京大心理学連合 21世紀COEプログラム Ｄチーム主催
ギャヴィン・ブレムナー教授講演会
演 題： Constraints on young Infants’perception
of object trajectories.
日 時： 2004年3月25日（木）16:00-17:30
場
所： 京都大学時計台記念館２階 国際交流ホール
https://www.kyoto-u.ac.jp/image-2002/kmap/map6r_y.htm
演者について：Professor Gavin Bremner (Lancaster University, England)
ブレムナー教授は、1949年スコットランド生まれ。1974年University
of St. Andrews卒、1977年University of Oxford大学院博士課程修了（D.Phil.）。Lancaster
University講師、助教授を経て、1997年教授。乳幼児の知覚・認知発達を研究。
代表的著作：
Bremner,
J.G. (1988) Infancy. Oxford: Blackwell.
Bremner, J.G. & Fogel, A.
(2001) Handbook of infant development. Oxford: Blackwell.
Slater,
A. & Bremner, J.G. (2003) Introduction to Developmental Psychology Oxford:
Blackwell.
講演要旨：
Central to our experience of
the perceptual environment are notions of object continuity, the understanding
that an object maintains its location or trajectory upon becoming occluded.
Infants have been claimed to possess such concepts innately, but such
accounts are based on violation-of-expectation methods, which have been
criticized for insufficient controls and the possibility that lower order
perceptual factors can explain the results.
Recently,
application of recovery-to-novelty methods to the issue of trajectory continuity
have yielded findings inconsistent with innate object concepts. Four-month-olds
were first habituated to a ball moving back and forth behind a box, such
that the central portion of the ball’s trajectory was occluded (Johnson,
Bremner, Slater, Mason, & Foster, 2003). After habituation, the
infants were presented with test displays in which the box was removed and
the ball shown on a complete trajectory, or a “broken” trajectory, with
a gap such that the ball seemed to disappear and then reappear on the other
side of the display. The infants exhibited a reliable posthabituation
preference for the complete trajectory, suggesting that they perceived the
occlusion display viewed during habituation as more similar to two discontinuous
trajectory segments than to a ball that moves on a continuous trajectory.
When 4-month-olds were habituated to a similar display with a narrow
occluder, however, this posthabituation preference pattern reversed, suggesting
that object continuity was perceived when spatiotemporal demands were eased.
Further research explored the conditions under which 4-month-olds
will perceive object continuity in occlusion displays, by manipulating spatiotemporal
characteristics of the stimuli. Given that previous work yielded positive
results when the screen was narrow, either time out of sight or distance
across which the object’s trajectory must be interpolated could be important
in determining whether infants perceive continuity. Thus, in the first
condition, infants were habituated to a wide screen display in which the
ball emerged immediately on the other side upon occlusion (the “fastball”
event). In the second condition, infants were habituated to a narrow
screen display and the ball emerged after a delay (the “slowball” event).
We reasoned that if time out of sight determines perception of object
continuity, independent of distance of interpolation, then positive results
(indicating perception of continuity) would be obtained in the first condition.
If, however, distance of interpolation determines perception of object
continuity, independent of time out of sight, then positive results would
be expected in the second condition. Interestingly, positive results
were obtained in both conditions, providing evidence that both these spatiotemporal
factors are important. Further work indicates the perception of trajectory
continuity is limited to the case of an object moving on a horizontal trajectory.
These results indicate that infants’ perception of object
continuity is closely tied to stimulus characteristics, and that concepts
of an object’s existence upon occlusion are fleeting and not robust. Such
findings provide strong evidence against innate object concepts, and are
consistent with the thesis that such concepts arise from perceptual experience
and emerging cognitive skills.