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Biomedical subjects

D Premack

Publications and source records attributed to D Premack.

At least 19 recordsLinked to original sources
PubMed1990

Words: what are they, and do animals have them?

Since the word is not a well-defined entity like the sentence, one looks for findings that may help to clarify it. The effect of nonsense words on the young child's sorting of taxonomic versus thematic alternatives is said to be such a finding. A young child given, say, duck as a sample, goose and nest as alternatives, picks nest (thematic alternative), whereas the older child picks goose (taxonomic). However, if told the duck is called "ZLT" in Croatian, and asked to "find another ZLT", the young child shifts to goose. Markman and Hutchinson (1984) claim this demonstrates that young children know that words are "names of object categories" (and that this knowledge protects them against false hypotheses, facilitating their acquisition of words). In the present study, we applied the Markman et al. procedure to young "language-trained" chimpanzees. The animals were at an early stage of training, having used "words" solely in the function "X goes with Y", or "if shown X, get Y". Although these functions are notably weaker than "X is the name of a category", the animals showed a thematic-taxonomic shift, thus behaving like young children. The Markman-Hutchinson interpretation of the shift effect is unsatisfactory in two respects: (1) the shift effect can be explained without attributing any knowledge of what a word is to either creature, child or ape; more important (2), the interpretation does not address the main question: what is a "name" and what does a child think it is? We conclude with a discussion of what a word is, appealing to information retrieval on the one hand, and intention to refer on the other.

Animal Communication↗
PubMed1990

The infant's theory of self-propelled objects.

"Theory of mind" is treated as a modular component of human social behavior and an attempt is made to find the origins of this component in the perception of the infant. According to the theory I describe here, the infant assigns a high priority to changes in motion and divides the world into two kinds of objects on the basis of this criterion: those that are and those that are not self-propelled. How the infant perceives these two kinds of objects is described by four basic assumptions. First, when the state of motion of a nonself-propelled object is changed by another object, the infant's principal hard-wired perception is causality; when a self-propelled object changes its motion without assistance from another object the infant's principal hard-wired perception is intention. Second, if two self-propelled objects are related in a special way--a relation called the BDR sequence--the infant perceives not only intentional movement but also one object as having the goal of affecting the other object. Third, the BDR sequence has a more powerful consequence: the infant perceives that the affected object intends to reciprocate. Fourth, the infant expects that reciprocation will preserve valence (not form), where valence is formulated either as the preservation/denial of liberty, or as an aesthetic response.

Concept Formation↗
PubMed1990

Infant chimpanzees spontaneously perceive both concrete and abstract same/different relations.

We used a familiarization-novelty procedure to determine whether 4 infant chimpanzees spontaneously perceive the sameness of and the difference between both concrete objects and relations between objects. In Experiment 1, a single object was presented on the Familiarization Trial 1 and the animal's looking time recorded. On the Test Trial 2, an object was presented that was either identical to or different from that shown on Trial 1. Looking times on Test Trial 2 were less when the same item had been presented on the preceding familiarization trial. Novel items on Trial 2 were attended to longer, indicating that the infant chimpanzees perceived concrete objects were either the same or different. In Experiment 2, a single pair of objects was presented on the Familiarization Trial 1, and handling time was measured. The objects in a pair were either the same or different (e.g., AA vs. CD). On the Test Trial 2, a new object pair (e.g., BB vs. EF) was presented that instantiated either the relation shown on Trial 1 or the alternative relation. Handling time on Trial 2 was influenced by the relation instantiated on Trial 1. Handling times on Test Trial 2 were less when the identical relation had been presented on the preceding familiarization trial. Novel relations on Trial 2 were attended to relatively longer. This result indicates that infant chimpanzees perceive similarities and differences between abstract relations as well as between concrete objects. That is to say, they perceived relations between relations in Experiment 2. Despite this ability to perceive both concrete and abstract "same/different" relations, the same chimpanzees subsequently failed to use the latter knowledge in a matching-to-sample task in Experiment 3. Although they successfully matched single objects, they were unable to match object pairs instantiating the same relation (e.g., if AA then match BB; if CD then match EF). These results contradict claims that failure to learn an instrumental discrimination involving abstract relations reflects an inability to detect such relations. In every species there may be a disparity between the ability to perceive spontaneously a property of the world and the ability to use the concept instrumentally.

Aging↗
PubMed1989

The perception of intention.

Classical work on the perception of causality in humans is extended to the perception of intention. Two experiments explored the sensitivity of preschool children to intentional events that can be stated in terms of time and distance only. In habituation-dishabituation of attention tests, preschool children differentiated between intentional movement patterns of two balls and the nonintentional control events where the movements were desynchronized. Also, reversal of the roles of the balls produced more recovery of attention in the intentional case than it did in the nonintentional case.

Child, Preschool↗
PubMed1988

Spontaneous transfer of matching by infant chimpanzees (Pan troglodytes).

Four infant chimpanzees learned a matching-to-sample task when only two training stimuli were used. They then spontaneously transferred the matching concept to novel items, including three-dimensional objects and fabric swatches, without any experimenter-provided differential feedback. These results support the view that the matching concept is broadly construed by chimpanzees from the beginning and does not depend upon explicit training.

Animals↗
PubMed1978

Chimpanzee problem-solving: a test for comprehension.

An adult chimpanzee was shown videotaped scenes of a human actor struggling with one of eight problems and was then shown two photographs, one of which depicted an action or an object (or both) that could constitute a solution to the problem. On seven of the eight problems, the animal consistently chose the correct photograph. This test problem-solving comprehension permits the animal's knowledge about problem-solving--its ability to infer the nature of problems and to recognize potential solutions to them--to be examined.

Animals↗
PubMed1978

Map reading by chimpanzees.

Infant chimpanzees, after watching a small black-and-white closed-circuit television picture of a familiar caretaker walking out into an outdoor field and disappearing from sight, were more successful in finding the person than if they had been given no such cue; and their performance approximated that which obtained after they had seen the same scene normally, via direct perception.

Animals↗
PubMed1969

Positive contrast in the runway obtained with delay of reward.

The failure to find positive contrast effects in the runway may be attributed to a ceiling effect that can be overcome with the use of delay of reward. Rats were trained one trial a day in a runway with small, medium, or large reward. When a shift to large reward was combined with delay of reward, shift groups slowed down less than controls.

Analysis of Variance↗
PubMedDate not supplied

Levels of causal understanding in chimpanzees and children.

We compare three levels of causal understanding in chimpanzees and children: (1) causal reasoning, (2) labelling the components (actor, object, and instrument) of a causal sequence, and (3) choosing the correct alternative for an incomplete representation of a causal sequence. We present two tests of causal reasoning, the first requiring chimpanzees to read and use as evidence the emotional state of a conspecific. Despite registering the emotion, they failed to use it as evidence. The second test, comparing children and chimpanzees, required them to infer the location of food eaten by a trainer. Children and, to a lesser extent, chimpanzees succeeded. When given information showing the inference to be unsound--physically impossible--4-year-old children abandoned the inference but younger children and chimpanzees did not. Children and chimpanzees are both capable of labelling causal sequences and completing incomplete representations of them. The chimpanzee Sarah labelled the components of a causal sequence, and completed incomplete representations of actions involving multiple transformations. We conclude the article with a general discussion of the concept of cause, suggesting that the concept evolved far earlier in the psychological domain than in the physical.

Animals↗