Observations
Observations are possibly the oldest scientific tool around. Likely, too, it is the cheapest method, and, in a manner of speaking (depending on the length of time of the observation), the least time-consuming. Certainly, it is the easiest. Observations are also more direct than questionnaires or experimental method in that they do not require the subjects to respond to written (or verbal) questions, nor attempt to persuade them to do so, nor, likewise, to gather in rarefied situations to respond to stimuli presented (usually) under certain constraints with much preparation done beforehand.
Observation in psychology today is less used than it used to be. It focuses more on the covert, cognitive aspects of human functioning, and, otherwise, assumes the term 'ethology' where it observes behavior in natural settings and aims to exert little or minimum experimental control over the subject/s. Observation has the advantage of the other methods in that it is the only tool that can be used in instances where...
Although it enables access to possibly more private events than external observation can provide, its primary criticism is that it is impossible for the observer to remain unbiased.
I will address the validity of carefully monitoring possible personal bias and thoroughly scrutinizing environment of potential confounding elements. I might discuss my observations and methodology with objective others, share my findings with participants in order to acquire their feedback, involve objective others into my research.
Sources
Blaxter, l., Hughes, C., & Tight, M. (1996). How to research. Phil: Open Univ. Press,
Breakwell, G., Hammond, S., & Fife-Schaw, C. (2000). Research methods in psychology. London: SAGE
