Final answer:
Observation in a contrived setting can threaten external validity, potentially reducing the ecological validity of the study and introducing observer bias, which can compromise internal validity.
Step-by-step explanation:
The disadvantages of observation in a contrived setting include the threat to external validity, where the findings may not generalize well to real-world settings because the observation is taking place in an unnatural, controlled environment. This can limit the ecological validity or realism of the study, making it less certain that the observed behaviors would occur in natural situations.
Additionally, while observation can be a cost-effective data collection method and can allow for more objective measurements, when conducted in artificial settings, the issue of observer bias can become a significant concern. This is because the observers, who may be closely involved with the research, might inadvertently record behaviors that confirm their expectations or research goals rather than what is truly occurring, thereby compromising the internal validity.
Therefore, one of the main disadvantages of conducting observation in a contrived setting is the potential threat to external validity.