An absorbing survey of knowledge in the relatively neglected area of experimental (as opposed to clinical, or psychotherapeutic) psychology. A cognitive-science researcher at the University of Arizona who also has taught at Yale, Cummins surveys such disparate fields as psychoneurology; human's development, beginning in infancy, of complex symbolic systems (most notably, language and mathematics); human brains and cognitive systems as compared with those of chimpanzees and other highly intelligent animals; and group psychology. In a particularly interesting chapter on the latter, the author introduces us to ""pluralistic ignorance""; this refers to the concept that one person's passivity in the face of another's real crisis (such as a mugging or serious car accident) is reinforced if others also treat the crisis as a nonproblem or at least as one that doesn't concern them. Cummins's chapters detailing scientific findings on the evolution and nature of human language and thinking conclude with the observation that ""except for language, we are dismally poor symbolic thinkers,"" although we're better ""pattern recognizers and classifiers."" Cummins draws upon and summarizes well an impressively varied amount of scientific data. Her book's only real shortcoming is a tendency sometimes to be nonspecific in reporting on data; she notes, for instance, that characteristic A occurs more frequently than characteristic B without specifying how much more. On balance, though, her style is admirably clear and succinct. Cummins may not be as colorful a writer as, say, Oliver Sacks, but she holds the reader's attention while covering a great deal more ground. Her fine work makes the sometimes dry and forbidding field of experimental psychology accessible and even quite engrossing to the layperson.