Tag Archives: traits

Never Forget Your Occam’s Razor When Travelling!

In my previous role in the UK, I was often confronted by very complex measures of psychological traits. This included the likes of multi-faceted competency models, complex appraisal forms, and measures of engagement with more scales than a grand piano.

Having factor analysed the results of many of these models, I can say that I rarely see them hold up. What does result is a far simpler structure of a few key constructs that account for most of the variability in job performance. I’m always reminded of the law of parsimony which results in simple models often being the finest.

In I/O psychology, we have examples where this is the case. Professor Paul Barrett, one of the most influential people in my career, was instrumental in creating a single psychometric tool that, while never fully commercialised, was a real innovation in our field.

For those that may have forgotten the role of parsimony, I draw your attention to some older papers that are often forgotten in this field. These indicate that simplicity will be more beneficial than complexity when measuring human behaviour.

Scarpello and Campbell (1983) in Personnel Psychology looked at whether a single item (1-5 scale) global measure of job satisfaction was equivalent to the sum of facet satisfactions. They concluded that the whole is more complex than the sum of the parts, and may in fact be more inclusive than facet measures.

Wanous, Reichers, and Hudy (1997) in the Journal of Applied Psychology evaluated single item measures of job satisfaction and concluded that they can be used instead of facet measures in some instances, including practical considerations of face validity, cost, and time. They suggested test-retest reliability of .70. A subsequent article by Wanous and Hudy (2001) in Organisational Research Methods confirmed this, looking at teacher effectiveness but with many of the same arguments.

The Biology of Traits

I have posted before about the value, or potential lack of, personality testing. A more fundamental question that has been raised is the basis for traits in the first place.

As a foundation, we must look to neuroscience and genetics. This is not my area but I have provided a synopsis for readers of this blog from another forum posted by an academic from Victoria University, New Zealand (Dr. Ron Fisher):

“We have very good evidence now from twin studies that there is a large genetic component to personality scores (with estimates varying between 30 and 70% of the variance being due to genetic differences). The search for the genetic encoding of these differences has started. I do not think we will find simple mappings that follow Mendel’s laws but rather complex interactions between different alleles positioned on different chromosomes. However, these studies will eventually give us some clues about the complex interaction of genes and how they then lead to personality expressions.

The expanding neuroscience mapping also opens up interesting opportunities. We will never be able to read a person’s mind based on the activation of cells in the brain (since this violates Heisenberg’s principle of uncertainty – a colleague in physics pointed this out once). However, I predict we will be able to map inter-individual differences in activation in specific parts of the brain that are akin to traits”.

So where does this leave personality testing? I, like Ron, believe that psychometrics is a step towards understanding human behaviour (specifically, the consistent part of human behaviour). I believe that consistence will be described semantically by traits, and understanding more fully the behaviours that make up those traits is the real question for trait based personality theorists. To achieve this we need a far more collaborative approach as scientists and practitioners. We must not be swayed by excessive commercialisation that is the bug-bear of this industry.

To conclude, I will leave the last word to Dr. Fisher who had this to say in a post on another forum:

“In the near future, genetic mapping and findings from neuroscience will complement psychometric findings in our understanding of why certain people behave in certain ways. Whether these techniques will ever find their application in work settings, I am not sure. But it would give us a better answer to what lies underneath the currently observed clusters of items as found in factor analytical studies”.