I'm under the impression that nematode worms just perform the same scripted actions over and over again in response to specific stimuli. They have 302 neurons. Chimpanzees display problem solving capabilities, as do other mammals with smaller brains (cats, for instance with ~ 1 billion neurons). You might say that bees demonstrate something more than reflexes when they communicate the location of nectar sources to the hive (~ 960,000 neurons).

What's the creature with the lowest number of neurons to demonstrate something more than mere scripted actions? I would imagine its somewhere between a bee and a nematode worm...

  • $\begingroup$ How would you demonstrate that human cognition cannot be boiled down to scripted actions? Your question seems to assume its answer. $\endgroup$
    – terdon
    Feb 27, 2014 at 23:07
  • $\begingroup$ Depending what you mean by cognition, it could be zero. $\endgroup$ Mar 2, 2014 at 13:04

1 Answer 1


Indeed, C. elegans nematodes (which are the ones you are talking about) do not show cognitive responses. AFAIK, Drosophila melanogaster is also able to learn and display some quite complex behaviors, but no cognitive functions. I believe the "simplest" organism known to display what could be called "cognitive" functions is the honeybee (see for example this article).

But as to your question:

to demonstrate something more than mere scripted actions

I would also ask "what is a scripted action?" and to what extend a complex, cognitive response from a monkey or a human isn't also scripted (though through many different interacting pathways)?

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    $\begingroup$ Ahh I guess I'm looking for learning or extremely basic problem solving. So, honeybees definitely learn. If two creatures are fighting and trying to anticipate each others moves, this would also fall under my definition of cognition, as this is not hard-coded genetically. $\endgroup$
    – John
    Feb 28, 2014 at 18:10
  • $\begingroup$ I wouldn't say learning is the criterion. In fact, nematodes can learn (see learnmem.cshlp.org/content/17/4/191.long). The ability to "anticipate each others moves" seems a bit hard to quantify in real life. I think the criterion would rather be "abstract learning". While drosophila can learn (by appetitive and aversive conditioning), honeybee can learn patterns, "concepts" to take the word of the article. They can then transfer what they have learned in one situation to a new situation they have never seen. Also, their "waggle dance" is flexible, and they can have a cognitive map. $\endgroup$
    – Alexlok
    Feb 28, 2014 at 21:20
  • $\begingroup$ What's a cognitive map? $\endgroup$
    – John
    Mar 3, 2014 at 21:28
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    $\begingroup$ You can find definitions in several articles [1,2], and a more general one on Wikipedia [3]. To summarize, it's a mental representation (e.g. from their spatial environment), which allows them to make plans and find novel solutions to a problem (e.g. find a new path to reach a goal). So it's not just "if the odor comes from the left, I go left", the bees "understand" where they want to go, and manage to find a way to go there. −−−−−−−−− [1] pnas.org/content/102/8/3040.full [2] colinallen.dnsalias.org/Secure/TCA/gould-final.pdf [3] en.wikipedia.org/wiki/Cognitive_map $\endgroup$
    – Alexlok
    Mar 4, 2014 at 22:20
  • $\begingroup$ So why do you say that Bees demonstrate a cognitive map, but Flies do not? Is it just that we haven't researched it yet, or do we know for sure? $\endgroup$
    – John
    Mar 6, 2014 at 18:18

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