Behaviourism grew from the work of many psychologists in the early 20th Century, such as Watson (1913), Thorndike (1898), and Skinner (1953), who hypothesised that learning occurs through interaction with the environment. Hence, observable behaviours resulting from a response to a stimulus followed by a reward or punishment based on the behaviour is how a behaviourist would condition learners to elicit the desired outcome. Conversely, if the stimulus is removed, then the behaviour will stop over time. This phenomenon is called extinction. Behaviourist theory informs key aspects of the instructional design process such as the task analysis. The task analysis involves identifying observable behaviours or steps learners need to take to achieve the desired learning outcome. A designer often observes learners from various expertise levels completing the task to create a thorough task analysis to inform the design of instruction. Behaviourism has been criticised due to the emphasis on external behaviours only, which led to the development of a new learning theory in the mid-1900s. (Oyarzun, B. & Sheri Conklin (2020). Learning Theories. In J. K. McDonald & R. E. West, Design for Learning: Principles, Processes, and Praxis. EdTech Books. Retrieved from https://edtechbooks.org/-CVIAL)