Jacob picks up a toy hammer and begins pounding on the floor just as his father is hammering nails into a wall. jacob's actions are best explained by:

Jacob's actions are best explained by "Identification".

Identification refers to a process where someone (like in this example Jacob does) by a psychological process tries to copy, assimilate some part of an action, an attribute or anything which another is performing, (like hammering in the example above). Sigmund Freud’s work carries some roots of this process.