that these concepts are inextricably related. The full benefit of scientific investigations can only be realised if learners are actively doing these investigations themselves.
2.6 A THEORETICAL FRAMEWORK FOR TEACHER SUPPORT OF
appears between people as an interpsychological category, and then within the child as an intrapsychological category. This is equally true with regard to voluntary attention, logical memory, the formation of concepts, and the development of volition. (p. 163)
The translation of development from a cultural to an internal plane happens in the zone of proximal development. According to Vygotsky (as cited in Roth, 1995), the zone of
proximal development (ZPD) is the difference between a child's independent problem solving ability and the level of problem solving possible under the guidance of an adult or from a more capable peer. While the theory mentions problem solving in the ZPD, the same applies to scientific investigations. The child's actions interact with those of the adult in the ZPD. It is in joint activities between adult and children that the latter appropriate into their own repertoires, knov, !edge and skills that were initially external to them. Critical to the development of skills is the engagement in joint activity. "Novices develop cognitive skills, that is they become fully-fledged members, by participating in joint activities with more knowledgeable others" (Roth, 1995, p. 17). The key element in this notion is that students can participate in tasks they are to learn without yet mastering the whole task on their own. Once appropriated, children can use knowledge and these skills to control their own actions. Cole (1985) extends the notion of ZPD in such a way that it becomes "the structure of joint activity in any context where there are participants who exercise differential responsibilities by virtue of differential expertise" (p. 155). Thus the zone of proximal development is a dynamic region of sensitivity to learning the skills of culture, in which children develop through participation in problem solving with more experienced members of the culture (Vygotsky, 1978). In this way, the learners "advance their capabilities for independently managing problem solving" (Rogoff, 1990, p. 146).
Vygotsky's model for the mechanism through which social interaction facilitates cognitive development resembles apprenticeship, in which a novice works closely with an expert in joint problem solving in the zone of proximal development. The novice is thereby able to
participate in the skills beyond those that he or she is independently capable of handling (Rogoff, 1990).
2.6.2 Rogoff's apprenticeship model
The apprenticeship model described by Rogoff (1990) considers children as apprentices who develop skills and understandings from participating with peers and more skilled
members of their society within the context of sociocultural activity. These learners who are novices in an activity are supported, challenged, and guided by more skilled members of the community (Rogoff, 1990). Rogoff points out this guidance may be tacit or explicit, and involves building bridges from children's present understanding and skills to reach new understanding and skills. Children therefore assume increasingly skilled roles in the activities of their communities.
Rogoff uses the example of shared problem solving to explain this guided participation. A similar explanation could be given for scientific investigations. Skilled partners guide novices with difficult problems by structuring sub-goals of problem solving to focus the novice on a manageable asp 'Lt of the problem. The structuring of the problem should be tailored to the child's level of skill. Such structuring does not focus on breaking a task into minutely ordered steps to be mastered in a lockstep fashion. Rather, effective structuring maintains children's involvement with the purpose of the activity, integrating varying aspects of the task in a manageable chunk. In this way children get to see how the steps fit together and to participate in aspects of the activity.
Rogoff explains that children take on increasing responsibility for managing situations as they become familiar with a particular task. This transfer of such responsibility depends upon the child's present level of competence in particular tasks. "With evidence of
increasing skill and understanding, expert partners can revise their level of support to be at the edge of the novice's skill, where it is needed for both mutual understanding and the novice's progress" (Rogoff, 1990, p. 100).
2.6.3 Commentary
Vygotsky's theory of learning and the related apprenticeship model as presented by Rogoff suggest that learner autonomy and teacher support are not mutually exclusive concepts.
Teacher support exists to guide learners through the stages of the investigation while they are doing the investigations on their own. Both the theory and the model therefore have i mplications for practical work in science education, and in particular the teaching of scientific investigations. Firstly, learners when doing investigations on their own should receive feedback and guidance as they attempt these tasks for themselves. Wellington (2000) in explaining this states that "as performance improves with feedback becoming
increasingly positive, guidance should be reduced until acceptable performance occurs unaided" (p. 222). In terms of Wood's (1989) theory of 'contingent control' (as cited in Wellington, 2000) there exists levels of directiveness which can be followed when offering guidance. An example of relatively low-level guidance would be indicating that a problem has occurred, while an example of relatively high-level guidance would be explaining the precise nature of the problem and suggesting an alternative approach. Wood proposed that guidance should progress upwards one level at a time until success is achieved, and then downwards one level at a time so that unaided success is approximated gradually.
Secondly, the apprenticeship model has the value of including more people than a single expert and a single novice. 1 c apprenticeship system often involves a group of novices (peers) who serve as resources for one another in exploring the new domain and aiding and challenging one another. The implication for scientific investigations in the classroom is that learners should be encouraged to work collaboratively with each other in groups.
Through groupwork the learners share, exchange and challenge each other's ideas. Lave (1988) suggests that "apprentices learn to think, argue, act, and interact in increasingly knowledgeable ways with people who do something well, by doing it with them as legitimate, peripheral participants" (p. 2). In this apprenticeship system, the expert too is still developing breadth and depth of skill and understanding in the process of carrying out the activity and guiding others in it. This is especially pertinent in the South African context where the teacher may lack experience and expertise in doing science investigations.
Thirdly, learners should also be encouraged to engage as far as possible in whole activities rather than partial ones. According to Roth (1995), "students should engage in entire research projects so that they would learn what is meant to conduct research from the beginning to the end of a project" (p. 18). That is, learners should be given the opportunity to do complete investigations where they are engaged in all stages of the investigation process, i.e. from formulating the investigation question to reporting their findings.
2.7 THE ROLE OF THE TEACHER IN SUPPORTING LEARNERS DOING