other's behavior, deviations from which may prompt adjustment of their own attitude' ' (p. 169). Charlotte Hemelrijk's chapter on reciprocation complements this theme. In two articles on chimpanzee and bonobo intelligence, Sue Savage-Rumbaugh and her colleagues consider ape language experiments and Tetsuro Matsuzawa examines symbol and tool use. Having long conducted language experiments on captive apes, Savage-Rumbaugh et al. recount their efforts in the field to discover whether the failure of wildape studies to find examples of symbolic communication owes to 1) scientists' reluctance to report what they see, or to 2) apes having no such system. Their provisional conclusion is that bonobos do have such a system and use vegetation in an intentionally symbolic manner.
In the following section (Part Five), William McGrew and Linda Marchant's chapter on laterality in hand use and John Mitani's on African ape vocal behavior continue this comparative perspective on the ape mind. The remaining two chapters are similarly comparative, Diane Doran's on positional behavior and Barbara Fruth and Gottfried Hohmann's on nest-building behavior.
Part Six considers great apes as models for ourselves. I read Jim Moore's article fully expecting to find a review of chimpanzee models for reconstructing the behavior of our early ancestors, but in addition I found an innovative and challenging critique of ''what a model is,'' and better yet, ''what it is not.'' Moore advocates a referential approach in which ''the model is not a single typological modern species per se, but the