The aging workforce: Implications for warning symbol design

or arbitrary warning symbols also would be problematic. These symbols lack a clear relationship with a real-world referent. More specifically, abstract symbols have a distant relationship with the concept, while arbitrary sym- bols have little meaning in and of themselves. On the other hand, representational symbols directly or closely relate to the concept. As Figure 2 shows, representational symbols resemble a snapshot or picture of a situation. A slightly different concept, comprehensibility, relates to how well a symbol can be understood without prior exposure or ad- ditional information—that is, how well it makes contact with long-term memory representations. Representational symbols tend to be highly comprehensible since they directly represent (i.e., picture) their referent. However, a representational symbol might not be highly comprehensible if it does not sufficiently specify the concept it is intend- ed to represent. For example, the symbol for safety shower (Figure 3) does not clearly specify that the shower serves a special safety function (i.e., aid in decontamination from dangerous chemicals). Do Older Adults Have Greater Difficulty With Certain Types of Symbols? To answer this question, Lesch, Horrey, Wogal- ter, et al. (2011), examine both younger and older workers’ comprehension of symbols that varied in terms of familiarity: “Before today, how often did you encounter this symbol?” This was rated on a scale from 1 to 5 (not at all to very frequently); complexity (“how complex is this symbol—not at all complex to extremely complex”); and compre- hensibility (“Pretend you are seeing this symbol for the first time and that you know nothing about it. How likely do you think it is that you could guess that it means [symbol label]?”) Figure 4 (p. 48) pro- vides an example of symbols, varying in terms of comprehensibility. Another key question is wheth- er training improves comprehension of symbols by younger and older workers. Experimental Setup Fifty “younger” adults between age 18 and 35, and 51 “older” adults between age 55 and 77 par- ticipated in the study. The research team purposely uses the terms younger and older to reflect a relative difference in age rather than an absolute classifi- cation as young or old. While the older age group might be more appropriately described as middle- aged (Nichols, Rogers & Fisk, 2003), the team se- Figure 1 High Complexity Symbol PERISHABLE The greater detail in highly complex symbols may com- pete for limited at- tentional resources, making it difficult for older adults to focus on a symbol’s most relevant aspects. www.asse.org MARCH 2012 ProfessionalSafety 47 lected these age ranges to 1) represent working age adults and 2) maximize the likelihood of observing age-related differences in warning symbol com- prehension. Forty-six symbols varying in terms of familiarity, complexity and comprehensibility were selected for use in the study. These symbols represented various industries including (but not limited to) medical, chemical, construction, laboratory and manual materials handling.