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Michael Tomasello

Publications and source records attributed to Michael Tomasello.

14 recordsLinked to original sources
PubMed2003

Gestural communication in young gorillas (Gorilla gorilla): gestural repertoire, learning, and use.

In the present study we investigated the gestural communication of gorillas (Gorilla gorilla). The subjects were 13 gorillas (1-6 years old) living in two different groups in captivity. Our goal was to compile the gestural repertoire of subadult gorillas, with a special focus on processes of social cognition, including attention to individual and developmental variability, group variability, and flexibility of use. Thirty-three different gestures (six auditory, 11 tactile, and 16 visual gestures) were recorded. We found idiosyncratic gestures, individual differences, and similar degrees of concordance between and within groups, as well as some group-specific gestures. These results provide evidence that ontogenetic ritualization is the main learning process involved, but some form of social learning may also be responsible for the acquisition of special gestures. The present study establishes that gorillas have a multifaceted gestural repertoire, characterized by a great deal of flexibility with accommodations to various communicative circumstances, including the attentional state of the recipient. The possibility of assigning Seyfarth and Cheney's [1997] model for nonhuman primate vocal development to the development of nonhuman primate gestural communication is discussed.

Aging↗
PubMed2003

Chimpanzees understand psychological states - the question is which ones and to what extent.

New data suggest that relatively drastic revisions are needed in our theoretical accounts of what other animal species understand about the psychological states of others. Specifically, chimpanzees seem to understand some things about what others do and do not see, or have and have not seen in the immediate past, as well as some things about others' goal-directed activities. This is especially so in competitive situations. They clearly do not have a human-like theory of mind, however, and so the challenge is to specify precisely how ape and human social cognition are similar and different.

Journal Article↗
PubMed2003

Understanding attention: 12- and 18-month-olds know what is new for other persons.

Infants at 12 and 18 months of age played with 2 adults and 2 new toys. For a 3rd toy, however, 1 of the adults left the room while the child and the other adult played with it. This adult then returned, looked at all 3 toys aligned on a tray, showed great excitement ("Wow! Cool!"), and then asked, "Can you give it to me?' To retrieve the toy the adult wanted, infants had to (a) know that people attend to and get excited about new things and (b) identify what was new for the adult even though it was not new for them. Infants at both ages did this successfully, lending support to the hypothesis that 1-year-old infants possess a genuine understanding of other persons as intentional and attentional agents.

Adult↗
PubMed2003

The role of the input in the acquisition of third person singular verbs in English.

During the early stages of language acquisition, children pass through a stage of development when they produce both finite and nonfinite verb forms in finite contexts (e.g., "it go there," "it goes there"). Theorists who assume that children operate with an abstract understanding of tense and agreement marking from the beginnings of language use tend to explain this phenomenon in terms of either performance limitations in production (e.g., V. Valian, 1991) or the optional use of finite forms in finite contexts due to a lack of knowledge that tense and agreement marking is obligatory (the optional infinitive hypothesis; K. Wexler, 1994, 1996). An alternative explanation, however, is that children's use of nonfinite forms is based on the presence of questions in the input ("Where does it go?") where the grammatical subject is immediately followed by a nonfinite verb form. To compare these explanations, 2 groups of 24 children aged between 2 years 6 months and 3 years were exposed to 6 known and 3 novel verbs produced in either declaratives or questions or in both declaratives and questions. The children were then questioned to elicit use of the verbs in either finite or nonfinite contexts. The results show that for novel verbs, the children's patterns of verb use were closely related to the patterns of verb use modeled in the language to which they were exposed. For known verbs, there were no differences in the children's use of individual verbs, regardless of the specific patterns of verb use modeled in the language they heard. The implications of these findings for theories of early verb use are discussed.

Child Language↗
PubMed2003

Early syntactic creativity: a usage-based approach.

The aim of the current study was to determine the degree to which a sample of one child's creative utterances related to utterances that the child previously produced. The utterances to be accounted for were all of the intelligible, multi-word utterances produced by the child in a single hour of interaction with her mother early in her third year of life (at age 2;1.11). We used a high-density database consisting of 5 hours of recordings per week together with a maternal diary for the previous 6 weeks. Of the 295 multi-word utterances on tape, 37% were 'novel' in the sense that they had not been said in their entirety before. Using a morpheme-matching method, we identified the way(s) in which each novel utterance differed from its closest match in the preceding corpus. In 74% of the cases we required only one operation to match the previous utterance and the great majority of these consisted of the substitution of a word (usually a noun) into a previous utterance or schema. Almost all the other single-operation utterances involved adding a word onto the beginning or end of a previous utterance. 26% of the novel, multi-word utterances required more than one operation to match the closest previous utterance, although many of these only involved a combination of the two operations seen for the single-operation utterances. Some others were, however, more complex to match. The results suggest that the relatively high degree of creativity in early English child language could be at least partially based upon entrenched schemas and a small number of simple operations to modify them. We discuss the implications of these results for the interplay in language production between strings registered in memory and categorial knowledge.

Child↗
PubMed2002

The domestication of social cognition in dogs.

Dogs are more skillful than great apes at a number of tasks in which they must read human communicative signals indicating the location of hidden food. In this study, we found that wolves who were raised by humans do not show these same skills, whereas domestic dog puppies only a few weeks old, even those that have had little human contact, do show these skills. These findings suggest that during the process of domestication, dogs have been selected for a set of social-cognitive abilities that enable them to communicate with humans in unique ways.

Animals↗
PubMed2002

German children's productivity with tense morphology: the Perfekt (present perfect).

Two nonce-word studies examined German-speaking children's productivity with the Perfekt (present perfect) from 2;6 to 3;6. The German Perfekt consists of the past participle of the main verb and an inflected form of an auxiliary (either haben 'have' or sein 'be'). In Study 1, nonce verbs were either introduced in the infinitival form, and children (seventy-two children, aged 2;6 to 3;6) were tested on their ability to produce the Perfekt, or introduced in the Perfekt, and children were tested on their ability to produce the infinitive. In Study 2 twenty-four children aged 3;6 were given the past participle form of nonce verbs to see if they could supply the appropriate auxiliary (based mainly on verb semantics). The results were that many children as young as 2;6 used past participles productively (more than used infinitival forms productively), but all children had much difficulty in supplying both auxiliaries appropriately. The current findings suggest that mastery of the Perfekt construction as a whole does not take place before the age of four and that frequency of exposure is an important factor in determining the age at which children acquire grammatical constructions.

Child Language↗
PubMed2002

Two-year-olds learn novel nouns, verbs, and conventional actions from massed or distributed exposures.

Two-year-old children were taught either 6 novel nouns, 6 novel verbs, or 6 novel actions over 1 month. In each condition, children were exposed to some items in massed presentations (on a single day) and some in distributed presentations (over the 2 weeks). Children's comprehension and production was tested at 3 intervals after training. In comprehension, children learned all types of items in all training conditions at all retention intervals. For production, the main findings were that (a) production was better for nonverbal actions than for either word type, (b) children produced more new nouns than verbs, (c) production of words was better following distributed than massed exposure, and (d) time to testing (immediate, 1 day, 1 week) did not affect retention. A follow-up study showed that the most important timing variable was the number of different days of exposure, with more days facilitating production. Results are discussed in terms of 2 key issues: (a) the domain-generality versus domain-specificity of processes of word learning and (b) the relative ease with which children learn nouns versus verbs.

Child, Preschool↗
PubMed2001

Do chimpanzees know what conspecifics know?

We conducted three experiments on social problem solving by chimpanzees, Pan troglodytes. In each experiment a subordinate and a dominant individual competed for food, which was placed in various ways on the subordinate's side of two opaque barriers. In some conditions dominants had not seen the food hidden, or food they had seen hidden was moved elsewhere when they were not watching (whereas in control conditions they saw the food being hidden or moved). At the same time, subordinates always saw the entire baiting procedure and could monitor the visual access of their dominant competitor as well. If subordinates were sensitive to what dominants did or did not see during baiting, they should have preferentially approached and retrieved the food that dominants had not seen hidden or moved. This is what they did in experiment 1 when dominants were either uninformed or misinformed about the food's location. In experiment 2 subordinates recognized, and adjusted their behaviour accordingly, when the dominant individual who witnessed the hiding was replaced with another dominant individual who had not witnessed it, thus demonstrating their ability to keep track of precisely who has witnessed what. In experiment 3 subordinates did not choose consistently between two pieces of hidden food, one of which dominants had seen hidden and one of which they had not seen hidden. However, their failure in this experiment was likely to be due to the changed nature of the competition under these circumstances and not to a failure of social-cognitive skills. These findings suggest that at least in some situations (i.e. competition with conspecifics) chimpanzees know what conspecifics have and have not seen (do and do not know), and that they use this information to devise effective social-cognitive strategies. Copyright 2001 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMedDate not supplied

Understanding "prior intentions" enables two-year-olds to imitatively learn a complex task.

This study investigated children's understanding of others' intentions in a social learning context. Specifically, it investigated whether knowing an adult's prior intention before the adult gives a demonstration influences what children learn from the demonstration. In the five main experimental conditions, ninety-six 2-year-old children watched as an experimenter (E) pulled out a pin and opened the door of a box. Children in two No Prior Intention conditions saw this demonstration alone or paired with an irrelevant action. Children in three Prior Intention conditions knew what E was trying to do before the demonstration: they first saw E either attempt unsuccessfully to open the door, or visit and open several other containers, or they first saw that the door opened. Children opened the box themselves more often in each of these three conditions than in the two No Prior Intention conditions, even though children in all five conditions saw the exact same demonstration of how to open the box.

Child, Preschool↗
PubMedDate not supplied

The role of language in the development of false belief understanding: a training study.

The current study used a training methodology to determine whether different kinds of linguistic interaction play a causal role in children's development of false belief understanding. After 3 training sessions, 3-year-old children improved their false belief understanding both in a training condition involving perspective-shifting discourse about deceptive objects (without mental state terms) and in a condition in which sentential complement syntax was used (without deceptive objects). Children did not improve in a condition in which they were exposed to deceptive objects without accompanying language. Children showed most improvement in a condition using both perspective-shifting discourse and sentential complement syntax, suggesting that each of these types of linguistic experience plays an independent role in the ontogeny of false belief understanding.

Child Language↗