National University of Singapore Department of Psychology PL1101E: INTRODUCTION TO PSYCHOLOGY Question 2 Classical Conditioning and the Pupil Dilation Response Here is a simple classical conditioning experiment that you can perform on yourself at home. You will need a bell (or something you can ring), a hand-held mirror, and a room that becomes completely dark when the light is turned off. Hold the bell while standing in the room near the light switch. Once in position, you should ring the bell and then immediately turn off the light.
After waiting in total darkness for about 15 seconds, turn the light back on. Wait another 15 seconds with the light on, and then ring the bell and immediately turn the light back off (again waiting 15 seconds in the dark). Repeat this procedure 20 to 30 times, making sure that in each case the bell is rung immediately before the light is turned off. After numerous pairings, you should be ready to see the results. With the light on, watch your eyes closely in the mirror and then ring the bell. Your pupils should dilate slightly even without a change in light!
Explain the above process in terms of classical conditioning. State explicitly what the US, UR, CS, and CR are. Propose another (i. e. , original, you cannot use examples from the textbook, the lecture slides or the one above! ) classical conditioning experiment that you can perform at home. Again, state explicitly what the US, UR, CS, and CR are in your proposed experiment. Classical conditioning was discovered by Ivan Pavlov, and it involves pairing a neutral stimulus (NS) with an unconditioned stimulus (UCS) that elicits an unconditioned response (UCR).
Through repeated pairings, the neutral stimulus becomes a conditioned stimulus (CS), which by itself evokes a conditioned response (CR) similar to the original UCR (as evoked by the UCS). Basically, the previously-neutral stimulus now acquires the same power as the unconditioned stimulus to elicit a reflex response. For the classical conditioning experiment in question, the darkness that lasts for 15 seconds, as caused by switching the light off, is the UCS, as it is a naturally-occurring stimulus that elicits an UCR, which in this case is the reflexive response of the dilation of the pupil.
After the light is switched back on, it is necessary for the experimenter to wait for another 15 seconds before repeating the procedure again. This is to allow some time for the light rays to elicit pupil constriction, enabling the reflexive response of pupil dilation to occur once more when the procedure is repeated. The distinctive ring of the bell was initially the NS, but eventually became the CS, after being repeatedly associated with the UCS within close intervals for 20 to 30 times during the experiment.
This is because after conditioning, the previously-neutral stimulus has became one, which through association with the 15-second darkness (UCS), comes to elicit the reflexive response of pupil dilation (CR) which is similar to the original response (UCR), even without darkness. This can be seen from the results shown by the classical conditioning experiment above, where after the numerous pairings between the bell ring (NS) and darkness (UCS), the reflexive response of pupil dilation will still occur after the bell is rung despite the absence of darkness (UCS; i. e. ith the lights on), hence successfully transforming the NS into the CS, and the UCR into the CR. A novel classical conditioning experiment that can be performed at home will require a buzzer (or something that produces a distinct sound), a blindfold to prevent additional anticipation of the experimenter’s actions except that elicited by the buzz, a chair to sit on, and a clinical hammer. After blindfolding a friend that is seated on the chair with his or her legs positioned one over the other, sound the buzzer before immediately tapping your friend just below his or her knee with the clinical hammer.
Wait for 5 seconds before repeating this procedure for 20 to 30 times, making sure in each trial that the buzzer is sounded immediately before the tapping of your friend’s knee. After numerous pairings, it is theoretically possible to observe a reflexive knee jerk even without tapping your friend’s knee, once the buzzer sounds. In this classical conditioning experiment, the tapping of the person’s knee with a clinical hammer is the UCS, as it is a aturally occurring stimulus that elicits the UCR, which in this case is the reflexive knee jerk action. The distinctive sound given out by the buzzer was initially the NS, but eventually became the CS, after 20 to 30 pairings with the UCS within close intervals of 5 seconds during the experiment. It has become a stimulus that is subsequently capable of eliciting a learned reflex response on its own (CR) which was originally an UCR, because it has been paired with the original UCS.
This can be seen from the results shown by the classical conditioning experiment conducted above. After the numerous pairings between the sound given out by the buzzer (NS) and the tapping of the knee using a clinical hammer (UCS), the reflexive knee jerk response (UCR) will still occur after the buzzer is sounded despite the absence of any tapping of the knee, hence successfully transforming the NS into the CS, and the UCR into the CR. Bibliography Passer, S. H. Psychology: The Science of Mind and Behaviour.