Author and journalist Carl Zimmer talks about the search for the physiological and biological basis of intelligence, the subject of his article in the October issue of Scientific American magazine. And Editor in Chief John Rennie discusses other articles in the issue, including the cover story on the possibility of a big bounce instead of the big bang and the science of the World Wide Web. Plus, we'll test your knowledge about some recent science in the news. Web sites mentioned in this episode include www.SciAm.com/sciammag; www.carlzimmer.com