Hi everyone, Our Lecturer has given us details of an experiment conducted by him on reinforcement and conditioning and we have to write up a lab report. Thats ok, but I am having trouble understanding the hypothesis. Briefly this how the experiment went. Two groups control and experimental. The task was to compare the length of lines displayed on a computer screen. A line of 10cm in length was permanently displayed as a guage for estimating the other line that popped up. Subjects responded by pressing keyboard keys matched to line length. Now the control group received no reinforcement on getting the correct or incorrect estimate, but the experimental group did in the form of "well done" which popped up on the screen before moving on to the next trial. Now the interesting bits, the experimental group received the reinforcer regardless of performance. If a subject in the experimental group got it right, they instantly received the reinforcer, if they got it wrong, they still received the reinforcer but there was a 5 second delay. The control group received no reinforcer at any time. Whether they got it right or wrong, they had to wait 5 seconds. Results were subjected to anova, total of 100 trials across 5 blocks. Pairwise comparisons were done between block 1 and block 5 in terms of accuracy and reaction time. No significant difference was found in terms of accuracy between the control and experimental groups indicating that the reinforcer to improve learning did not work. However learning did occur, but there was no difference between groups. Is this learning simply a result of practice and familiarisation with the experiment? Is it possible that the increase in accuracy was simply a result of latent learning for both groups? However in terms of reaction time there was a significant difference between the experimental and control groups. The experimental group got faster, the control group got slower! Whats happening here? Did reaction time increase with the control group simply because of a lack of reward? Is it possible that higher cognitive thinking can not be reinforced, but motor control can?Was the keyboard pressing what was being reinforced rather than correct answer? Did the reinforcer arouse motivation in the experimental group to only respond faster rather than get the estimation correct? Was the implementation of the "well done" on a 5 second delay designed to limit learning, hence forcing only a change in reaction time?
I am having trouble understanding the hypothesis and design. Would it not of been better to have another control group that is overtly rewarded for correctness as well as overtly punished for incorrectness with no delays? Any thoughts greatly appreciated. Cheers Wy
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