Psychology experiments are a great way to communicate the principles of the discipline to students. Even a simple experiment will demonstrate the ways in which observing behaviour can help us draw conclusions about the ways in which people think, act and communicate. Quick experiments can even be performed in the classroom to give students valuable hands-on experience.
The Stroop effect
The Stroop effect demonstrates that unseen factors can interfere with the reaction time involved in a particular task. To demonstrate the Stroop effect, prepare two sheets with six words on them. The words should be the names of colours. On the first sheet, the names of the colours should be written in the relevant colour; for instance, the word "blue" should be blue, red should be red, and so on. On the second sheet, the word and the colour should not match. Ask students to read each sheet aloud and time them as they do so. The second sheet will take longer, even though the words are the same. This is the result of what psychologist John Ridley Stroop called incongruent stimuli.
One important application of psychology in society is the study of memory and perception. A famous experiment by EF Loftus and JC Palmer demonstrated how malleable memory can be. To replicate this experiment, show students a film of two cars colliding. Ask students how fast the cars were going when they collided, but word the question differently -- ask one group how fast the cars were going when they "smashed" into each other, another how fast they were going when they "bumped" into each other, and another how fast they were going when they "hit" each other. Loftus and Palmer found that the more forceful the word used in the question was, the higher the estimate of the speed was.
The invisible gorilla
The selective attention task, more commonly known as the invisible gorilla test, is a perception test developed by researchers Daniel Simons and Christopher Chabris. Simons and Chabris asked subjects to count the number of times players in a video passed a basketball between them. During the video, a woman in a gorilla suit walked into the frame, beat her chest and left again. Startlingly, around half of the participants failed to perceive the gorilla. The invisible gorilla test is now sufficiently famous that some students will have heard of it, but Simon and Chabris have developed a new version of the test, the "monkey business illusion," that makes a useful classroom experiment. A link to the video is in the Resources section below.
Asch conformity experiment
To demonstrate the effect of peer pressure and the desire to conform, psychologist Solomon Asch devised an experiment that is easy to replicate in the classroom. Asch asked a group of subjects a series of questions. Only one of the participants was genuine; the others were plants. The plants answered the early questions correctly, but gave obviously wrong answers to some later questions. Subjects surrounded by plants loudly giving the wrong answer gave an increasing percentage of wrong answers themselves. Replicating this experiment is a great way to demonstrate the effect of outside influences on decision-making to students.