So, how does lying begin? In order to tell a lie, a child must understand that what we say
doesn’t always correspond to what we are really thinking (as above), and that sometimes
people hide what they really think and feel [2]. This ability to understand “hidden
feelings” also enables children to understand jokes, teasing, and sarcasm [2]. It’s not
surprising to hear that while one third of three year olds lie, over 80% of four year olds lie,
because a child’s theory of mind and ability to understand the perspectives of others
develops significantly between ages three and four [3]