The lab The colony consists up
to 14 cotton-top tamarins housed in mated pairs in two different colony
rooms (the Seinfeld room and the Simpsons room).
The research Currently, there
are three main research topics under investigation in the lab.
Comparative Language Research
One of the longstanding debates in the study of language has been whether
acquisition requires specialized mechanisms or whether it is supported
solely by generalized auditory mechanisms. In efforts to resolve this
issue, over the course of the last 25 years many researchers have used
a comparative approach, comparing the performance of nonhumans and humans
on a variety of speech perception tasks that are fundamental to language
development. Recently, in efforts to provide a more transparent comparison
with human data, a series of experiments have utilized methods that do
not reward performance and do not involve any explicit training. These
experiments have focused on different aspects of speech perception, such
as perceiving rhythmicity (Ramus et al., 2000, Tincoff, 2004), rule learning
(Hauser, Weiss, and Marcus, 2002), and word segmentation (Hauser, Newport,
and Aslin, 2001). The results from these studies, conducted with cotton-top
tamarins (a small New World monkey), suggest that there are many similarities
in the way that humans and nonhumans perceive speech and the types of
computations they are able to perform. However, there have also been a
number of studies that have reported differences in the abilities of humans
and Cotton-tops (e.g., Fitch and Hauser, 2004, Newport et al., 2004).
One of the primary research goals for the CCL is to compare the abilities
of humans and nonhumans on a variety of tasks that tap the mechanisms
underlying language acquisition (note, all studies conducted at the CCL
are behavioral and completely non-invasive). Specifically, we are interested
in more finely delineating the types of computational abilities and computational
primitives that are used by each species, and then investigating how these
mechanisms may have been shaped by natural selection for use in acquiring
language.
Our upcoming studies include phonetic discrimination and generalization,
vowel preferences, grammatical learning, and further tests of statistical
learning in word segmentation.
Comparative Motor Research
This is a relatively new area of investigation undertaken originally in
collaboration with David Rosenbaum (see the Cognitive Area homepage to
read more about David's work). Over the course of the last six months
we have begun investigating motor planning, specifically focusing on the
"end-state comfort effect". Our study has shown that, like humans,
tamarins can accommodate future positions or postures by altering their
initial movements. This finding opens up many exciting avenues for future
research. In addition, starting in the Fall semester of 2006, we will
be investigating how tamarins locomote in their environment and the degree
to which they have an underlying knowledge about the physical principles
related to natural maneuvering in their surroundings.
Comparative Communications Research
A third program of research involves studying conspecific vocal communication.
One direction for this research will be to better understand vocal learning.
While one of the fundamental differences between humans and primates vocal
systems relates to the stages of acquisition (humans go through elaborate
stages in order to acquire language, yet other primates seem to be born
with their vocal repertoire), recent research has shown that as adults
primates are quite capable of some types of vocal learning. We hope to
explore the issue of vocal learning, including the underlying mechanisms
(e.g., template matching or probabilistic learning).
One present study that is ongoing in the lab aims at investigating the
degree to which conspecific vocalizations are lateralized to one hemisphere.
Converting a technique employed by Hauser & Andersson (1994) in the
field, we are using a headturn playback paradigm in the lab, presenting
many types sounds (conspecific calls, heterospecific calls, and environmental
noise) to gauge asymmetries in head turn behavior.
In addition to the aforementioned lines of research, in the future we
may explore a select number of topics pertaining to cognition, such as
theory of mind, rule learning, and intentional communication. Stay tuned….
Relevant Publications
Weiss D.J., Kralik, J.D., & Hauser, M.D. (2001). Face processing
in cotton-top tamarins (Saguinus oedipus). Animal Cognition, 3,(4)191-205.
Weiss, D.J., Garibaldi, B. T., & Hauser, M. D. (2001). The production
and perception of long calls by cotton-top tamarins (Saguinus oedipus):
Acoustic analyses and playback experiments. Journal of Comparative
Psychology, 15(3), 258-271.
Hauser, M.D., Weiss, D.J. & Marcus, G. (2002) Rule learning by cotton-top
tamarins. Cognition, 86, B15-B22.
Miller C., Weiss, D.J. & Hauser, M.D. (2002) Mechanisms of acoustic
classification in primates. A. Ghazanfar (Ed.), Primate Audition:
Ethology and Neurobiology. CRC Press. 43-61.
Weiss, D.J., Ghazanfar, A.A., Miller, C.T., & Hauser, M.D. (2002).
Specialized processing of primate facial and vocal expressions: Evidence
for cerebral asymmetries. L. Rogers and R. Andrew (Eds.), Comparative
Vertebrate Laterality. 480-531.
Weiss, D.J. & Hauser, M.D. (2002) Perception of harmonics in the combination
long call of cotton-top tamarins (Saguinus oedipus) Animal Behaviour
64, 415-426.
Jordan, K., Weiss, D., Hauser, M., & McMurray, B. (2004) Individual
recognition and antiphonal responses to loud contact calls produced by
cotton-top tamarins (Saguinus oedipus). International Journal of Primatology
25(2), 465-475.
Weiss, D.J. & Newport E. (2006) Mechanisms Underlying Language Acquisition:
Benefits From a Comparative Approach. Infancy 9(2), 241-257.
Weiss, D.J. & Santos, L. (2006) Introduction to Thematic Collection:
Why Primates?: The Importance of Non-Human Primates for Understanding
Human Infancy. Infancy 9(2), 133-146.
Weiss, D.J., Rosenbaum, D., & Wark, J. (in prep) Motor planning in
a nonhuman primate species: A demonstration of the "end-state comfort
effect" in nonhuman primates
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