Advanced Deep Learning Interview Questions, issue 23, Apr 13, 2026
The Independent Discriminator Trap
Senior Computer Vision Engineer interview at Google DeepMind, and the interviewer asks:
“In staging, your GAN produces stunning, photorealistic faces, but QA reports that every generated face looks like the exact same three people. Why is your highly optimized discriminator completely blind to this severe mode collapse, and what specific architectural change must you make to penalize this behavior at the batch level?”
Don’t say: “We just need to tune the hyperparameters.”
Per-sample discrimination creates a blind spot where perfect duplicates maximize reward with zero penalty.
The full answer, with the mechanism and the arithmetic, is for paid subscribers on Substack.