Maternal sensitivity is a mother's ability to perceive and infer the meaning behind her infant's behavioural signals, and to respond to them promptly and appropriately. Maternal sensitivity affects child development at all stages through life, from infancy, all the way to adulthood. In general, more sensitive mothers have healthier, more socially and cognitively developed children than those who are not as sensitive. Also, maternal sensitivity has been found to affect the person psychologically even as an adult. Adults who experienced high maternal sensitivity during their childhood were found to be more secure than those who experienced less sensitive mothers. Once the adult becomes a parent themselves, their own understanding of maternal sensitivity will affect their own children's development. Some research suggests that adult mothers display more maternal sensitivity than adolescent mothers who may in turn have children with a lower IQ and reading level than children of adult mothers.There are different ways of assessing maternal sensitivity, such as through the use of naturalistic observation, the Strange Situation, maternal-synchrony, and maternal mind-mindedness. There are also a number of ways of measuring maternal sensitivity in the scientific world, which include Ainsworth's Maternal Sensitivity Scale (AMSS), the Maternal Behaviour Q-sort (MBQS), and the Pederson and Moran Sensitivity Q-Sort.