 Wallace’s criticisms were overshadowed by Darwin’s popularity and influence. The final decade of the 19th century saw growing scientific interest in the study of instincts, much of it in a Darwinian vein. This was also a period of intense dispute about the nature of instincts. A key point of disagreement concerned the relationship between instinct and habit during development. William James outlined a list of roughly forty human instincts in his Principles of Psychology, and famously proclaimed that humans possess more (not fewer) instincts compared to other animals. His list included such eyebrow-raising candidates as “a native impulse in everyone to conceal love affairs”, a “genuine instinct of cleanliness”, and an “instinct of personal isolation, which in women is called coyness” (1890, 393). It is important to understand what James meant when classifying such behaviors as instinctive. For James, the influence of instinct on behavior takes place during early stages of development. As he explained in Principles of Psychology, “Most instincts are implanted for the sake of giving rise to habits and… this purpose, once accomplished, the instincts themselves, as such, have no raison d’être in the psychical economy, and consequently fade away” (1890, 398). Thus, to call a behavior “instinctive” meant, for James, that it has a developmental origin in some more basic behavior which itself required no prior experience. After first performance, however, the original behavior is modified by reason, learning, and habit. This developmental model stood in contrast to the more static view of instinct defended by Romanes and others, wherein instincts often remain unmodified by experience into maturity.