How was hypnopaedia discovered?

Hypnopaedia was discovered during the time that parents were still allowed to raise their own children. Little Reuben woke up one morning after his parents had neglected to turn of the radio, repeating "word for word" a lecture he'd heard on the radio. His parents called the doctor, and boom...... he realized the boy had memorized the discourse in his sleep.

He returned to Little Reuben–to Little Reuben, in whose room, one evening, by an oversight, his father and mother (crash, crash!) happened to leave the radio turned on.

("For you must remember that in those days of gross viviparous reproduction, children were always brought up by their parents and not in State Conditioning Centres.")

While the child was asleep, a broadcast programme from London suddenly started to come through; and the next morning, to the astonishment of his crash and crash (the more daring of the boys ventured to grin at one another), Little Reuben woke up repeating word for word a long lecture by that curious old writer ("one of the very few whose works have been permitted to come down to us"), George Bernard Shaw, who was speaking, according to a well-authenticated tradition, about his own genius. To Little Reuben's wink and snigger, this lecture was, of course, perfectly incomprehensible and, imagining that their child had suddenly gone mad, they sent for a doctor. He, fortunately, understood English, recognized the discourse as that which Shaw had broadcasted the previous evening, realized the significance of what had happened, and sent a letter to the medical press about it.

"The principle of sleep-teaching, or hypnopædia, had been discovered." The D.H.C. made an impressive pause.