Does anyone remember the case of a little girl who was locked in isolation from a very young age in an attic? When she was rescued as a 9 year-old, she had little verbal capabilities.  Now after viewing these brain videos, her case really makes sense--growing up in isolation, she had no experiences to build her brain architecture. And it really points to the fact that we humans are social animals, and need interaction in order to learn. As a language teacher I've always tried to use pair work and group work activities,  but I think I need to take it a step further, and ask myself, "how does what I do in the classroom strengthen the connections between the students in my class?"