Female college students and rats agree on what makes a particular mineral water tasty, research suggests. A study called Similar Preference for Natural Mineral Water between Female College Students and Rats pulls off a nice bit of interspecies diplomacy. Reading it end to end, you would be hard pressed to say who - the college students or the rats - was most intended to benefit from the research.

Written by Esumi Yukiko of Shimane Women's Junior College in Matsui, Japan, and Ohara Ikuo of Kobe Women's University, and published in the Journal of Home Economics of Japan, this six-page monograph describes a simple experiment.

The authors explain their work was partly inspired by a simple fact: "The Society for the Study of Tasty Water, which is sponsored by the Ministry of Public Welfare, proposed hardness to be one of the most important requirements for tasty water."

Therefore, they say, "the objectives of this study are to investigate the best mineral water for drinking by using hardness as an index, and whether the response of rats to mineral water can be extrapolated to that of humans."

Yukiko and Ikua conducted taste tests with 16 healthy female humans, 16 healthy female rats, and 14 different brands (nine Japanese, two Belgian and two French) of bottled water. The water, all of it, was uncarbonated. For good measure, the taste testers also taste-tested tap water.

The women drank from cups, the rats from "drinking tubes". The report specifies that the rats each weighed 160 grams, give or take three grams, and were "housed individually". We are told nothing, not a blessed iota of fact, about the weight of the women, or about their living arrangements.

The report also specifies that "before beginning the experiment, each animal was fed on a commercial stock diet", but says nothing about what the women consumed.
Yukiko and Ikua reached two main conclusions.

First, they write, "appropriate levels of minerals are needed for tasty drinking water, too little being as bad as too much, with around 58.3 milligrams/litre of hardness being most favourable."

Second, and perhaps more memorably: "The present study has demonstrated that the preference for different types of natural mineral water by female college students was similar to that by rats."
Yukiko and Ikua make no claim that theirs is the final word. For one thing, they point out, "the menstrual cycle of the subjects was not considered in this experiment, although taste sensitivity can be influenced by it."

Similar Preference for Natural Mineral Water between Female College Students and Rats is not the only research study to proudly, explicitly comparison-test college students and rats. But it may be the most exhuberant since C Lathan and PE Fields's 1936 classic A Report on the Test-Retest Performances of 38 College Students and 27 White Rats on the Identical 25 Choice Elevated Maze.

Marc Abrahams is editor of the bimonthly Annals of Improbable Research and organiser of the Ig Nobel prize Rats have impeccable taste in mineral water, research shows