THE KING'S SINGERS (next week's R3 Artist of the Week), are 30 years old. Brian Kay tells a story from their early days, when he sang with them in broadcast "invitation" concerts. One night absolutely nobody came. The resourceful producer decided that the minute they stopped singing they were to drop their scores and applaud vigorously ...

That must be what they do on Full Orchestra (R4). When six clapping people try to sound like 300, you can virtually identify their nail-varnish. Relentlessly cheery, Tommy Pearson chairs resolutely on, giving the impression that he's been doing it for centuries, pretending that each round will provoke gleeful recognition, that it doesn't matter that the questions are so easy that even a tone-deaf carpet-fitter would probably get them right, given 24 hours with Classic FM.

But Pearson's job is easier than Barry Took's. His unenviable fate is to introduce Guess What? (R4), alias Animal, Vegetable, Mineral. Both shows occupy a time hitherto sacred to The World at One and The Archers. We've had a month now to adjust to these untimely quizzes, but untimely they still seem.

I'd hate to be like the R4 listener who abhors change and moans drearily on Feedback about how his life has been ruined. And yet Guess What? is like reverting to a nightmare from earliest childhood, full of inane, repetitive questions, leading to destinations of terrifying tedium. "Is the animal human?" a panellist enquires, yet again. "Er, could be," says Took, brightly. I don't care. I don't care if it's a whole studio full of cobras. The animal's a dinosaur.

But even Guess What? is better than I'm Glad You Asked Me That (R4), a "comedy guide for surviving the millennium". The audience for this one must be primed with gin-and-Prozac - how else could they possibly guffaw when somebody quips "I've discovered I can do all my shopping on the Net"? It's unnerving to hear such turgid stuff greeted by riotous mirth. This show descends from a long-dead series called Does the Team Think?, in which old comics fired off corny jokes in response to silly questions. But it's not as good.

New Radio 4 is making a mess of being light-hearted but it's doing rather well in the heavyweight division. Take The Choice: at first, Michael Buerk seemed uneasy as an amateur Anthony Clare, but in this week's session with Steven Owens he was first-class. Owens is the man who pursued and shot the hit-and-run driver who killed his son. Buerk, a compassionate man, discovered that it was the driver's lack of remorse that enraged him. By the end nobody - not even Owens himself - condoned the shooting, but we all understood why he did it.

Another successful innovation is the "factual reading" slot at 9.45am, though this week's readings, Telling the Workers About Science (R4), were certainly demanding. However, Einstein's explanation of relativity, On Being the Right Size, was surprisingly accessible. If you really concentrated, you could understand why a mouse can fall 1,000 yards without injury but a giant is terrified of gravity. And I now know why, when I took my small daughter to a circus and she gazed for the first time on a recumbent llama, she identified it without hesitation as a snail.