The release of the names of the prisoners at Guantanamo (see Monday's papers and today's NYTimes editorial: They Came for the Chicken Farmer reminds us of the dangers of lumping--when DOD said the prisoners were "terrorists", we (i.e., any reasonable person) are led to visualize a bearded violent man (somewhat as the pirate Blackbeard was pictured in my youth). When you know the names and backgrounds you see a much more disparate group than you visualized, differences that inevitably increase the odds that mistakes were made in their capture and retention.
On the other hand the New York Review of Books has an article by Tim Flannery, reviewing 3 books on nature, including David Attenborough's latest venture on insects. He found spiders of the same species seeming to display personality differences, leading Flannery to this statement:
"The fact that invertebrates have characters seemingly similar in their fundamentals to those possessed by ourselves is a theme to which Attenborough returns repeatedly, and as he does so the gulf between the least and greatest of living things diminishes."
So it goes, the back and forth between lumping and splitting, on which see wikipedia.