It has long been that facial expressions may be a sensitive indicator of an organism’s emotional state. Who can forget Darwin’s classic work, The Expression of the Emotions in Man and the Animals (1872), in which he painstakingly catalogued the faces of primates to illustrate his point. This area of investigation has found favor with modern researchers as well. Mariott and Salzen (1978) have analyzed the facial expressions in a colony of captive squirrel monkeys and they, like Darwin, have concluded that a smile is worth a thousand words. All things considered, it is really surprising that no one has gone to the trouble to record and analyze the facial expressions of the ubiquitous rat. This surely must be an oversight and we intend to put things right. There has, of course, been related work with mice (Disney), thus indicating that the problem is not in soluable. A little effort is all that’s needed. If we’ve learned anything from the past decade of animal psychology, it’s that we must really know our subjects before we can work with them. And what better way to know anyone than to study his or her face?
Subjects. Our subjects came from a colony of laboratory rats. We could only get used ones, so they came to us in a variety of moods; some happy, some sad, some scared to hell, depending upon the studies in which they’d participated.
Procedure. We watched our subjects for three months. Really watched them. Then we drew them.
Figure 1 illustrates the faces of rats produced by 12 separate and distinct mood states. It is notable that a high degree of similarity exists between the facial expressions associated with each of these moods. We’re not too sure why this happened. Without getting too graphic, we can assure you that the procedures we used to induce the different mood states were effective. Similarly, our artists and observers were no slouches.
One possibility is that our rats, born and reared in the lab, have been stultified for generations and have lost their facial-expressive abilities. It is therefore essential that our study be repeated under more natural conditions. The only remaining conclusion, and it’s a bit late to be worrying about this, is that rats may not be as facially expressive as we initially thought. Maybe this is why nobody else has messed around with this stuff before. Anyway, it may be about time to validate some of the widely circulating reports of Disney and the colleagues.