What's wrong with the TED talk? Like most, it can be summarized in 5 sentences, but I think it is worth summarizing, which makes it one of the best ever:
When people talk about brain size, they mainly talk about brain mass, because that's easy to measure. Wouldn't neuron count be better? Primate neuron count is proportional to brain mass, but rodent neuron count is sublinear. Energy expenditure is proportional to neuron count. Humans can only afford to spend so much energy on their brains because of cooking.
The talk fails to address why rodents have bigger neurons, rather than small neurons in small brains. And whether rodents are typical in this pattern. The well-known pattern is that brain mass grows like a power (2/3 or 3/4) of body mass, and that the ratio is a good measure of intelligence. I think the implication is that neurons counts grow at a lower power, but still grow. I think that there is data at the web site of the speaker, Suzana Herculano-Houzel.
You should also account for how myelinated the neurons are, and how many of them are not myelinated at all, since this affects neuron size and energy expenditure a lot.
Without myelin, the conduction speed of a neuron is mainly determined by its diameter. Some animals don't have myelin at all, and their neurons can be huge because of this reason. I'm not sure if this applies to rodents, but it would explain why their neurons grow in size as the brain grows, because conduction distances grow too, and therefore you need a higher conduction speed, and this can...
Notes I took while listening to the speech:
Eliezer Yudkowsky on Friendly AI
If the human race is down to 1000 people, what are the odds that it will continue and do well? I realize this is a nitpick-- the argument would be the same if the human race were reduced to a million or ten million.
Suppose that a blind person in a first world country wants help paying for a guide dog and/or wants guide dogs for other blind people in first world countries, but has heard of effective altruism. What honest arguments could the blind person use?
If I were designing an intelligence, I'm not sure how much control I would give it over its own brain. People are already able to damage themselves pretty badly, even with the crude tools they've got. I would experiment with intelligent species to see how they'd behave with more control over their brains. What would you do?
Sidenote: Birds show some possibilities of making brains more efficient per weight.
TED talk about neurons and brains. This is not a great TED talk, but it's got somewhat about comparisons between brains in different species, in particular that neuron size and density varies between species. Comparisons of brain size tells you less than people assume.
Brains and competition aren't just about sexual selection: Females (especially) compete for resources to feed and care for themselves and their children. In some species, males also compete for resources for their children. Reproductive selection isn't just about mating selection. See Mother Nature by Sarah Hrdy. Interview about humans as cooperative breeders
Do we need to think about hardware, software, and firmware (at least) for brains, rather than just hardware and software?
[Sound cuts off at 38:00. comes back at 39:10]
How much of organisms consist of traits which aren't being selected for?
The sound quality deteriorates enough at about an hour that I'm giving up.