Sylvia Bell of Johns Hopkins University reported: by the end of the first year individual differences in crying reflect the history of maternal responsiveness rather than constitutional differences in infant irritability. She also notes: consistency and promptness of maternal response is associated with decline in frequency and duration of infant crying. When following through with this maternal response, Bell notes that it is most effective to apply physical contact with the infant.The sleep position is also important to prevent Sudden Infant Death Syndrome (SIDS). It is recommended that the proper position for children to sleep in to avoid SIDS is laying on their back throughout the night. Their bedding should be firm and crib should be free from toys or blankets that could cause injury or suffocation to the child. Loose blankets and toys in the crib can increase the child’s risk of SIDS.