14/08/2014 12:38 BST | Updated 22/05/2015 06:12 BST

Christmas Time Machine: Why Does Going Home For The Holidays Turn Us Back Into Teenagers?

We're successful, responsible adults - so what is it about returning to the family home for Christmas that turns us into children again? ponders Anna Hart

It happens every year. I depart London as a worldly, sorted, professional woman, but within two hours of getting back to my parents house in Belfast, I'm a snotty 14-year old, nose in the fridge, moaning at my mum for not having free range eggs or organic carrots.

I'll flop on the sofa for a bit, stabbing at the remote control with my fingernail and making grumpy noises about how it's not an HD TV. Then perhaps I'll bicker with my sister (a 32-year-old artist and art educator) about who should go buy soya milk, before making narky noises when my brother (a 30-year-old anaesthetist) heads out with his friends rather than staying home to watch Sherlock with me. And if I go out, my dad still offers to run me into town in our cosy family Volvo, and I still shamelessly abuse this privilege.

Every year I tell myself it's going to be different - that I'm not going to regress into a teenager - but I'm powerless; it's like muscle memory. I walk into my old bedroom and turn into my old self. All my old clothes, books and miscellaneous tat exercise a mysterious power over my personality; I feel the painful tug of long-suppressed petty insecurities (is my sister better than me?) and the subtle push to act on old urges (to see a schoolfriend I lost touch with). How does STUFF do this? It's just cloth and plastic.

But perhaps it's not my surroundings; perhaps I'm wrong to blame the curling Britpop images still bluetacked to the inside of my wardrobe for hypnotising me into thinking I'm 15 again. Maybe it's the whole Christmas routine, the rituals we do every year. We've done Christmas so many times we can now do it on autopilot; we just forget to update the software to "adult" rather than "child".

Or maybe it's something about the family unit. When we're all together, I'm suddenly an eldest child again, a hat I haven't had to wear for a while. I'm too busy wearing my "friend" or "co-worker" hat. Obviously nobody in my office cares I'm the first-born child in my family. But being the eldest is still clearly something I carry within me.

Occasionally I can hear her, when friends can't decide what pub to go to, or someone tries to change the radio station in my shared office, or when someone is a bit sad. I feel an overwhelming duty to cheer them up, with dumb jokes, twerk links or plain old cuddles. The eldest child within me is definitely still there, and she never misses a Christmas.

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