Ba? Fa!

By Phil Plait | September 19, 2011 6:30 am

Via MadArtLab comes this amazing optical/aural illusion that you have to see and hear to believe!

Cool, isn’t it? I’ve heard (haha) of this illusion before — it’s called the McGurk effect — but it’s still fun to see it done this way. When the man is shown side-by-side saying it, switch your attention back and forth between them with each syllable. Even knowing it’s an illusion, it’s still overwhelming. I can’t not hear it.

I would venture to guess that this is related to the audio version of pareidolia; seeing patterns in random shapes. This sort of thing is why people think they hear words when songs are played backwards, but that’s completely wrong, just like seeing Elvis in a bit of reflected light. If you don’t think this is possible, then simply watch this video of Carmina Burana and prepare to laugh your head off.

As always, the lesson here is that while we think our senses give us a clear view of the world, they not only don’t, they can really screw it up. You can’t always trust your what you see or hear! In fact, you rarely can. That’s why we invented science.


Related posts:

- Carmina Buraneidolia
- ?eb ecneicsitna nac yfoog woH
- The Hallmark of a black hole
- Cosmically creepy chords

CATEGORIZED UNDER: Cool stuff, illusion
MORE ABOUT: McGurk effect

Comments (50)

  1. Gehackte

    awesome, thanks for posting this

  2. Roach

    So what does it mean if I almost always hear “ba” regardless of what the picture is?

    Interestingly, when the narrator is talking over the sound and they’re showing the one that’s supposed to trick us, I can sometimes (not always) hear something that might be a “fa,” but as soon as she stops talking it’s definitely “ba” to me.

  3. CJSF

    I love this stuff! And Phil, thanks for the post, because you provided a link to your older post with the church hymn with the hysterical lyrics! Yay!

    CJSF

  4. Grant Gordon

    That’s absolutely incredible. The brain is such a fascinating device.

  5. Chris

    watch this video of Carmina Burana and prepare to laugh your head off.
    I was all prepared to laugh but unfortunately Schott Music didn’t laugh as much and told youtube to remove the video :-(

    OK found a new link
    http://www.dailymotion.com/video/x5k8ip_ytmnd-carmina-burana-alternate-lyri_fun
    Now I’m laughing :-)

  6. James

    What about the distinction between “Ba” and “Pa”? The difference in the lips is more subtle (being a sort of inward curling for “Pa” vs. the simple pressing together of “Ba”.

  7. Bigfoot

    Very effective! Holy buck!

  8. Paul from VA

    How long until someone uses this in a music video to sneak something past the censors?

  9. Dragonchild

    I like the tone of this illusion post a lot more than the last one, but you tripped up at the very end. We can RARELY trust our senses? Aaargh!

    Sigh. . . I don’t want to be annoying, but in the absence of true objectivity, I think proper perspective is very important here. In most cases, you can trust what you see just fine. In fact, it’s what keeps you alive and allows you to function in most cases. You can’t NOT trust them. Do you drive with your eyes closed? (Yes, some blind people do quite well but there are definitely things they can’t do by themselves.) You trust your senses to get you through each day; just try not to and see how far you get.

    These illusions are more accurately described as “stress tests” that reveal how our eyes and ears process information. What we need to keep in mind, definitely, is that our senses are NOT OBJECTIVE. Apparently that’s not the point, though people like to believe it is. It’s not — here is where Phil is 100% correct. But while objectivity is critical to science, it’s not for living, and here’s where some perspective is in order. Our vision is analogous to a fisheye lens — distorted, but useful precisely because it is. To get the information we need we sacrifice accuracy and objectivity — but that doesn’t make it untrustworthy. The distortion of fisheye lenses is accepted precisely because people are aware of the trade-off. Back to human vision, like a fisheye lens, we can’t possibly get the information we need without sacrificing some accuracy and objectivity. It’s not a flaw; it’s a requirement. The price is some distortion, but it’s the only practical way our senses can help us in the most efficient way possible.

    It’s not the distortion that’s untrustworthy. It’s not knowing it’s there that’s dangerous. Science helped us discover how our own senses worked, and helped us get at the objective truth.

  10. PayasYouStargaze

    My mind is officially flown ;)

  11. James

    There’s an interesting effect at the 2:51 mark. The speaker is a ghostly figure, and I wondered why they were distorting him so much. When the focus shifted from the background to clearly show the speaker, it didn’t seem to be nearly as odd.

    I suppose that may be more of a learned viewpoint, but the former was far more striking than the latter.

  12. Chris

    I remember this being a fascinating edition of Horizon – well worth watching if you can find it anywhere.

  13. JonMcP

    If I were the type to enjoy the effects of certain cannabinoid I probably would want to watch this again and again and again….

  14. Chief

    I guess lipreading screws it up. Understand the logic behind it though.

  15. I wonder if this is related to why, when I’m trying to find the source of some sound, I often close my eyes?

    Though I have to agree somewhat with Roach (#2) that I usually heard “ba”, regardless of which video I was looking at — _if_ I was thinking about it. Typically, I did hear “fa” if I wasn’t concentrating.

    (And I remember that Carmina Burana video from what you first posted it.)

  16. In (written) Japanese “Ba” is actually “Ha” plus an extra (diacritical?) mark over it – at least in two of their alphabets – the hiragana and katakana ones. (Click my name for Nihongo’s wiki-basics.)

    Wonder if they hear ‘ha’ not ‘fa’ given that liguistic context?

  17. This is a really cool effect!

    > As always, the lesson here is that while we think our senses give us a clear view of the world, they not only don’t, they can really screw it up.

    Vision is an incredibly active, complicated process. We see by piecing together tiny swatches of extremely high-res, high-color imagery into an asynchronously-updated tapestry, built up through a semiautomatic process that tries to track interesting features (which operates on a feedback loop, guided by broad filters run on the working version of the tapestry itself). The result looks to us like a roughly static picture/camera image, but that’s only because that’s the most convenient way for our brain to summarize the data it’s gathering through a huge amount of detective work. If any one part of that process became a little less fine-tuned, the number of optical illusions would skyrocket as the complex workings of the vision process our brain is used to became much more apparent.

    I think these “screwups” are really revealing errors, when we push a system outside its normal operating parameters and discover that it’s not at all what we thought. Rather than thinking of optical illusions as examples of our vision “breaking” under us, I think it’s more like walking too far off the edge of a movie set, and suddenly being able to see that the houses around you have no backs.

  18. WJM

    I agree, Dave, frains are wierd.

  19. And of course, I immediately thought of The Day of the Dolphin. “Fa LOVES Pa!”

    (Check it out on Wikipedia – that movie has the funniest promotional tagline possible, and certainly not one that could be copied by other films!)

  20. Gary Ansorge

    ,,,and as every musician knows, to hear better,,,close your eyes(Hey. It works for me.)

    Gary 7

  21. …hmmm. I just watched this with the picture offscreen, and I’m hearing “bhA BA fA, bhA BA fA.” I’d love to see a waveform analysis of these sounds. I think a little bit of deliberate ambiguity may have been introduced (much like in Blade Runner, when Rutger Hauer’s replicant says to Tyrell “I want more life, father!” – only Hauer deliberately slurred the word “father” so it could sound like something else at the same time.)

  22. Gary Ansorge

    2. Roach

    “So what does it mean if I almost always hear “ba” regardless of what the picture is?”

    It just means your brain is wired differently,,,or you’re blind,,,

    Gary 7

  23. RobT

    I never actually hear Fa with an F, and I sometimes hear Va, but most of the time it sounds slightly different from Ba, like a combination of Ba and Va, when looking at the face supposedly saying Fa. I also agree there seems to be some ambiguity in how the speaker is saying Ba as it never seems too clear to begin with whether looking at the face saying Ba or with my eyes closed.

  24. Peptron

    I am really a fan of illusions, but sadly it seems that the McGurk effect doesn’t work on me…

    I don’t know if there is a link, but I know that I cannot look at people’s eyes and pay attention to what they are saying at the same time. If I do, it’s either that I look and don’t listen or I listen and don’t look. It might be that my brain doesn’t do this “merging” of image and sound in communication.

  25. JohnnyV

    There must be a regional component to getting or hearing this illusion.
    I’ll admit there’s some ambiguity in the way his pronouncement is done, but I hear a clear distinction between Ba, Va and Fa.
    Yes, Va and Fa. At least in my native tongue, danish, the three sounds Ba, Va and Fa are clearly distinct and easily recognizable as such – visual component or not. He muddles up Va and Fa in some of the examples he gives, but even with my eyes closed, I can clearly hear when it Ba, Va or Fa.

    One man’s illusion is another man’s reality apparently :)

  26. sad

    sorry to say but i think im one of the low % that is not getting touched by this illusion (other works for me).
    I have always heard ba-ba-ba no matter what kind of visual they showed me … had read the first sentence – watch the video twice and had to read the text after – to understand the illusion :/

  27. Sili

    Odd. Usually the effect is far stronger with me, but I had to struggle to even get a hint of /fa/ this time. I think it’s because they kept speaking over the demonstration of /fa/ while being relatively silent for the /ba/s.

  28. Oh, oh, oh,
    Totus rideo.

  29. Random Excess

    I enjoy reading the conspiracy people’s comments that something is fishy about the audio, that somehow the effect is the result of some actual difference in the way “ba” is being pronounced. Because everyone looks away, looks to the left side, looks to the right side in a predictable pattern, amirite? If you do not hear the effect that is one thing, the visual clues are not contributing significantly to your audio perception… but, if you are hearing the difference in sound, then go ahead and listen but do not look. Note what you hear. Look only at the left. Note what you hear. Look only at the right. Note what you hear. THEN REPORT YOUR FINDINGS… your speculation of audio manipulation is as embarrassing as it is comical.

  30. Melissa Dow

    “You can’t always trust your what you see or hear! In fact, you rarely can. That’s why we invented science.”

    I’m all for science, but this doesn’t seem like a great argument to me. I mean, isn’t science based on *observation* (i.e. what we see or hear)? I’m not even sure that repeated observation is a good defense, because the researcher in the video admits that he’s repeatedly fooled by the effect.

  31. Stan

    WOO_HOOO!!!!!!!!!!!!!! I’m an animator, and former teacher of animation, and this is an incredibly elegant explanation of something we’ve dealt with for years. Specifically, doing lip-synch sound animation. It doesn’t (or shouldn’t) take a tyro too long to notice that if you try and draw lip positions for every phoneme on the soundtrack, the “sound-synch” effect may be a lot less effective than if you just drew an open mouth for vowels and a slack or closed mouth for consonants. I’ve had to lead oh-so-many students past this basic knowledge, which we animators mostly dealt with heuristically: draw your mouths as you wish, but the viewer’s brains will synch the lips– provided you don’t get in the way.
    (note, for enthusiasts only: Treg Brown, Chuck Jones’ sound editor started using gongs, horns, and bells to replace the standard “bang! boom!” noises in the later Road Runner cartoons. It worked great, and was as funny as hell. I’ve done the same thing every time anyone will let me.)

  32. orkybash

    The carmina burana video you linked to is unfortunately removed due to a copyright claim. Too bad, I’m always a fan of alternate hearings of lyrics!

  33. Joseph G

    This makes a lot of sense to me. I was born with a condition that causes hearing loss, and at various points in my life my hearing has improved or deteriorated significantly (often as the result of surgery; ie one surgery makes my hearing worse, the next one reconstructs the stuff taken out in the first one). I finally have hearing aids now, thank FSM, but there were points in my life when, looking back, I realize that the majority of “listening” I did was actually lip-reading. If my eyes were closed, for example, I simply couldn’t understand people. I actually noticed that I could usually “hear” the people who I know particularly well, better – even when I couldn’t really hear them at all due to background noise or something. I believe this is due to the fact that if I’m intimately familiar with their faces and pronunciation, I can better interpret their lip movements.
    All this stuff is hindsight, though – I never realized I was reading lips at the time, and it only really all “fell into place for me” a few years ago.

  34. Joseph G

    That Carmina Burana vid is LOLsome!

    Salsa cookies!
    Windmill cookies!
    They’ll give you gonorrhea!
    This octopus!
    Let’s give him boots!

    Best laugh I’ve had all day :) Dang, what does that say about my life :-P

    Also, I laughed way too hard at “suck juice from moose”.
    Wayyyyyyyyyy too hard.

  35. Joseph G

    Also, am I the only one who pictures a bright red Russian space shuttle when I see “Carmina Burana”?

  36. Nigel Depledge

    The BA said:

    You can’t always trust your what you see or hear!

    [My bolding]

    Erm … que?

    Can we trust what we type? Or what you type? Or anything?

  37. Nigel Depledge

    CJSF (3) said:

    the church hymn with the hysterical lyrics

    Church hymn? You mean Carmina burana? Oh, no. No, indeed!

    Carmina burana is subtitled cantiones profanae or, very roughly, “dirty songs”.

    Here’s an example:
    Si puer cum puellula / Moraretur in cellula / Felix coniunctio!

    When a boy comes upon a girl in the woods, happy their joining! (approximately, and it certainly contains a nudge and a wink).

  38. Nigel Depledge

    Dragonchild (9) said:

    To get the information we need we sacrifice accuracy and objectivity — but that doesn’t make it untrustworthy. The distortion of fisheye lenses is accepted precisely because people are aware of the trade-off. Back to human vision, like a fisheye lens, we can’t possibly get the information we need without sacrificing some accuracy and objectivity. It’s not a flaw; it’s a requirement. The price is some distortion, but it’s the only practical way our senses can help us in the most efficient way possible.

    It’s not the distortion that’s untrustworthy. It’s not knowing it’s there that’s dangerous. Science helped us discover how our own senses worked, and helped us get at the objective truth.

    There’s a hell of a lot more to it than this.

    Our perception of the world is unreliable for more reasons than this.

    For example, there’s change blindness – the phenomenon whereby we fail to notice something change unless we are looking directly at it when it changes. This arises from the way we observe the world and the fact that our vision shuts down briefly while our eyes flick from one focus of attention to another (sacchades).

    There’s also attention blindness – when we focus intently on one aspect of our field of view, we cannot perceive anything in the rest of it (there’s the famous experiment where volunteers watch a video of basketball players passing the ball, and are asked to count the number of passes, and they fail to notice the guy in the gorilla suit who enters the scene and stands right in the middle of the action for several seconds).

    In addition to these failures of our perceptive systems to actually give us data about the world, there are many ways in which our mind tricks us into seeing things that are not there – most of which come under the aegis of paraeidolia. An example of this is if you are trying to observe small birds in woodland. It is sometimes amazing how often you can think you see a bird when what you are actually seeing is a couple of twigs or a bunch of leaves.

    In short, people really are unreliable witnesses of anything that does not match their expectations, and the BA is right to exhort us not to trust our perceptions.

  39. Catalyst

    @#30 I listened to the piece the whole way through with my eyes shut and I did notice some things. First, he seems to say the word ‘ba’ three times, and it is this audio clip that keeps playing. He does accent the second ‘b’ sound, but other than that, pretty consistent. However, every time the narrator set up looking for a ‘fa’ sound, the pitch of the first ‘ah’ sound is dramatically increased, with the following sounds also at that increased pitch ( listen to :48 and 1:26) These two sounds, the original and pitch shifted, are used as necessary. It seems likely that this was done in the editing room as part of normal sound cleanup rather than a deliberate attempt to mislead. That and the years of research which inspired the show in the first place.

    On a side note, I wonder if this is related to Grimm’s law? In general, in any given language, the ‘p’ descends to ‘b’, which then descends to ‘f’, and sometimes to ‘v’. There is little change in facial expression between both ‘p to b’ and ‘f to v’, so any visual illusion would be hampered. The difference in sound between ‘p’ and ‘v’ is much greater than ‘b’ and ‘f’, and so the visual illusion might not be strong enough to overcome the difference in sound. By this logic, ‘b’ and ‘f’ would work best for the illusion by having the greatest facial change with the smallest audio change. This might explain why the experiment is known for it’s ‘bah’ ‘fah’ sounds, and why some people in this thread reported hearing other sounds like ‘vah’.

  40. Joseph G

    @Nigel Depledge: Pardon my n00bness, but how do you indent quotes like that?

    Also, I wonder if this effect would be any stronger (or weaker) when real words are used? For instance, if the guy in the video had been saying “base”, would this morph into “face” (and even “vase”, see Catalyst’s comment #40) just as effectively?

  41. Unaspammer

    I also hear only “ba”s. I have noted in the past that I am utterly incapable of lip-reading — for example, it always frustrates me in shows when they have two characters mouthing words at each other, because I have no clue what they’re saying — so I wonder if that may be related.

  42. TR

    If you liked the Carmina Burana video, go to Google, type in “benny lava” and hit “I’m Feeling Lucky.” But you might want to put on some Depends first! (Note: Some of the subtitles are a bit risque/vulgar, but all of the imagery and audio are SFW.)

  43. Nigel Depledge

    Joseph G (41) said:

    @Nigel Depledge: Pardon my n00bness, but how do you indent quotes like that?

    The tag is “blockquote”, enclosed between “less than” and “greater than” symbols (sometimes incorrectly called angle brackets). To return to your normal text, as you’d expect, simply “/blockquote” within the same pair of symbols.

  44. Nigel Depledge

    To clarify (because I realised what I wrote above might be ambiguous) – each blockquote tag should have its own pair of “” symbols.

  45. Hemogoblin

    So it works with “ba” and “fa” as well? Interesting!
    There’s another version – the only I’d seen/heard (seard?) before – where you use “ba” for the audio and “ga” for the video. Interestingly enough, the result comes out as neither “ba” nor “ga” but “da“.

  46. Joseph G

    @Nigel:

    To clarify (because I realised what I wrote above might be ambiguous) – each blockquote tag should have its own pair of “” symbols.

    Heh, I know how HTML works, thanks.
    Well, ok, obviously I don’t know it that well, but… er… yeah. Thanks. :-P

  47. Nigel Depledge

    That’s weird.

    When I first posted #45, it displayed the less-than and greater-than symbols. Now it does not.

  48. Interesting to hear there are a minority of people where it doesn’t work. I’m not hugely surprised… I definitely experience the effect, but I think it is weaker than in others. Phil says, for instance, “I can’t not hear it.” I can — but only just barely. If I look at the guy mouthing “Fa” but concentrate really hard on telling myself he is saying “Ba”, I hear “Ba” a little more than half the time. (The reverse does not work, i.e. if I look at “Ba” but tell myself he’s saying “Fa”, I still hear “Ba”)

    However, if I just listen and look without actively thinking “Ba”, the effect works on me every time. And even if I do think to myself “Ba ba ba”, I still hear “Fa” a non-trivial amount of the time.

    But it does appear susceptibility to the effect is on a continuum. Fascinating!

  49. Lorena

    I didn’t hear it. In fact, I had to watch the video a second time because I thought I hadn’t understood what it was about, but then I realised I had understood it, it was just that the illusion didn’t work on me. I always hear BA or something more close to PA actually, but never Fa. Maybe because my first language is spanish????

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