The internet is severely lacking in accurate references for the lip tightener shape – AU 23. If you don’t own a copy of the FACS manual, chances are – you have been living a lie.
¿Pero por qué?
Lip tightener is quite difficult to perform voluntarily. Though it appears frequently in speech and is a common component of anger, most sources fail to supply an isolated lip tightener image or video.
Even commonly used references from sources such as Carnegie Mellon, iMotions, and Noldus FaceReader have dropped the ball:
Rather than displaying a clean lip tightener, the above resources show blends of lip pucker – AU 18 and lip presser – AU 24, with little to no lip tightener.
For comparison, here is an example of an accurate lip tightener performed by Paul Ekman in the 2002 FACS manual:
In the Ekman images, notice how the width of the lips have minimal shortening. Also note how the expression does not resemble the puckered look of the former references. Instead, the lips are thinned and the skin surrounding the lips (as opposed to the lips themselves) is wrinkled.
For further reference, below are two images of actor Maggie Lawson, from Netflix Original – Santa Clarita Diet, performing a relaxed lip pose followed by a lip tightener. Her lip tightener appears as she declares she does not wish to have a particular potato salad. (To each their own.)
I watch a lot of Netflix, and I’ll be damned if I don’t screenshot a solid lip tightener display.
To combat the abundance of misinformation regarding the lip tightener expression, here are two accurate video references:
(Below) Lip tightener performed by female (me!) with medium lips –
(Below) Less extreme lip tightener performed by male with full lips (Ryan Arnanjaya – student from my guest lecture at Academy of Art, San Francisco) ***Notice how the upper lip is more prominent in tightness for this particular case of fuller lips. –