Sex and face recognition: Are male and female faces processed completely separately?

Take a look at these photos of Jim and Nora:

i-3f91e9042c1bdeaba9d63787bb3b1d04-jaquet1.jpg

ResearchBlogging.orgThey've clearly been distorted (using the "spherize" filter in Photoshop), but in opposite directions. Jim's been "expanded" to make more spherical, while Nora has been "contracted" to look more concave. If you look at these photos for a while, you might have difficulty recognizing how Jim and Nora look normally.

i-050af1a034ce729ccd92bb14f7ab895d-jaquet2.jpg

This is an aftereffect. Aftereffects can be experienced in a number of ways, with dizziness being perhaps the most frequently observed -- spin around a few times with your eyes open and the room will appear to be spinning in the opposite direction. Researchers have found a number of different aftereffects in face perception. If you see a lot of spherically expanded faces, then normal faces will start to look contracted. If you look at a face that has the opposite characteristics of Jim's face, then you might think an "average" face looks like Jim.

Two aftereffects can actually be induced simultaneously. If you look at pictures of Caucasian expanded faces and Chinese contracted faces, then normal Caucasian faces will seem contracted and normal Chinese faces will seem expanded. But there is still some transfer between races: If you look at only contracted Chinese faces, then both Chinese and Caucasian faces will seem expanded (though Caucasian faces won't seem as expanded as Chinese faces).

So a 2005 study by a team led by A.C. Little was rather surprising. They found that some face aftereffects did not transfer from one sex to another. For example, if observers saw male faces with wide-set eyes, then normal male eyes seemed narrow-set, but normal female faces just seemed normal. Similar effects were found for masculinized and feminized faces of both genders.

Emma Jacquet and Gillian Rhodes decided to test these findings with a different type of transformation: the expansion and contraction I showed you above.

They divided 64 students into four groups. Each group saw only either male or female faces, which were only either expanded or contracted. So, for example, the male/expanded group saw six different expanded male faces, for two seconds at a time, flashed in random order, repeatedly for two minutes. Then they were shown a pair of faces of the same male or female. One face was expanded a small amount (10%, compared to 70% during the adaptation phase), and the other was contracted a small amount. They were instructed to choose the more "normal" face. This was repeated for 11 different faces, both male and female. Here are the results:

i-bc18f7029e63730dac14de7f5582bb0f-jaquet3.gif

The graph shows the aftereffects divided by sex and expansion/contraction of the original images seen. A significant aftereffect was observed in every case except when viewers saw contracted female faces and then tried to judge male faces. What's more, there was no significant difference in aftereffects observed when rating faces that were the same sex as the originally viewed faces and faces that were the opposite sex.

Jaquet and Rhodes repeated the study with simultaneous adaptation to male and female faces (e.g. male contracting and female expanding). This time, their results were mixed. They found some sex-specific aftereffects and some that were not.

The researchers say this suggests that while there are some sex differences in aftereffects, for the most part male and female faces are processed in the same way. Little's team's results, which consistently point to sex-specific aftereffects, may be due to the fact that most of the manipulations they did were sex-related (e.g. masculinizing or feminizing a face). Sex clearly plays a role in face recognition and processing, but some aspects of face processing are independent of the sex of the face being processed.

Jaquet, E., & Rhodes, G. (2008). Face aftereffects indicate dissociable, but not distinct, coding of male and female faces. Journal of Experimental Psychology: Human Perception and Performance, 34 (1), 101-112 DOI: 10.1037/0096-1523.34.1.101

More like this

I've created a quick animation of distorted pictures of my son Jim, together with some normal ones. Take a minute or so to watch the animation, then decide if the last picture you're shown looks "normal" to you. Click on the normal (but pre-eyeglasses and braces) photo of Jim below to begin: I'…
Click on the image below to be taken to a quicktime movie showing 9 different faces. When the movie is finished playing, drag the slider back and forth to pick the face you think is the most attractive. The faces are composite images—"average" faces made by morphing together 48 different photos…
VIEWING a stimulus for a prolonged period of time results in a bias in the perception of a stimulus viewed afterwards. For example, after looking at a moving stimulus for some time, a stationary stimulus that is viewed subsequently appears to drift in the opposite direction. These after-effects…
In yesterday's post on afterimages and aftereffects, I mentioned that demonstrations of neural adaptation for a particular feature (in the post, I used the examples of color and motion) is generally taken as evidence of the existence of specific neurons or groups of neurons that detect/process that…

What about androgynous people?

By fullerenedream (not verified) on 13 Aug 2009 #permalink

I would like to see this kind of study applied to other things that are generally agreed to be socially constructed such as race.

I would agree with fullerenedream. Spend some time around people who are transgender, for example, and you will find that it is not so easy to identify sex by facial features.

The same goes for identifying racial characteristics. What about people whose race is not clearly identifiable?

Also are you referring to gender or sex here - gender being how one is categorised socially; sex referring to biological characteristics like genitalia?

Good questions. These studies used individuals that were easily identifiable as one sex (or race) or another. I'm not sure how you'd construct a similar study when these characteristics were less well-defined.

You might also think about objects that are more or less clearly faces, like a coffee mug in the shape of a face, or a line-drawing of a face. How would we process them? Do we perceive them as faces, or as coffee mugs and sheets of paper? Clearly at some point the face-processing system would not be activated and we'd just think of these things as mugs or whatever they are.

The point is, there are mental systems for processing faces in the perceptual system, and there may also be separate systems for processing things like "male faces" and "female faces," and "my-race faces" and "other-race faces." This study shows some of the boundaries between the systems: sometimes the boundaries are heeded, and sometimes they are not.

I would agree with fullerenedream. Spend some time around people who are transgender, for example, and you will find that it is not so easy to identify sex by facial features.

There are no absolutes in nature, our perceptions are based on many simultaneous inputs. There are features or groups of features that statistically (and perhaps through natural selection) are associated with different genders. The fact that some people are androgenous does not mean that there are not male dominant or female dominant facial features, merely that some people are more mixed (and indeed some TG people actually endeavor to enhance, through grooming, makeup and expression, the attributes that associate them with their preferred gender. But over the course of time, there have evolved cross cultural preferences (again not absolute) on the part of heterosexual individuals in their mate selection criteria (face, body build etc), and their potential mates have tended to enhance these features to emphasize their gender rather than de-emphasize it as the TG people are tempted to do.

Why bother...if you need to make a living I guess any question can be studied I just hope no tax dollars are wasted on it.

By wildthing (not verified) on 14 Aug 2009 #permalink

In reply to commentor #6, I feel that any subject is worthy of scientific study for no one knows what the results might lead to in other fields as well. There will never be enough knowledge for mankind to unravel anything as deep and tantalizing as the human brain and its role in consciousness.

These studies used individuals that were easily identifiable as one sex (or race) or another. I'm not sure how you'd construct a similar study when these characteristics were less well-defined.

I disagree. I've known biological women whose faces were very similar to Jim's. Take off the beard and I see a nice full "feminine" face.

In addition, whether or not you define two people as belonging the same race depends very much on your culture. For example, growing up in the US, I always considered people who are identifiable as being from South Asia - India, Pakistan, Bangladesh - as being white. I was surprised to learn, after moving to the UK, that these people are considered to be non-white here.

I think that the point isn't so much that the faces were intrinsically "male" or "female", but that they were *processed as* male versus female. My prediction would be that if you took photographs of the same individuals accoutred in two conditions: with female (hairstyle, earrings, makeup) versus male (again hairstyle, facial hair or stubble, no makeup), you would get the same effect, perhaps even with different photographs of the same individuals (that is, individual A[male accoutrements] would be seen as having (e.g.) wider eyes than individual A[female accoutrements]).

By Greg Shenaut (not verified) on 18 Aug 2009 #permalink

I think that the point isn't so much that the faces were intrinsically "male" or "female", but that they were *processed as* male versus female. My prediction would be that if you took photographs of the same individuals accoutred in two conditions: with female (hairstyle, earrings, makeup) versus male (again hairstyle, facial hair or stubble, no makeup), you would get the same effect, perhaps even with different photographs of the same individuals (that is, individual A[male accoutrements] would be seen as having (e.g.) wider eyes than individual A[female accoutrements]).

I would agree with fullerenedream. Spend some time around people who are transgender, for example, and you will find that it is not so easy to identify sex by facial features.

The same goes for identifying racial characteristics. What about people whose race is not clearly identifiable?

Also are you referring to gender or sex here - gender being how one is categorised socially; sex referring to biological characteristics like genitalia?

These studies used individuals that were easily identifiable as one sex (or race) or another. I'm not sure how you'd construct a similar study when these characteristics were less well-defined.

I disagree. I've known biological women whose faces were very similar to Jim's. Take off the beard and I see a nice full "feminine" face.

In addition, whether or not you define two people as belonging the same race depends very much on your culture. For example, growing up in the US, I always considered people who are identifiable as being from South Asia - India, Pakistan, Bangladesh - as being white. I was surprised to learn, after moving to the UK, that these people are considered to be non-white here.

Is Emma Jacquet related to our own Jennifer Jacquet of the "Guilty Planet" blog, by any chance?