|
Fall 2005
| |
09/29 |
Peter Tse
(Dartmouth College)
The role of contour discontinuities in form-based motion processing [more...]
| |
10/06 |
Gennaro
Chierchia (University of Milan-Bicocca/Visiting)
On the logicality of language [more...]
| |
10/13 |
Elizabeth Chua (Harvard
Psychology)
Neural underpinnings of 'knowing you
know' [more...]
| |
10/20 |
Olivia
Carter (Harvard Psychology post-doc)
The malleability of consciousness: Exploring the affects of
hallucinogenic drugs and meditation on visual perception [more...]
| |
10/27 |
Dave Sobel (Brown
University/Visiting)
Babies, blickets, and Bayesian inference: What's developing in
children's causal reasoning [more...]
| |
11/03 |
Laurie Santos
(Yale University/Visiting)
Evolution of Theory of Mind [more...]
| |
11/10 |
Alec Marantz
(MIT)
Using Evoked Magnetoencephalographic
Responses for the Cognitive
Neuroscience of Language [more...]
| |
11/17 |
Steven Sloman (Brown
University)
Causal reasoning and decision making: Intervention and signaling [more...]
| |
11/24 |
Thanksgiving Day
| |
12/01 |
Laura Gibson (Harvard
Psychology)
Person perception and impression formation of point-light walkers [more...]
| |
12/08 |
Mark
Williams (MIT)
The role of attention in the perception of facial affect: evidence from
neuropsychology and functional brain imaging [more...]
| |
12/15 |
Edwin Robertson
(Beth Israel Medical Center)
Learning off-line: converging biological and
psychological observations [more...]
|
|
Thursdays at 12:00-1:30pm
William James Hall 765
Interested parties from outside the
Harvard community are welcome to attend.
E-mail Laura to subscribe
to weekly e-mail reminders
Links:
Past speakers
Social Lunch
Social and Affective Neuroscience Series
Psychology Department
Questions?
Contact:
Laura Gibson
(gibson@wjh)
|
Peter Tse
The role of contour discontinuities in form-based motion processing
Discontinuities in the contour-curvature of an object are vital cues for
the
analysis of form and motion. Using fMRI, we localized the neural
correlates of
contour-curvature discontinuities as cues for the processing and
perception of
rotational motion. We found the blood oxygen level dependent (BOLD)
signal in
retinotopic area V3A/B varied parametrically with the degree of
curvature-discontinuity. Control experiments ruled out the possibility
that
these modulations resulted from changes in the area of the stimuli,
perceived
3D shape, the velocity with which contour elements were translating, and
perceived angular velocity. A further control demonstrated that the BOLD
signal in this area does not modulate when the stimuli are set in repeated
translational apparent motion. We conclude that neurons within V3A/B,
process
continuously moving contour curvature as a trackable feature, and these
form-based features are used to determine the speed and direction of
motion.
Implications for our understanding of low- and high-level motion
processing
will be discussed.
|
|
|
Gennaro Chierchia
On the logicality of language
Is logic a cultural artifact? or is it a natural skill? One way to address this question is by looking at how logic
and language are related. Here is how our initial question might be rephrased from this point of view. Is logic an artificial
set of norms "distilled" from language? Or is it a set of laws of thought spontaneously operative in, e.g., semantic
interpretation? Prima facie, our logical capacities appear to be quite faulty, if compared to the standards of, say, classical
logic. In fact, Chomsky himself seems to sharply distinguish between our capacity for constructing complex recursive
structures (constitutive of Universal Grammar) and our capacity to grasp entailment patterns: he often compares the latter to
our ability to catch rhyming sounds (a widespread but inessential property of sound patterns). I'll discuss evidence that
seems to show that logic is an essential component of grammar (and hence, arguably, part of our biological endowment)
|
|
|
Elizabeth Chua
Neural underpinnings of 'knowing you know'
How do we know that we know? Characterization of the neural mechanisms
underlying 'knowing you know' requires examination of memory monitoring
processes as well as the signal for the subjective sense of remembering.
I will present fMRI data from studies on confidence assessment and the
feeling-of-knowing for face-name associations that suggest specific brain
regions are related to the different aspects of 'knowing you know'.
|
|
|
Olivia Carter
The malleability of consciousness: Exploring the affects of
hallucinogenic drugs and meditation on visual perception
The occurrence of any given conscious state depends on many factors,
this talk will consider the role of two - neuropharmacology and
behavior. Results will be discussed from one study involving the
administration of psilocybin (the active compound in 'magic mushrooms')
to a group of healthy human volunteers and a second study looking at the
affects of meditation in a population of Tibetan Buddhist monks. The
main variable of interest in both studies is the timing of visual
fluctuations characteristic of binocular rivalry. However, the findings
will also be considered in respect to their broader implications for
mental health and the more general roles that pharmacology and behavior
can have in 'altering' an individual's perceptual state.
|
|
|
Dave Sobel
Babies, blickets, and Bayesian inference: What's developing in
children's causal reasoning
In this talk, I will present a theory of children's causal
reasoning, based on Bayesian inference. I will first present evidence
that 4-year-olds possess such an inferential system, and data that suggest
3-year-olds do not. I will then evaluate this developmental data to show
that certain pieces of substantive information develop between ages 3 and
4, and when this knowledge is provided to 3-year-olds, their inferences
are similar to older children (and adults). I will then present
speculative data suggesting that even infants may have such a reasoning
system at their disposal.
|
|
|
Laurie Santos
Evolution of theory of mind
|
|
|
Alec Marantz
Using Evoked Magnetoencephalographic Responses for the Cognitive
Neuroscience of Language
The talk will introduce MEG as a tool for cognitive neuroscience, with
some recent examples of how MEG provides additional "reaction times" in
experiments, over and above behavioral measures. In fact, stimulus
manipulations may speed up brain responses at the same time as they slow
down behavioral reaction times, as expected by cognitive models that
postulate stages in, e.g., linguistic computation. I will demonstrate
the feasibility of using single trials, rather than averages by
conditions or by subjects, in statistical analysis of MEG data, allowing
one truly to treat MEG brain responses on par with behavioral reaction
times.
|
|
|
Steve Sloman
Causal reasoning and decision making: Intervention and signaling
A framework for reasoning about causality has been developed by
Spirtes, Glymour, and Scheines (1993) and is reviewed in Pearl (2000).
The fundamental idea is that people represent the world by decomposing
it into autonomous causal mechanisms that support interventions. On
this view, human reasoning is a tool to support human action. I report
studies showing that people are highly sensitive to the logic of
intervention when reasoning counterfactually and when making
decisions. The application of the ideas to decision making reveals
that good decisions depend on causal analysis and that preferential
choice is a form of intervention. However, not all choices are made for
the sake of their perceived consequences; some are made based on their
value as signals. I'll discuss what this entails for the logic of
intervention.
|
|
|
Laura Gibson
Person perception and impression formation of point-light walkers
I am interested in understanding the way we perceive humans in light of
the limitations of the real world. I focus on person perception available
from motion, so that we will have a good idea of which cues are being used
in our studies to form impressions and perceptions. One line of research
concerns the limitations the environment places on person perception,
specifically where a walker is in relation to your gaze. The other
concerns the limitations of social cues provided through motion
information, specifically the consistency with which first impressions of
confidence are formed across perceivers.
|
|
|
Mark Williams
The role of attention in the perception of facial affect: evidence from
neuropsychology and functional brain imaging
|
|
|
Edwin Robertson
Learning off-line: converging biological and psychological observations.
We spend a large proportion of our lives learning skills, but not all skill is
acquired during practice. Skill can also develop off-line during a period of
consolidation. I shall describe recent work showing that a critical factor in
determining when such improvements develop can be an individual’s awareness of
learning. Following explicit learning, improvements only develop over a night of
sleep; whereas, following implicit learning improvements develop over both wake and
sleep. The magnitudes of these later time-dependent improvements are similar. However,
I will show, that the nature of these improvements differs (i.e. the improvements over
sleep and wake are expressed in distinct co-ordinate frames), and that distinct brain
areas are responsible for supporting off-line learning over wake and sleep.
|
|
|
|
|
|
