is the act of acquiring new, or modifying and reinforcing, existing knowledge
s, or preferences
and may involve synthesizing different types of information
. The ability to learn is possessed by humans, animals, plants and some machines
. Progress over time tends to follow a learning curve
. It does not happen all at once, but builds upon and is shaped by previous knowledge. To that end, learning may be viewed as a process, rather than a collection of factual and procedural knowledge. Learning produces changes in the organism and the changes produced are relatively permanent.