Would you make an efficient assembly line worker? It only costs $150 to find out!

Alternate Title: “Why you should never use an anthropologist as a participant in your research study“.

I recently participated in a Kinesiology study that tested reaction times between two different sets of individuals. Despite my frequent lack of coordination, I was actually placed in the ‘healthy’ or “control” group. One key task participants were asked to perform involved the use of a Purdue Board to quantify  fine motor dexterity. The board itself is simple: three different types of small metal objects (pins, collars and washers)  are housed in four circular depressions on the top of the board, and two lines of peg holes run the length of the board. Subjects are given a set amount of time (usually 30 seconds to one minute) and asked to place either pins or a specific sequence of objects (e.g. washer, pin, rod) in the holes, using either one hand or both hands depending on what is being tested.

Right off the bat (or, more accurately, right off the peg) I found the results of the test to be intriguing. You’re asked to repeat each task several times to control for the learning curve, and patterns emerge immediately: your dominant hand always fills in a few more pegs than your less-dominant hand, for instance, and your speed clearly increases with experience. While chatting with the researcher collecting the data, I also learned that the test was originally developed to quantify the skills of factory-workers; there have been times in the past when your job security could ride on the results of playing this “game”!  Additionally, he told me that certain groups of people tend to perform particularly well – sewing machine workers were cited as the most adept profession. Finally, women are generally ‘better’ at the peg board test than men.

I  of course immediately began to dream up evolutionary explanations for this sex-related difference in performance (Why yes, Gould & Lewontin, I’ll take my spandrels functional, thank you), until the researcher immediately followed up with “….because women’s hands tend to be smaller than men’s”. Since the peg board requires an intricate precision grip, best managed by smaller fingers, this explanation made intuitive sense. However, adaptationist fallacy aside, I was still intrigued by the possibility of using the game as a teaching aid. These peg boards could easily be used as a tool for teaching students about how biological anthropologists develop hypotheses, control for specific variables, collect data, and then reject or produce alternate hypotheses as a result of this process.

Stage One: If you can get a hold of more than one Purdue board, you could divide students into groups and have them time each other and keep records of their performance in the various exercises (e.g. how many pegs or series of metal objects each individual placed each round). I find it easier to motivate students when you have them engaged in an activity, particularly if it’s competitive without being judgemental (e.g. if you’re bad at the peg board game, no one will mock you for it, whereas if you’re good at the peg board game, you can sit and bask in a misguided sense of superiority for an hour). I would recommend limiting students to using only their left hands, because then “sex” and “handedness” are two categorical variables they can examine relative to quantitative performance.

Stage Two: After initial data collection, have students compare their ‘scores’ and develop behavioral hypotheses to explain any disparities between individuals or between groups,  sharing these hypotheses as a class.

Stage 3: Afterward the hypothesis discussion, have students measure some of their hand dimensions using calipers (width of palm and distance from base of palm to tip of middle finger are likely good dimensional measures), and re-evaluate their orignal behavioral hypotheses in light of these new results. Based on my discussion with the kinesiology researcher, I would expect a strong negative relationship between hand size and performance, independent of sex. Part of this activity could also be a take home exercise, where students manipulate the class data and run very simple stats on it. All in all, in one fell swoop Purdue peg boards could be used to teach an important and interactive lesson about data collection, hypothesis development and hypothesis testing in science.

Dear Kellogg Company, As you can see, I have long been familiar with what is justifiably one of your most popular products…

As an aside, I now know that if I don’t make it in academia, my performance on the Purdue board suggests I would qualify for any number of assembly line jobs. I wonder if Kellogg needs any new workers…and also what their employee discount is.

Original images found here & here. Thanks to my buddy Aaron Sandel for buying me all the poptarts in the picture to the left! Though admittedly, that particular adventure had nothing to do with the Purdue board study.