The need for sound Instructional Design, and thus the impetus for treating it as a science, has much of its roots in addressing the needs of military, especially the efforts of the United States military to train soldiers and civilian workers during World War II. Clearly, the margin for error in the military realm favors highly controlled training. The success of training programs during World War II led to efforts to apply similar techniques to the private sector. An important post war milestone was the publishing of Benjamin Bloom’s Taxonomy of Educational Objectives in 1956. Bloom described three domains of learning: Cognitive (what we know or believe), Psychomotor (what we do are able to do physically) and Affective (consisting of our feelings and attitudes). These terms and concepts are still considered important foundations in the design of instruction.

Early efforts to improve the efficiency of training focused on observable behaviors. The models in use required that tasks be subdivided into subtasks, with each subtask considered a separate learning goal.  The benefits of this approach are obvious.  If there is no margin for error assumed, then it does not make sense to guess which components of an activity a learner could perform -- in essence, a "chain is only as strong as its weakest link" approach. The goal of training was framed in terms of a requirement of achieving mastery by all learners, which was achieved through repetition and feedback.

Learning theories were influenced by increasing influence of digital computers in the 1960s and 1970s. As a result, many models adopted an "information-processing" approach. More recently, an important trend in Instructional Design is recognition of the importance of managing and optimizing cognitive load during learning activities.

As an Instructional Designer in a corporate setting, it is very valuable to keep abreast of research findings related to learning. This is a vital and evolving science. Keep in mind that the ways that people learn do not change significantly over time. Rather, our understanding is increasingly refined by new information. Many of the bedrock principles of Instructional Design are well established and will remain useful, so it is advisable to keep a balanced perspective on what appears to be “trendy” at any given time.