Role of sign in concept formation
In our previous studies, we found that in a situation where the formation of concepts takes place in conditions that hamper the selection of rule (eg, the presence of "noise" objects), the sign facilitates learning. These results are consistent with other studies that show the role of the sign in the strengthening of categorization (Lupyan, Rakison & McClelland, 2007), selecting information about an object for the formation of meaning (Bloom, 2002) and help children to transfer the meanings ( Gelman & Coley, 1990). In our current studies we are checking the hypothesis of sign's polyfunctionality - the possibility of the sign to assume different functions (remembering, planning, monitoring, etc.) in different contexts and at different ages. We also explore on which properties of the sign depends its ability to perform these functions, most of which are connected with regulation of the process of creating generalizations. We believe that not every object can act as a sign, but only one that differs from other natural properties of the object of categorization. This hypothesis was verified by means of special tasks in which we change the properties of the sign, along with changes in the natural properties of the object of categorization. We are also interested in the effect on the concept formation of integrated sign consisting of several parts and sending in its form to different cultural symbol systems. So now we test the hypothesis that the addition to the name of category the numeral should change the categorization of children between the ages of 4 to 5 years.
Development of word meanings
Next area of our research is ontogenetical development of speech and word meanings. We explore various phenomena of meanings development in two-to-five-years children such as fast mapping and shape bias. Our previous research show the high value of such environment characteristic as dynamics of object's features. We showed that bringing dynamics of shape, color or other object's features into the task makes the property of this dynamics more significant for categorization than static features. One more theme connected with speech development is influence of adult's behaviour on how child acquires the meanings of new words. At the present time we check up hypothesis that appearance of the real word meanings is a result of joint adult and child activity which is revealed on speech and behavioral level of them both.
The declarative gesture function in 2-year-olds
A well known investigation of U.Liszkowsky and coll. (2004) proved that a protodeclarative gesture of an infant of 12 months is a tool to obtain adult attention and that for instance, showing and pointing as attempts to share attention and interest to an object or an event. This data is very important for the social-functional approach to the development that suggest that even before the appearence of speech an infant has a motive to share the experience with the interaction partner. But we suggest that the origin of this infants' communicative behavior consists not only in the general infant orientation to the interaction with the others (as describe U.Liszkowsky following the M.Tomasello tradition), but in the specific organization of the perceptive field at this age: in the perception of infant appears a completely new way of it functionning that requires an adult involved in the interaction and that is hapening only in a shared way. If our suggestion is true, the infant will not be satisfied by the modification of the experiment of U.Liszkowsky et al (2004), in the case when only the adult will see the object after the infant’s pointing and the infant will not see it. By the way we would like to test hypotheses about the object naming and the adult's expression as the factors of the declarative gesture.
Mechanism of Overimitation Effect
The overimitation effect is specifically human way of children behavior when adult intentionally demonstrate irrelevant actions with a new object. A number of works suggests that "social" variations did not influence this effect. But our experiments reveal that children overimitate irrelevant action set even after its change, because their manipulation with an object is under the influence of adult's manipulation with object. We have demonstrated an unfamiliar object to every subject with two different irrelevant action sets twice with a time interval between them and children preferred to overimitate Set 2 after Phase 2. To make sure that preference for Set 2 in Experiment 1 wasn't the effect of memory deficit, we conducted Experiment 2. It was only the demonstration before Phase 1, and during Phase 2 children overimitated actions which they have seen 7 days ago. We suppose that children make conclusions about the rules for this object, but these rules include an object user. First of all they include user's intention for object. Such rules are not rules of object's functioning, and they are not rules of adult-child convention. They are rules of convention about object's functioning.