Final answer:
The described behavior is an example of the palmar grasp reflex in newborns and infants.
Step-by-step explanation:
The behavior described in the question is best considered to be an example of the palmar grasp reflex. This reflex is present in newborns and infants and is characterized by their fingers closing tightly in response to stimulation of the palm of their hand. It is an innate and automatic response that helps infants hold onto objects or their caregiver.