They could be overfitting somehow, but I don't see how you get that from the quoted paragraph. Of course they need to use the same subject (i.e. human brain) fo

They could be overfitting somehow, but I don't see how you get that from the quoted paragraph. Of course they need to use the same subject (i.e. human brain) for training and testing. Otherwise one would need to assume that different people's brains represent visual concepts in the same way.