Structured observations are one of the many ways to gather data. Observing behavior rather than asking questions about it can provide you with a multitude of valuable information.
Controlled conditions and accurate data recording are key in scientific success and a stationary lab provides these controlled conditions while allowing scientists to observe test participants unobtrusively.
Wouldn’t every researcher want to automate certain measurements and save valuable time? In the 1800s, the study of eye movements for instance was done by means of direct observations!
In infancy you can observe an explosive growth. A lot of researchers focus on this age group and observe parent-infant dyads to get more insight in specific behaviors.