CRUCIAL role in the development of learners' COGNITIVE ability. Hence, effective learning is the RESULT of the interaction between the learner and the more knowledgeable person in a social context.According to Vygotsky, 'zone of proximal development' or 'ZPD' refers to the:the gap between what the child can do independently and with assistance.difference between what a learner can do on his/her own and what he/she can do with someone's help.range of tasks too difficult for the child to do alone, but possible with the help of adults and more skilled peer.distance between learners' actual development level and his/her level of development under someone's guidance. Jean Piaget’s Theory of Cognitive Development:According to him, cognitive structures are the basic mental pattern people use to process any information.Piaget explained that children progress through four stages. The Four Stages of Cognitive Development are as follows:-J.B. Watson: An American psychologist who has proposed the 'theory of behaviourism' in which he emphasized that the environment is the prime factor in shaping the behaviour and actions of a child.J. Bruner: Jerome S. Bruner is a proponent of cognitive learning and a developmental psychologist.His APPROACH to psychology is eclectic (i:e. he selects the best or the most useful features from the various conflicting theories available).He looks at human beings as information processors, thinkers, and creators, and treats them as a reactive organism who actively selects, structures, retains, and TRANSFORMS learning/information to achieve certain goals