Last Night's TV - The Young Ones, BBC1; First Light, BBC2; Wellington Bomber, BBC4

When you hear someone using the word "experiment" on television you can usually be sure that it is being applied in its loosest possible sense. It's intended to convey a perfume of scientific rigour, when what is actually being done often has all the methodological stringency of a five year old pouring Ribena into an ant's nest. Watching The Young Ones – which sets out to replicate a famous Harvard experiment into the effects of mental attitude on the ageing process – it may have occurred to you that not a few controls were missing. The procedure was this: six ageing celebrities were taken to a house decorated and equipped as if it was the mid Seventies. Nothing that entered the house – including television transmissions and newspapers – came from a later date and they were encouraged to think, talk and behave as if they actually had been taken back more than 30 years. Even their bedrooms were, where possible, exact replicas of those they'd occupied back in 1975. Naturally, within hours of entering the house the observers – who included Ellen Langer, the psychologist who first applied this lateral form of rejuvenation – were detecting signs of increased vigour and sprightliness in their elderly guinea pigs. How can they be sure, though, that irritation at being put through silly hoops for a television programme wasn't the active ingredient, rather than the orange shag pile carpets and the Betamax video recorder?

The shag pile carpet, incidentally, presented another scientific problem, since it was in place for two quite different reasons: to summon Proustian memories of the decade that taste forgot but also to provide a kind of gentle geriatric assault course. One of the rules of the house was that no one would be treated as if they were elderly and infirm. So, no stairlifts and lots of uneven surfaces to provide an extra bodily challenge. As Derek Jameson huffed his way up the stairs, hauling a suitcase behind him, he grouched loudly about the impossibility of the task. "It'll kill me," he complained, making you wonder briefly how exactly the BBC press office would have spun his death if it had. The observers sat tight as he heaved and gasped, happy to congratulate Jameson for completing the task, but not to assist him with it. "You can be helped to death," said Langer sternly. And again, it occurred to you that this tough-love, use-it-or-lose-it strategy might work perfectly well without the hideous Seventies wallpaper or mind-scrambling three-piece suite.

Not really an experiment at all then, but modestly watchable for all that, as a kind of Saga holiday version of Celebrity Big Brother. There is already enjoyable evidence of rampant denial (Lionel Blair standing in his shrieking yellow bedroom and insisting that he "never" would have slept in purple sheets, when the accompanying photograph of his bedroom proved otherwise) and promising tetchiness from some quarters (Sylvia Syms, who snaps at every hint of condescension). There was also an entertaining moment that demonstrated that going back in time may not involve quite as much travel for some participants as others. Presented with a classic Seventies party spread – cheese and pineapple hedgehog, vol-au-vents and prawn cocktail – the cricket umpire Dickie Bird was well pleased. "I think it's a nice buffet," he said. "Well... it's lovely... if you're a Northerner," Syms said scornfully. And yes, they do look a touch more upright and lively already, but wouldn't they anyway since they know that everything they do is going to be shown on telly? There's a fountain of youth, if you want one.

Eighty and 90 year olds were also taken back to their heyday in First Light and Wellington Bomber, two of the programmes marking the BBC's commemoration of the Battle of Britain. The first – a docudrama based on Geoffrey Wellum's excellent memoir of the same name – achieved the implausible task of making the subject a tiny bit dull, partly because of a creditable desire to reflect the intense psychological strain on the pilots, but also because it seemed to list towards the clichés of genre war films. "It's all right," said a pilot as the scramble bell rang, "I'll get another six when I'm back," and instantly you know that it's his plane they'll anxiously be scanning the skies for when the sortie returns, though you might not have predicted the meaningful close-up on the abandoned bat. Wellington Bomber – a documentary built around a wartime propaganda stunt in which aircraft workers constructed a plane in under 30 hours – was more successful at conveying the intensity of those years and the poignancy of looking back at them now, mostly because the intensity of the individual voices hadn't been varnished with actorly intensity. "You couldn't call it dancing," said one old lady recalling her husband's performance on the dance floor, "it was like taking a wheelbarrow round the room." And an ex-Wellington bomber pilot called "Tiny" Cooling heartbreakingly recalled a young flyer called Naylor ("everybody liked him but nobody took the blindest bit of notice of him because he looked like he was just out of his pram") coming into his room at the base and weeping like a child because his best friend hadn't returned. Three weeks later, Cooling was clearing out Naylor's barracks room because he hadn't returned from a mission. Ways of making you feel younger than you are may be disputed. But if you want to make young men feel a hundred years old war seems to work every time.