Imperfect Perception: Illusions, Gestalt Principles of Grouping, and Language Relativism

We learned about sensation and perception in the biopsychology series. But there is a lot more to talk about in the context of psychology, in terms of imperfect perception. Do we always see things the way they really are? Can our minds play tricks on us? How do we perceive groups of objects? How does language affect our perceptions? Some of this stuff might blow your mind!
Script by Caitlyn Finton
Animation by Ignacio Triana: / unraveled
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[@foppishdilletaunt9911]

Sensational vid, Professor Dave.

[@DanyalArcadio]

pun intended i hope

[@kylezo]

I perceive what u did there.

[@rgmafi4900]

This is just great foundational knowledge. I was taught how the checkered shadow illusion works multiple times and NEVER got it. That rectangular connection blew my fucking mind. Thank you sir.

[@TheCgOrion]

I agree. I've seen it several times as well, and I just can't reconcile it before the connection is drawn. Even with my belief in it being the same 😉.

You just revived an interest on human perception I had some time ago.

[@markfarnsworth8685]

Back in the 90s when I was in grad school, my linguistics professors were _highly_ allergic to anything even hinting at Sapir-Whorf. If you chanced to mention that hypothesis, they’d look at you like the hostess of an elegant dinner party would look at a loudly and repeatedly farting guest. I was always puzzled by that because it seems obvious to me that language and perception influence each other. I felt vindicated when I read Guy Deutscher’s book, Through the Language Glass. Great vid, by the way!

[@larrykent196]

Professor Dave, very interesting concept and well done explaining it. Thank you for what you do. Cheers!

[@WanderTheNomad]

I was longing so hard for proof that the two rectangles were actually the same color in that short amount of time between you explaining it and you showing it. I tried to connect the two colors in my mind but I just couldn't do it.

[@lifeisstr4nge]

No fucking way. Its a pattern, and B has to be different, because otherwise it's not a pattern. Wtf

[@davidkolo]

@@lifeisstr4nge that's the part i never get, where does the pattern breakdown

[@philw6056]

@@davidkolo Everything inside the shadow becomes darker and the light tiles in the shadow have the same brightness as the dark tiles outside of the shadow. Without the shadow it would be a perfectly regular light-dark pattern.

[@nateb7638]

@@lifeisstr4nge so there are two theories of color, that color is determined by light reflection, or that color is essentialized in the makeup of matter. This illusion simulates an example of light color theory.

[@madaemon]

For an extra little mind trip, start at 2:40 where Prof Dave has made the bridge, pause it, then press the left arrow once to go back about five seconds. Look back and forth between A and B while it's paused, and even though it's a still frame, the A square will seem to "darken" and the B square "lighten" Even though you've already confirmed they're the same color, your brain forgets and slips back into its original perception. Do it a few times; it's pretty cool!

[@kurage_medusa]

To me, neither square appears darken or lighten, but it still makes one appear darker relative to the other

[@liptonpipton4135]

Great vid Dave! As a Russian I have to say that in Russian language light green means - салатовый (salatoviy) and common green - зелёный (zelonyi). But that not a thing in whole country.

[@arcadiusvincentius3296]

Thanks for another great video! I'm really doing well in my astronomy class because of your videos! Great teacher!!

[@karlwhite2733]

Awesome Prof. Dave

[@helpyourcattodrive]

Thanks, Professor Dave. I listened to your bio vid. I’m inspired.

[@severinkolb1062]

Amazing as always

[@savagetr1539]

Love your content! Thanks professor Dave.

[@charlesrusshel6924]

You are a very good teacher, great video

[@tassimo9995]

this video is very beautiful, great work

[@ilyas_elouchihi]

The best notification today, thanks Dave!

[@maximilyen]

Very good

[@SigmaElement]

Great video!

[@fizzbot.]

Very interesting topic, thanks

[@X1Y0Z0]

Prof. Again, another interesting & important topic

[@TheseNuts2]

WOW! That was so interesting, thanks!

[@relaxwitheliza]

Dude, thank you! This was brilliant👌

[@Nikson2981]

Excellent video as usual, this is fascinating stuff. On a side note, have you considered throwing your images here up on a darker background? I frequent your tutorials at night and the eye strain is really starting to take its toll. Thanks!

[@ProfessorDaveExplains]

Eh, white is the cleanest and also easiest to work with since lots of images have white backgrounds and I don't have to crop anything. Just turn the brightness down on your device!

[@ericpierce3660]

Love, love, love your channel.

[@ofdlttwo]

Awesome! You probably don't want to dig into these "perceptions/sensations" that flat earths have. But I would love to see it.

[@RMunoz-te7jc]

Great stuff.

[@95TurboSol]

This was a good one!

[@1SLMusic]

It’s been awhile since I’ve been exposed to perception and illusions. Thanks for the video Dave!

[@sylviaculpepper8536]

Thanks!

[@-JA-]

Thank you.👍

[@AndyMarsh]

Fascinating stuff, Thanks. On the subject of colour perception, Technology Connections video on the colour Brown is very interesting.

[@richardddoulas182]

Dave I'm so happy you exist

[@Blubb5000]

This video make a lot of Sense.

[@mdug7224]

Brilliant presentation. I did study language acquisition for a couple of years and this is an awesome supplement (and to mention that quite a few of the primed subject tests echo some points that pop up when talking about faith fundamentalist indoctrination).

[@himsoni7112]

Such an Amazing Content... Lots of thank you for this I promise I'll Contribute.. When i could..

[@YuvrajSingh-wf9jn]

Such a deep explanation. That explains why I don't feel tired while going to college but feel to tired while going to a shop.

[@mamin3152]

Ight but did nobody notice how your animation is actually really good now

[@WengineerKimProductions]

Very interesting

[@SuillaIsAwesome]

what a great video

[@funnyduckgamin2451]

That intro is just perfect

[@S1nwar]

our signal processing professor at university beautifully used to say that our brain basically does fourier transformations for us since timedependent wave inputs like sound and light get processed to be timeINdependent tones or colors.

[@HeyHeyHarmonicaLuke]

Ahh I always wondered how to parse that out. Interesting!

[@DayuWenling]

good video

[@MaryAnnNytowl]

I'm usually very good at telling colors and hues apart, better than most I know, but the shadows thing gets me nearly every time, especially when I'm tired. 😄

[@marvinalejandroarancibiata3345]

I dont speak very well english but glad to understand and like how you explain.

[@ctpaul1261]

Thanks Professor Dave! Also, I really enjoyed your book "Is This Wi-Fi Organic? A Guide to Spotting Misleading Science Online", so I want to recommend that to your viewers. Would love to see more debunking videos and maybe even some more debates where you take on psychics, theists, alternative medicine practitioners, etc. 🙂

[@kylezo]

It's not possible to debate topics that have facts on only one side. The problem with debating the types of people you mentioned is that it's never in good faith because they always already know that their positions are unsupported by facts and they exist in the absence of logic and knowledge, therefore, there's nothing to debate.

[@ctpaul1261]

@@kylezo Agreed. However, I see those types of debates as being more for the benefit of any fence-sitting viewers than for the debate opponent.

[@empmachine]

I had no idea that wanting something (bad enough) could truly make it seem closer. I wonder if that helps with some of the mental gymnastics for those arguing the experience of telekinesis (like when they SWEAR they can do it and we assume they're not lying tools).

[@bettercalldelta]

The chessboard shadow illusion also gets impacted by expectation, because we remember how a chessboard looks and that a white shade should be in the B tile

[@thesilentshadow1256]

2:41 that freaked me out Dave

[@melissaattaway7426]

Your a great and gifted teacher bud. I hope you continue doing these straight educational videos. But I hope you always remember how gifted you are at owning conspiracy theorists. As much as you may not like it, you have a gift. I keep watching your videos like this. But I hope you step into the conspiracy arena at least once per year to spill some truther blood. Sorry you had to hear it again. But I really believe that you can keep your channel the way it is and simultaneously pwn some science noobs every once in a while. And I hope you do. Now, im gonna watch your video out of respect for you and as an offering towards a potential future conspiracy video. I'm presonally already well read in this subject, but your teaching ability is great enough that its entertaining to reingest anyways. And I wouldnt be surprised if you threw something out there that's new to me. Keep on keeping on bud.

[@ProfessorDaveExplains]

Don't you worry, I'm getting ahead on the academic content and then I'm coming back to the debunks to rapid fire off some con men sniper style!

[@Gxlto]

@@ProfessorDaveExplains Lol I see you're enjoying this, can't wait

[@windigo000]

@@ProfessorDaveExplains yey, Dave 720 no scope 😁 exciting times

[@Ewgene]

@@ProfessorDaveExplains great news, can't wait

[@ProfessorDaveExplains]

Many. You'll see.

[@MrJeanMaker]

I have a theory that the reason we don't remeber our life when we were babies is because we didn't speak yet, making impossible for us to form memories since we couldn't describe them to ourselfs. It's hard to explain but if you think about it, it makes sense. I also believe that our perception of time is related with language. If we couldn't count time in any way using words or numbers, how would we understand it's passing? Yeah, we would still have the sun, days and nights, but I don't think we would care about weeks, months and years. We would have no way to know our bithdays, so years wouldn't matter too.

[@kaantax8666]

it looks like someone watched Arrival lmao

[@corberus3119]

then how do mute people remember things? you're ascribing meaning to something without any evidence there's plenty of research on early memory and memory formation that you might want to read before you start making philosophical statements with no science birthdays are meaningless, you're viewing time from your modern and narrow point of view without considering how it would have been different in the past people used things like seasons/crops/animals and other natural cycles to measure time without the need for complex language, and yes to them years were very much important measurement.

[@MrJeanMaker]

@@corberus3119 mute people can learn language, like sign language

[@crimescenepharmacist]

Can you do the 4th dimension explanation?

[@cheese7119]

This is a lesson that can be very useful for drawing :v Woah I'm impressed every school subject seems to have a connection with how reality works. Trying to redo reality by drawing it uses these exact rules too

[@Naiki_Eri_Vescida_Yanmi]

I know it's a really random question but if i were suddenly teleported to a universe with 4 spacial dimensions and 1 time dimension and lets say somebody were to shine a light bulb from some point on its w axis, just beyond our perception, would all which we see around us be illuminated by that light even though the torch does not exist in the same 3d space we are in? (Not 100 percent sure i explained it well enough) Would objects in that light be shining all the way through regardless of the material or would the way it shines look as it normally would because maybe the light which is emitted by the bulb is restricted to the 3 dimensional slice it exists on? Also great video as always!

[@trucutru3]

Think about a 2-dimensional being that comes to our 3-dimensional world. They are inside a a cubical room with a chair on it. They are only aware of the stuff at floor-level so to them the room appears like a square with four small wooden circles inside (the four legs of the chair). If you turn on a ceiling light, that is beyond their perception what they 2-D being will experience is that some of the floor will be brightly illuminated, some of it will be in the chair's shadow, and the inner part of the circles won't be illuminated (since the rest of the chair blocks the light). So something similar would happen to us in the 4-dimensional world. We would see things illuminated or not depending on how their shape actually blocks the light in the 4th dimension.

[@andynewman835]

@@trucutru3 speculative. Evidence would be compelling but how do we prove your point?

[@trucutru3]

@@andynewman835 It's easy, just travel to a 4-dimensional space and check if the point stands.

[@andynewman835]

@@trucutru3 faith in a theory can keep one motivated, but without a demonstration, a theory it remains.

[@trucutru3]

@@andynewman835 Hi, you asked how could we prove the point and I replied how. BTW traveling to a 4-dimensional place and testing the theory has nothing to do with faith and would prove/disprove it.

[@jamesmackie6641]

So why do I have pain from my MS and why does my mind not cut it out

[@DGaming1_]

The stuff that we supposed to be learning in school

[@AcaciaAvenue]

Very interesting video, expecially the last part about the 2010 study. I have a question about this study: can this conclusion be extended? I mean, I don't know if it can be applied in reverse (aka perceiving something as more far as it actually is when you don't want it), but I wonder if that conclusion can be applied at more than just physical distance to an object and use it as some kind of "life helper": I think it would be a mistake to say something like, "if you can't reach a goal it's because deep down you don't want to reach it", but I wonder if you can trick yourself into "wanting" or "needing" a certain goal, whatever it is, to trick your mind into perceiving it as closer that it really is, in order to have an easier way achieving it. Or am I into a fallacy here?

[@memitim171]

Your subconscious is pretty dumb, you can trick it into doing all kinds of things. It's generally busy with lower brain functions and doesn't worry too much about 'fact checking' the way your conscious mind does. How much it would help you in this particular hypothetical is debatable, perceiving your goal as closer or more achievable could be helpful, but it could also blow up in your face...

[@trippyliquids]

Sweet

[@limitbreak2966]

*Dave can you pleasedo a video on why there are no green or purple stars? is there ANY possibility with specific gases stars are made of to make a star look purple or green to us* ? please if you can answer this in a video Dave? I really liked this video so far (im like 4 minutes in its super cool!!!) and it made me wonder whys there no purple or green stars ( *at least from what I’ve seen , maybe there’s a couple rare examples or something* )

[@elimhorn3308]

I was just watching your video on standing waves and harmonics. You claimed that 3D waves have 2D nodes. I have a question for anyone in the comments. Would a magnet produce a wave with this feature?

[@youri655]

1:32 well rip now I can't unsee my nose haha

[@cameronpierce3749]

I don't know if it would be something your other viewers would be interested in but in the future if you've got free time between your usual content, would you ever be willing to dedicate time to making videos discussing the various paradoxes out there? I find them fascinating and I feel like your style could be rather fitting when discussing them.

[@fabianfeilcke7220]

I do encounter this color issue with my wife. Apparently German has more colors than Malay as we keep arguing about the color of things. To her a lot of things are just a basic color, while i see different variations.

[@Eodemus]

Hey Dave, just one slight correction.. We do have very distinct words for light and dark blue in german.

[@corberus3119]

they both include the root 'blau' making them connected. the Russian words don't share any linguistic similarities. they are as different as blue and red are in German

[@Eodemus]

@@corberus3119 ah now I get it. In that case I was wrong sorry!

[@sirzn]

eye enjoy this video why am i like this

[@mgsp5871]

I have my brain well trained to ignore the mess on my desk

[@resident1123]

My boy

[@musafirtaiwan]

wow

[@ezthatsme5813]

Hello Dave I have a question and I hope it's one you could answer for me . What are all those lines in the sky ever day I look up and I see two three planes leaving these lines in the sky and I have no idea what they are and I definitely dont know what to tell my Grandson. Thank you for your time and consideration.

[@corberus3119]

condensation formed by water crystallization due to the plane altering the air pressure as it moves en.wikipedia.org/wiki/Contrail

[@paul-ye3ut]

dave is the new and improved bill nye

[@seanconstable8135]

Dude, that was fucking fascinating.

[@paul-ye3ut]

sensational

[@helpyourcattodrive]

I love this channel. I was listening to Jordan Peterson and getting into it and it’s definitely interesting and these people are these wild intellectuals I mean way out of my league … and I didn’t give a poop about what they say. It sounded like a bunch of elitist meaningless somewhat interesting info at times, that mostly doesn’t apply to life. I don’t wanna know what they know. I like coming over here and listening to Dave. The thing I did find interesting was with Camille Paglia, he was in a discussion with, it’s a famous discussion, I guess, and they’re talking about gender, which I did find very interesting, and it was great to hear them both talk about that, but all the upper level, academia, intellectual part of what they were talking about just doesn’t apply. it doesn’t matter. Camille paglia’s voice was like a shrew … Jordan Peterson sat there utterly poised in the discussion. It was interesting.

[@andreasplosky8516]

I disagree, I really do need information about my nose. I want to know where it is all the time. But jokes aside... Another wonderful video. Thank you.

[@SmashingCapital]

In italian we have azzurro for light blue

[@palantir135]

Sense of temperature

[@RohanPShemi]

ya learn something everyday

[@leonburns997]

This videos very informative but for some reason I’ve the urge to download heyday 😂😂

[@WiiFlow2511]

Aren't "Hellblau" and "Dunkelblau" dedicated words for blue in germany?

[@corberus3119]

no since they both use the root 'blau' they are connected, where as the Russian words are completely different, to a Russian they are a different as you would say blue is from red

[@onlinestudy365]

you know a lot about science stuff

[@CHKNSkratch]

I wonder then if this video makes illusions slightly less or more effective?

[@trippyliquids]

Dude right when you said our noses are always in our field of vision, I noticed my nose hahaha

[@Ryan-ii8xo]

8:51 Could a hypothesis similar to this one explain why women are able to differentiate between the shades of a certain colour better than men?

[@FawadAli_SST]

There are some. while there are a lot of studies that have shown that women are better perceivers of colours than men and are better in their spatial perception (locating points in space, determining the orientation of lines and objects etc). men on the other hand have better depth perception and track moving objects. In my evolutionary psychology class, it was told that theorists suggest these differences in abilities evolved due to the environment. They say that men were to hunt and women would store food which they would later have to take out. As you see hunting requires tracking moving prey and distance of prey, while storing things in different locations require remembering the texture of the locations and recognizing them later.

[@mgsp5871]

@@FawadAli_SST I think such viewing capabilites can be learned and trained. If you constantly exercise to hit a bird with a stone, your perception of distance bill become better. If you collect apples all day, you will soon differentiate between the sweet and the sour ones by colour.

[@FawadAli_SST]

@@mgsp5871 You are absolutely right. Most of such capabilities are learned. But studies show that there are biological bases of many such capabilities (and the gender differences in them). Men tend to have those parts of the brain larger than women which are involved in depth perception while women tend to have those parts larger which are involved in spatial perception as well as those involved in vocabulary and language.

[@mgsp5871]

@@FawadAli_SST I am very sceptical of such studies, as i have never seen one. But i have experienced the learning effect myself and know of its strength

[@FawadAli_SST]

@@mgsp5871 There's an entire field that studies such biological bases of behavior (the Biopsychology).

[@adam2aces]

Did anyone else have a drink of water at 10:35

[@12345.......]

Pretty wild what the brain does subconsciously.

[@friedmule5403]

There is another funny fact. Your sensation can influence how you perceive a person. Example 1: You get a stranger to hold a warm cup of water while talking to them, and they'll think more fondly of you after your meeting, compared to if you gave them a cup of cold water to hold. Example 2: By inconspicuously touching a cashiers hand while receiving or giving money, will the cashier think you were a nicer person than if you had not touched their hand at all.

[@corberus3119]

another example if you are on a date and do something that increases the other persons heart rate e.g. rock climbing. they are more likely to fall in love with you

[@friedmule5403]

@@corberus3119 Yes and that even includes being frightened, as long you are not the cause:-)

[@ThievesHand]

Damnit Professor Dave... Now I am completely and annoyingly aware of my nose.

[@mshahzadsamimkharal6655]

😇😇😇😇

[@jana731]

In german we indeed have words for both light and dark blue and light and dark green that are widespread.

[@helpme5gmeltedmyweenor908]

Fantastic video, other than the fact that that wasn’t a moose

[@DanielKosterKnives]

Except that’s not a moose…that’s an elk.

[@Poptizzle]

Based

[@WanderTheNomad]

3:56 man, that gave me farmville flashbacks

[@adambeaudoin8818]

I saw a caribou

[@travisskyski]

Have you broke down the 911 conspiracy yet? Would love to hear your take on that

[@tmwolf100]

My mom told me, our language has 8 different words of beating children with hand and she only shown us 3.

[@chair547]

alzheimers patients forgetting the word for die and becoming immortal (because of the sapir whorf hypothesis)

[@GrungeMaster92]

So are the bugs in my skin real or not?

[@MonsieurNarlan]

This is the second time I hear someone saying that the brain filters the nose... I see my nose all the time.

[@Blubb5000]

9:33 FALSE! There are dedicated words words light blue and dark blue in German. "Hellblau" and "Dunkelblau" are the words used in German. (I am German, so I know this.)

[@theodiscusgaming3909]

Yes but those are more specific types or 'subsets' of Blau. You can just say something is Blau. Even in english you can say there are dedicated words for blue like 'azure' or 'sapphire' or something like that, but still ultimately they are more specific subsets of blue. On the other hand in Russian, синий and голубой are the least specific you can possibly get and they are not subsets of some overlying 'blue'. You have to specify is something is синий or голубой, just like you have to specify if something is green or blue in English. On the other hand, you don't need to do that in Japanese, you can just say something is 青い (aoi) which can be either blue or green. Another example: there are two words for 'red' in Hungarian, 'piros' and 'vörös' where 'piros' is a lighter shade of red and 'vörös' is a darker shade. And again, they are both the least specific you can get. You just can't say something is 'red' in the English sense, you have to specify if it's 'piros' or 'vörös'. TL;DR: It's not that they have different words for a color, it's that those different words are the least specific they can get in their language.

[@upseguest]

Only 6 comments!?!

[@jeromebirth2693]

At that moment in time, yes.

[@OldBenOne]

@@jeromebirth2693 Well let me say this about that....