The author replies to Clark:

The theory of affordances was originally developed during Gibson’s research on visual perception and its application in chemistry education research is relatively new. We understand it may be difficult to initially understand the theory of affordances; however, we also believe that affordances can give us new insight into student learning, especially student learning in the laboratory.

The term “affordance” is not found in the dictionary. Gibson created the term, as is common in the science community, to accurately describe his new concept. Gibson (1) defined affordances as “what it provides or furnishes, either good or ill” (p 127). What an object affords someone are that object’s affordances. (Affordances can be applied to everything from objects and organisms to complete social interactions; however, we will limit our discussion to objects for simplicity.) Unlike characteristics or physical properties, affordances cannot exist independently of the person perceiving the object and the context in which the object is perceived. For example, a chair is about knee high to the individual, solid, and possessing a level surface. These characteristics are not what a chair affords. Most people perceive a chair as a tool for sitting; thus a chair affords sitting. However, a chair also affords our students the ability to prop open the lecture hall door when it is too hot and affords the ability to reach a book on the top shelf in our offices. Affordances of a particular object vary with the person perceiving the object and the needs of the person at the time they perceive it. Therefore, the affordances of the CCD spectrophotometer are dependent upon a person’s background (previous experience with the spectrophotometer, understanding of its designed purpose, etc.) and current need for the spectrophotometer.

Gibson argues that affordances are the primary level for perception; we instinctively look for the affordances in our environment. Therefore, we cannot effectively evaluate student learning in the laboratory until we understand the affordances of that environment. We must know how students perceive the laboratory environment in order to better understand how that environment influences student learning by prompting or directing students’ perceptions to the affordances that we, as educators, would like them to perceive.

This is a new theory for chemical education, and we believe it is one that will prove useful both in research and in the practical aspects of teaching chemistry. Indeed, the idea of affordances is not limited to education. As stated in our article (2), affordances have been applied to many areas, such as communication technologies, theories of tool use, developmental psychology of art, geographic information systems, and unique identifier characteristics, such as universal price codes. In a very real sense, we must afford “affordances”!

Literature Cited

1. Gibson, J. J. The Ecological Approach to Visual Perceptions; Houghton Mifflin: Boston, 1979.
2. Malina, Eric G.; Nakhleh, Mary B. J. Chem. Educ. 2003, 80, 691-698.