Behaviourism: Learning occurs as stimuli are introduced in a strategic way with the objective of illiciting a specific or desired response. Behaviourists are concerned with what people do (observable behaviours). Factors influencing the learning include the various stimuli that are presented, the sequence and timing in which this occurs, and the environment in which the learner finds themselves because these all have a bearing on the type of response that occurs. Behaviourists explain transfer in terms of the learner's ability to generate the desired response in an environment similar to the original "learning environment". This is sometimes referred to as "generalization". The objective is for the learner to have a generalized response that occurs in a variety of environment sharing key features. Behaviourist theory suggests that there is no real role of memory in learning because learning has to do with observable behaviours, not necessarily cognitive processes of storage, recall, etc. Learning such as repetitive motor skill acquisition or other types of procedural tasks are easily explained by behaviourist theory. In terms of structuring instruction, behaviourists would be likely to focus a great deal on the environment in which learning is taking place (e.g. what are the stimuli that can be controlled? How should they be introduced in a way that will elicit the desired response). Providing the learner with opportunities to practice making the proper response would also be important. For example, a PE teacher who views learning through a behaviourist lens would structure their class so that students have opportunities to practice particular skills and would be very intentional about providing feedback (the stimulus) in a way that would encourage the student to perform the skill to the instructors specifications (the desired response).
Cognitivism: According to cognitivist theory, learning occurs as individuals receive, organize, store, and then retrieve information or knowledge. Cognitivists are concerned with what learners know and how they organize that knowledge and then retrieve it. Factors influencing learning include the cognitive processes/strategies employed for organizing, storing, and retrieving information. This is a more learner centric theory than is behaviourism because the learner is seen as having an active role in the learning process. The big focus here is on employing effective learning strategies. The role of memory is critical in this learning process because it is the storing and then retrieving of information that is the measure for the success of the learning process. According to Constructivist theory transfer occurs as learners receive information in one environment and then recall & apply it in a new or different environment. This can only be accomplished as the learner develops rules or sets of guidelines for when and how to apply information. So, transfer can only occur if the learner has a strategy for making judgments about new environments (e.g. their characteristics, the type of knowledge that might be needed, etc.) and then recalling information useful or pertinent in the new environment. Learning such as reasoning, problem solving, and information-processing is easily explained by this theory. For example, a cognitivist would say that a child who is very good at the game "Memory" experiences the success that they do because they have learned to structure and organize the layout of the game (i.e. where the various cards are) and can recall that information at the appropriate time to make "matches". According to cognitivist theory, instruction should be structured with a heavy emphasis on the learning strategies employed by the learners. Instructors would assist students in organizing new information and connecting it to existing information ("chunking") and might then help the learner develop strategies for effective recall.
Constructivism: According to constructivists, learning occurs as individuals make meaning from their lived experiences. Essentially, what we "know" stems from the experiences that we have and the way that we interpret these experiences. Thus, our knowledge is dynamic and highly influenced by subsequent experiences. Factors influencing learning include the learners environment and the context in which it takes place, as well as the cognition of the learner and how they make sense of their experiences (e.g. reflection upon experiences). A constructivist would view memory as always under construction and that there is not a well-defined "known" that can be remembered. Rather, we remember past experiences and use what we know from those experiences to make sense of new experiences. Transfer is facilitated by opportunities for the learner to practice and learn in authentic environments that closely parallel the setting in which knowledge will be used or applied (Situated Learning dictates that the learning & application settings should be identical). Constructivist theory best explains advanced, nuanced learning like that experienced by individuals as they develop expertise. Learning that occurs in ill-structured or dynamic environments is also easily explained by Constructivist theory. Instructors who have constructivist leanings would be very mindful of the context in which learning is taking place and would do all they can to make sure that learning takes place in an authentic way with opportunities for the learner to be exposed to multiple perspectives and a diversity of experiences so as to develop a more refined knowledge. The instructor would also need to help the learner develop metacognitive skills to facilitate more effective reflection and meaning-making.