Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

Program Name/Specialization

Cognitive Neuroscience

Faculty/School

Faculty of Science

First Advisor

Todd Ferretti

Advisor Role

Associate Professor

Abstract

Mental representation is the process by which an individual simulates an event in their mind’s eye. This process is the foundation of the ability to remember the past, engage in prospective thinking, or imagine fictitious scenarios. An individual can mentally represent any event through their own eyes—the first-person perspective or from the viewpoint of an external observer—the third-person perspective. The perspective of representation influences outcomes related to memory, visuospatial processing, affect, social cognition, clinical diagnoses, and language processing. In turn, an individual’s tendency to favour either perspective is shaped by related factors.

The current research consists of four experiments, designed to characterize and contrast the electrophysiological correlates of mental representation from each perspective and the associated cognitive load. To this end, electroencephalography (EEG) was used to capture changes in slow-cortical potentials (SCPs), while participants formed mental representations based on short sentences, from either visual perspective. SCPs have a longer duration than other event-related potentials (ERPs) and originate primarily in the cortex; SCP negativity was used to index the cognitive load associated with mental representation.

Experiment 1 showed that third-person perspective imagining required more cognitive effort and that switching from the first- to the third-person perspective required more cognitive effort than performing the opposite switch. This difference was primarily observed in prefrontal electrodes, leading up to the perspective switch, at which point the effect the effect was observed across all but occipital electrodes. Third-person perspective events were rated as being easier to imagine when initially generated from the first-person perspective. Experiment 2 showed that concurrently manipulating personal pronouns and perspective cues did not effect reliable differences in SCP amplitudes but did influence the vividness of objects, locations, emotions, and the sense of touch. Experiments 3a and 3b showed that (morphosyntactic-given) temporal information modulated the impact of perspective on SCPs, during autobiographical memory (AM) retrieval/maintenance. Following perfective (but not imperfective) accomplishment cues, vividness ratings were higher for the first-person perspective.

Discussions further interpret and contextualize these novel results. Together, the current experiments showed that SCP amplitudes differentiated between first- and third-person perspective mental representation, but the timeline and magnitude of the observed differences varied greatly across experiments based on the influences of perspective-switching, lexical aspect (activities versus accomplishments), grammatical aspect (imperfective versus perfective), personal pronouns (“I” versus “He”/“She”), and type of mental representation (imagined events versus autobiographical memories). These variations occurred despite the consistency of the experimental stimuli and their presentation, across all experiments. As such, recommendations are provided for greater control of these factors in further SCP-based research.

Convocation Year

2024

Convocation Season

Spring

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