Creating standardized expressions for the RaFD

Target Face Action Units

There are lots of ways that one can express the same emotion through the face, and there are, of course, huge individual differences based on physiology, prior personal experiences, and culture, just to name a few factors. However, one of the main goals for the RaFD is to produce a standardized set of facial expressions in which people are more or less using the same facial muscles to convey the emotion. This has obvious benefits for psychological research - in facial mimicry studies, for example, this standardization means that you can be sure that participants are mimicking something that is actually there in every picture being shown to them. To my knowledge, there is currently no other existing database of static images that has attempted to have standard facial expressions available for such a large number of models.

When developing the faces used for the RaFD, Job van der Schalk and I based our target expressions upon prototypes defined by Paul Ekman and Walter Friesen, and attempted to elicit these expressions through a variation of the Directed Facial Action Task (DFAT)1. Our knowledge of the Facial Action Coding System (FACS) was invaluable to this process.

Below are the target codes (in terms of FACS Action Units) that we attempted to elicit from the models. AUs in boldface are "core AUs" that we considered to be absolutely essential to photographing before moving on to the next emotion, and were the main requisites for selecting pictures used in pilot tests.

Anger: 4CDE + 5CDE + 7 + 17 + 23/24
Contempt: Unilateral 14
Disgust: 9 + 10 + 25
Fear: 1 + 2 + 4 + 5DE + 20 + 25
Happiness: 6 + 12CDE + 25
Sadness: 1 + 4 + 15ABC + 17
Surprise: 1 + 2 + 5AB + 26

References

1. Ekman, P. ( 2007). The directed facial action task. In J. A. Coan and J. J. B. Allen (Eds.), Handbook of Emotion Elicitation and Assessment (pp. 47-53). Oxford University Press.