

The illusion of gender - robg
http://illusioncontest.neuralcorrelate.com/2009/the-illusion-of-sex/

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jacquesm
The total lack of facial hair, even the slightest stubble on either of them
has me classifying them both as female. I know they're the same pictures that
are manipulated to make me 'believe' one is male the other female, but there
is much more to identifying faces than just contrast, and absent other clues I
seem to default to 'female'.

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lunchbox
The reason there is no stubble is that these photos are composites (averages)
of multiple faces. Any small irregularities in the original photos (not just
stubble, but also wrinkles, blemishes, and facial asymmetries) are smoothed
out through this process.

Incidentally, this is one of the theories behind why facial composites tend to
be more attractive than the sum of their parts. Here's an interactive demo:

<http://faceresearch.org/demos/average>

Also, you can experiment with your own images here:

<http://www.morphthing.com/>

~~~
DarkShikari
This is a classic problem of averaging. The average of multiple data sets
doesn't retain the average of all the properties of the originals. A simple
case of this is averaging two similar images: the local variance will go
_down_ because you've blurred out detail and noise that varied between the two
images.

Thus, as you average large numbers of images together, the composite you get
is not necessarily representative of any of those that went in, and for that
matter is not necessarily useful for any purpose at all, given that it didn't
retain a lot of the properties of the input images.

~~~
roundsquare
Thats a great point. Two things come to mind:

1) Even if your wrong, and this does make a statement about how we perceive
real faces, then contrast would only be a really useful indicator in the case
of a _very_ average face. Generally speaking it would probably be a very weak
variable in our analysis.

2) It seems like they needed to find a way to separate out just the
experimental variable in a way to make its amplitude higher than other
variables. The only other way I can think of is to find someone who looks
pretty much like the image. When looking at it, I don't see anything that
makes me think its a composite (or strange, etc...).

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bprater
Consider me completely surprised. I'm still looking at both photos and trying
to figure out why I key one in as male and one as female. And then trying to
resolve that it's the same face!

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randallsquared
I couldn't tell which one was supposed to seem female and which male, myself,
although I have some problem differentiating faces, anyway.

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bd
The difference is much easier to perceive after further increase of contrast
and brightness:

[http://alteredqualia.com/visualization/hn/illusion-of-
sex.pn...](http://alteredqualia.com/visualization/hn/illusion-of-sex.png)

~~~
randallsquared
Indeed. I had no trouble at all with the top one. Well, "trouble", given that
this is an error. :)

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pg
I wonder if merely increasing the contrast of the lips is sufficient. Any
photoshop experts want to try?

~~~
greendestiny
<http://imgur.com/DPHAI>

Although I used GIMP and I'm no expert. I'd say it's not as clearly masculine
as the first version. *Edit: It's a version with the right subject copied from
the left and the lips with less contrast - the original images were generated
from a middle contrast image that isn't available.

~~~
pg
Interesting, but it was the other case I was curious about: what happens if
you give the "masculine" higher contrast lips?

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greendestiny
<http://imgur.com/wPIfm>

So now the left is also the masculine image, but the lips have had their
contrast increased.

Actually just playing with it, I can't turn the whole male image into the
female one or vice versa. The GIMP tools probably have a subtly different
effect than the ones the paper used.

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araneae
Well, I guess this explains why women wear eye and lip make-up.

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m_eiman
Do we have data from other cultures on this? Is makeup used to achieve the
same effects in "all" cultures, especially ones that haven't been in contact
with ours? Kinda hard to find new cultures to compare with, but descriptions
from old time explorers etc should be useful.

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louislouis
Majority of Asian girls, be it Chinese, Japanese, Korean don't like to be
tanned. Having light skin is seen as beautiful. I guess this could be related.

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bonaldi
Did the copy get this right? It says the face with more contrast is perceived
as female, but to me the more contrasty face is the one on the right, which I
see as male. Adding to this, in my days as a retouch man, we'd add shadows and
contrast to men's portraits, but remove it and soften for women's.

~~~
timr
The pic on the right is definitely less contrasty than the one on the left.
Look at the lips relative to the skin.

That said, it looks like it was a non-linear change to the contrast curve. The
eyebrows have roughly the same tone in both images, as do the eyes. If I had
to guess, the contrast was adjusted in the mid-gray region, with the extremes
left unaffected. I'm also guessing that this illusion has to do with the
contrast of skin tone between facial features -- not facial shadows (which can
definitely affect the perception of beauty).

~~~
colanderman
While the eyes look the same to me, the eyebrows look much lighter (and
therefore thinner) to me in the higher-contrast image. (Perhaps we have
different monitor curves?) I wish they had kept them the same, and only
adjusted the contrast of the cheeks.

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bprater
I'd like to hear a theory about why this might be evolutionarily true. Was it
because the men were out in the sun all day, decreasing the contrast of their
skin, while women working together tend to have more contrast because they
likely lived and worked in the shade?

~~~
colanderman
I wouldn't think evolution has anything to do with it. Quite simply, the face
with lower contrast is perceived to be _flatter_. (The reason is purely
geometric -- a curvier surface contains a wider range of angles-of-incidence
with respect to the lighting source, thus resulting in a higher-contrast
image.)

By placing the two images next to each other, our brain assumes that they are
illuminated by the same lighting source, immediately tags one as "round" and
one as "flat". Women, by the very nature of having "higher cheekbones" (and
typically more facial fat), have rounder cheeks. Thus, if the brain tries to
tag the two images as different sexes, it's much more likely to tag the
higher-contrast (rounder-looking) face as female and the lower-contrast
(flatter-looking) face as male.

Helping (hurting?) the situation is also the fact that the black level of the
eyebrows was not kept constant when adjusting the contrast, thus causing them
to lighten and look thinner in the higher-contrast image. Women tend to have
thinner eyebrows (at least in modern society, due to the fashion trend of
eyebrow plucking), no doubt lending weight to the brain's decision.

As to why women have higher cheekbones and more facial fat, well that question
I'll have to defer to an evolutionary biologist :)

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arithmetic
The example here (and the theory that the more the contrast, the more
"female") is too black-and-white (no pun intended). It's not just contrast -
there is a reason why women are called the "fairer sex". A face that is
whiter, has no visible facial hair (and smooth skin) is natually perceived as
female.

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emilis_info
Why change "sex" into "gender" in title?

The original article title and the scientific article title have the word
"sex".

Seriously, WTF? I am reminded of "gender mainstreaming" conspiracy theories
some of my friends have. Is word "sex" a taboo?

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emilis_info
Yay! A taboo!

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TrevorJ
I don't really think this classifies as an illusion. Granted, it is
fascinating that a simple change in contrast can cause our perception to
change, but I don't quite track with how this is considered an illusion.

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zby
The 'male' picture seems darker - did they control for that?

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modelic3
The post doesn't mention which is which. Holy shit. What if I got it wrong?
(Please don't be alarmed. I'm just being overly dramatic.)

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ElbertF
It does actually.

"One face was created by increasing the contrast of the androgynous face,
while the other face was created by decreasing the contrast. The face with
more contrast is perceived as female, while the face with less contrast is
perceived as male."

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rpcutts
You mean the illusion of sex. Sex and Gender are not the same.

