Training on hard one-hot labels teaches a model to be infinitely confident — it pushes the correct logit toward +∞ and overfits. Label smoothing softens the target: give the true class 1−ε and spread ε across the rest. The model learns to leave a little probability for other answers, which calibrates its confidence and generalizes better. A one-line humility.
The demo smooths a one-hot label with ε=0.1 over K=10 classes — true class 0.91, others 0.01, sums to 1: live demo
“Label smoothing always improves accuracy.” — it improves calibration and often accuracy, but can hurt when you later distill the model (it erases useful logit structure). cited
A little doubt, deliberately trained in. regularization
On i-13, ε=0.1 over K=10: true class 0.91, each other 0.01, summing to 1: