We ignore some noises while others make us take action. Why? In sudden unusual circumstances, as with Hurricane Katrina and the Indonesian Tsunami in the past year, how we process such information can have life-and-death consequences. A new theory suggests a novel mathematical explanation of how brains measure 'surprise' in a data stream—a theory that an NSF funded study will explore.
Information theorists Pierre Baldi of UC Irvine and Laurent Itti of the University of Southern California are joining with electro physiologist Douglas Muñoz of Queens University, Canada on the study.
"This is a very exciting project," said Kenneth Whang, program director at NSF's Computer and Information Science & Engineering (CISE) directorate. "The researchers have developed an elegant theory from first principles that has a lot of explanatory potential."
The computational theory of surprise was developed by Baldi in 1999 and first published in 2002 (see note for reference). The NSF award will allow the multi-organizational team to put the theory to test. Early laboratory experiments have shown the Bayesian model of surprise outperforms previous theories in predicting human responses to suddenly unusual stimuli.
"We believe this approach has potential for profoundly changing our current notions of how 'important' or 'surprising' information is understood," said Baldi, Professor of Computer Science and Director of the Institute for Genomics and Informatics (IGB) at UCI. IGB is known for fostering cross-disciplinary research at the intersection of the life and computational sciences.
Itti, an assistant professor of computer science at USC's Viterbi School of Engineering, notes that "rapid reaction to change is often a matter of life or death for animals. A faint rustle or puff of dust can signal the presence of food to seek, or a predator to flee. But what marks some changes as demanding attention?"
Baldi and Itti will present the outlines of their new mathematical understanding of surprise — along with their empirical studies on human subjects that support their theory — on Wednesday, December 7 at the Neural Information Processing Systems (NIPS) Conference in Vancouver, British Columbia.
The new NSF project combines forces of Baldi's computational and theory labs with the modeling and psychophysics lab of USC's Laurent Itti, and expands the research to include neurophysiological studies of brain mechanisms in Muñoz electrophysiology lab at Queen's University (Canada). Both experiments and modeling will be combined in the project to develop a new understanding of how the brain codes for novelty and importance.
"Our new model has implications not only for neuroscience, but for many fields, including information theory, psychology and engineering," said Muñoz, who has established worldwide leadership in the study of problems related to surprise using animal physiology and human psychophysics.
"This is exactly the kind of collaboration we were hoping to encourage," said Whang, who coordinates the Collaborative Research in Computational Neuroscience (CRCNS) program involving five NSF directorates and nine NIH institutes. Collectively, the CRCNS program has awarded over $70 million since its inception in 2002. The IGB project is jointly funded by NSF's Division of Information and Intelligent Systems and the Division of Behavioral and Cognitive Sciences.
Notes: The original reference on surprise theory can be found at: IGB News. P. Baldi. A Computational Theory of Surprise, in Information, Coding, and Mathematics. M. Blaum Editor, Kluwer, 1-25, (2002). A detailed account of the research supporting the Dec. 7 NIPS presentation can be found at:
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