Infant behavior during impossible events without occlusion
1
619 INFANT BEHAVIOR DURING IMPOSSIBLE EVENTS WITHOUT OCCLUSION Eric Peterson and Bruce Hood Department of Psychology, Harvard University, Cambridge, MA 02138 Extensive research using the visual dishabituation paradigm has demonstrated that infants discriminate sequences of object events which violate principles of physics. The present study is part of an investigation of infant object knowledge focusing on a single paradigm developed by Baillargeon (1986). We provide further insight into the knowledge that drives longer looking times during impossible events by observing infant behavior during different versions of a single paradigm. In the original Baillargeon paradigm, infants saw an object placed on a track (impossible event) or behind a track (possible event), before a screen was lowered. Then the infant watched a car roll along the track, pass behind the screen, and reemerge before disappearing from view. Six and eight month old infants looked longer to the impossible event. We replicated and extended the Baillargeon finding in a modified version of the original paradigm. In this experiment (experiment I), infants observed a similar display except that the car stopped at the end of the track and the full outcome position of block and car was revealed. We reasoned that if a violation of expectancy generated uncertainty infants identified the specific agents involved they may look back and forth between the block and the car more after the impossible event. As predicted, we found an increase in the amount of scanning between the relevant objects during the impossible events by six month old infants. This behavior suggested a richer analysis of object events than increased looking time alone. In the present study younger infants observed the same event except that a trick block is used in order to present the events without occlusion. Eliminating the screen reduces the memorial and attentional demands and isolates the violation of solidity from other aspects of object knowledge. In a simplified task, infants may demonstrate knowledge of solidity by scanning at a younger age (in experiment 1, scanning was observed in six month olds but not in five month olds.) Also, the evidence of scanning may be stronger in this version due to the elimination of any distraction created by use of an occluder. Most important, in experiment 1 meaningful infant behavior could only be observed when the outcome event was revealed approximately three seconds after the instant of the impossible event. The present experiment allows measurement of the immediate behavioral responses that may precede scanning such as facial expression and immediate fixation to the block. Infants between five and six months of age were tested in this experiment. Results at each age were compared to the previous results obtained in experiment 1. Facial expression starting at the instant the car passes through the block was examined by slow motion video analysis. A number of manipulations of the sequence were tested in order to investigate the role of perceptual features in this object event. The findings are discussed in relation to alternative interpretations of naive knowledge.
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Transcript of Infant behavior during impossible events without occlusion
619
INFANT BEHAVIOR DURING IMPOSSIBLE EVENTS WITHOUT OCCLUSION
Eric Peterson and Bruce Hood
Department of Psychology, Harvard University, Cambridge, MA 02138
Extensive research using the visual dishabituation paradigm has demonstrated that infants discriminate sequences of object events which violate principles of physics. The present study is part of an investigation of infant object knowledge focusing on a single paradigm developed by Baillargeon (1986). We provide further insight into the knowledge that drives longer looking times during impossible events by observing infant behavior during different versions of a single paradigm.
In the original Baillargeon paradigm, infants saw an object placed on a track (impossible event) or behind a track (possible event), before a screen was lowered. Then the infant watched a car roll along the track, pass behind the screen, and reemerge before disappearing from view. Six and eight month old infants looked longer to the impossible event. We replicated and extended the Baillargeon finding in a modified version of the original paradigm. In this experiment (experiment I), infants observed a similar display except that the car stopped at the end of the track and the full outcome position of block and car was revealed. We reasoned that if a violation of expectancy generated uncertainty infants identified the specific agents involved they may look back and forth between the block and the car more after the impossible event. As predicted, we found an increase in the amount of scanning between the relevant objects during the impossible events by six month old infants. This behavior suggested a richer analysis of object events than increased looking time alone.
In the present study younger infants observed the same event except that a trick block is used in order to present the events without occlusion. Eliminating the screen reduces the memorial and attentional demands and isolates the violation of solidity from other aspects of object knowledge. In a simplified task, infants may demonstrate knowledge of solidity by scanning at a younger age (in experiment 1, scanning was observed in six month olds but not in five month olds.) Also, the evidence of scanning may be stronger in this version due to the elimination of any distraction created by use of an occluder. Most important, in experiment 1 meaningful infant behavior could only be observed when the outcome event was revealed approximately three seconds after the instant of the impossible event. The present experiment allows measurement of the immediate behavioral responses that may precede scanning such as facial expression and immediate fixation to the block.
Infants between five and six months of age were tested in this experiment. Results at each age were compared to the previous results obtained in experiment 1. Facial expression starting at the instant the car passes through the block was examined by slow motion video analysis. A number of manipulations of the sequence were tested in order to investigate the role of perceptual features in this object event. The findings are discussed in relation to alternative interpretations of naive knowledge.
