The study, published in the Journal of Family Psychology, looked at five decades of research involving over 160,000 children. For the purposes of the analysis, spanking was defined as an "!open-handed hit on the behind or extremities".

“We found that spanking was associated with unintended detrimental outcomes and was not associated with more immediate or long-term compliance, which are parents’ intended outcomes when they discipline their children,” said Elizabeth Gershoff, associate professor of human development and family sciences at The University of Texas at Austin.

Co-author Andrew Grogan-Kaylor, from the University of Michigan School of Social Work, said: "The upshot of the study is that spanking increases the likelihood of a wide variety of undesired outcomes for children. Spanking thus does the opposite of what parents usually want it to do."