
Crayfish kept alone found to develop higher alcohol tolerance - pirocks
https://www.newscientist.com/article/2128357-drunken-crayfish-show-that-loneliness-raises-alcohol-tolerance/
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hbbio
This is clearly a contender for the Ig Nobel!

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lutusp
As usual in articles of this kind, the article's content contradicts its
title. The study doesn't show that "loneliness raises alcohol tolerance," it
shows a correlation between two measured traits.

In studies like this, two _effects_ are measured and found to be correlated.
For lack of evidence, an assertion about _cause_ can only be conjecture.

~~~
kevinalexbrown
I'm not sure that's true here.

They went further than showing a correlation between two traits. They directly
manipulated the pre-alcohol state (alone, or with other crayfish), and
measured whether that change outcomes in behavior and neural activity.
Presumably they kept everything else the same[0], randomly assigned crayfish
to isolation and social environments, and placed them in the same alcohol
environment.

Just because the chain of causation is fuzzy doesn't mean A doesn't cause B.
Maybe social isolation and alcohol response are trivially connected to
something else like movement rate and other variables. That doesn't mean you
can't make causal inferences.

[0] I don't know much about crayfish experiments - maybe there's some latent
cause like isolated crayfish are handled differently and that causes changes
in alcohol-induced behavior and neural activity. I would want to know whether
the crayfish showed similar or divergent behavior in an alcohol-free
environment. It's _possible_ that alcohol has identical 'gain' on behavior and
neural activity, but that still indicates an effect, technically. And nothing
is ever 100 percent the same across conditions (this is the fundamental
problem with causal analysis) but that's true across every discipline.

If there's an objection to the title, it's that loneliness and social
isolation are not the same thing.

~~~
lutusp
> Just because the chain of causation isn't clear doesn't mean A doesn't cause
> B.

Yes, that's true, but science isn't based on what can't be excluded, it's
based on what the evidence supports. If this were not true, any claim that
couldn't be disproven would _ipso facto_ become true.

Some have said it this way -- to a pseudoscientist, things are assumed to be
true until they're disproven. To a scientist, things are assumed to be false
until evidence supports them (the _null hypothesis_ ).

> That doesn't mean you can't make causal inferences.

Yes, you can do that, but it's not science. In science, it's not about
inference, it's about evidence.

Before publication, any sort of speculation is the norm, it's part of the
creative process. But when the science gets published and the title
contradicts the article, something went wrong.

~~~
benchaney
Except that there is evidence of causation, not just correlation. That is the
purpose of performing a rigorously controlled experiment. If all we were
looking for was evidence of correlation, that would be unnecessary.

~~~
lutusp
> Except that there is evidence of causation, not just correlation.

In science, addressing causation requires a testable, falsifiable theory.
Without a theory -- an explanation -- we can only _describe_ what took place.
The authors of the paper freely acknowledge that they don't understand their
result in a theoretical sense. But the article's title -- "Drunken crayfish
show that loneliness raises alcohol tolerance" \-- is perfect nonsense and an
embarrassment for a half-dozen reasons.

By the way, the moderators edited the submission's title since I posted this
morning. Unfortunately, it seems that New Scientist's editorial standards
aren't as high as those at HN.

~~~
benchaney
The theory in this case is "Isolations affects alcohol tolerance in crayfish".
This is falsifiable and testable. A theory does not need to contain an
explanation to be a valid scientific theory.

The experiment that was done is evidence in favor of this theory. It is not
conclusive, because it is only one experiment, but it does suggest a causal
relationship, and not just a correlation.

~~~
lutusp
> The theory in this case is "Isolations affects alcohol tolerance in
> crayfish".

That is not a theory, it's a statement about an observation -- it describes,
it doesn't explain. Theories explain observations.

> A theory does not need to contain an explanation to be a valid scientific
> theory.

A scientific theory _is_ an explanation[1]. That's how it's defined. A
description cannot be a theory because it doesn't say _why_ the result took
place, only that it did.

If I say, “The night sky is filled with tiny points of light,” I've offered a
description. Another observer might contradict my description, for example by
emerging from his cave on an overcast night and not seeing any points of
light, but that contradicting observation can itself be contradicted on the
next clear night, without any chance for resolution (so a contradiction is not
a falsification). Apart from being shallow, inconclusive and trivial, this
process is not science.

If instead I say, “Those points of light are distant thermonuclear furnaces
like our sun,” I've offered an explanation, one that makes predictions about
phenomena not yet observed and that's falsifiable by empirical test. On the
basis of this explanation we might build a small-scale star (a fusion reactor)
to see if our experiment shows any similarity to the spectra and behavior of
stars. This deep explanation represents a theoretical claim that's linked to
other areas of human knowledge, predicts phenomena not yet observed and is
conclusively falsifiable by comparison with reality (our fusion reactor might
fail to imitate the stars). It's science.

1\.
[https://en.wikipedia.org/wiki/Scientific_theory](https://en.wikipedia.org/wiki/Scientific_theory)

Quote: "A scientific theory _is an explanation_ of some aspect of the natural
world that can, in accordance with the scientific method, be repeatedly
tested, using a predefined protocol of observations and experiments.
Established scientific theories have withstood rigorous scrutiny and are a
comprehensive form of scientific knowledge." (emphasis added)

~~~
benchaney
"Isolation affects alcohol tolerance in crayfish" is not just an observation.
An observation would be "Crayfish #5 has behavior X".

You are conflating two different definitions of explain. It is possible to
explain what is happening without explaining how. It is possible to know that
A causes B without knowing why (This is purpose of the scientific method). If
it were actually impossible to have evidence that something is true without
knowing why it is true, than it would be impossible to have evidence of
anything at all. You could invalidate any knowledge by just asking "why",
because there is always another "why". To give an example, we know that mass
causes gravitational attraction even though we don't fully understand the
mechanism that causes it.

~~~
lutusp
> It is possible to explain what is happening without explaining how.

That's a description -- an account of what was observed. By definition, an
explanation must add something to a description.

"The night sky is filled with points of light." \-- a description.

"Those points are distant thermonuclear furnaces, powered by atomic fusion."
\-- an explanation.

"Similar bird species have differently shaped beaks." \-- a description.

"Bird species evolve traits that confer a survival advantage in their distinct
environments." \-- an explanation.

> It is possible to know that A causes B without knowing why ..."

One cannot claim to know that A causes B without also knowing why, otherwise
puddles cause rain. Science is not merely about knowing -- it's about knowing
that we know. An observation asserts a fact without context. A scientific
theory offers more than mere description, and its standing rests solely on the
fact that it has resisted falsification.

> To give an example, we know that mass causes gravitational attraction even
> though we don't fully understand the mechanism that causes it.

Yes, but that's not a scientific theory, it's a description -- mass causes
gravitational attraction, or equivalently, gravitational attraction causes
mass (my point is the claim is wrong but without a theory, we can't know that
it's wrong). As long as there's no testable theory, the two descriptions are
equivalent.

The Greeks believed our sight resulted from our eyes shooting beams out into
the environment. Until we had a testable theory, no one could reasonably
dispute that idea.

A theory is not a description -- it offers more than an account of observed
facts. The water rises across the beach over a period of hours: a description.
The sun and moon apply tidal forces -- a spatial differential in gravitational
force -- to the water, causing it to periodically rise and fall: an
explanation, one that can be tested and potentially falsified.

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UhUhUhUh
The story of my life.

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mdekkers
I must be a crayfish....

~~~
nhebb
Depends - where do you live? You might be a crawdad or crawfish:
[http://blog.revolutionanalytics.com/2013/06/r-and-
language.h...](http://blog.revolutionanalytics.com/2013/06/r-and-
language.html)

