Although there has been over a century of research on memory and consolidation, there remains no consensus with respect to the nature of episodic memories over time. This study tests two prominent theories (Standard Consolidation Theory and Trace Transformation Hypothesis), which make opposing predictions as to the quality of remote episodic memory, by investigating memories for film clips. Using true/false questions to test recall immediately, 3 days, and 7 days after encoding, these experiments demonstrate that details (both perceptual and story-line details) are lost, while the gist of memories is maintained over time. These data also suggest that gist and detail may be maintained independently in the brain. These results broaden our understanding of recent and remote memory, and provide support for the transformation view of consolidation. In the future, the transfer of this paradigm to neuroimaging will allow us to investigate the neural basis of episodic memory over time.

Although there has been over a century of research on memory and consolidation, there remains no consensus with respect to the nature of episodic memories over time. This study tests two prominent theories (Standard Consolidation Theory and Trace Transformation Hypothesis), which make opposing predictions as to the quality of remote episodic memory, by investigating memories for film clips. Using true/false questions to test recall immediately, 3 days, and 7 days after encoding, these experiments demonstrate that details (both perceptual and story-line details) are lost, while the gist of memories is maintained over time. These data also suggest that gist and detail may be maintained independently in the brain. These results broaden our understanding of recent and remote memory, and provide support for the transformation view of consolidation. In the future, the transfer of this paradigm to neuroimaging will allow us to investigate the neural basis of episodic memory over time.

A reasoner’s beliefs can compromise or inflate the accuracy of their syllogistic judgments when syllogistic content and structure are incongruent or congruent, respectively. An integrated approach to the study of syllogistic reasoning led to the investigation of premise-based belief-content conflict and its impact on belief bias. The belief-content conflict cue attenuated belief bias in incongruent valid and invalid trials, as well as congruent invalid trials. Its efficacy was found to depend on the difficulty level of the syllogism in which it was embedded and the location of its placement. Reaction time analyses were used to guide interpretations about the relative engagement of Systems 1 and 2. The key findings suggested that belief-content conflict activated System 2 for invalid incongruent trials which would otherwise have been processed using low-cost heuristic means due to their inherent difficulty. In contrast, it appeared that in valid trials the cue led to a redirection of System 2 resources such that specialized analytic strategies were applied in incongruent trials preceded by belief-content conflict compared to those lacking this cue. Finally, belief bias was successfully offset by belief-content conflict even in cases of congruency. In congruent invalid trials without this cue participants’ intuitive awareness of the content-structure match appeared to lead to low-cost, belief-based guesses; yet when presented as the major premise this conflict cue appeared to shift System 1 processing away from content and towards structure. Albeit less diligent than System 2 analysis, the shallow consideration of structural features may have been viewed as a safer bet than any shortcut aiming to capitalize on syllogistic content. This set of findings cannot be fully accounted for by the selective scrutiny, misinterpreted necessity, mental models, verbal reasoning, selective processing, or Receiver Operating Characteristics accounts thereby highlighting the need for considering belief-content conflict in future models of belief bias.

Lifespan theories of emotion suggest that the ability to regulate emotion improves with age. The supporting evidence, however, is indirect: older adults pay less attention to negative events, remember less negative information, and report fewer experiences of negative emotion. Few studies directly measure emotion regulation by explicitly instructing older adults to modulate their feelings while exposed to emotion-evoking stimuli. The purpose of this thesis was to directly compare younger and older adults in their ability to modulate feelings to investigate whether aging results in decline, stability, or improvement in emotion regulation and also to examine potential mechanisms underlying regulation skills. The study employed a startle modulation paradigm to measure both emotional reactivity and regulation. Two experimental tasks (Stroop colour-word interference, reversal learning) were also administered to explore the relationship between emotion regulation and two theoretically-relevant processes: (a) cognitive control and (b) modification of learned emotional associations. There were three main findings: (1) emotional reactivity was preserved in older adults. Both age groups showed emotion-modulated startle (negative > neutral) during the pre-regulation viewing period; (2) age-related decline in emotion regulation was evident on an objective measure of emotion regulation (startle eyeblink reflex) but not on a subjective measure (self-ratings). Specifically, for older adults, startle eyeblink was not enhanced or attenuated following increase and decrease instructions, respectively. In contrast, both groups showed similar modulation of valence and arousal ratings by regulation instruction (increase > look > decrease); (3) for older adults, reversal learning performance correlated positively with the degree of reappraisal-related startle attenuation in the decrease condition, suggesting a possible mechanism for impaired down-regulation. These findings suggest that even when emotional reactivity is similar, older adults are less effective at modulating their physiological responses.

Recent evidence suggests that the task of managing a bilingual individual’s two languages is carried out by general attentional mechanisms. Researchers have found evidence for bilingual advantages in attention, specifically on tasks that involve inhibiting irrelevant information, which are believed to stem from lifelong practice at inhibiting the language system not currently in use. In the present study we hypothesized that, since bilinguals are better at inhibiting irrelevant information, they should show memory disadvantages if previously irrelevant information becomes relevant. 12 bilingual and 12 monolingual participants (age range:19-27) were tested in an eye tracking paradigm where the relational manipulation effect (the tendency to direct more viewing to manipulated regions of previously viewed scenes) was used to access memory for scenes that had been presented as distractors during a study block. No differences in memory were observed. However, we observed a significant difference in general viewing patterns between the two language groups, such that bilinguals made significantly shorter fixations.

Many people who sustain traumatic brain injuries (TBI) have poor psychosocial outcomes. Previous research has indicated that poor outcomes are related to the use of avoidant coping following TBI, although the mechanisms of this relationship are not clear. The major pathological consequence of TBI is damage to the frontal lobes and/or their connections, resulting for most people in executive and/or affective dysfunction. The purpose of this dissertation study was to delineate the neuropsychological, psychiatric, personality and physiological mechanisms of avoidant coping following TBI. Controls and people with TBI completed the Baycrest Psychosocial Stress Test (BPST), where coping behaviour was observed directly, and physiological measures were recorded. Participants also completed a neuropsychological test battery, and a series of questionnaires assessing coping, psychiatric status, personality and outcomes. There were no significant differences between groups in self reported coping. However, the control and mild TBI group engaged in more planful than avoidant behaviour on the BPST. As a group, individuals with moderate-to-severe injury, in contrast, engaged in more avoidant than planful behaviour. However, analysis of individual differences in coping behaviour within the moderate-to-severe group revealed a bimodal distribution, allowing classification of people in this group as ‘planners’, or ‘avoiders’ (this distribution was not evident in the mild TBI group). Within the moderate-to-severe group, planners had better executive function, were more reactive to stress (psychologically and physiologically), performed better on the speech task during the BPST, and had greater return to productivity. However, planners also had worse psychosocial outcomes as compared to the avoiders. This was the first study, to the author’s knowledge, to examine coping behaviour during a simulated real-world stress test. Results indicate that behavioural measures of coping, such as the BPST, are more sensitive to changes in coping post TBI than are self and significant other reported questionnaires. Results also demonstrate that executive function and psychological and physiological reactivity are important factors that contribute to coping following moderate-to-severe TBI. These data raise important questions about the challenges of targeting coping through rehabilitation.

This project investigated the statistical learning of musical expectancy. As a secondary goal, the effects of the perceptual properties of tone set familiarity (Western vs. Bohlen-Pierce) and textural complexity (melody vs. harmony) on the robustness of that learning process were assessed. A series of five experiments was conducted, varying in terms of these perceptual properties, the grammatical structure used to generate musical sequences, and the methods used to measure musical expectancy. Results indicated that expectancies can indeed be developed following statistical learning, particularly for materials composed from familiar tone sets. Moreover, some expectancy effects were observed in the absence of the ability to successfully discriminate between grammatical and ungrammatical items. The effect of these results on our current understanding of expectancy formation is discussed, as is the appropriateness of the behavioural methods used in this research.

SFWT Zebrafish were exposed to various concentrations of EtOH at 24 hours post-fertilization for a period of two hours. When fish reached maturity they were placed in individual tanks in a larger open field. A preliminary strain comparison was also conducted using control (EtOH untreated) SFWT and AB fish. The behaviour of fish was recorded for 24 hours during a normal light:dark cycle. Motor patterns and general activity were quantified and analyzed and several behaviors were found to change significantly throughout the daytime and nighttime period. Also, fish exposed to the highest concentration of alcohol were found to exhibit significantly reduced amount of thrashing towards other subjects as compared to fish in the control group confirming previous results that demonstrated reduction of shoaling after early embryonic alcohol exposure.

Previous research on mind wandering has used subjective verbal reports as a means to acquire the frequency and rate of its occurrence. I proposed the use of eye movements as an objective measure of mind wandering while participants attempted a reading task. Participants were placed in a self-classified probe-caught mind wandering paradigm while their eye movements were recorded. They were randomly probed every 2-3 minutes and were required to indicate whether their mind had been wandering before they were allowed to continue reading. The overall pattern showed that eye movement behaviour was slower and less frequent when participants reported mind wandering episodes, with duration and frequency of within-word regressions reaching levels of statistical significance. It may be that the cognitive processes that normally guide eye movements during reading exert less control during mind wandering episodes. Other implications and limitations are discussed.

Current theories of auditory attention are largely based upon studies examining either the presentation of a single auditory stimulus or requiring the identification and labeling of stimuli presented sequentially. Whether or not these theories apply in more complex ecologically-valid environments where multiple sound sources are simultaneously active is still unknown. This study examined the pattern of neuromagnetic responses elicited when participants had to perform a search in an auditory language-based `scene` for a stimulus matching an imperative target held in working memory. The analysis of source waveforms revealed left lateralized patterns of activity that distinguished target present from target absent trials. Similar source waveform amplitudes were found when the target was presented in the left or right hemispace. The results suggest that auditory search for speech sounds engage a left lateralized process in the superior temporal gyrus.