So what features are those networks actually learning? What are thy looking for? They can not be much like features used by humans because the features used by humans are robust against such adversarial noise. I am also somewhat tempted to say that they can also not be to different from the features used by humans because otherwise, it seems, they would not generalize well. If they just learned some random accidental details in the trainings set, they would probably fail spectacularly in the validation phase with high probability but they don't. And we would of course have a contradiction with the former statement.<p>So it seems that there are features quite different from the features used by humans that are still similarly robust unless you specifically target them. And they also correlate well with features used by humans unless you specifically target them. Real world images are very unusual images in the sense that almost all possible images are random noise while real world images are [almost] never random noise. And here I get a bit stuck, I have this diffuse idea in my head that most possible images do not occur in the real world and that there are way more degrees of freedom into direction that just don't occur in the real world but this idea is just too diffuse so that I am currently unable to pin and write down.