What is the Hawthorne Effect?
This morning I was doing some research for an upcoming essay I'll be releasing on office lighting when I came across a few articles on the famous Hawthorne Effect. If you've never heard of the Hawthorne Effect here it is in a nutshell.
Essentially in the 1920s designers wanted to understand what the perfect level of illumination was to maximize worker productivity on assembly lines. So at one telephone assembly plant they decided to conduct an experiment and consistently raise the wattage of the bulbs, each time measuring output per worker. There was a control group and a test group, much to their surprise each time the wattage was raised worker productivity for both groups rose. This led experimenters to assume that by word of mouth everyone assumed their lighting had gotten brighter. The power of suggestion made all workers increase their productivity.
The true surprise of the experiment came when they started to steadily decrease the wattage below the original base line the workers were used to. Even then for all groups worker productivity increased until it was so dim the workers complained they couldn't see what they were doing.
The result of these experiments was dubbed the Hawthorne Effect (after the plant in which it took place) and wisdom gleaned from it was that people's behavior always changes when they think they are being watched thus making this kind of experimentation inherently flawed.
Is it Real?
Despite its ubiquity, it's hard to know if this effect is legitmate. In the years since scientists have gone back to look at the experiment methodology and have found several factors to be flawed.
It turns out that idiosyncrasies in the way the experiments were conducted may have led to misleading interpretations of what happened. For example, lighting was always changed on a Sunday, when the plant was closed. When it reopened on Monday, output duly rose compared with Saturday, the last working day before the change, and continued to rise for the next couple of days. But a comparison with data for weeks when there was no experimentation showed that output always went up on Mondays. Workers tended to beaver away for the first few days of the working week in any case, before hitting a plateau and then slackening off.
In my research I came across a paper written for the Oxford Press' Journal of Occupational Medicine. While I didn't download the entire paper, the abstract refers to the Hawthorne Effect as "an ‘effect’ that everyone refers to, but no one can source or define."
What Does This Mean for Office Lighting?
So what does this mean for designing lighting for office or other productive spaces? I think there are several takeaways:
- The Hawthorne effect was a study of assembly line workers. If you're designing an office, it might not be particularly relevant. Assembly work is about turning out widgets over and over again. It's about visual acuity, not comfort. The modern office expects far more concentration and creativity that the assembly line for Bell telephone did.
- Productivity alone is a bad measure for design success. The Hawthorne effect tells us that if workers knew they were being experimented on their behavior changed. When productivity is being measured people will be more productive, because they know they are being watched. That won't last forever. If you're redesigning an office think about worker happiness first. Are they more comfortable in their space, are they happier to come to work...that might go a long way to defining success.
- Think beyond brightness - remember this effect was a simple change in light bulbs. It has nothing to do with where the light comes from or it's quality.
So what do you think? Does the Hawthorne effect scare you, or is it just common sense? Hit me in the comment section below.