Chapt 2 experimental and non experimental designs: studies that use naturalistic observation methodology are non experimental in that actions and events are carefully measured and catalogued but independent variables cannot be directly manipulated. Experimental can be used when researchers want to test cause and effect ex. investigating whether smiling causes positive changes in emotional feelings. In an experimental design, a researcher is able to exercise control over the variable or variables that are assumed to be the causal agents producing thepredicted effect. Scientific understanding entails two distinct but related processes: description and explanation. Conceptual definition: provides the meaning of an abstract term such as intelligence, anxiety or emotion. Demarcates a semantic or linguistic meaning of a psychological term (texts and language) Similar to what you would find in a dictionary. Operational definition: indicates how a concept is coded, measured or quantified. Can include both prediction as well as establishing cause and effect.