Cognitive impairment affects approximately half of multiple sclerosis (MS) patients. The Multiple Sclerosis Neuropsychological Questionnaire (MSNQ) has previously demonstrated validity for detecting cognitive impairment in MS, and is quick and easy to complete. The objective was to validate an internet version of the MSNQ. The following were completed at home over the internet for 82 MS patients: (a) patient self-report version of the MSNQ (P-MSNQ), (b) informant version of the MSNQ (I-MSNQ), and (c) Centre for Epidemiological Studies Depression Scale (CES-D). Thereafter, patients completed in-office neuropsychological testing using the Brief Repeatable Battery of Neuropsychological Tests (BRB-N). Both the P-MSNQ and I-MSNQ were highly correlated with depression. The best-cut off score on the I-MSNQ was a 26, which gave a sensitivity of 72% and 60% for detecting cognitive impairment on the BRB-N. Given the modest sensitivity and specificity values, the MSNQ is not recommended for neuropsychological screening purposes over the internet.

Impaired social interaction is one of the hallmarks of autism spectrum disorders (ASDs). Emotional faces are arguably the most critical visual emotional stimuli and the ability to perceive, recognize, and interpret emotions is central to social interaction and communication as well as healthy development. There is however, a paucity of studies devoted to neural and cognitive mechanisms underlying emotional face processing in adolescents with ASD. Through an implicit emotional face processing task completed in the MEG, we examined spatiotemporal differences in neural activation during angry and happy emotional face processing. Results suggest atypical frontal involvement in ASD adolescents during angry and happy face processing. In particular, orbitofrontal activation in participants with ASD was found to be delayed but greater in amplitude, relative to controls.

The objective of this research was to investigate the extent to which context contributes to the learning and recognition of episodic auditory-verbal memories (EAM). By combining the Hebb repetition paradigm (HRP) and continuous recognition paradigm (CRP), I capitalized on the advantages of both while manipulating the context in which EAM were retrieved. Through repetition, participants learned sequences of pseudowords in which word order and speaker were varied. A recognition test of either a pseudoword (Experiment I) or the speaker of a pseudoword (Experiment II) revealed temporal and sensory context effects. Results showed that the encoding manipulation did not impact short-term memory but did have an effect on long-term learning. This research helped to clarify the role of context in EAM in both short- and long-term memory, as well as added to the current literature of HRP and CRP. Future directions are discussed.

Arousal-biased competition (ABC; Mather & Sutherland, 2011) theory predicts that emotional arousal increases both the activation of relevant items and the suppression of irrelevant items in working memory. Study 1 tested ABC theory’s prediction in young and older adults. Suppression was measured with the Healey et al. (2010) paradigm and arousal was manipulated during interference resolution. Item accessibility was measured by comparing naming times of target and competitor words to baseline naming times. Young adults showed suppression of competitors while older adults did not. Arousal did not affect young adults’ naming times, but a mild suppression effect was seen in older adults whose arousal increased after the manipulation. A follow-up study showed that older and younger adults generally agreed on the arousing quality of the stimuli in Study 1. These studies partially support ABC theory and suggest that older adults may retain the ability to suppress irrelevant information when aroused.

It is widely thought that emotional stimuli receive privileged neural status compared to their non-affective counterparts. This prioritization, however, comes at a cost, as the neural capacity of the human brain is finite; the prioritization of any one object comes at the expense of other concurrent objects in the visual array competing for awareness (Desimone & Duncan, 1995). Despite this reality, little work has examined the functional benefit derived from the perceptual prioritization of affective information. Why do we preferentially attend to emotional faces? According to evolutionary accounts, emotions originated as adaptations towards action, helping to prepare the organism for movement (Darwin, 1872; Frijda, 1986). The current dissertation examines this from the perceptive of visual neuroscience and motor cognition. Chapters 1 and 2 examine the mechanisms involved during the perceptual prioritization of emotional content in the context of action system modulation. Chapters 3 and 4 then directly examine emotions effect on oculomotor action output. Results across the studies are discussed in the context of evolutionary theories related to biological origins of emotional expression.

The Uses of Objects Task is a widely used assessment of creative performance, but it relies on subjective scoring methods for evaluation. A new version of the task was devised using Latent Semantic Analysis (LSA), a computational tool used to measure semantic distance. 135 participants provided as many creative uses for as they could for 20 separate objects. Responses were analyzed for strategy use, category switching, variety, and originality of responses, as well as subjective measure of creativity by independent raters. The LSA originality measure was more reliable than the subjective measure, and values averaged over participants correlated with both subjective evaluations and self-assessment of creativity. The score appeared to successfully isolate the creativity of the people themselves, rather than the potential creativity afforded by a given object.

Six experiments were conducted to examine the factors modulating the size of age differences in recollection. The research presented in the current thesis was guided by the notions of self-initiated processing and environmental support. Older and younger adults’ performance in recollection was measured by Jacoby’s (1990) process dissociation procedure (PDP); the age differences as a function of self-initiated processing demands of the task and the amount of support provided to the participants were assessed by manipulating the encoding (Experiments 2.1, 2.2, and 2.3) and retrieval (Experiments 3.1, 3.2, and 3.3) contexts. Experiments 2.1, 2.2, and 2.3 examined interactions of aging and encoding contexts. Recollection under baseline conditions (i.e. visually presented words) was contrasted with recollection of items encoded under contexts that are assumed to enhance memory. The results showed differential age-related patterns of benefits from encoding conditions: Presenting pictures with words benefited older adults more than younger adults; word generation benefited both groups equally; and presenting sound effects with visual words benefited younger more than older adults. Experiments 3.1, 3.2, and 3.3 investigated age-related changes in retrieval processes and their interactions with retrieval contexts. In each of the three experiments, some of the test lists were constructed so that participants had to recollect specific aspects of the encoding event to differentiate between the to-be-included and to-be-excluded items, whereas other test lists were constructed so that they only had to recollect general aspects. Older adults showed reduced levels of recollection than younger adults for the high-specificity test lists only (Experiment 3.1). Encoding manipulations improved (Experiment 3.2) or reduced (Experiment 3.3) recollection performance but the effects did not interact with test, whereas DA at retrieval (Experiment 3.3) in younger adults partly mimicked aging. In summary, the six experiments showed that older adults have greater difficulties in spontaneously carrying out distinctive and integrative processes at encoding, and in accessing specific information at retrieval compared to their younger counterparts. These age-related changes further interact with the processing demanded or afforded by the encoding and retrieval conditions.

Nine experiments were conducted to explore pitch-time integration in music. In Experiments 1-6, listeners heard a musical context followed by probe events that varied in pitch class and temporal position. When evaluating the goodness-of-fit of the probe (Experiment 1), listeners’ ratings showed more influence of pitch class than of temporal position. The tonal and metric hierarchies contributed additively to ratings. Listeners again rated goodness-of-fit in Experiment 2, but with instructions to ignore pitch. Temporal position dominated ratings, but an effect of pitch consistent with the tonal hierarchy remained. Again, these two factors contributed additively. A speeded classification task in Experiments 3 and 4 revealed asymmetric interference. When making a temporal judgment (Experiment 3), listeners exhibited a response bias consistent with the tonal hierarchy, but the metric hierarchy did not affect their pitch judgments (Experiment 4). Experiments 5 and 6 ruled out alternative explanations based on the presence of pitch classes and temporal positions in the context, unequal numbers of pitch classes and temporal positions in the probe events, and differential difficulty of pitch versus temporal classification. Experiments 7-9 examined the factors that modulate the effect of temporal variation on pitch judgments. In Experiment 7, a standard tone was followed by a tonal context and then a comparison tone. Participants judged whether the comparison tone was in the key of the context or whether it was higher or lower than the standard tone. For both tasks, the comparison tone occurred early, on time, or late with respect to temporal expectancies established by the context. Temporal variation did not affect accuracy in either task. Experiment 8 used the pitch height comparison task, and had either a tonal or an atonal context. Temporal variation affected accuracy only for atonal contexts. Experiment 9 replicated these results and controlled for potential confounds. The findings imply that the tonal contexts found in typical Western music bias attention toward pitch, increasing the salience of this dimension at the expense of time. Pitch salience likely arises from long-term exposure to the statistical properties of Western music and is not linked to the relative discriminability of pitch and time.

Working memory, or the ability to maintain and manipulate information in mind when it is no longer physically present, is a pervasive yet severely capacity-limited component of cognition. Visual working memory, also known as visual short-term memory (VSTM), is limited to three or four items on average, with individual differences that range from roughly two to up to six items. Despite agreement that capacity is functionally limited, the current literature is split with respect to the nature of VSTM representations on two key questions: (1) What information is maintained in VSTM? (2) How is information stored in VSTM? The studies presented here address these questions using an event-related potential (ERP) task and a series of behavioural experiments that incorporate attentional selection via retrospective cueing (retro-cues). Experiment 1 manipulated both the number of features and the number of locations to be remembered in a lateralized change-detection task, with differences in the amplitude and topography of the resulting contralateral delay activity (CDA) indicating separate stores for features and locations. Experiments 2a-c established the basic effects of retro-cues on change-detection tasks, showing that attentional selection operated on one system at a time, with overall shorter response times and increased capacity estimates once baseline capacity was exceeded. Experiments 3a-b demonstrated that retro-cues biased VSTM resources to the cued item at the expense of representational strength of the other, non-cued items, showing flexible reallocation of resources. Experiments 4a-b presented multiple retro-cues to further examine the flexible reallocation of resources in VSTM, showing that capacity benefits depended on spatial specificity of retro-cues and that VSTM weights could be reallocated multiple times before probe comparison. Experiment 5 discounted the potential role of a general alerting mechanism in boosting capacity estimates, showing again that the retro-cue benefit required specificity of the cue. Experiment 6 showed that flexible reallocation of resources within one system did not change the online maintenance of representations within the other system. Thus, the studies collectively address the questions of (1) what and (2) how information is stored by supporting a two-system model of VSTM in which (1) locations and features are stored (2) independently via flexibly allocated resources.

It is widely thought that emotional stimuli receive privileged neural status compared to their non-affective counterparts. This prioritization, however, comes at a cost, as the neural capacity of the human brain is finite; the prioritization of any one object comes at the expense of other concurrent objects in the visual array competing for awareness (Desimone & Duncan, 1995). Despite this reality, little work has examined the functional benefit derived from the perceptual prioritization of affective information. Why do we preferentially attend to emotional faces? According to evolutionary accounts, emotions originated as adaptations towards action, helping to prepare the organism for movement (Darwin, 1872; Frijda, 1986). The current dissertation examines this from the perceptive of visual neuroscience and motor cognition. Chapters 1 and 2 examine the mechanisms involved during the perceptual prioritization of emotional content in the context of action system modulation. Chapters 3 and 4 then directly examine emotions effect on oculomotor action output. Results across the studies are discussed in the context of evolutionary theories related to biological origins of emotional expression.