This document discusses the experimental method in psychology. It notes that Wilhelm Wundt opened the first experimental laboratory in 1879. The experimental method involves manipulating an independent variable and observing its effects on a dependent variable while controlling for extraneous variables. There are three types of experiments: laboratory experiments with strict control, field experiments with less control in natural environments, and quasi-experiments that manipulate variables without random assignment. The experimental method generally compares an experimental group exposed to the independent variable to a control group that is not exposed, to test hypotheses about causal relationships between variables. Techniques like random assignment and counterbalancing help control for extraneous variables.