Re: Fermi's Paradox, again

Robin Hanson (
Sat, 12 Jul 1997 10:18:26 -0700 (PDT)

"Dan Hook" writes:
>It almost did on earth. Just before the meteor hit that wiped out the
>dinosaurs there was a bird-like creature with the intelligence of an
>ostrich. Granted, it wasn't much, but the extinction may have set back the
>evolution of intelligence on earth, or it may have moved it forward.
>Depends whether primitive mammals or birds as smart as an ostrich could
>evolve to intelligence faster. Is there any data for the relative
>intelligence of mammals over time? How long did it take from cretaceous
>mammals to ostrich level mammals? Idle speculation of course, but
>interesting none the less.

There is interesting data on brain size that seems to show its
increase as a relatively steady process.

I quote from my great filter paper:
>Finally, brain size relative to body size has been increasing somewhat
>steadily for both mammals and birds ever since the mass extinction of
>65 million years ago (most likely also caused by an external event
>such as an asteroid) eliminated the dinosaur competition [Russell 83,
>Jerison 91]. ...
>Harry J. Jerison (1991) <i>Brain Size and the Evolution of Mind</i>,
>American Museum of Natural History, New York. ...
>Dale A. Russell (1983) "Exponential Evolution: Implications for
>Intelligent Extraterrestrial Life" <i>Adv. Space Res.</i> 3(9):95-103. <p>