Hey he's back and on my Birthday too!
Thanks J

...what they said! SO glad you're writing again; i learn so much from your blog!

Hi J.
Wondering what you make of this. It seems the Expensive Tissue Hypothesis may not be as rock solid as we all have been led to believe. The vegans are rejoicing:

http://paleovegan.blogspot.com/2011/11/its-curtains-for-expensive-tissue.html

"The key way they tested the overall hypothesis across various mammal groups was controlling for adipose tissue deposits in their calculation of a given animal's mass. In short, they omitted fat deposit mass from all specimens, eliminating it as a variable. This was an important control tactic (and one not used by Aiello & Wheeler in their original paper), because adipose mass varies by season and habitat among many species, and can thus be a major confounding variable... Under these conditions, no negative correlation between brain size and digestive tract mass was found. In fact, no negative correlation was found between brain size and the mass of any expensive tissue. The authors did, however, uncover a tight negative correlation between brain size and adipose tissue depots: the fattest species had the smallest brains."

Hey, it's nice to have gnolls rolling again.

Looking forward to part 2.

Great to see this article.
I hope that you will answer my question in your next article.

Why don't carnivorous cats have bigger brains than chimpanzees or even humans.

I believe that ETH will cause a increased brain size if there is available energy.

My belief is that carnivores do not have extra available energy because they convert protein to glucose, which is a very thermogenic process and wastes almost 30% of the energy. Which is only slightly more efficient than fermenting fiber.

Chimpanzees and gorilla on the other hand can use freely available sugars from fruits, which provides them slightly more energy than cats, allowing them to have bigger brain. Chimpanzees does one better by able to find and eat meat.

Humans have the biggest brain because we can find and utilize fat and starch, due to our ability to handle weapons and fire.

Interesting stuff, hope you enjoyed your sabbatical 😉

Sam K, I don't think we can make too strong an inference on iteligence levels then and now based on this data, but technological advance depends on so much more than just inteligence.

It's really more about culture, civilization, big numbers and previous knowlodge, so one doesn't just get technology advanced, it's a lenghty precess. You could compare technology (let alone science) now to 150 yeas ago to 300 years ago and so on and it's clearly not linear at all.

Besides, those guys with the supposedly bigger brains were the ones to get the ball rolling for these conditions to thrive by introducing agriculture, so that's arguably a big deal.

Again, not that they necessarily were, all I'm saying is that I see no reason to believe they couldn't be as inteligent as the average human or even a bit above that.

Good to have you back, and good to see that you're delving into evolutionary psychology as well. I've understood Natural Selection to refer more to traits that enhance survival, and Sexual Selection to refer more to traits that enhance mating potential. The two can go together, but are sometimes at odd (like a peacock tail- it can lead to a shorter lifespan as a handicap, but lead to better mating cause it impresses more peahens). Wondering if you have read The Mating Mind by Geoffrey Miller, as he argues that our minds were more a product of Sexual Selection than Natural, and that there was indeed an intellegence that helped design us, but that intelligence and design came from the species choices itself.

I saw your comment on my website the other day and thought, my god, he's alive! yippee! And now you're back here too. I can't wait to read your posts again. You're one of my favorite bloggers. Keep up the good work!

PS. I will read this post later this week. I have been swamped with book deadlines...

Welcome back!