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You’ve probably heard that  diamonds are a girl’s best friend, but it might actually be more accurate to say  that diamonds are everyone’s best friend.  Humans love shiny things, from  jewelry to cars to even buildings. And you might think it’s because we  associate shiny things with value, from precious metals to glossy packaging.  But some researchers think that our  love of shininess goes way deeper, and might even be an evolutionary  means of finding water. So let’s look at the evidence.

Studies have shown that people find shiny, glossy   things more attractive and might actually  perceive them as being higher quality.  But that’s probably not just an artifact  of our polished consumer culture. There’s evidence that pretty much all  humans like shiny stuff, and always have. The archeological record suggests our love  of shiny things goes a long way back.  Archaeologists have found bone tools polished  to a shine dating back 70,000 years.  Sometimes that polishing was  part of shaping the tool,   but at other times it was purely for  aesthetic or even symbolic reasons.

We seem to pick it up at an early age, too. Kids as young as two pick out shiny surfaces and   gold and silver things as their  favorite pieces in art museums. In other words, we really like shiny stuff.

And if it goes that deep,  researchers would love to know why. The field of evolutionary aesthetics studies   how evolution may have shaped our brains  to influence what we like to look at.  And several researchers in this area have  suggested that our love of glossy, shiny things might actually be due to the fact that  humans rely on fresh water for survival. The hypothesis is simple: Because  water is so critical for life, brain mechanisms evolved that  help us spot and recognize it.  In natural environments, shiny,  sparkly surfaces are often... water.

So our brains may have evolved to associate  those features with being good, or safe, or pleasing so that we’ll know  to go over to them and get water. This is a fairly complex argument, and hypotheses   in evolutionary psychology can  be very difficult to prove. So let’s look at some of the  pieces, and how they fit together.

First, our brains would need to  have a way to pick out shiny things. And that seems to be the case. Actually, it turns out that  spotting shiny is really complex.  To process glossiness, our brains  take into account light, object shape, color, texture, motion, and reflection.  Like other properties of surfaces,  information about gloss is   mostly processed in the ventral visual stream.

That’s a series of brain areas that are associated  with understanding an object’s form and identity.  And glossiness-related activity in these  brain areas is not unique to humans. Other primates, like macaques and  marmosets, demonstrate similar patterns. So it’s likely that gloss perception is  something that developed a long time ago in our shared evolutionary history.  Research in those primates has identified  neurons that respond especially well to gloss, which suggests that the brain  can specifically process shine,   not just general information about texture.  Secondly in support of the shiny hypothesis,  we’d need to associate shine and water.  A study published in 1990 suggested that people  tend to perceive glossy things as being wet, even when we’re just looking at painted panels   with no other context that would  indicate the presence of water.  And it turns out that people like glossy  things even more when they’re thirsty.  In another study published in 2013, researchers   showed 126 people pictures of planets  printed on glossy and non-glossy paper and asked them to rate what  they thought about them.

The twist was that some of the participants  were asked to eat salty crackers, and then rate the pictures.  It turns out that the people who were made thirsty  by the crackers rated the glossy pictures higher, and the non-glossy pictures lower,  than the non-thirsty people did.  Now, third, it helps to show that  our brains drive us to like water. And it turns out that we do have  aesthetic preferences for water, and it can make us feel good,  even if it’s not drinkable.  A 2003 study of water features in urban plazas   found that people tend to  give them positive ratings. They can make us feel calm or excited,   but either way water seems to have a  mostly positive effect on our emotions.  Other researchers show that  when kids look at paintings, they tend to prefer ones that have water in them.  So let’s add it up.

Our brains have evolved circuits for detecting  features of water, like glossiness and shine. We tend to associate glossy things with water. And we like water and it makes us feel good.

So does that mean we like shiny things  because they remind us of water?  Well, we’re not quite there yet. While a lot of the pieces are  there, some are still missing. For example, you’d expect that there would be   overlap between how our brains process  water and how they process gloss, and we don’t know if that’s the case yet!

And even then, that wouldn’t mean that  this is why our brains evolved this way, or if it’s a happy side effect of  some other evolutionary factor.  Like we said, brains are super complex,   and evolutionary theories like  this can be very hard to test.  So we still need more research into the  relationship between water and shiny,   and how we process that information, before we can say for sure that all  that glitters... is actually water. It can be hard to find the time to  learn everything we want to learn! But Blinkist is here to make things faster.

Blinkist is an app that takes the best  insights from over 3,000 nonfiction books and condenses them down into just 15  minutes that you can read or listen to. For example, if you’re into biographies, they’ve got Genghis Khan and Ruth Bader  Ginsburg, and everyone in between. So now you have no excuses to  not be caught up on your history!

They’ve also got everything else  too, from science to self-help. The first 100 people to go  to Blinkist.com/SciShowPsych   will get unlimited access  for 1 week to try it out. You’ll also get 25% off if  you want the full membership.

If you’re interested, you can click the link  in the description to start your free trial. [♪ OUTRO].