Monday, April 18, 2016

Eyebrows and Face Recognition

Do you recognize these two people? In both photographs, the eyebrows have been removed. 

Here are the photos of the same faces. Is it easier to recognize them this way? This time the eyes have been digitally removed instead of the eyebrows. (Hint: one is a politician, and the other an actor) 

Richard Nixon and Winona Ryder
Scientists have done facial recognition experiments where subjects were presented with many faces altered to have either the eyebrows or the eyes removed. It turns out that subjects perform better on faces with no eyes, compared to faces with no eyebrows. 

As the authors put it, "The absence of eyebrows in familiar faces leads to a very large and significant disruption in recognition performance."

This came as a surprise to me, since I have always assumed that the eyes were the most important elements to help us recognize and remember a face, with the mouth being perhaps second most important.

Anselm van Hulle, 1649. Anna Margareta
It's remarkable that humans of both sexes have these patches of hair on our faces, compared to primates who generally have more facial hair. The muscles controlling their movement are sophisticated and largely unconscious. We express much about our emotional state to others, even at long distances away. This central role as a social signaler may be related to why eyebrows are also so important for recognition.

The authors of the paper note that:
"During the 18th century, in fact, in Western Europe full eyebrows were considered so essential to facial beauty that some upper-class women and courtiers would affix mouse hide to their foreheads. The perceived importance of the eyebrows for enhancing beauty has not waned to this day. Currently, it is relatively common cosmetic practice to use tweezers or depilatories to narrow and accentuate the arch of the eyebrows, as well as to remove any hair at the bridge of the nose. Cosmetics may also be used to alter the color (especially the darkness) and exaggerate the shape and length of the eyebrows."
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J. Sadr, I. Jarudi, and P. Sinha, B, The role of eyebrows in face recognition, [Perception, vol. 32, pp. 285–293, 2003.

12 comments:

  1. It is also very interesting to note the role that eyebrows play in denoting aging. On a woman the eyebrows become much thinner and less intense in colouring. Not gray, just not as dark. In a man they tend to become much bushier. It makes for a powerful change in the look of the face and announces "AGE" very clearly.

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  2. Not surprising, nor eyebrow raising, at all. The eyebrows (protectors of the eye) rest atop bone. The eyes are set back surrounded/protected by bone (and eyebrows). We recognize (through) bone structure (and posture) not features. Hence why we recognized in dim light or from distance - structure/planes illuminated, or not.

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  3. I learned in a portrait drawing class the importance of the shape of the head and hair. We drew these shapes of classmates and could name each person by these simple shapes The face was a mere outline with the shape of the hair on top. I am very conscious of paying attention to the shape of the hair when I draw or paint. But I never have paid close attention to the eyebrows. What a surprise to realize their importance! Thank you for this insightful post.

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  4. I'm not convinced that missing eyebrows make it harder to recognize a face than missing eyes. I recognized Nixon instantly, from the ski-slope nose and the whiney pursing around his lips. Looking at the photo with the eyes missing wasn't necessary for recognition. I didn't recognize Ryder in either version.

    Key for me was that I had seen Nixon's face from the time I was a teenager, so I think almost any part of it was recognizable, whereas while I know Ryder's name and I'm sure I've seen her face before, she's not someone I would recognize, even if you showed me a full face and body photo.

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  5. Jean, I recognized Nixon, too, with or without eyebrows. This small example isn't meant to be conclusive. It's just a sample of the more than 50 faces altered in that way and shown in controlled experimental conditions to a lot of subjects. The results of the study demonstrated a significantly better performance in in recognition when the faces had eyebrows.

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  6. It is the same if someone who normally wears eyeglasses, isn't wearing them...or changes to a very different shape and style of glasses.

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  7. Did recognize Nixon as well. But not instantaneously:...
    ... "Who the deuce is that guy?" I kept on asking myself... "know him from somewhere"...buttt...

    It took me almost a minute for the final recognition, without those eyebrows.


    (The other one chap(ess) was anyway unknown to me, as a far-off-european:-))

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  8. The eyes had to be there for me to recognize them especially the female actor. Taking away the eyes created some vagueness, especially the female actor.

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  9. Makes me think of the Mona Lisa. She doesn't have any eyebrows.

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  10. James,
    I looked at the PubMed Abstract. I'd be interested in their methodology, but no longer have PubMed access. Do you know if they did any analysis based on subject age vs. age of person in photo?

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  11. I admit I hadn't recognized Nixon without eyebrows. I am actually surprised by how much eyebrows count in face recognition, I would have never thought so. I guess I will pay more attention to them as specific characteristic next time I draw a portrait :)

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  12. Very interesting, indeed.I have quite a bit of face-blindness; perhaps that's a feature I need to pay more attention to. I recognised Nixon from the eyebrow photo but not the eyebrowless one.

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