What is an instinct? It’s usually defined as an innate tendency to a behavior, especially as contrasted to learned behaviors. Baby birds, for example, fly upon reaching sufficient physical maturity without the help of any lessons. Similarly, ants and termites don’t need instruction on how build their elaborate nests – the program for that is already in the firmware when shipped. Such preprogrammed behaviors are hardly absent in primates or humans, but they do tend to become more complicated by the necessity of learning.
Birds learn too, of course, and so do bees, but the element of learning is far more prominent in humans. Human babies are born with instinctive tendencies to crawl, walk and speak but they can’t do any of them at birth, and each skill requires progressively more learning. Other instincts are perhaps even more subtle. Humans and our fellow higher primates can all throw, but only humans seem to be able to do so with range and precision. It takes a lot of mental machinery to solve the differential equation of projectile flight and convert results to appropriate muscle impulse patterns, and our hairier fellows seem to lack it. I call this a subtle instinct because most humans don’t bother to develop it – at least not in the modern world.
Note that this definition of instinct is a combination of abilities and tendencies – you won’t fly unless you have the wings, muscles, and control systems for flight on the one hand, and the desire to launch yourself into space with nothing but air to hold you up on the other. As the example of throwing indicates, that machinery can be complex and subtle. Man’s tool making instinct is another classic example. The beautiful and subtly wrought projectile points that first occur in the archeological records a few tens of thousands of years ago probably represent the full maturity of this talent.
As it happens, chimps and gorillas can be taught to make stone tools by the flaking process that humans have used. However, they are unable to become good at it. Here the reason is especially clear – they lack the fine hand muscles and control needed for the task. Today, probably only a few hundred individuals still exist in the world with any skill at flaking stone tools, but it happens that the subtlety of hand and mind developed for that task is transferrable. Surgeons, artists, tailors and craftsmen still depend on those skills and are probably still motivated, in part, by same instinctive pleasure that our ancestors took in finding a nice piece of stone and whacking away at it to create a tool.