Pigeons trained with food pellets to sort breast tissue images became so accurate as a group that their pooled judgments scored 0.99 on a standard accuracy measure, a result the researchers described as 99% group accuracy. Yet pigeons hit a wall on suspicious masses in mammograms, memorizing the training pictures and then guessing on new ones. That 2015 finding has gained a second life in 2026, as two new pigeon studies of heart ultrasound videos and lung CT scans produced strikingly different outcomes.
