Cognitive Daily

The Rokeby Venus by Diego Velázquez is a good example of a very common illusion in many paintings:

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ResearchBlogging.orgMost viewers would say this picture depicts a woman viewing her own reflection in a mirror. But based on the orientation of the mirror, it’s actually physically impossible for her to see her own reflection. Since we can see her face, then if she could see face in the mirror, her head would have to be positioned between us and the the mirror. At best all she would be able to see is us (or rather, the painter painting her picture).

Art critics have suggested that there’s another problem with this particular painting. The head of Venus in the mirror is also much too large, they say: it’s roughly the size of her face, which would be impossible if the observer were standing relatively close to Venus — it should probably be at least half the size of the real thing (though if you assume the viewer is standing a relatively large distance away, this problem disappears).

Marco Bertamini, Richard Latto, and Alice Spooner confirmed this “Venus effect” by asking twelve observers to describe the picture in their own words. Seventy-five percent said it depicted a woman looking at herself in a mirror. So even though the situation they describe would be physically impossible, it’s by far the most common explanation of what they see.

After looking a dozens of famous paintings involving people regarding themselves in mirrors, the researchers found that in most cases the painter made some effort to replicate the experience of looking in the mirror, not necessarily what the painter might have seen while painting. Take a look at these two pictures, for example:

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The painting on the left, Vasari’s Toilet of Venus, shows Venus looking at the familiar mirror. The image we see is a face looking back at her. But if this was a real scene, even acknowledging that she couldn’t actually see herself in the mirror at the same time we do, the orientation of the face in the mirror is wrong, too. For us to see a face pointing to the left, the mirror would have to be much closer to use than Venus is. But from the position of the attendant’s arm relative to Venus’, it’s impossible for that to be the case. So the painter couldn’t have seen this view while he was making the painting.

The other painting, Couple with Mirror by Hans von Aachen, offers and even more implausible view. It’s hard to imagine how it would be remotely possible to see the woman’s face based on the orientation of the mirror in the painting. What’s more, though it’s difficult to see in this jpeg, the mirror-image’s eyes are shifted to the left, looking back at the woman, while she stares straight ahead.

The researchers say that artists deliberately manipulated these images to create the impression we get when looking at ourselves in the mirror. If you can see your mirror image, it’s always looking straight back at you, just like the images in the paintings appear to be looking back at their beholders. If the painters had actually painted these images the way they saw them, the effect may have been less realistic.

Bertamini, M., Latto, R., & Spooner, A. (2003). The Venus effect: people’s understanding of mirror reflections in paintings Perception, 32 (5), 593-599 DOI: 10.1068/p3418

Comments

  1. #1 peter
    March 26, 2009

    one does have to remember… art is only an interpretation of real life, not a reflection.

    sigh…

  2. #2 Phillip IV
    March 26, 2009

    Frankly, I don’t think the artists have much choice in that matter – if the task is to illustrate the concept of ‘somebody looking at themselves in a mirror’, actually showing the subject’s reflection (even if physically impossible) is probably the only way to communicate the idea immediately and directly.

    If the artists had depicted realistic reflections (i.e. some nondescript corner of the other side of the room), arriving at the same concept of ‘somebody looking at themselves in a mirror’ would have required a certain degree of abstract thinking on the part of a viewer (‘I see only another part of the room, but judging by the angle Venus would probably see her own reflection’), and thus prevented the immediate and emotional perception the artists likely wanted.

    It would have been interesting to have had a kind of control group for this – if the paintings had been modified to feature realistic reflections, would the percentage of viewers that describe them as showing ‘people looking at themselves’ have gone up or down? I think it might actually have gone down, paradoxical as that might appear.

  3. #3 Aler
    March 26, 2009

    I agree with Phillip – the 75% of people who declared that this was a painting of Venus looking at herself in the mirror were correct, even if this is not physically correct.

    It would be interesting to see this experiment replicated with a photograph instead of a painting. We expect painterly shortcuts and tricks, but we usually expect a photograph to document reality.

  4. #4 tbell
    March 26, 2009

    a tiny quibble,
    her face could appear larger in the mirror if it were curved. I don’t know when these types of mirrors were first made, but ‘magnifying’ mirrors are quite common now, especially for examining ones face. Not sure how hard it would be to make a good polished metal surface mirror with the right curvature.

  5. #5 curious
    March 26, 2009

    this is a case where the survey wording/methodology may have been misleading (not necessarily intentionally) enough to cause the “effect” that was supposedly observed.

    when i look at these images, it is immediately obvious to me that they are not optically correct and that the mirrors’ contents are not depicted realistically. but if you simply asked me to describe what was shown in the painting (which i would interpret to mean, describe what the artist was trying to represent), i might simply say it’s a painting of someone looking in a mirror, even though i can see that it’s not done in a physically accurate manner.

    the full-text of the paper (available here http://www.liv.ac.uk/vp/Publications/BertaminiLattoSpooner2003.pdf ) does not give the word-for-word phrasing of the survey question, but says that they “asked twelve naive observers to describe the scene… Nine volunteered the description that Venus is looking at herself in the mirror.”

    this question does not seem remotely sufficient to determine whether people are falling for the impossible-reflection illusion–it’s just asking what the contents of the painting are. there should be a follow-up question about the realism or accuracy of the depiction.

    i think their results say more about a weak methodology than about the reality of a “venus effect.”

  6. #6 Matthew
    March 26, 2009

    As for the size of the object in the mirror – take a mirror, and notice what percentage of it your face takes up. Then walk to the other side of the room, and look again.

    Try it, you’ll probably be surprised.

  7. #7 arthistory girl
    March 26, 2009

    What is more significant about this painting is how Venus’ back is towards the viewer, and not her front, as conventionally seen with Venus paintings. Why would Velasquez have chosen the Venus to be in this position? Also, mirrors are often tools used by the artist to show off their painterly skills. Another sidenote, Velasquez’ Rokeby painting was attacked TWICE by visitors!

  8. #8 Alex M.
    March 26, 2009

    Here’s another illusion: the picture seems to depict a cherub. Cherubs, in the sense of magical winged boys who can fly, are physically impossible. Therefore the picture doesn’t *really* depict a cherub after all!

  9. #9 Dave Munger
    March 26, 2009

    Matthew:
    But that doesn’t work for someone else’s face in a mirror.

    Curious:
    This article doesn’t really address whether people fall for the illusion, but some other research by this same team suggests that people don’t have a very good grasp of the basic physics behind mirrors, including some of the phenomena discussed here. What’s most interesting to me is the clear evidence that artists must necessarily have been aware of the “deception” while creating the works, Alex M.’s joke notwithstanding.

  10. #10 LtStorm
    March 26, 2009

    Sounds like an application of the Coconut Effect.

    I.E. unrealistic things look more realistic because of how we’re used to seeing them depicted. We always see coconuts as being brown hairy things with divots in them, so when we’re presented with a green smooth-husked coconut straight off the tree, it’s confusing and unrealistic looking.

  11. #11 Lilian Nattel
    March 26, 2009

    It’s fiction. To use a parallel example in writing, if anyone wrote dialogue as it actually is (for example when you see it transcribed), it would be unreadable.

  12. #12 DDeden
    March 26, 2009

    I had an entirely different interpretation of the third picture: the couple’s child (not actually in the picture, but would be at bottom) is looking at her reflection in the mirror held by her mother. The mother and father are not looking in the mirror, but just angling it correctly (imagine if the child had her hands full, asking her mother to hold it for her). Still a bit awkward though.

  13. #13 Markummm
    March 26, 2009

    Why is no one addressing the fact that the first one is of a naked broad on a hefty bag staring at a fat naked baby with a dead bird strapped to its back?

  14. #14 Timothy Claypole
    March 27, 2009

    This whole laboured discussion is based on a misperception. Velazquez’s Venus isn’t looking at herself in the mirror at all, she’s looking at us. She sees the reflection of the onlooker’s face, the onlooker sees the reflection of hers. The optical situation as depicted by Velazquez does actually work – not that that is really the point of the painting, it being a densely symbolic and enigmatic work of art, and all.

  15. #15 Stefano Bertolo
    March 27, 2009

    Roberto Casati has documented a similar effect for shadows:

    http://www.shadowes.org/wiki/index.php?title=Main_Page#Recent_work_on_shadows

  16. #16 Ian
    March 27, 2009

    Nice blog about mirrors. When will you do smoke?!

  17. #17 Ian
    March 27, 2009

    Top 10 Reasons Why the Mirror Reflection Looks Wrong:

    10. The speed of light was slower back then

    9. The artists all had defective vision, which also explains the short paint brushes

    8. Quantum chromodynamics

    7. Japanese artists are afraid of losing face

    6. As the oil aged and cracked, so, too, did the mirror, distorting the image

    5. The impressionists made a poor impression

    4. The pointillists didn’t see the point

    3. The neo-classicists were trying to emulate “The Matrix”

    2. The post-modernists got behind with their work (you can actually see the behind in the Rokeby Venus)

    1. Hello Dali!

    On a serious note, how, exactly, did Bertamini, Latto, & Spooner determine that the angles were wrong? Did they use real people to emulate the pictures, or did they simply do the math? Might the artists have used more than one mirror to get the reflection they wanted in some of those paintings?

  18. #18 A.K.
    March 27, 2009

    Thanks for another interesting “perspective” on art and perception. The comment threads are always interesting, too. Hope you’ll continue to write more on related topics! Regarding the use of mirrors and reflections in paintings: perhaps the artist’s intent in using mirrors as a device is to make a symbolic comment on narcissism, or self knowledge, or self reflection. The reflected image, whether larger than it should be, prettier or homelier than it should be, or however distorted it may be, is intended as metaphor, not a mathematically accurate depiction.

  19. #19 Gordon Worley
    March 27, 2009

    It may only be me, but what you show here of Couple with Mirror (I assume this is cropped from the full image) appears not only to have problems with the mirror, but problems correctly showing the spacial relationship of objects. In particular, the mirror appears to be pointed at, well, nothing, yet it has an image in it. Very confusing to the eyes.

  20. #20 Donna B.
    March 27, 2009

    Ian, you made my day!

  21. #21 Marco Bertamini
    March 30, 2009

    I would like to thank the author of the article and also those who wrote comments. It is nice to know that other people find mirrors interesting. Just a few quick notes to try and answer some questions:

    1. We have tried to be careful not to make statements about what the artists intended. The Venus effect is not about that, it is about how observers interpret an image.

    2. The Venus effect is not specific to paintings. Indeed the best examples are on TV and in movies. Actors can pretend that they see themselves nicely framed in a mirror while the camera is to the side, showing both actor and the actor’s reflection. This is convenient because if the camera were to be behind the actor, without special effects, we would see it in the mirror.

    3. We have tried with photographs and even in a real room, the Venus effect is very robust.

    4. There are a few other interesting aspects of how we understand mirrors. The issue of size on the glass surface is fascinating, unfortunately it is too complicated to discuss in a couple of sentences (if interested take a look at Bertamini and Parks 2005 in Cognition).

    5. What the article says about the size of the head is not correct. The image of the head does not have to be small, it is possible for it to be approximately the same as the head we see as long as we are not too close to the woman (roughly speaking some 6 or 7 meters away). See the paper I mentioned earlier for the geometrical analysis.

    6. The “Couple with Mirror” is not cropped.

    Thanks again!

    Marco Bertamini
    http://www.liv.ac.uk/vp/Publications/publications.html

  22. #22 barry jackson
    March 30, 2009

    Blimey! You mean paintings don’t actually reproduce accurately the optical image of the world in front of them? Well, there’s news! We might learn next that the painting of Rokeby Venus’s hair is not actually made up of separate hairs…

  23. #23 Dave Munger
    April 6, 2009

    Thanks for your comments, Marco. I fixed the post to clarify the issue with the size of Venus’s reflection.

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