Re-thinking the Role of Perceptual Acuity – A Review and Commentary on Veazie, Landen, Bender, & Amandus (1994)

This article is a review of the epidemiological literature on occupational injuries spanning 1970 to 1992. While there are brief sections on worker populations (i.e., industries represented in the studies they reviewed), and outcomes (i.e., injuries, ranging from minor to severe), the most interesting and potentially insightful section is on risk factors. The remainder of the article focuses on where research efforts should be directed, such as studying specific risk factors, as well as a thorough consideration of methodological issues related to this line of inquiry.

The worker populations found within the studies Veazie and colleagues reviewed were predominantely from industries that are known to be hazardous or simply accessibile to researchers but not particularly hazardous. Consider manufacturing with regards to the latter.  Manufacturing is an industry commonly examined in research because of the relative practicality of conducting research in this industry and not because of any particular unique hazardous conditions. As such, our understanding of occupational injuries, be it outcomes or risk factors, is potentially industry biased when aggregated.

Meanwhile, Veazie and colleagues contrast the practical motivations with motivations driven by actual hazards, such as the focus on transportation and mining. Both of these industries are recognized as relatively high-risk industries. However, as hinted at above, whether an industry is hazardous does not mean it is more likely to be the target of researchers, as many extremely hazardous industries are underrepresented (at least when this paper was published) as they are less accessible, such as agriculture, logging, construction, and fishing. Veazie and colleagues suggest this is largely due to the “transient and independent nature of their workers” (p. 205). Fair enough.

The next notable section is on the outcomes found in the literature they reviewed. The authors note that most non-injury mishaps are excluded and that most studies focus on accidents. Alas, this causes tremendous grief to other safety researchers as the recording and measurement of accidents does not allow us to separate accidents that result in injuries and those that do not. This inability to isolate injuries from accidents is still a problem for those of us joining the field of occupational safety and searching for empirical precision. Another notable shortcoming of the literature on outcomes that Veazie and colleagues pointed out, and which caused my head to nod incessantly in agreement, was that it has been rare for researchers to isolate severity in their measures of accidents and injuries – an idea that still requires empirical attention.

The most insightful section in this paper is on risk factors. Veazie and colleagues classify three categories of risk factors: human, job content, and environment. Human risk factors include things such as demographics, experience, stress reactions, knowledge, and attitudes (p. 206), job content includes factors such as work design and scheduling, while environmental factors include social and organizational features such as physical stressors and hazards.

Veazie and colleagues outline risk factors found in 32 studies that meet their standard of quality to infer an existing relationship. While these specific factors can be found outlined in the three tables on page 207 onwards, the most insightful comment about human risk factors, and I think potentially overlooked theme for all risk factors, is that these factors in some way influence perceptual acuity. While the authors do not expand on what they mean by this, I think the summary of factors found in one study they mention is worth expanding upon.

Veazie and colleagues use the term perceptual acuity when discussing one study where it was found that noise exposure, hearing loss, and alcohol use (among others) were related to injury in shipyard workers (Moll van Charante & Mulder, 1990). They summarized these and the other factors as those which influence perceptual acuity and left it at that. However, I think this idea could be expanded to explain the connection between not only majority of the human factors, but also the job content and environmental factors.  It can be inferred that human factors infringe upon or dampen perceptual acuity. In turn, this leaves individuals vulnerable to hazards that, under better conditions, they would be fully attentive towards and better able to avoid.

The idea that under better conditions individuals would be better prepared for and able to prevent injuries is only part of the story. Other human factors, such as experience, tell us something else.  For one, less experience is typically related to a higher likelihood of injury at work. This lack of experience plays a role on what people perceive to be hazards in their work place, making them more vulnerable to injury. Perceptual acuity is still an accurate mechanism, but instead of it being hampered attention or focus, it is the nature of the perception. As such, a lack of experience fully well influences perceptual acuity, but not in such a way that under better conditions, fully attentive individuals would be prepared for and able to prevent injuries. Instead, individuals who lack experience would still overlook hazards or engage in work activities that carry job specific risks. How can someone prevent an injury if they are not aware of the hazards or risks or the circumstances that increase the likelihood of increasing these very hazards or risks.

The next sections do not at all discuss the effects that job content nor environmental factors have on perceptual acuity. But again, I argue that these can be roughly described as factors that either infringe upon or shape motivations to allocate attention towards hazards in the workplace. In some sense, this may just me forcibly imposing a way of connecting the factors described in these sections. I argue that job content, represented by aspects of job design and layout (e.g., job difficulty, workload, shift work, and so forth), is largely that which can infringe upon or limit perceptual acuity. Meanwhile I would place environmental factors as those which direct or explain how perceptual acuity is devised and divided, such as physical environmental obstacles, structural incentives, and dealing with other human beings.

While I may be over-simplifying things by stretching the idea of perceptual acuity as something that connects the categories provided by Veazie and colleagues, I found it to be an insightful and fun exercise. Reading through much of the literature on workplace safety has left me thinking there is a lot more room for theoretical improvement. As such, part of my approach in familiarizing myself with the literature has been to take that which we know in different directions – even if I know the odds suggest it will be a dead end.

References

Moll van Charante, A. W., & Mulder, p. G. (1990). Perceptual acuity and the risk of industrial accidents. American Journal of Epidemiology131(4), 652-663.

Veazie, M. A., Landen, D. D., Bender, T. R., & Amandus, H. E. (1994). Epidemiologic research on the etiology of injuries at work. Annual Review of Public Health15(1), 203-221.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s