Why Do Some Vegetable Seeds Need a Cold Period Before They Sprout?

I’ve noticed that some seeds seem to germinate better after spending time in cold conditions, while others sprout readily from a packet at room temperature. Is this just a way of delaying growth until spring, or does cold exposure change something inside the seed?

I’m curious whether this applies to particular vegetables or varieties, and how gardeners distinguish a genuine cold requirement from seeds that simply need more time or different moisture conditions.