It is commonly understood that as humans get older, our imaginations become less active: this is how children once afraid of the dark can grow up to become potholers.
But a study has revealed that when it comes to believing in aliens, the opposite may be true.
On answering a questionnaire, half of key stage 3 pupils said they believed the Earth had been visited by aliens, but this increased to 58 per cent at KS4.
Interviews revealed that pupils' factual knowledge of space and astronomy dissipated as they moved through secondary school. Younger children gave slightly more accurate answers to questions about phenomena such as black holes.
In the classrooms of Cambridgeshire, where 244 pupils were surveyed, fewer than 10 per cent believed God created the universe.
Fran Riga, a PhD student at Cambridge University, said she had been shocked to find that pupils of all ages based many of their ideas about the universe on "beliefs" rather than scientific evidence.
Crop circles, she said, were given as evidence for alien landings, but few pupils look beyond this theory.
Ms Riga, who will talk about her research to the annual Association for Science Education conference tomorrow, said: "Children are getting lots of astronomy at primary school, but they are losing it. They may also be susceptible to picking up ideas from films and the media."
She said her research would continue with pupils beyond Cambridgeshire to test the effect of the 21st-century curriculum.
Dr Nick Lister, who runs the Lawrence House Space Science Centre near Blackpool, said: "A lot of science teachers struggle with the astronomy curriculum. I have lots of school groups here and pupils bombard me with questions. If teachers can't answer them, pupils are going to latch on to other stuff, such as alien landings."