Cognitive Daily

ResearchBlogging.orgWe can quickly spot a face staring at us in a crowd. We can do this much quicker, for example, than we can determine that no one is staring at us, as this movie demonstrates. A grid of 100 pictures of Greta will be flashed for about 1/3 of a second. Can you spot the photos where she’s looking at you? You’ll see two different grids.

Most people are able to detect the staring faces much faster than those looking to the side. But we can also sometimes be fooled by faces, something we discussed on one of the first-ever CogDaily posts:

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In this picture, the eyes for each face are exactly the same, but the face on the right appears to be staring directly at us, while the face on the left seems to be looking off to the viewer’s right.

A similar effect can be achieved in reverse, keeping the head position the same while changing the eyes:

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Faces 1 and 2 are identical except for the eyes, and face 1 appears to be looking at us while face 2 seems to be looking away. Meanwhile, neither face 3 nor face 4, which use the same eyes as faces 1 and 2, seems to be looking at us. So when the only difference between the faces in a group is a subtle difference in eye position, will we still spot the pictures that seem to be looking at us faster?

Hirokazu Doi and Kazuhiro Ueda showed volunteers these faces arranged in groups of nine:

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In every case, eight of the faces were the same. Half the time, the ninth face was subtly different (only the eye orientation was different), and half the time it was the same as the other eight. Viewers pressed a key as quickly as possible to indicate whether all the faces were the same or there was one different face. Here are the results:

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This graph shows the average reaction time when one of the faces was different from the others. When the different face appeared to be looking right at the viewers, they reacted significantly faster than when it was looking slightly to the side.

This occurred even in the case of pictures 1 and 2, where the head orientation was identical.

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A similar pattern was found when all the faces were the same: people took longer to decide that the faces were the same when it was looking straight at them, compared to faces looking away, even when the head orientation is the same.

Doi and Ueda say that in one sense this is unsurprising because staring faces attract our attention faster than faces looking away. But what’s surprising is that we appear to process the whole face (is it looking at us or not?) faster than we process the local features about that face (the orientation of the head and eyes).

Hirokazu Doi, Kazuhiro Ueda (2007). Searching for a perceived stare in the crowd Perception, 36 (5), 773-780 DOI: 10.1068/p5614

Comments

  1. #1 Cyfra
    December 2, 2008

    I had to look at those top two pictures several times before I realized that there even was a difference between them!

  2. #2 Freiddie
    December 2, 2008

    I tried the demo several times and I didn’t see the one looking at me. I gave up and just paused the video instead. I guess I’m not good at face-reading.

  3. #3 Nigel
    December 2, 2008

    The still pictures were clear enough to me (though I do not see anything particularly surprising about the fact that different eye or head orientations will change where a face seems to be looking), but the video demo did not work at all. After several tries, I had to pause it and rewind to see which face is different. Even after doing that, when I replayed the video the grid flashed so quickly that I did not see the different face unless I was deliberately fixating beforehand close to where I now knew it to be. Is the exposure time really meant to be quite so brief? I do not think it provides enough time to saccade to the different face (not for me, anyway).

    Perhaps the problem (or part of it) is that even with the video paused on the grid it is not obvious that the full-face picture of Greta is actually looking at me, probably because it is just too small and blurry to make out much about her eyes (and the fact that she has glasses probably does not help).

    Also, the text says there are two grids, but, after multiple replays and pausings, I only see one. Is the video working correctly?

  4. #4 ...tom...
    December 2, 2008

    Ditto the comments about too fast and too small. Even with repeated tries I was only able to ‘see’ maybe a 3×3 square of the faces and apparently never picked the right area to look at as it played…

    I saw ‘grids’ at approx 4 and 8 seconds. I assume those were the ‘different grids’ promised.

    …tom…

  5. #5 Martin Belanger
    December 2, 2008

    As the others commenters, I can only see the picture of Greta facing me when I pause the video…

    Martin!

  6. #6 Kristjan
    December 3, 2008

    I could not spot the face staring at me for six tries. I am certain that I won’t be able to notice it in the next six attempts either.

  7. #7 Ron
    December 3, 2008

    I did not notice the picture that was looking at me; however on my 5th attempth I did notice a area that seem to be different and when I paused the clip it was the location of the pic looking at me.

  8. #8 RoaldFalcon
    December 3, 2008

    Like the others, I couldn’t detect the unique photo at all until finally pausing the video. When I did pause it to find the other photo, I got the subjective sense that I found it because it broke the pattern rather than because the face was looking at me.

  9. #9 TJ
    December 3, 2008

    The video worked a teeny bit better for me if I clicked through to vimeo, but I still couldn’t really see the faces. But wow! The lego campanile is fantastic! :^)

  10. #10 KC
    December 5, 2008

    I had the same problem with the video going to fast for me to catch the face staring at me. But once paused it seemed to be dramatically different from the others.

    On an unrelated note found that if you pause on the second image you can do the magic eye thing with the image to add some depth to it.

  11. #11 Alex
    December 5, 2008

    Echoing Nigel, Tom, et al… In my opinion the video provided is a poor example. That’s because the quality is low (or the video is compressed, or the size is too small, etc.) that you can barely discern that you’re looking at a face much less the whites (fuzzy grays in this case) of somebody’s eyes. It’s really just a pick-which-one-is-different quiz, not something that represents the topic at hand.

  12. #12 gregorylent
    December 6, 2008

    energy follows intention, what would you expect? the face has nothing to do with it

  13. #13 gh
    December 7, 2008

    Perhaps a better experiment would have been to flash a photo of a crowd of people, with only one of them looking directly into the camera. Although, to be honest, I could hardly make out what was flashed at me. I’m glad to see that I’m not the only one who had to pause the video before attempting to spot the person looking at me.

    To more realistically measure how long it takes a person to spot who’s staring at them, why not have an actual crowd stand in front of a group of actual subjects and act this out?