There are several that I've wondered about:
Raise a kid by machine, with physical needs provided for, and expose the kid to language using books, recordings, and video displays, but no interactive communication or contact with humans. After 20 years or so, see what the person is like.
Try to create a society of unconscious people with bicameral minds, as described in Julian Jaynes's "The Origin of Consciousness in the Breakdown of the Bicameral Mind", using actors taking on the appropriate roles. (Jaynes's theory, which influenced Daniel Dennett, was that consciousness is a recent cultural innovation.)
Try to create a society where people grow up seeing sexual activity as casual, ordinary, and expected as shaking hands or saying hello, and see whether sexual taboos develop, and study how sexual relationships form.
Raise a bunch of kids speaking artificial languages, designed to be unlike any human language, and study how they learn and modify the language they're taught. Or give them a language without certain concepts (relatives, ethics, the self) and see how the language influences they way they think and act.
Point 1: I'm not sure what you mean by physical needs. If human babies aren't cuddled, they die. Humans are the only known species to do this.
A General Theory of Love describes the connection between the limbic system and love-- I thought it was a good book, but to judge by the Amazon reviews, it's more personally important to a lot of intellectual readers than I would have expected.
And happy new year to everyone.