A couple evenings ago I attended a presentation by Laura Bix from the MSU School of Packaging. The presentation was about how Laura and a couple of her graduate students have been employing user experience design methods in the package design process.
The short of it is, they’re doing great work. I appreciated seeing usability work done in a field different from my own.
Of the many different examples they showed, one concept really stood out to me as a nice application of thinking about human factors: That is, the design of child-resistant medicine bottles. (Or did they call them vials? Packaging jargon escapes me.)
Laura and her student co-presenters showed usability tests of people from different age groups trying to open a push-and-turn style bottle. What seemed typical was that the people in their 80s had a lot of trouble opening the bottles. In one case, a woman reported resorting to cutting the bottle open with a serrated knife. Meanwhile, there was a video of a little girl, perhaps four years old, who had the bottle open in about 10 seconds. So, more like elderly-resistant than child-resistant.
The presenters offered the notion that the human factors used in the design of the typical push-and-turn style bottles are dexterity and strength. Based on testing across different age groups, they suggest that those two factors can’t really be used as a differentiator between the elderly and children.
Instead, they researched anthropometrics, which I took to be the measurements of the human body, such as the distance between the tip of your forefinger and thumb when you spread your fingers out or the lengths of your phalanges.
The physical dimensions of hands are noticeably different between adults and children, so that factor may have much more potential in the design of a child-resistant bottle, than dexterity and strength.
Their presentation made me think of two notions from the usability realm:
- the usability heuristic of error prevention (I’ve recently seen this principle referred to as the poka-yoke principle, attributed to Shigeo Shingo from Toyota)
- the similarity of why a CAPTCHA works
One of the design requirements of a child-resistant bottle should be that a child can’t open it, without resorting to extreme workarounds (such as cutting it open with a knife). I see this as the poka-yoke principle in that, just like you cannot physically plug your USB cable into your Firewire/1394 port, so there should be physical aspects to the bottle design that prevent children from opening it while allowing adults. I’m sure the packaging people appreciate how this is not a simple challenge.
Related, a CAPTCHA (you see the warped letters that you need to enter all the time with online forms, like blog comment entries or when you sign up for services) operates by asking you, a human, to answer a question that will be fairly trivial for you to answer correctly, while it would be confounding to a computer system, like a character recognition software. The point is, the CAPTCHA tries to guarantee that only humans can enter data, not automated systems. So, just as a CAPTCHA tells humans and computers apart, so part of the design challenge for the packaging people is to devise a system that can be trivial for an elderly adult while confounding to a child.
Hats off to Laura Bix and her grad students (sorry guys, I’m blanking on your names…Joe and Javier maybe?) on the great work they are doing, and presenting for the MIUPA event.