Piaget stressed cognitive development, intelligence, and learning as a function of age. He suggested that children developed step by step through different stages of development. According to him to move next stage children could complete cognitive development steps of former stage. Piaget determined approximate age periods for these stages, however, he stated that stages should be longer or shorter. He claimed that there were four main stages of development which are, sensorimotor(0-2 years), pre-operational(2-7 years), concrete operational(7-11 years) and formal operations(11 years and up). Nevertheless, he claims that every child could not pass next stage before completing former one. In contrast, Bruner emphasised that all knowledge should be thought at every age. However, Bruner gives importance that how the knowledge is presented. According to him, different ways of representation were important at different ages. Like Piaget, Bruner stated that intellectual development occur sequentially through enactive representation, iconic representation, and symbolic representation. However, unlike Piaget's stages, Bruner's modes did not necessarily depend on age. Enactive mode refers using of motor skills. (Julie Mckoy). I think it corresponds with Piaget's sensorimotor stage. At this mode; knowledge is stored by the form of physical actions. Children learn by doing, rather than by thinking. At this mode, physical activities are important such as learning to ride a bike. At iconic mode, knowledge is stored as visual images. For instance we can imagine an empty plate or a plate that is full with fruits. We can think about differences of two situations separately. At symbolic mode, knowledge is stored as words, symbols. This mode includes advanced symbols or advanced language skills and I think it corresponds to Piaget's operation stage. The development of the symbolic mode of representation, particularly the acquisition of language, allows children to think about abstract concepts.
Both of these theories require that active participation and constructing knowledge on by own. So we can put under constructivist view both of two theories. Piaget's theory is constructivist because individual acquire knowledge from their interaction with the world and then take those concepts and makes sense the world through cognitive schemes and these schemes are changed as a result of individual actions on objects in the world. Bruner's theory is also constructivist, because learner constructs his knowledge by discovering. For Piaget in learning process, cognitive conflict and disequilibrium is necessary; for Bruner obtaining knowledge by discovering knowledge is an important process in learning.
Instructional approaches
While Piaget argued that stages of development is important concept to determine which information a child can learn ,according to Bruner's notion of 'spiral curriculum', knowledge can be represent to child at almost any age with appropriate material for child. According to him curriculum should be designed from simple to complex, general to detailed and abstract to concrete manner and it named as spiral curriculum. Bruner suggested that learner obtain knowledge by discovering. Hence, sometimes learners are not presented subject matter as a whole and they are allowed to develop their own learning. So, in the discovery process teacher should be as a guide. In Bruner's theory the guide of teacher is much more than Piaget's theory. In my opinion, while in Piagetian perspective, instruction is based on exploration within the real life; Bruner gives importance learning by discovering. So, instructions should be organized by giving opportunities to learner for discovering. For instance, in schools role playing, group projects or computer simulations can be help for discovery (Schunk, 2008). For Bruner, sequence is important while presenting material. In both of the theories, instruction should encourage the child for discovery learning; lead individual to make sense the world through cognitive schemes; for example, experiments with real objects may make learning better and in both of the two theories students are actively engaged in the learning process. Also for effective instruction, Bruner states that instruction should associated with learners' predisposition.
Role of teacher
For both Bruner and Piaget, teacher is a guide. For Piaget, teacher is an organizer who guides stimulating plan and research. Teacher encourages stimulate and support exploration and invention and recognize and what provides disequilibrium and curiosity for children and how to use it in an appropriate way. Also according to Bruner's theory instructor has also a crucial role in terms of guiding students' learning. The instructor provides adequate tools and support to stimulate the student into discovering the knowledge on his own. Teacher is guidance in learning environment.
Social aspect
Like Piaget, Bruner believes that cognitive skills develop through active interaction. Piaget emphasizes the importance of interaction which leads disequilibrium among peers. He views social interactions as source of cognitive conflict, equilibrium, and development. However, according to Bruner social factors, particularly language, were important for cognitive growth. As a difference, Bruner also emphasizes the importance of cultural differences are important in learning.
Prior knowledge
For Piaget's theory children acquire new knowledge with accommodation and assimilation of existing knowledge. So, prior knowledge is an important term in learning for Piagetian perspective. However, for Bruner students require background preparation for discovery learning. Discovery process also can inhibit learning when students have no prior knowledge (Schunk. 2008). So I think prior knowledge requires for discovery learning process and affects the speed of discovery.
Role of the learner
For Piaget and Bruner learner are active in learning processes. According to Bruner, in the lessons learners ask questions and find their own answers, and to deduce general principles from examples or experiences and obtain knowledge. The knowledge is grasped by the learner itself.
For Piaget, learner acquires his own form of existing knowledge through their personal construction of knowledge. The learner constructs knowledge from his explorations on the environment similar with Bruner's discovery learning.
