somewhere at the output here of these so they they do a weighted sum of the inputs and then they do a nonlinear nonlinear function and then they propagate that signal to the next layer and till then to finally to the output all right so how do these networks learn the one way of learning is called hebbian learning the interesting thing here is that it requires no feedback from the outside world basically what you want to do in hebbian learning is you want to update the connections such that they kind of match their own