REMINDER:
The CEU Department of Cognitive Science cordially invites you to its talk
as part of the Departmental Colloquium series
by
David
Burr<http://www.pisavisionlab.org/index.php/people/faculty/burr> Department of
Neuroscience, University of Florence, Italy
Date: Wednesday, October 26, 2016 - 17:00-18:30
Host: Jozsef Fiser
Positive and negative serial-dependencies in face perception
Perception is driven not only by the stimuli currently impinging on our senses, but also
depends on the immediate past history. I will talk about these serial dependencies,
showing how they are the product of efficient mechanisms exploiting temporal redundancies
in natural scenes, and may be critical for understanding perception. Serial dependencies
can be negative - such as visual aftereffects - where viewing motion in one direction
causes stationary stimuli to appear to move in the other; or they can be positive - such
as "priming" - where viewing a stimulus distorts subsequent stimuli in the same
direction. Many factors influence whether the dependencies are positive or negative,
including the strength and salience of the priming stimulus. However, if the serial
dependencies reflect efficient processing, they should also depend on the attribute being
tested. Negative aftereffects optimize sensitivity to change, while positive serial
dependencies integrate successive image views, improving signal-to-noise ratios. On this
logic, positive dependencies should occur for stable attributes - such as identity and
gender - and negative dependencies for changeable attributes - such as expression. Indeed,
when we asked subjects to judge both the expression and gender of a sequence of faces, we
found strong and consistent positive serial dependencies for gender, but negative serial
dependency for expression. These results show that both positive and negative serial
dependencies can operate at the same time, on the same stimuli, depending on the attribute
being judged, pointing to very flexible and sophisticated optimization of past
information. The results were well modelled by a Kalman filter type model, showing that
the strategies led to improvement in efficiencies.
Location: Department of Cognitive Science, CEU, Oktober 6 street 7, room 101.
https://cognitivescience.ceu.edu/events/2016-10-26/departmental-colloquium-…
We are looking forward to see you there!
Cognitive Science Events at CEU:
http://cognitivescience.ceu.edu/events
Györgyné Finta (Réka)
Department Coordinator
~~~~~~~~~~~~~~~~~~~~~~~~
Central European University
Department of Cognitive Science
H-1051 Budapest
Oktober 6 utca 7.
tel: (36-1) 887-5138
fax: (36-1) 887-5010
http://www.ceu.edu
http://cognitivescience.ceu.edu
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