BABIES grasp the art of deception even before their first birthday, a study has found.
The littlest liar was aged just eight months, researchers said.
About a quarter understand deception by ten months, rising to half at 17 months.
They become more expert, creative and frequent at lying by three.
The findings are from University of Bristol researchers who questioned parents of more than 750 children in the UK, US, Australia and Canada.
Of these, 130 parents reported children engaged in 16 deception types before 47 months.
These included pretending not to hear to avoid doing something and hiding things so a rival could not have them.
Other tricks were denial, doing forbidden activities in secret, making an excuse, exaggeration and understatement.
They also left out details on purpose and used distraction.
Researcher Elena Hoicka said: “It was fascinating to uncover how children’s understanding and usage of deception evolves from a surprisingly young age and builds in their first years so they become quite adept ‘little liars’.
“From two years, deception tends to be action-based, or require only basic spoken responses, like pretending not to hear their parent say ‘time to tidy up’, hiding things from others, or denial — such as eating chocolate but shaking head to say ‘no’ when asked if they ate chocolate.
“It could extend to doing forbidden activities in secret — for example looking in a bag they were told not to look in when no one is apparently watching. Or they’d make excuses such as claiming to need the toilet when asked to tidy up.”
Prof Hoicka added: “Parents can be reassured deception is entirely normal in toddler development.
“They can also look at our findings to know which types of deception to expect by age, so they can better understand and communicate with their children in order to stay one step ahead of their deceit.”
Co-researcher Jennifer Saul, from Canada’s University of Waterloo, said: “Philosophers have long reflected on the morality of human deception, but always focused on adults deceiving one another.
“This study shows just how much complexity gets overlooked by that focus.”
