The Chinese saying "Three years old fixes eighty" (三歲定八十) means roughly: From the character and personality traits revealed by a three year old, one can infer that he will have similar traits as an eighty year old. So e.g. if a three year old does something crafty or sneaky, the parent might use this idiom to mean (usually half-jokingly) that he will be just as crafty or sneaky when he is eighty.
Is there an English idiom that closely corresponds to this Chinese idiom?
(Briefly Googling, one blogger claims that Wordsworth's "The Child is father of the Man" is suitable, but I am not sure if this is really what Wordsworth meant, and even if it were, this idiom seems to be rarely if ever used. )
Best Answer
According to the Oxford Dictionary of Phrase and Fable,
as the poet Alexander Pope wrote around 1732, means early influences have a permanent effect.