[diminoten]

I sometimes feel like we talk about evolution wrong. Here, for example; it's not like gazelles couldn't take advantage of being smarter, there are plenty of advantages to be had if you can outsmart your predator, it's just that the smarter gazelles weren't ever smart enough for that to matter.

It's more about if it's possible for minute intelligence improvements to produce higher survival chances. For a gazelle, the intellect leap needed to be substantial, and random genetic mutations weren't going to get there. For an octopus, each little intellect bump meant little survival bumps too.

[nicoburns]

That's part of it, but there's also the fact that bigger brains qhoch lead to being smarter have downsides in terms of resource usage (needing to eat more, or reduce physical movement), which might not pay off for the smarter gazelles as it might make them slower and thus more likely to be eaten...

[goldenkey]

You could formulate this argument simply as a differential equation.

d(SurvivalGazel) = 0.001 dIntelligence

d(SurvivalOctopus) = dIntelligence^2

[pbhjpbhj]

Surely survivability has to decrease with intelligence otherwise all intelligence would rise over time.

We have an expression (aphorism), something like "clever enough to be dangerous".

Intelligent enough to experiment, but not too realise the dangers involved is relatively common in humans; the societal system in the past mitigated the dangers by pairing younglings with adults who can tell them when they're being dumb.