what is a method of distinguishing sensory stimuli that takes into account not only the stimuli's strengths but also such variable elements as the setting, your physical state, your mood, and your attitudes

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?