Failing to give babies cuddles and affection subtly changes how their brains develop, and in later life can leave them anxious and poor at forming relationships.

Love and affection from parents and carers are vital to developing the brain "pathways" involved in dealing with stress and forming social bonds, according to a study published yesterday.

Seth Pollak, a psychologist at the University of Wisconsin, led a research team that compared the progress of children raised by their biological parents with children who had come from crowded orphanages in Russia and Romania and had been adopted by parents in the US.