DRAFT

Seminars on the Temporal Dynamics of Decision-Making

Monday, February 10, 2014
10:30am to 12:00pm
Add to Cal
Baxter B125
Social Science Event

Seminars on the Temporal Dynamics of Decision-Making

Title: Bursts and Heavy Tails in Temporal and Sequential Dynamics of Foraging Decisions 
Speaker: Jaeseung Jeong, Ph.D., Visiting Associate in Neuroscience, Caltech
Department of Bio and Brain Engineering, 
KAIST, South Korea

Abstract

A fundamental understanding of behavior requires predicting when and what an individual will choose. However, the actual temporal and sequential dynamics of successive choices made among multiple alternatives remain unclear. Thus, we tested the hypothesis that there is a general bursting property in both the timing and sequential patterns of foraging decisions. We conducted a foraging experiment in which rats chose among four different foods over a continuous two-week time period. Regarding when choices were made, we found bursts of rapidly occurring actions separated by time-varying inactive periods, partially based on a circadian rhythm. Regarding what was chosen, we found sequential dynamics in affective choices characterized by two key features: (a) a highly biased choice distribution; and (b) preferential attachment, in which the animals were more likely to choose what they had previously chosen. To capture the temporal dynamics, we propose a dual-state model consisting of active and inactive states. We also introduce a satiation-attainment process for bursty activity, and a non-homogeneous Poisson process for longer inactivity between bursts. For the sequential dynamics, we propose a dual-control model consisting of goal-directed and habit systems, based on outcome valuation and choice history, respectively. This study provides insights into how the bursty nature of behavior emerges from the interaction of different underlying systems, leading to heavy tails in the distribution of behavior over time and choices. In addition, since it has been suggested that the nucleus accumbens (NAc) shell is associated with reward processing and preference development, we investigated its potential role in the temporal and sequential dynamics of decision-making when continuously choosing among multiple food options both by electrolytically lesioning the nucleus accumbens (NAc) shell in rats. We found that the NAc shell-lesioned rats showed longer runs of consecutive identical choices, suggesting a dominant influence of habit-control in the balance between goal-directed and habitual valuations. The findings suggest that the NAc shell selectively affects the sequential dynamics of choices by enhancing habitual control but does not influence temporal dynamics. 

 

Title: Cognitive dynamics of real-world decisions: Attentional modulation of bursty choice sequences; and a large-scale neural network for creative problem-solving
Speaker: Jerald D. Kralik, Ph.D., Assistant Professor in Psychological and Brain Sciences
Department of Psychological and Brain Sciences
Dartmouth College

Abstract

Cognitive dynamics of real-world decisions: Attentional modulation of bursty choice sequences; and a large-scale neural network for creative problem-solving In two studies with rhesus monkeys, one behavioral and one neurophysiological, we examined ecologically valid decision problems.  First, we focused on the dynamics of multiple successive decisions.  Sequential choices exhibit a bursty property, with multiple switches among choice options interspersed with long consecutive choices of identical options.  Real-world decision problems also typically consist of multiple options, each composed of multiple attributes; and mechanisms such as selective attention help to reduce the computational load.  However, how attentional processes influence decision-making remains unclear.  To address this question, rhesus monkeys made simple multi-attribute decisions over three experiments that manipulated the degree of distinctiveness between alternatives: (1) four foods of different size; (2) four pieces of the same food in different colors; and (3) four identical pieces of food.  We found evidence for a differential influence of attention on two key components of sequential choices.  Top-down, goal-directed attention appeared to modulate the preference bias (i.e., the skew of the choice distribution), determining which attributes to evaluate; and bottom-up, stimulus-driven attention appeared to affect choice persistence (i.e., the length of runs of repeated choices).  Second, real-world decision problems also sometimes require indirect, creative solutions.  By recording the activity of individual neurons from ten parts of the primate brain, we found evidence for two large-scale networks underlying problem-solving.  One of these networks comprised four cortical regions, the dorsolateral prefrontal, medial prefrontal, agranular insula, and dorsal premotor areas, and it was particularly active when problem-solving required an indirect, creative solution.  The other was more active when the solutions were of a more conventional nature.  Taken together, these findings reveal underlying cognitive dynamics and large-scale networks that compute solutions to potentially challenging decision problems.

 

For more information, please contact Jenny Niese by phone at Ext. 6010 or by email at jenny@hss.caltech.edu.