theory is the concept of a decision weight that is applied to reflect the importance of consequences when evaluating an action. However, little is known about the source of these decision weights. Where do these importance weights come from? I will present a computational model that derives these decision weights from elementary attentional processing mechanisms. Then I will show how this cognitive model for weights provides a coherent explanation for the paradoxes of decision makng.

02/16: Ji Son
Relational Words as Handles that Bring Along Baggage

Most people simply expect learning words to lead to learning concepts because we use language to communicate ideas. Two experiments examined the role of relational language on analogical transfer. Participants were taught Signal Detection Theory (SDT) embedded in a doctor story. The experimental condition had relational words accompany the story while the control condition did not have those words. Participants were given an opportunity to transfer their learning by taking a SDT quiz embedded in a new story about exporting melons. Relational words that shared superficial similarity with the contextual elements facilitated transfer performance. Without the shared semantics, relational words were detrimental to transfer. The generic properties of language alone, such as being non-iconic arbitrary symbols, did not make SDT relations easier to use. Rather it was a combination of the content-specific aspect of language and the generic properties that led to more flexible learning.

02/23: Hong Jiang

Expected Utility Theory and Prospect Theory both evaluate prospects based on the independence of v(x) and w(p). The present study creates a novel method (relay) to examine the assumed independence without prior assumption of functional forms. If v(x) and w(p) are independent, the data should satisfy two criteria: v(x) and w(p) are monotonically increasing functions of x and p, respectively. However, the results show that independence is violated. A set of models are created to explore possible interactions between v(x) and w(p). The results of model comparison suggest that large contrast along one dimension, either x or p, results in lower overall evaluation of the other and probability contrast plays a more important role than the value contrast.

03/02: Ido Erev, Alvin E. Roth, Robert L. Slonim & Greg Barron
Descriptive Models as Generators of Prior Beliefs with Known Equivalent Number of Observations (ENO)

When descriptive models are used to predict behavior in a novel condition, the predictions can be treated as "objective prior beliefs." The current paper shows that an extension of the generalization criterion methodology proposed by Busemeyer and Wang (2000) can be used to facilitate objective updating of these beliefs. The optimal weighting of the initial prediction and the new data can be summarized with a single number: the model's equivalent number of observations (ENO). The value of this measure is demonstrated with the analysis of models in three domains: Decision making, Direct perception, and Basketball.

03/09: Olaf Sporns
The Structure of Brain Networks

Recent research has revealed general principles governing the structural and functional organization of complex networks which are shared by various natural, social and technological systems. A central question is whether some of these principles can usefully be applied to the organization, development and function of complex brain networks. In addressing this question, we will examine the structural properties of large-scale anatomical and functional brain networks. We will discuss candidate mechanisms of network growth, evolution and rewiring that may be responsible for generating different classes of network topologies. We will also examine the relationship between the structural substrate of neuroanatomy and more dynamic functional and effective connectivity patterns that underlie human cognition. Specifically, we will introduce the method of motif analysis and highlight the potential roles of structural and functional motifs in brain networks. In summary, various modes of network analysis offer new insights into global and integrative aspects of brain function, including the origin of flexible and coherent cognitive states within the neural architecture.

03/30: Eldad Yechiam
Knowing what could have happened: The effect of foregone payoffs on risk taking

Foregone payoffs add information about the outcomes for alternatives that are not chosen: Knowing what could have happened if I had made a different choice than the one I made. The present lecture examines the effect of foregone payoffs on risk taking. Previous studies have demonstrated that foregone payoffs have no or transitory effects when they do not add much information. The present paper highlights the conditions for the occurrence of such long-lasting effects of foregone payoffs. An experimental study compares the effect of foregone payoffs under different degrees of rarity of the negative payoff. It is demonstrated that foregone payoffs increase the selection from risky alternatives with extremely rare and highly negative outcomes, and that this effect does not diminish with repeated presentation of the task. These findings can be summarized using a surprisingly simple reinforcement-learning model. The findings suggest a simple 2 X 2 model of the effect of foregone payoffs on taking small probability risks, with the sign of the modal outcome of the risky alternative (whether most of the time a positive or a negative outcome occurs) and the number of risky alternatives as the main factors.

04/06: Leslie Blaha and Shannon Johnson
Perceptual and Cognitive Processing in Autism Spectrum Disorders

Multiple cognitive studies of individuals with autism spectrum disorders (ASD) have indicated altered perceptual processing, including enhanced discrimination of non-social stimuli and deficits in face processing. Accumulating evidence from studies of global-local processing suggests a lack of global precedence and lack of global interference in HFA and ASP individuals. This has been interpreted as either a lack of interference from a competing visual gestalt or lack of ability to unite local elements into a global gestalt. Despite the potential importance of such perceptual differences, current cognitive theories of ASD fail to explain dissimilarities in global-local performance. In a series of selective and divided attention tasks, we begin to investigate these fundamental aspects of visual information processing in ASD. In particular, we examine the roles of competing information in Garner-style (1974) interference tasks employing selective attention to either the global or local dimension. Further, we apply the double factorial paradigm (Townsend & Nozawa, 1995) to investigate the architecture, stopping rule and capacity of the information processing system involved in a global-local divided attention task. Modeling results indicate that cognitive strategies employed during the global-local tasks vary across individuals and that some ASD participants use approaches that are distinct from control subjects. Furthermore, we find similar patterns of global and local interference across all groups of participants, a clear departure from the findings in the commonly cited ASD reports. These results offer potential explanations for previous findings of global-local processing differences in ASD and importantly, offer an example of the need for rigorous cognitive methods and modeling in shaping cognitive theories in clinical populations.

04/13: Chris Honey
Base Time and its Consequences

In the Townsend Lab we treat the stages in human information processing as black-boxes constrained by their statistical properties. Distinct classes of information processing systems (as characterized by channel architecture, informational interactions, process-seriality, process-stopping criteria etc.) exhibit distinct distributions of processing-time. By comparing these signature distributions to those obtained empirically we try to determine the functional architecture of human information processing systems.

Recently I have been investigating the behavior of these mathematical models and statistical tests in the presence of noisy data. In particular, reaction time data is almost always contaminated by fluctuations in basic perceptual transmission time and in motor response time. The time taken to complete these "non-cognitive" tasks is referred to as base time. When base time makes up a major component of measured reaction times, then our data provides a poor estimate of the durations of the cognitive processes in which we are interested.

How bad can it get? Pretty bad; I provide some quantitative results.

04/20: Colin Allen
Monkey see, monkey do? The puzzle of macaque mirror neuron function

Primatologists generally agree that monkeys lack higher-order intentional capacities related to theory of mind. Yet the discovery of mirror neurons in monkeys suggests to many neuroscientists that they have the rudiments of intentional understanding. Given a standard philosophical view about intentional understanding which requires higher-order intentionality, a paradox arises. I discuss different ways of resolving the paradox, including rejecting the standard philosophical view.

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