A study reported in the September 24 Proceedings of the National Academy of Sciences reported that humans pay greater attention to animals than to other things (such as vehicles). In the December 2007 Scientific American, Charles Q. Choi commented on the study (page 37) saying that “visual priorities of our hunter-gatherer ancestors evidently remain embedded in the modern brain, regardless of how relatively useless they often are now.”
I found this comment rather odd, especially given the fact that the researchers themselves noticed that humans paid more attention to other humans as well. First, since we interact with humans all the time, we would have a great deal of experience observing humans. Since animals are similar to humans (more similar than cars, certainly) our experience with humans would extend analogically to animals. Also, many people have pets and hence also have ongoing interaction with animals. Second, the humans and animals we interact with tend to be more important to us than non-living things. Further, my truck rarely demands my attention but my pets and friends do so regularly. Second, since we interact with humans and animals on a regular basis, these perceptual abilities are hardly useless.