We often hear how scientists have discovered that a certain human trait – or a trait of another type of organism – is innate, genetic, heritable, inherited, naturally selected etc. All these claims have something in common: they all declare a trait to have significant organism internal (for instance genetic) causes that are present in the organism at its birth. I call claims like these “nativist claims”. Nativist claims are important. They shape our overall understanding of what we are, what (...) we can do and what is good for us. They also impact our practical decision making. For instance, we know that certain types of genes increase the risk of certain diseases, and increasingly this has an effect on healthcare practices. Many people believe that in the matter of children’s education we should consider the fact that many cognitive abilities are highly heritable. Associations between genetics and aggressive behavior have been taken to be alleviating circumstances in criminal sentencing. It is therefore important to correctly understand the content and implications of nativist claims. In this doctoral thesis I analyze, by philosophical means, the content of different kinds of nativist claim. What does it mean that some psychological tendency is innate? What does it mean that intelligence is 50% heritable? How (if at all) do genes come to carry information about the traits of an organism – they are nothing like the information carriers familiar to us, such as newspapers, e-mails, secret codes, and audio files. This thesis emphasizes two things. Firstly, I demonstrate, that in different scientific contexts these words ('innate', 'genetically caused' etc.) can mean very different things. Therefore, the implications of a given nativist claim in one scientific context can be remarkably different from another nativist claim’s implications in some other scientific context. Secondly, I explain how the development of innate, heritable and genetically caused traits can be determined in different and often unexpected ways by our environment and experiences. I demonstrate that the content of a concept that is considered innate by cognitive scientists can be determined by what the organism that possesses the concept has experienced. I also show that even a trait which is 100% heritable can at the same time be a socially constructed trait. (shrink)