The Effect of Subjective Mental State on Memory Test Performance

Introduction

One’s subjective mental state can have a large impact on how they are able to function throughout the day; a poor mental state may make even simple tasks difficult to do. One of these tasks could include simple memorization (Butler and Zeman). Existing research on subjects’ mental state looked at memory complaints and memory performance when subjects were asked to memorize objects under a negative context. In this research where 87% of participants said they were having depressive symptoms, it was found that there was only a correlation between these symptoms and self-reported memory complaints. The study also measured hippocampal volume to look for a correlation between subjective depression symptoms and objective memory performance, but hippocampal size did not significantly differ between any of the subjects. The only memory performance actually tested involved negative association with the objects they were asked to memorize (Schweizer et al.). Therefore, there was no standard, objective measure of performance on a memory test.

Since almost 90% of the subjects reported having symptoms of depression, this study particularly lacked in assessing a balance of subjects in a “good” and “bad” mental state. The study also failed to examine subjects’ performance on a normal memory test. Using the Memory Interference Test (MIT) database, this experiment was able to compare the memory performance of subjects who were both feeling subjectively “good” and “bad”. The study evaluated the number of correct responses on the Picture MIT (PMIT) of each group. The alternate hypothesis assessed for this experiment was that there would be a significant difference between PMIT performance of subjects feeling “good” and subjects feeling “bad”. In turn, the null hypothesis for this study was that there would be no difference in performance between subjects feeling “good” and subjects feeling “bad” on the PMIT.

Materials and Methods

This study involved participation from undergraduate students at the University of California, Los Angeles (UCLA) who could voluntarily take the MIT as a part of a course entitled Life Sciences 23L. When subjects logged onto the MIT portal to take the test, they were first asked to complete a demographic questionnaire. The questions on the questionnaire ranged from primary language spoken to number of hours of slept to one’s mental state. From the answer options in the mental state category, the study compared the subjects who said they felt mentally “good” upon taking the test versus those who felt mentally “bad”.

There were five different components of the PMIT; the first four were in order of increasing difficulty, and the fifth assessed reaction time. For this study, only responses for the first four sections of the PMIT were analyzed. In the first three sections of the test, the subject was shown 20 images which they attempted to memorize. Subjects were tasked with identifying those specific 20 images when shown a total of 50 images. The fourth test required subjects to identify which list pictures they recognized came from when shown 60 total images: 10 from the first three lists and 30 distractor images (Pfleugl, 2019). 

In order to analyze the results of the PMIT, a student’s t-test was used to determine the t-value for the data gathered for the parameter of mental state. The t-value was then used to determine the p-value to see if the null hypothesis could be rejected.

Results

The p-value was calculated to be less than 0.001.

Discussion

Because a p-value of 0.001 is less than 0.05, the null hypothesis was rejected. There was a significant difference in the correct number of responses on the MIT between subjects who were feeling “good” and subjects who were feeling “bad”.

References

Butler, C., and A. Z. J. Zeman. “Neurological Syndromes Which Can Be Mistaken for Psychiatric Conditions.” Journal of Neurology, Neurosurgery & Psychiatry, vol. 76, no. suppl 1, Mar. 2005, pp. i31–38. jnnp.bmj.com, doi:10.1136/jnnp.2004.060459.

Pfluegl, Gaston M. U. Introduction to Laboratory and Scientific Methodology: Laboratory Manual: LifeSciences 23l. 2019.

Schweizer, S., et al. “Symptoms of Depression in a Large Healthy Population Cohort Are Related to Subjective Memory Complaints and Memory Performance in Negative Contexts.” Psychological Medicine, vol. 48, no. 1, Jan. 2018, pp. 104–14. PubMed Central, doi:10.1017/S0033291717001519.