Answer: ethologists
Explanation: Ethologists study the character or fundamental values of a person, people, culture, or movement—human and animal behaviours. According to them, a critical period critical period is a phase in the life span of an organism during which there is heightened sensitivity to external stimuli that are compulsory for the development of a particular skill. This is due to the fact that an individual's behavioral characteristics can be more strongly influenced by some stimulus at one stage of development than at other stages. As such for some reason, if the individual does not receive the appropriate stimulus during this time to learn a given skill or trait, it may be difficult, less successful, or most times even impossible, to develop certain associated functions later in life—functions that are indispensable to its survival.