Final answer:
A weakness of Bowlby's study on attachment is the potential oversight of attachment diversity and complexity as later revealed by Ainsworth's Strange Situation procedure and Harlow's monkey experiments, which highlighted comfort and security as crucial to attachment beyond the provision of nourishment.
Step-by-step explanation:
One additional weakness of Bowlby's study on deprivation and privation is that it may have underestimated the diversity of attachment types and the subtleties in how attachment can manifest differently among children. While Bowlby posited that attachment was a crucial binary process, later research by Mary Ainsworth through the Strange Situation procedure suggested a more nuanced spectrum of attachment styles, such as secure, avoidant, and ambivalent attachment. This indicates that Bowlby's theory may not adequately account for the varying responses children have towards caregivers and the complexity of attachment behaviors shaped by caregiver sensitivity and responsiveness.
Moreover, studies by researchers such as Harlow with rhesus monkeys emphasized the importance of comfort and security over mere nourishment in the formation of parent-offspring bonding, illustrating potential limitations in Bowlby's emphasis on the caregiver as primarily a source of food and sustenance in building attachment.