Environmental support: An integrative framework

Objective: In this qualitative review, we develop an integrative framework to bring coherence to the concept of environmental support (ES) in the fields of human factors and cognitive aging. Background: The ES hypothesis, originally formulated to explain effects of retrieval support on age-related differences in memory by reducing need for self-initiated processing, has been applied to many domains, such that the concept now encompasses many manipulations and measures. We developed a framework in which different types of ES share a common function (external support of performance) but differ in how this function is accomplished. ES improves performance by reducing task demands on mental resources or promoting effective use of resources. Previous reviews show that ES can decrease age-related differences in performance (more benefit for older adults), provide equal benefit, or increase differences (more benefit for younger adults). We proposed that the outcome will depend on properties of the ES, task, and person. Method: We applied our framework to the domains of language comprehension and human-computer interaction, selecting studies representative of differing outcomes for ES. Results: In both domains, we found that outcomes depended on ES, task, and person. Age differences were more likely to be reduced by ES that imposed minimal prerequisites for use and targeted processes that needed support. Conclusion: Our review helps refine the ES concept by identifying conditions under which age differences in performance are reduced or magnified by ES. Applications: The framework provides guidance for human factors practitioners to design tasks and environments for older adults.