Alan Stocker | University of Pennsylvania Department of Psychology

Assistant Professor

Department:

Psychology

Education:

Ph.D., Physics, ETH, Zurich, Switzerland

Address:

3401 Walnut St., Room 313C

Phone:

215-573-9341

Email:

astocker@sas.upenn.edu

Personal Page

Lab Page

Research Themes:

Behavioral Neuroscience

Cognitive Neuroscience

Sensation and Perception

Specific Research Areas:

Models of visual perception; linking theory to psychophysical and physiological data

Research Synopsis:

"Believing is seeing." - My research interest is to understand how our visual percept of the world is shaped by our beliefs and expectations about what there is to be perceived. More specifically, research in my laboratory is currently exploring (1) how the statistical properties of our visual environment shape our expectations (i.e. objective expectations), and (2) the degree by which our expectations reflect our own previous perceptual decisions (i.e. subjective expectations). How are these expectations formed? What are the computations by which they are combined with sensory information in order to generate our percepts? And what are the underlying neural processes that perform these computations?

We approach these questions with the combined effort of theory and experiment. Theory provides the hypotheses necessary to derive models that then can be validated with carefully targeted psychophysical and (through collaboration) physiological experiments. The theory of evolution motivates us to consider vision as an optimal inference problem. Using the framework of probability theory, our goal is to derive meaningful computational models that can quantitatively account for perceptual behavior of human subjects over a wide range of visual tasks.

Dr. Stocker will be accepting new graduate students for admission in fall 2012.

Representative Courses:

Psych 111, Perception

Psych 739, Probabilistic Models in Perception and Cognition

Appointments:

Psychology Graduate Group; Neuroscience Graduate Group; Bioengineering Graduate Group; Electrical and Systems Engineering (Secondary apppointment)

Advisees:

Matjaz Jogan [Post-doc]
Xuexin Wei [Psychology graduate student]

Representative Publications:

(click here for the full list)

Nicole C Rust and Alan A Stocker, Ambiguity and invariance: two fundamental challenges for visual processing, Current Opinion in Neurobiology, 20:3, June 2010, p. 382-388

James H Hedges, Alan A Stocker and Eero P Simoncelli, Optimal inference explains the perceptual coherence of visual motion stimuli, Journal of Vision, 11(6):14, May 2011, p. 1-16

Peggy Series, Alan A. Stocker, Eero P. Simoncelli (2009), Is the homunculus 'aware of sensory adaptation? Neural Computation, vol. 21, p. 3271-3304.

Alan A Stocker and Eero P Simoncelli (2009), Visual motion aftereffects arise from a cascade of two isomorphic adaptation mechanisms, Journal of Vision, vol. 9, no. 9, p. 1-14.

Alan A Stocker and Eero P Simoncelli (2008), A Bayesian Model of Conditioned Perception, NIPS Advances in Neural Information Processing Systems 20, Vancouver Canada, May, MIT Press, p. 1409-1416

Alan A Stocker and Eero P Simoncelli (2006), Noise characteristics and prior expectations in human visual speed perception, Nature Neuroscience, vol.9, no.4, April, p. 578-585

Alan A Stocker (2006), Analog Integrated 2D Optical Flow Sensor, Analog Integrated Circuits and Signal Processing, vol. 46, no. 2, January, p. 121-138

Alan A Stocker and Eero P Simoncelli (2006), Sensory Adaptation within a Bayesian Framework for Perception, NIPS Advances in Neural Information Processing Systems 18, Vancouver Canada, May, MIT Press, p. 1291-1298

Alan A Stocker (2004), Analog VLSI focal-plane array with dynamic connections for the estimation of piecewise-smooth optical flow, IEEE Transactions on Circuits and Systems-1; vol. 51, no. 5, May, p. 963-973

Alan A Stocker and Rodney J Douglas (2004), Analog Integrated 2-D Optical Flow Sensor with Programmable Pixels, ISCAS2004, Vancouver Canada, May, vol. 3, p. 9-12