Extinction Control Group

The article suggests that a stimulus could be correlated with alcohol or caffeine, or any type of drug. For this article they tested reaction time based on whether or not the individual drank coffee/caffeine (paired group) or juice (unpaired group), concluding that a conditioned response was a result of in the group that consumed the coffee, which is something that occurs so often in our daily lives (Fukuda and Aoyama, 2017). The experiment was a blind design which means that the experimenters did not tell the participants whether they were given a test treatment or a control treatment. The two experiments were conducted to analyze the results of an individual’s reaction when consuming decaffeinated coffee (versus water) and the “caffeine-associated stimuli”, and whether or not there was a conditioned response or stimulus as well as the reaction time that occurred.

There is no evidence of a study investigating decaffeinated coffee where the participants are informed of the decaffeination of the drink. There have been three different studies examining the effect of decaffeinated coffee. In the first study, participants were told they were drinking caffeinated coffee, but they were really drinking caffeinated coffee. The second was a blind design. Participants were expecting to be affected by caffeine, but they were given only decaffeinated coffee. In the third study, several studies used a balanced-placebo design either decaffeinated or caffeinated coffee and they were told what kind of coffee they were given. This study aimed to examine the expectancy effect of caffeine. These three types of studies were not designed to investigate the effect of decaffeinated coffee when the participants were informed that their drink was decaffeinated.

In experiment 1, the participants were required to either drink decaffeinated coffee or water after abstaining from caffeinated drinks for 2 hours prior to the test, and then had their reaction time tested. Their hypothesis was that there would be a conditioned response for those consuming the coffee. From the results, the reaction times showed to be quicker in the decaffeinated coffee group that in the water group, and the reaction time in the group drinking water decreased compared to the pre-session, but not in the decaffeinated coffee group (Fukuda and Aoyama, 2017). The coffee stopped or shorted a longer reaction time which correlated with their hypothesis. This study is the first to show that decaffeinated coffee improves performance even when participants are aware of the lack of caffeine or do not have expectations of the type of coffee they are drinking.

In experiment 2, researchers studied the repeated consumption of the [decaffeinated] coffee. Two groups were presented: the extinction group (consumed the coffee five times outside the experimental room) and the no-extinction control group (consumed the water five times outside the experimental room), after which both groups would consume the coffee and perform a test of their reaction time (Fukuda and Aoyama, 2017). The hypothesis was that if the coffee created an effect of classical conditioning, the shorter reaction time would decrease in the extinction group. No major difference in the participants’ reaction times before they drank the drink, which indicates that the effect caused by the coffee in the extinction session was not consistent or significant for the pre-session. Reaction time decreased from the pre-session for the extinction group though.

These results indicated that for the post-session 1, the no-extinction control group reacted with quicker reaction times than the extinction group, though the time decreased considerably [for the extinction-group] during post-sessions 1 and 3 compared to that of the pre-session (Fukuda and Aoyama, 2017). Overall, the longer reaction times were averted in both the decaffeinated coffee group in the first experiment and the no-extinction control group in the second experiment. This suggests the hypothesis was correct in that the conditioned response to the coffee was less in the extinction group though the effect of the coffee was less in the no-extinction group in the second experiment than in the water group for the first experiment.

Pavlov found when researching classical conditioning that when extinction occurs, it does not mean that the subject returns to their unconditioned state. Even after a long duration of time after a response has been extinguished, spontaneous recovery of the response can occur (Cherry and Gans, 2018). So, for instance, after someone who has been reliant on caffeine switches to decaf, they can be addicted to caffeine again after having one cup of caffeinated coffee. The strength of the original conditioning plays an important role in extinction. The longer conditioning has taken the response more resistant to extinction.