List of top two psychological experiments on reaction time!
Experiment # 1. Simple Reaction Time:
Problem:
To determine the simple reaction time of a subject to visual and auditory stimuli.
Materials Required:
A reaction-time apparatus and a chronoscope.
Description of the Reaction-Time Apparatus:
It consists of a wooden board with a screen in the middle. On one side of the screen (the subject’s side) there are two lights, red and white and two press keys. Each one of the keys is connected to one of the lights. If the key is pressed while the light is on, the circuit will automatically break and the light will go off.
On the other side, i.e., experimenter’s side, there are a series of keys which serve to switch on the two lights on the subject’s side. Along with this, a buzzer is also fixed on the experimenter’s side, and there is a key to which the buzzer is connected. With the help of these keys, the experimenter can switch on or switch off the lights or ring the buzzer.
Chronoscope:
A chronoscope is an electrically operated timing instrument which measures very short time interval up to a millisecond.
The batteries or the electrical main, the chronoscope and the reaction time apparatus are connected such that they forma circuit. Whenever the experimenter switches on the lights or the buzzer, the chronoscope also starts working and when the subject switches off the light, the chronoscope also stops. The reading in the chronoscope gives the reaction time, i.e., the time between the experimenter’s switching on the light and the subject’s switching it off.
Procedure:
Give the following instructions to the subject:
‘You have got a red light here. As soon as you see it burning, press the key on your left side, as quickly as you can.’ The experimenter gives a few trials for demonstration. Now the experimenter starts the experiment. He presses the key for the red light and as soon as the subject presses the key, he notes the time recorded on the Chronoscope.
Before switching on the light, each time a ready signal is given. The experiment is repeated about twenty times. The average reaction time for the twenty trials is calculated. The experiment is then repeated using the buzzer as the stimulus instead of the red light.
Results:
Tabulate the results for the entire group as follows:
Calculate the average for the group and discuss the variability among the subjects.
Experiment # 2. Discrimination Reaction Time:
Problem:
To study the reaction time when the subject has to discriminate one stimulus from another, and then respond.
Materials Required:
Reaction-time apparatus, chronoscope, batteries.
Procedure:
This experiment involves presentation of two stimuli, i.e., the red light and the white light on different trials. The experimenter, therefore prepares a preliminary list of stimuli, 40 in number (20 with red light, and 20 with white light) presented in a random order.
Instructions:
“This time on some occasions you will see a red light and on others a white light, but you have to respond to only the white light. Whenever you see the white light, you press the key on your right side.” The experimenter as in the previous experiment presents the 40 stimuli preceded by a ‘ready’ signal each time. The reaction time for the 20 white light trials are noted down.
Results:
Calculate the average reaction time for the white light stimuli.
Tabulate the results as follows:
Study the Variability of the Group:
Note:
Repeat the experiment with two auditory stimuli, a buzzer and a bell, included in the circuit. It may also be interesting to employ one visual stimulus and one auditory stimulus and study the discrimination reaction time for them. Compare these results with those obtained under simple reaction time.