Yet, this wanes by the time the child reaches the age of 11, the research adds.
The study also found parents having IVF are generally more educated and have a higher income and socioeconomic status, which may help to 'override' factors that would otherwise impact IVF babies' cognitive development, such as a higher risk of a premature birth.
Researchers also believe IVF causes parents considerable psychological and financial stress, resulting in them being more attentive during a child's early years, which boosts their youngster's development.
This research adds to previous studies which have produced mixed results regarding the development of IVF babies, with some saying they are more, less or equally as advanced as naturally-conceived infants.
Researchers from the University of Oxford analysed 218 UK children born via IVF or ICSI (when a single sperm is inserted into an egg) between 2000 and 2001.
Standard ability tests assessed their vocabulary at the ages of three and five, reading at age seven and use of verbs at 11.
The scores were compared against naturally-conceived children.
Results, published in the journal Human Reproduction, revealed children born via artificial conception are significantly more cognitively developed than naturally conceived children at the ages of three and five.
Yet, the findings further showed this diminishes by the age of 11.
Parents of artificially-conceived babies are generally more educated and of a higher socioeconomic status, the research adds.
The researchers believe the children's parents' statuses overcome factors that may otherwise hinder artificially-conceived babies' development, such as a higher risk of being born prematurely or as a multiple birth.
Parents undergoing artificial conception may also be more attentive during an infant's early life due to the likely psychological and financial stresses they were under, however, this may wane up the time their child reaches the age of 11, the researchers said.
Study author Professor Melinda Mills said: "The findings suggest that the positive effect of the family background of children conceived through artificial reproduction techniques 'overrides' the risks of related poor health impairing their cognitive ability.
"Although artificially conceived babies have a higher risk of being born prematurely or as a multiple birth, we have found they also have parents who are older, better educated and from a higher income bracket.
"These are all factors linked with better outcomes for children. What is significant is that this positive effect is over the long term up to the age of 11.
"The findings support other studies showing that, on balance, such fertility treatments do not impair a child's higher thinking skills."
Lead author Anna Barbuscia said: "The strong desire and considerable psychological and financial effort involved in having a child through artificial conception treatments undoubtedly contributes to more attentive parenting.
"Parents may perceive their children as more fragile but once past the period of greatest risk, their parenting style may change to become more like other parents.
"This might account for the fact that the gap in higher cognitive ability has closed by the time both groups of children had reached the age of 11 with only slightly better scores for artificially conceived children at this later stage ."
Previous studies show a mixed picture, with some suggesting assisted reproduction can hinder a child's behavioural, social, emotional and cognitive development, as well as increasing their risk of suffering mental disorders or physical problems such as low birthweight and premature delivery.
Yet, a series of reviews previously concluded there were no developmental differences once the baby was a few weeks old.
Other studies draw similar conclusions to the Oxford study, showing not only comparable but higher mental health and social development in IVF children.
