Amajor limitation of naturalistic observation in the study of human behavior is that

A major limitation of naturalistic observation in the study of human behavior is that extraneous variables outside the researcher's control that might compromise the validity of the study. 

A naturalistic observation study involves observing and studying participants' behavior in their natural setting, without manipulating any variables. While naturalistic observations have advantages such as avoiding social desirability bias and experimenter effects, its main disadvantage is that extraneous variables might lead to dependent variables, lowering the validity of the study.