
Ask HN: Do animals grasp the concept of solid-liquid-gas? - hhs
I&#x27;m curious if there are specialists out there knowing if animals understand the concept of solid to liquid to gas phase changes?  Is this an &quot;advanced&quot; concept for animals or do they intuit this?
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larnmar
How would we determine whether an animal understands something? Presumably you
could do experiments which test whether they can predict what will happen — eg
if a thirsty monkey collects ice, expecting it to melt. (Although you can
obtain water by licking ice, so maybe that’s not a good example.)

Anyway my prediction would be that many colder-climate animals have some
intuitive grasp of the ice to water transition specifically because it’s so
important to their lives. I would not expect them to understand water to steam
since it’s not something they’re likely to encounter — even those who live
near geysers have no reason to know that steam is actually water, they just
need to know they should stay away from it. Many animals would understand the
relationship between clouds and rain, though.

I wouldn’t expect them to understand phase changes in any material other than
water, since it’s hard to think of examples where phase changes actually occur
in animals’ natural habitats.

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yesenadam
> How would we determine whether an animal understands something?

Alison Gopnik's _The Philosophical Baby_ is full of remarkable experiments to
determine what babies understand. (At least, I assume it is! I haven't read it
- just saw her give a talk about the book and her research when the book came
out, and she talked about lots of different experiments.) Stuff like showing
babies white and black balls going in a container, then when one is picked
out, the babies look longer at it if they're surprised, if it's an unlikely
event. They have much better models of probability younger than anyone
thought. Or they show them animations of dots shaped like Momma dot and baby
dot, and see how the babies react when various things happen to the baby dot..
Totally ingenious. A lot of them, or something similar, could be done with
animals; I wonder how much has.

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omar_a1
My money's on No, because of a slightly related psychological concept:
_conservation_.

Conservation is the cognitive understanding of whether or not the amount of a
given (inert) solid or liquid will change despite its presentation. For
example, human toddlers don't grasp conservation, and will erroneously believe
that pouring water from a tall glass into a wide bowl makes more water, since
it "looks" bigger in the wider container (e.g. it takes up more visual space
in a wider vessel, and therefore must be "more"). No other animals possess
this skill either (thank you Wikipedia [0]).

Combine that with the nebulous nature of gas - it's not intuitive to
understand that an empty glass is, in fact, full of air - and understanding
phase changes become that much more difficult.

It's kind of like how most people won't intuitively understand how discrete
phases can break down at higher temperatures and pressures, or the differences
between different lattice configurations of the same substance. If it's not
something we encounter every day, or aren't taught at an early age, the
intuition simply won't be there.

[0][https://en.wikipedia.org/wiki/Conservation_(psychology)](https://en.wikipedia.org/wiki/Conservation_\(psychology\))

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gus_massa
It's a very interesting question. I guess big apes can, but I have no proof at
all. Also, the extension of the question to the ice-water transition in the
other comment is interesting too.

Anyway, the first thing that came to me mind was " _Causal understanding of
water displacement by a crow_ "
[https://www.youtube.com/watch?v=ZerUbHmuY04](https://www.youtube.com/watch?v=ZerUbHmuY04)

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simonblack
Even humans grasping the concept of solid-liquid-gas is a very recent
historical thing, only happening in the last several hundred years after
millions of years of human development.

Therefore, I doubt greatly that animals would ever understand that concept.
They might catch a glimmer of the truth, in the ice/water model, but not the
whole concept.

~~~
badpun
> Even humans grasping the concept of solid-liquid-gas is a very recent
> historical thing, only happening in the last several hundred years

I bet people were heating up ice to melt it to get water way before that...

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omar_a1
Yes, but did they understand that the change occurring was a physical one,
rather than a chemical one? As opposed to cooking other forms of food and
beverage save for ice, which would fall under chemical reactions rather than
phase transition.

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h2odragon
FWIW, I've had puppies discover ice in the outside water dish, and work out
that if they bring some inside it should go into the inside water dish. I
don't think any have figured out why it vanishes then.

