My guess is that there probably aren’t a lot of simple mutations which just increase intelligence without increasing cortical neuron count. (Though probably simple mutations can shift the balance between different sub-dimensions of intelligence as constrained through cortical neuron count.) (Also of course any particular species has a lot of deleterious mutations going around and getting rid of those may often just increase intelligence, but I’m talking about intelligence-increasing changes to the base genome.)
But there could be complex adaptations that are very important for abstract reasoning. Metacognition and language are the main ones that come to mind.
So even if the experiment my friends to will show that the number of cortical neurons is a strong indicator, it could still be that humans were just one of the rare cases which evolved a relevant complex adaptation. But it would be significant evidence for orcas being smarter.
My guess is that there probably aren’t a lot of simple mutations which just increase intelligence without increasing cortical neuron count. (Though probably simple mutations can shift the balance between different sub-dimensions of intelligence as constrained through cortical neuron count.) (Also of course any particular species has a lot of deleterious mutations going around and getting rid of those may often just increase intelligence, but I’m talking about intelligence-increasing changes to the base genome.)
But there could be complex adaptations that are very important for abstract reasoning. Metacognition and language are the main ones that come to mind.
So even if the experiment my friends to will show that the number of cortical neurons is a strong indicator, it could still be that humans were just one of the rare cases which evolved a relevant complex adaptation. But it would be significant evidence for orcas being smarter.