My goal is to understand the fundamentals of curiosity so it can be implemented in some algorithm (e.g. for Artificial General Intelligence research), probably using genetic and evolutionary algorithms. What do you consider as the most basic trait of curiosity in simple forms of live or animals? Do you you think invertebrates have curiosity? Do you think bacterias have curiosity? Probably it depends on the definition of curiosity.. By analogy, there is "Microbial intelligence" (there's even an entry on Wikipedia about this). In machine learning programs, "curiosity" could be the initial random states that search for solution. And this initial "curiosity" (search for different possibilities and solutions) decreases as the solution is found.