By: Courtney Breyer, Greg Gianopoulos, Erik Money, Nora Uhrich, Nicole Valencia

HUMAN CLASSICAL CONDITIONING

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Human Classical Conditioning

By: Courtney Breyer, Greg Gianopoulos, Erik Money, Nora Uhrich, Nicole Valencia

Organisms make associations between a specific stimulus and a response in single-stimulus learning events. An example of a single-stimulus learning event is a student learning to associate a time on a clock (stimulus) with his action of leaving a classroom (response). Single-stimulus learning events are taken a step further when organisms associate two stimuli together. For example, a professor might learn to associate a time on a clock (stimulus 1) with the occurrence of students packing up to leave class (stimulus 2), also learning to associate one or both of the stimuli with her action of leaving the classroom (response). The professor might not need to see the clock to understand that it is time for her to leave the classroom, because she has associated the time on the clock (stimulus 1) with the occurrence of students packing up to leave class (stimulus 2). This example demonstrates associative learning, a phenomenon in which multiple stimuli are related to each other as well as a response. There are many different types of associative learning. This lab report focuses on one of these types of associative learning—classical conditioning.

Classical conditioning is often traced back to the story of Ivan Pavlov and his salivating dogs. In this story, Pavlov trained his dogs to salivate to the sound of a bell by presenting the sound at the same time as meat powder, which he noticed to naturally elicit salivation in his dogs. In this way, classical conditioning allows an organism to learn a conditioned response (e.g. salivation) to a conditioned stimulus (e.g. the sound of a bell), even though that stimulus may not naturally cause that response (unlike would an unconditioned stimulus such as meat powder). Much like dogs, classical conditioning also occurs in humans.

This experiment explored whether a conditioned response (CR) could be created in response to a verbalized word. The unconditioned stimulus (US) was a squirt of water to a squirtee’s goggles and the unconditioned response (UR) included blinking, flinching, and smiling. Lastly, the conditioned stimulus (CS) was the word “BED”.

Method

Participants

This experiment was performed with a group of five students of Conditioning and Learning (Psych 236). There was one reader, one squirter, one squirtee, and two observers.

Materials

1 squirt gun

1 instruction sheet

2 word sheets

Procedure

To ensure the squirtee would not prematurely learn the purpose of the experiment, the squirtee was sent into the hall while the other team members received directions and necessary sheets. Next, the squirtee was retrieved and given goggles, then seated in a chair facing the squirter, who stood holding the squirt gun aimed at the squirtee’s goggles. The reader stood behind the squirtee, completely out of the squirtee’s view, and the observers sat facing the squirtee for a clear view of the squirtee’s behavior.

In an even tone, the reader read aloud a series of words at a rate of one every 2 seconds, nodding vigorously when the word “BED” (capitalized) occurred. This nod signaled the squirter to squirt the squirtee’s goggles while the observers recorded squirtee behavior on their corresponding word sheets. Sometimes the word “bed” (lowercase) occurred, to which no squirt was administered. Observers noted the squirtee’s reaction to this on the word sheets as well.

Results

The squirtee reacted with face flinches, blinks, and/or laughing when the word “BED” was paired with a water squirt. When the word “bed” was not reinforced with a squirt, the squirtee still displayed face flinches and blinks for two trials. The squirtee seemed confused and displayed this through a furrowed brow, wide eyes, tense face, or smile. After the third “bed” trial, the squirtee did not respond. The squirtee had similar responses to “BED” when it was reintroduced halfway through the experiment.

Discussion

The results show that learning occurred because the squirtee continued to flinch or blink even when the word “bed” was not reinforced with a squirt of water to the eye. Since there was only one subject, this experiment conformed to a within-subjects design; thus, learning could be inferred by (a) observing the squirtee’s flinches and blinks and (b) assuming that the squirtee would not flinch or blink if the word “BED” was not paired with the squirts over trials. In addition, alternative explanations for the CR are taken into account. For instance, stimulus change is an unacceptable explanation because the US remained the same throughout the experiment. Likewise, evolution and maturation aren’t acceptable explanations because the experiment took place over a short period of time with a single participant.

A trial was completed each time a squirt was administered. It took at most 25 trials for the subject to learn the association between “BED” and a squirt. In order to know if the squirtee’s response was due to the squirt of water or to the word “BED,” the experimenters used a CS alone test by using the word “bed” without capitalization. The experiment demonstrates classical conditioning because an US was paired with a CS to produce a CR. In the experiment the US was water to the squirtee’s eye. The UR was the squirtee blinking/flinching, smiling, and/or jumping. The CS was the word “BED” when capitalized and the CR was blinking/flinching, smiling, and/or jumping to the word “bed.”

In addition to learning, extinction also occurred. Extinction refers to the gradual weakening of a CR that results in the behavior decreasing or disappearing. In classical conditioning, extinction can occur when a CS is no longer paired with an US. Because the subject did not respond to the word “bed” after the third trial, the researchers concluded that extinction occurred.

There are some possible extraneous factors that could provide an alternate explanation for the data. First, the squirtee was positioned in such a way that the observers were visible. It is possible that the observers unintentionally offered nonverbal cues such as facial gestures or eye contact, which led the squirtee to expect a squirt in the eye. This may have caused the squirtee to flinch or blink less frequently, as the squirtee may have attempted to hold back any reactions after noticing the nonverbal cues. In addition, the squirtee could have observed the eye movement of the squirter and thus anticipated the squirt, reducing the intensity of the reflex for similar reasons. Lastly, the squirtee was in an environment in which other experiments were using the word “bed”, possibly causing the squirtee to flinch or blink at times unrelated to the present experiment’s word sheet. Also, this may have confused the squirtee by causing the squirtee to experience extinction, hearing other pronunciations of the word “bed” while not being squirted. Despite possible extraneous factors that can occur in human classical conditioning, there are many possible future experiments that can help researchers discover more about human conditioning. Other avenues of research include differing test subjects, independent variables, aversive or positive stimuli, and focus of research question. The importance of classical conditioning cannot be understated, as many different applications may exist. There is a great amount of research already accomplished in the classical conditioning field, but there are still many possible opportunities for further research.

References

Domjan, M. (2005). The Essentials of Conditioning and Learning (Third ed.). Belmont, CA: Wadsworth,

Cendage Learning.