Date of Award

6-2019

Document Type

Thesis

Degree Name

Master of Arts in Psychological Science

Department

Psychology

First Reader/Committee Chair

Addante, Richard

Abstract

The Dunning-Kruger Effect is a metacognitive phenomenon in which individuals who perform poorly on a task believe they performed well, whereas individuals who performed very well believe their performance was only average. To date, this effect has only been investigated in the context of performance on mathematical, logical, or lexical tasks, but has yet to be explored for its generalizability in episodic memory task performance. We used a novel method to elicit the Dunning-Kruger Effect via a memory test of item and source recognition confidence. Participants studied 4 lists of words and were asked to make a simple decision about the words (source memory, i.e. Is it manmade? Is it alive?). They were later tested on their episodic memory and source memory for the words using a five-point recognition confidence scale, while electroencephalography (EEG) was recorded. After the test, participants were asked to estimate the percentile in which they performed compared to other students. Participants were separated into four quartiles based on their performance accuracy. Results showed that participants in all four groups estimated the same percentile for their performance. Participants in the bottom 25th percentile overestimated their percentile the most, while participants in the top 75th percentile slightly under-estimated their percentile, exhibiting the DKE and extending its phenomenon into studies of episodic memory. Groups were then re-categorized into participants that over-estimated, correctly estimated, and under-estimated their percentile estimate. Over-estimators responded significantly faster than under-estimators when estimating themselves as in the top percentile and they responded slower when evaluating themselves as in the bottom percentile. EEG first revealed generic scalp-wide differences within-subjects for all memory judgments as compared to all self-estimates of metacognition, indicating an effective sensitivity to task differences. More specific differences in late parietal sites were evident between high percentile estimates and low percentile estimates. Between-group differences were evident between over-estimators and under-estimators when collapsing across all Dunning-Kruger responses, which revealed a larger late parietal component (LPC) associated with recollection-based processing in under-estimators compared to those of over-estimators when assessing their memory judgements. These findings suggest that over- and under-estimators use differing cognitive strategies when assessing their performance and that under-estimators use less recollection when remembering episodic items, thereby revealing that episodic memory processes are playing a contributory role in the metacognitive judgments of illusory superiority that are characterized by the Dunning-Kruger Effect.

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