Abstract
This paper argues for incorporation of an individual differences approach into human factors/ergonomics research and practice. Description of the systematic variation in the human portion (e.g. cognitive and personality traits; motivational and emotional states) of human–technology systems can complement the existing design methods (e.g. task analysis) to yield better models of system performance and improve system design and operation. Individual differences research should not and need not be atheoretical and opportunistic and applications should not and need not be restricted to selection. Instead, consideration of individual differences will lead to a more inclusive human factors/ergonomics in which the properties of the human are described in a level of detail commensurate with the properties of the displays and controls. Three theories are described and their implications for human factors/ergonomics are discussed. Key issues for future research and practice are identified, including a set of guidelines for implementing an individual differences approach.