I have a question about neural networks.<p>Say, you are training a NN to recognize handwritten characters 0 and 1, and you have 1000 training images for each character (so 2000 images in total). All images are bitmaps with 0 for black and 1 for white.<p>Now, by accident, all the &quot;0&quot; training-images have an even number of black pixels, and all the &quot;1&quot; training-images have an odd number of black pixels.<p>How do you know that the NN really learns to recognize 0&#x27;s and 1&#x27;s, as opposed to recognizing whether the number of pixels in an image is even or odd?