A smiley-face is very expressive, statistically. By tweaking the eyes, mouth and other bits, you can literally put a meaningful face on any jumble of numbers. Herman Chernoff pointed this out in 1973 in the Journal of the American Statistical Association, in a monograph called The Use of Faces to ­Represent Points in K-Dimensional Space ­Graphically.

Subsequently, folks took to calling these things Chernoff faces. Chernoff faces can make statistical analysis into a recognisably human activity.

Most people, when shown some statistics, sigh and get boggled. But Chernoff realised that almost everyone is good at reading faces. So he devised recipes to convert any set of statistics into an equivalent bunch of smiley-face drawings.

Each data point, he wrote, "is represented by a cartoon of a face whose features, such as length of nose and curvature of mouth, correspond to components of the point. Thus every multi­variate observation is visualised as a computer-drawn face. This presentation makes it easy for the human mind to grasp many of the essential regularities and irregularities present in the data."

The Use of Faces to Represent Points in K-Dimensional Space Graphically is one of the few statistics papers that is visually goofy, rather than arid.

One page is filled with 87 cartoon faces, each slightly different. Some faces have little beady eyes, others have big, startled, wide-awake peepers. There are wide mouths, little dried-up "I'm not here, don't notice me" mouths, and ­middling mouths. Another page shows off some of the cartoony variety that's possible: roundish simpleton heads, jowly alien-visitor heads, and a smattering of noggins that look froggy. Elsewhere, the study perhaps inevitably includes conventional statistics machinery – charts of numbers, differential and integral calculus equations, and plenty of technical lingo.

Chernoff discovered, by experiment, that people could comfortably interpret a face that expresses quite large amounts of data. "At this point," he wrote, "one can treat up to 18 variables, but it would be relatively easy to increase that number by adding other features such as ears, hair, [and] facial lines."

The world has gone on to employ Chernoff faces a little, but not yet a lot. A 1981 report in the Journal of Marketing, for example, used them to display corporate financial data, with this ­explanation:

"From year 5 to year 1, the nose ­narrows as well as increases in length, and the eccentricity of the eyes increases. Respectively, these facial features represent a decrease in total assets, an increase in the ratio of retained earnings to total assets, and an increase in cash flow."

A note at the very end of Chernoff's 1973 paper hints at a practical reason why his idea would not catch on immediately: "At this time, the cost of drawing these faces is about 20 to 25 cents per face on the IBM 360-67 at Stanford University using the Calcomp Plotter. Most of this cost is in the computing, and I believe that it should be possible to reduce it considerably."

• Marc Abrahams is editor of the bimonthly Annals of Improbable Research and organiser of the Ig Nobel prize