Final answer:
Participant observation is the ethnographic technique where researchers immerse themselves in a culture to observe behaviors and social practices firsthand.
Step-by-step explanation:
The ethnographic technique most associated with firsthand observation of behavior is participant observation. This methodology involves researchers immersing themselves directly into a cultural context to gain an insider's perspective. Through participating in the daily activities of the community or group, the researcher makes systematic observations, sometimes without fully disclosing their true identity or purpose to avoid influencing the behavior they are studying. Whether it's living among indigenous peoples, working as a waiter, or shadowing officers on patrol, participant observation enables a deep understanding of social practices and cultural norms from an emic, or insider's, viewpoint.