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The emergence of an ontological distinction in infancy
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DISTINCTIONIN INFANCY TBEEXER(ZI’KEOFAN ONTOLOGICAL Rosemary Rosser, Rebecca Hill Dept. of Educational Psychology, The University of Arizona, Tucson AZ 85721; Dana Narter, Southern Illinois University Understanding the physical world depends on knowing about the objects in it. From infancy humans construe the world as comprised of entities which take up space, occupy location and move about in rule-governed ways. Infants act as if they expect objects to trace continuous paths and to do so in accord with the rule that: One object cannot be in two places nor two objects one place at the same time. This presumes that an object is identified as a individual and its identity tracked over space and time, but this is where infants might experience difficulty. Individual identity is signaled by property nfonnation, and infants may have a limited capacity to use such information Were an infant unable to use featural information to 1o mark individuality. decide whether an entity was the same individual as one previously encountered, then the infant is forced to fall back on spatio-temporal information to make the determination. That leaves the infant with two default assungtions about a target’s identity. If the target object is located in the same place as one previously encountered, then it is probably the same object; then it is probably a new or, if the target object appears at a new location, object. Default assumptions could be overridden by featural information. In our studies, we violated those assurrptions by varying the properties of objects involved in an occlusion task to see if 7-month olds could detect those violations. Spatio-temporal information could help infants come to make categorical distinction among entities. All individuated items in the ontological category PHYSICALENTITIES are governed by spatio-temporal principles in the same way Specifically, all physical entities follow a single path through space, a core principleaccessible to the youngest of babies. Elements making up items within the ontological category PHYSICALAGCREGATE do not (imagine dropping a handful of sticks). Some featural properties distinguish items within an ontological category, eg . , color. Other properties distinguish items between categories, eg., the VVpiecenesstt appearance of an aggregate versus the %nitness” of an object. Perhaps infants are differentially sensitive to feature information, using that which denotes ontological boundaries while appearing insensitive to that which does not. When an object is hidden at one location and retrieved from another, infants exhibit surprise. With one individual, identity is a constant and spatio-temporal information is the only relevant variable; with r&tiple individuals, identity can vary as well. In our task the infant sees a stage displaying two locations, A and B. An object--TOY LION--is placed at A; the locations are occluded; an object is retrieved either from A or B. The retrieved object can be either (1) the sam? one--TOY LION, (2) one from another ontological category, an aggregate--TOY FRENCH FRIES. or (3) another individual from the same category--TOY -HART. All infants observed the lion hidden and retrieved at A; then infants observed 1 of 5 alternative retrieval events (LION at B; ELEPHANT at A or B; FRENCH FRIES at A or B). Type of occlusion varied across the two studies. In both, analysis of cumulative looking time was a&iguous, but analysis of first-look data revealed that infants treated the LION and EtEpHANTas equivalent but differentiated them from the FRENCH FRIES. These data suggest a very early sensitivity to distinctions on the basis of ontological kind: A differentiation of individual entities and aggregates.
DISTINCTIONIN INFANCY TBEEXER(ZI’KEOFAN ONTOLOGICAL Rosemary Rosser, Rebecca Hill Dept. of Educational Psychology, The University of Arizona, Tucson AZ 85721; Dana Narter, Southern Illinois University Understanding the physical world depends on knowing about the objects in it. From infancy humans construe the world as comprised of entities which take up space, occupy location and move about in rule-governed ways. Infants act as if they expect objects to trace continuous paths and to do so in accord with the rule that: One object cannot be in two places nor two objects one place at the same time. This presumes that an object is identified as a individual and its identity tracked over space and time, but this is where infants might experience difficulty. Individual identity is signaled by property nfonnation, and infants may have a limited capacity to use such information Were an infant unable to use featural information to 1o mark individuality. decide whether an entity was the same individual as one previously encountered, then the infant is forced to fall back on spatio-temporal information to make the determination. That leaves the infant with two default assungtions about a target’s identity. If the target object is located in the same place as one previously encountered, then it is probably the same object; then it is probably a new or, if the target object appears at a new location, object. Default assumptions could be overridden by featural information. In our studies, we violated those assurrptions by varying the properties of objects involved in an occlusion task to see if 7-month olds could detect those violations. Spatio-temporal information could help infants come to make categorical distinction among entities. All individuated items in the ontological category PHYSICALENTITIES are governed by spatio-temporal principles in the same way Specifically, all physical entities follow a single path through space, a core principleaccessible to the youngest of babies. Elements making up items within the ontological category PHYSICALAGCREGATE do not (imagine dropping a handful of sticks). Some featural properties distinguish items within an ontological category, eg . , color. Other properties distinguish items between categories, eg., the VVpiecenesstt appearance of an aggregate versus the %nitness” of an object. Perhaps infants are differentially sensitive to feature information, using that which denotes ontological boundaries while appearing insensitive to that which does not. When an object is hidden at one location and retrieved from another, infants exhibit surprise. With one individual, identity is a constant and spatio-temporal information is the only relevant variable; with r&tiple individuals, identity can vary as well. In our task the infant sees a stage displaying two locations, A and B. An object--TOY LION--is placed at A; the locations are occluded; an object is retrieved either from A or B. The retrieved object can be either (1) the sam? one--TOY LION, (2) one from another ontological category, an aggregate--TOY FRENCH FRIES. or (3) another individual from the same category--TOY -HART. All infants observed the lion hidden and retrieved at A; then infants observed 1 of 5 alternative retrieval events (LION at B; ELEPHANT at A or B; FRENCH FRIES at A or B). Type of occlusion varied across the two studies. In both, analysis of cumulative looking time was a&iguous, but analysis of first-look data revealed that infants treated the LION and EtEpHANTas equivalent but differentiated them from the FRENCH FRIES. These data suggest a very early sensitivity to distinctions on the basis of ontological kind: A differentiation of individual entities and aggregates.