You Fall in Love Because Your Brain is a Jellyfish, Lizard, and Mouse Ice Cream Cone

By Kyle Munkittrick | August 19, 2010 10:45 am

braincreamconeHuman beings are the peak of evolution, right? Our advanced brains allow us to poke one another on Facebook, send rockets to the moon, and order complex drinks at Starbucks. We can even fall in love. How are we able to do all of that? NPR’s Science Podcast has been doing a running series “The Human Edge” in which they discuss various things about humans that make us, well, human. NPR’s John Hamilton tackled brain evolution and how we humans still carry parts of other ancestral animal brains within us. Feel that pebble in your shoe? Thank a jellyfish. Ever duck before a rogue Frisbee collides with your noggin? Thank a lizard. Remember where you left your keys? Thank a mouse.

Hamilton interviewed David Linden from John Hopkins University who explained that our brain is the way it is because evolution is “the ultimate tinkerer and cheapskate.” Evolution built our brain by taking simpler brains and just piling more brains on top – like adding scoops of ice cream to an ice cream cone. Hence, the pieces of our brain inherited from these other creatures are largely unchanged. The result is that our advanced, intricate, special gray-matter is spectacularly inefficient, poorly designed, and ill-suited to many of our daily needs. On the flipside, evolution’s Frankensteinian cobbling together of various animal brains is precisely why human beings can experience higher emotions like love. Our ice-cream-cone-brain has created some of our best, and most uniquely human, attributes. After the jump is an illustrated guide of how the forces of natural selection shaped your mighty mind from distant relatives of jellyfish, lizards, and mice.

The Cone: Nervous Jellyfish

JellyJellyfish were among the first animals to evolve anything resembling a nervous system, specifically a “nerve net.” Our sensory nervous system, the part that lets you know if your hand is on a hot stove, sends signals the same slow way as the jellyfish nerve net does and at the same slow speed: 100 meters per second. For perspective, Hamilton notes that a landline telephone signal is “a million times faster.” The speed of thought is none-too-impressive in the age of electronics.

An example: if your foot was a mile away and someone shot you in that same foot, you would see the gun shot instantly, hear it four seconds later, then feel it twelve seconds after hearing it – a full sixteen seconds after the gun was actually fired. Nerves are sloooooow.

Pro: Without the jellyfish neural net, our nervous system would never have evolved. You couldn’t shake a hand, feel sun on your skin, or pull away from a cactus.

Con: Your nerve cells would communicate more quickly if they yelled messages to one another.

First Scoop: Instinctive Lizard

lizard“Lizard brain” has become somewhat synonymous with our base instincts. Fight-or-flight reactions originate here, as do many of your unconscious reflexes, like ducking when you see something hurdling towards your head or automatically trying to catch something you drop. The downside is that fears of public speaking and panic attacks are related to your lizard brain misinterpreting a stressful situation as dangerous and overriding the rational, relaxed part of  your mind. The “lizard brain” represents many core, instinctual actions.

Pro: The lizard brain is as close to a Spider-Sense as a normal person is going to get. You react to danger unconsciously.

Con: Because the lizard brain reacts to danger unconsciously, you don’t get to pick when it decides to hijack your higher functions, send you into fight-or-flight and kick on the adrenal glands. Not convenient when giving a presentation at work.

Second Scoop: Memory Mouse

mousyThe mammalian brain at is exemplified by that little workhorse of science labs everywhere: the mouse. Mice brains are able to remember and anticipate. Memory is what lets a mouse solve a maze it’s seen before and the expectation of cheese is what encourages a mouse to figure out a new one. In short: a mouse brain can process time. It can remember the past and guess at the future in a rudimentary way. Every time you remember how to walk home from a new bar or think to buy toilet paper before running out, that’s the mouse brain kicking in. And the anger you feel when you forget how to do either of those things? That’s the mouse brain too – mammalian brains were the first complex enough to emote.

Pro: We remember, anticipate, and emote because of the mighty mouse brain. Mammalian complexity – social nature, nurturing behavior, cross-species bonding – stems from these three essential additions.

Con: In a word: Pavlov. The mouse brain allows rote conditioning. They don’t call it the rat race for nothing.

Third Scoop: The Thinking Ape

Great apes, elephants, dolphins, some pinnipeds and maybe parrots can reason out solutions to problems and abstract situations. Why? The third and final brain scoop does three things. 1) It dramatically amplifies the mouse brain’s anticipatory, memory, and emotional capabilities. 2) It adds the problem solving functions of reason, symbolic communication and abstract thought. 3) It makes powerful, complex connections within itself and the lower parts of the brain. Humans and intelligent animals are able to communicate, recognize themselves in mirrors, plan far in advance, grieve, and develop tight, complex communities all thanks to this final blob of neurons.

Pros: Every aspect of higher thought is a result of the ape brain. Tool use, sympathy, group hunting, symbolic recognition, among many others.

Cons: Complexity results in complications: emotional and mental disorders aren’t something a lizard worries about. And we need an enormous energy budget. Our brain uses approximately 20% of our daily calories. Thinking is hard.

According to Linden, the key separation between humans and apes isn’t brain type but size – Humans just got a super-duper-sized third scoop. Start with a jellyfish cone, add scoops of lizard and mouse, then a gigantic ape scoop, throw on some sprinkles for culture, and you’ve got the human brain. Most astounding, however, is not our closeness to animals, nor that the good-enough-for-now parts evolution decided to preserve hinder us from becoming hyper-logical super beings, but that our most human behaviors come from all our brains working together. Linden asserts that love – a mental state that requires instinctual emotion, higher understanding, and logical reasoning while simultaneously transcending all three – would not be present in human beings if our brains were not so poorly engineered by evolution.

So the next time you get that dreamy feeling when you look at your special someone, remember it’s because your animalistic ice-cream-cone brain.

Ice Cream Cone photo by stevendepolo, brain added by me, Jellyfish by strollers, Lizard by SivamDesign, and Mouse by Olis Olois edited by me; all via Flickr

MORE ABOUT: evolution, Love, the Brain

Comments (14)

  1. pj

    I love the brain Ice cream cone picture. Fantastic article.

  2. Steve

    Certain birds and dolphins have been seen using tools. Does that mean they have ‘ape brains’ too?

  3. Maxp

    Please stop anthropomorphizing evolution and stop the mischaracterization of evolution having “engineered” things.

    This is unscientific and dangerously misleading considering the present (poor) comprehension of the evolutionary process by the American (and global) publics.

    Evolution is volition-less, it is not an “intelligent designer”.

  4. Xalem

    Jellyfish, mice and modern lizards are not our direct ancestors. Yes, some primordial creature common to us and jellyfish gave us nerves, but it wasn’t the jellyfish, and thanks to a common ancestor to lizards and mammals we can duck, and thanks to a common ancestor to mice and primates, we can remember where we left something. So, I think I am going to pass on the thanks yous suggested in the first paragraph.

  5. JAM

    So, just a quick analysis: out of 4 comments 3 are making very valid complaints about your (mis)treatment and (mis)representation of science and evolutionary theory. The positive review likes the picture. This is your approval rating, and a good cross section of the people on either side.

  6. Kyle Munkittrick

    @Steve Says: Did you read the “Thinking Ape” paragraph? The first sentence: “Great apes, elephants, dolphins, some pinnipeds and maybe parrots can reason out solutions to problems and abstract situations.” Ape brain is shorthand for discussion purposes.

    @Maxp: I agree, evolution is volition-less, but that does not mean it cannot “build” something. Physics and chemistry work to “build” stalagmites and stalactites in the same sense. The most figurative language, describing evolution as a “cheapskate and tinkerer,” was from David Linden, a professor of neuroscience at Johns Hopkins. It means that if something works, the forces of natural selection will preserve it. I’m not implying a “designer” anywhere.

    @Xalem: Where do I say the modern versions of these animals are our direct ancestors?

    @JAM: Isn’t it funny how the critiques seem unable to provide direct quotations? It’s as if they merely skimmed the article and formed an opinion without actually perusing the piece. But for the sake of clarity, I’ve made some minor adjustments.

  7. JAM

    @Kyle – Here some quotes from this article:

    “Every aspect of higher thought is a result of the ape brain. Tool use, sympathy, group hunting, symbolic recognition, among many others.”

    “…our advanced, intricate, special gray-matter is spectacularly inefficient, poorly designed, and ill-suited to many of our daily needs. On the flipside, evolution’s Frankensteinian cobbling together of various animal brains…”

    “Feel that pebble in your shoe? Thank a jellyfish. Ever duck before a rogue Frisbee collides with your noggin? Thank a lizard. Remember where you left your keys? Thank a mouse.”

    “Human beings are the peak of evolution, right?”

    The first three were to answer your question. The fourth one was from me, and the answer to that last quote is… no. We are neither the “most” evolved nor are we the most plentiful on earth, but we are definitely the most arrogant.

    You’re a careless writer. Elephants, dolphins, etc. don’t have ape brains and calling it an ape brain is just dumb and inaccurate. When you were telling us to thank jellyfish, lizards and mice, you forgot the part about the time machine; all of the current versions of those animals came from the same ancestors (or concestors, if you want) as us. Our brains were not designed, are not actually little animal brains on top of one another, and evolution does not, in any way, resemble Frankenstein.

    To the people who do know about what you’re explaining, this article is just poor. To the people that don’t, your implications are misleading.

    You’re a careless writer using careless analogies and metaphors.

    Go read Not Exactly Rocket Science for an example of how to write about complicated things in an accessible way.

  8. Maxp


    Had “build” been the active verb I would not have a quibble as the various natural phenomena you enumerate are commonly characterized as having built over time and overall “directionless building” is a reasonable characterization of stochastic processes, unfortunately in this article (and I keep my remarks purely outside of the quotations you have used) evolution is variously characterized as having “poorly designed” or having engineered something: “[. . .]brains were not so poorly engineered.”

    These are direct quotations, though I would hope they would be apparent to a critical reader. See: paragraph 2 and also the second paragraph from the end.

    It would be awkward and strange to characterize a mountain as having “poorly designed” it’s north face, just as it would be very odd to characterize the Colorado River as having “engineered” the Grand Canyon. I work purely from the phrasing of this article.

  9. Sonali

    Kyle, these are great criticisms. You could really draw from them and become a better writer. Go with it. Sincerely.

  10. The “lizard brain” is NOT the part responsible for social stress. No lizard gets panicky in front of an audience. :-) It’s the social brain (mouse brain) and primate brain (with it’s future thinking skills) that gets worried about what people might think of what they have to say. So it’s illogical to chalk it up to our lizard bits when it comes to things like social anxiety. Yes, the lizard brain controls the chemicals that prep you for fight-or-flight, but it’s acting under the direction of the mouse and primate brain in the case of performance anxiety.

    So it’s the other way around from what you suggest. The lizard brain doesn’t “hijack” the higher functions, the lizard brain is itself being hijacked by the higher functions.

  11. Also, as a comment on the commentary, all of these comments appear to come straight from Reddit (the Cogsci subreddit, where this article was linked). Which, while full of highly intelligent people, is also full of people with people with lots of repressed emotion, including a lot of that anxiety that comes with having a higher functioning ape-and-probably-several-other-species-such-as-dolphin-and-parrot-brain. :-)

    Redditors are kind of famous for being really uptight about creativity and metaphor and spiritual and artistic approaches to life. With a lot of them (especially the ones with more free time on their hands), anything that veers away from extreme black-or-white thinking about reality makes their higher functioning brain bits tell the lower functioning brain bits to fight-or-flight.

    Ideally, we can all take what others write with a grain of salt, while being open to the idea that other people have different opinions that are equally valid and important, even if we don’t share them, or have the ability to focus on them at the moment. For example, there is a huge problem with people getting confused about the term “designed” that involves a whole lot of very deep inquiry into free will, consciousness, and system’s theory. But that’s not something that you, Kyle, are probably ready to address in your work right now, especially since you’re focused on some other very interesting stuff that’s also quite important. So maybe you can admit that “design” is a somewhat controversial term, while saying that it seemed to be the most appropriate word for your overall goals of helping people understand the very directional structure of Evolution.

    • Kyle Munkittrick

      Turil, thanks for your commentary and your addenda to my larger point. Huge fan of Reddit and actually pretty psyched to know I ended up on a subreddit. Popularizing science is a tough, fine, fickle line between too simple and too complex. I really do appreciate the comments, particularly yours.

  12. Maxp

    I agree with Turil’s assessment.

  13. This is getting a little more subjective, but I much rather the Zune Marketplace. The user interface is multi-colored, has more sparkle, and some great characteristics like ‘Mixview’ which let you rapidly see associated cds, songs, or other users associated to what you’re playing. Clicking on one of them will center on that item, and one more set of “friends” will come into view, allowing you to navigate around exploring by the same artists, songs, or users. Speaking of users, the Zune “Social” can be excellent fun, letting you locate other people with shared tastes and becoming buddies with them. You then can listen to a playlist produced based on an combinations of what all your friends are listening to, which is also enjoyable. Individuals worried with privacy will be relieved to know you’ll be able to prevent the public from seeing your personal listening routines should you so choose.


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