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Psychology (Functional Area: Brain, Behaviour & Cognitive Science)

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  • ItemOpen Access
    Examining the Effects of Real-World Experience on Lab-Based Scene Memory
    (2023-12-08) Orlando, Maria Sara; Rosenbaum, Shayna
    Boundary extension (BE) is as an error in scene memory, such that participants retrieve details beyond the given boundaries of a scene image. Boundary contraction (BC) is the opposite effect, whereby participants retrieve less context within the boundaries of a given scene image. Some research supports the view that BE reflects (re)construction of the scene from an internal representation that was formed, whereas other research supports the view that BE (and BC) emerge from image-based properties. This study tested the influence of familiarity on scene recognition through the comparison of lab-based encoding of images of pre-experimentally familiar (real-world) places with images of unfamiliar places. There was a tendency for BC across both image conditions, with evidence of maintained, and an instance of greater, BC for familiar than unfamiliar scene images. Importantly, the lack of evidence for increased BE with greater familiarity favours an image-based theoretical account of BE and BC.
  • ItemOpen Access
    Modelling the Effects of Demographics and Lifestyle on Cognitive Performance
    (2023-12-08) Park, Sarah Victoria Sanhua; Henriques, Denise
    Human cognitive performance is ultimately the result of many factors. Previous inquiries note the contributions of demographic and lifestyle cognitive performance. I used a series of structural equation models and dimensionality reduction methods to identify how demographic and lifestyle measures simultaneously contribute to cognitive performance: a theory-driven model using combined measures of cognitive performance and latent variable structure; and a data- driven model using principal components analysis. Participants (N = 1141, Mage = 23.13 years) completed a battery of tasks and questionnaires measuring cognitive performance and collecting demographic and lifestyle measures. Overall, both models provided evidence that the inclusion of lifestyle measures over and above demographic measures accounted for and predicted cognitive performance. Further, the two models give rise to complementary but distinct insights into the basic components of cognitive performance. This work provides a methodology and evidence for accounting for difference in cognitive performance with demographic and lifestyle measures.
  • ItemOpen Access
    Investigating neuromodulation with theta burst stimulation to primary visual cortex and subsequent effects on resting state networks: A multi-echo fMRI study
    (2023-12-08) Cohan, Remy; Steeves, Jennifer
    Theta burst stimulation (TBS) is a type of rTMS protocol which has the advantage of a shorter delivery time over traditional rTMS. When applied to motor cortex, intermittent TBS (iTBS) has been shown to yield excitatory aftereffects, whereas continuous TBS (cTBS) may lead to inhibitory aftereffects, both lasting from minutes to hours. The majority of TBS research has targeted motor and non-motor frontal areas of the brain, and to date very few studies have examined its efficacy at visual areas. In a sham-controlled study we investigated the immediate poststimulation and short-term (1 h post-stimulation) effects of iTBS and cTBS to V1.
  • ItemOpen Access
    Examining Cognitive-Motor Integration, Persistent Symptoms, and Brain Function in Individuals with Concussion
    (2023-12-08) Ozzoude, Miracle Ebelechukwu; Sergio, Lauren E.
    In everyday life we interact with our environment in an indirect way, where there is a mapping between the viewed goal of our action and the required movement (e.g., using a computer mouse). Such tasks require cognitive-motor integration (CMI), where rules dictate the relationship between perception and action. The underlying CMI control networks that rely on intact frontal, parietal, and subcortical brain region connectivity may be compromised following concussion, resulting in an impaired ability to engage in complex movements. Here we investigate whether such relationships also exist in working-aged adults with persistent post-concussion symptoms (PPCS). Methods: Twenty-two individuals (5 males) performed two visuomotor tasks: one requiring direct (standard) interaction with visual targets, and one comprising a plane-change and feedback reversal (non-standard interaction) between viewed target and required hand motion (CMI). PPCS and dizziness were related to brain network function via resting state functional connectivity (RSFC) in six networks and structural integrity via cortical thickness in CMI-related brain regions and white matter tracts via diffusion tensor imaging. Results: We observed that lower cortical thickness in the inferior and superior parietal cortices were associated with dizziness and impaired non-standard visuomotor performance, respectively. Furthermore, higher PPCS severity was associated with hyperconnectivity within the visual, sensorimotor control, frontoparietal control, and dorsal attention networks, whilst hyperconnectivity within the salience ventral attention network was associated with higher non-standard visuomotor performance. Lastly, we found that lower white matter tract integrity in several long associative, projection, and commissural tracts were associated with lower visuomotor performance, PPCS severity, and dizziness. Conclusions: These findings characterise the impact of PPCS on the structure and function underlying impaired visuomotor performance, and suggest that CMI may be a non-invasive, easily accessible tool for brain network function assessment in those affected by concussion.
  • ItemOpen Access
    Did The Pandemic Lockdowns Affect The Welfare of The Sumatran Orangutans (Pongo abelii) At The Toronto Zoo?
    (2023-12-08) Gading, Ezekiel Franco; MacDonald, Suzanne
    The COVID-19 pandemic led to unprecedented lockdowns with rippling impacts on the lives of humans and animals alike. Fortunately, these lockdowns also presented the opportunity to study the relationship of visitor presence with the welfare of zoo-housed animals as natural experiments. The reduction of visitor counts to zero for several consecutive months allowed researchers to study visitor effects on welfare measures and address the confounding variables associated with the time of the day. The purpose of this thesis was to study how the welfare measures of the Toronto Zoo Sumatran orangutans (Pongo abelii) changed when visitors were reintroduced after the lockdowns were lifted. I compared behavioural and physiological measures of stress between the lockdown and visitor introduction phases. Specifically, I studied changes in aversive behaviour by measuring the equality of physical enclosure space use, as well as changes in behavioural indicators of arousal (self-directed behaviours, agonistic behaviours, and object-directed displacement) and a physiological indicator of arousal (fecal consistency) as visitors were reintroduced to the orangutan pavilion. I found that the orangutans did not change their space use when visitors were introduced. In fact, the orangutans hid less when visitors were introduced than during the lockdown. This suggests that visitor presence was not aversive to these orangutans. Foraging and inactivity levels did not change across the phases of the study. Behavioural indicators of arousal also did not change when visitors were introduced. Fecal consistency did not change across the study. However, the presence of conspecifics and keepers strongly affected the behaviours of the orangutans. The results are congruent with studies that found that the pandemic lockdown measures did not negatively affect the welfare of a variety of species.
  • ItemOpen Access
    Factors Impacting the Time Course of Visuomotor Reach Adaptation
    (2023-08-04) Ruttle, Jennifer Elizabeth; Henriques, Denise
    Reaching with altered visual feedback leads to adaptation of internal motor plans, which result in aftereffects, deviated reaching without visual feedback, and proprioceptive recalibration, a shift in perceived hand location (Cressman & Henriques, 2010). However, the rate or speed by which these implicit motor and sensory changes emerge and how this timecourse may be affected by the quality of the feedback during training has yet to be investigated. In a series of experiments, I looked at the speed and size of implicit changes, specifically reach aftereffects and shifts in felt hand position, how fast they emerge and how they vary as a function of the quality of error signals and certainty of the rotation during training. In the first experiment, participants had full access to error signals during training with altered visual feedback of their hand, and during this training, reach aftereffects, and active and passive hand localizations were measured after every single reach-training trial. This gave us a baseline of how fast these implicit components shifted during ‘classic’ training. Shifts in felt hand position reached saturation within one trial and reach aftereffects also reached saturation within three trials of visuomotor rotation training which is much faster than previously believed. In the second experiment we reduced error signal information during training by removing the hand cursor until the reach movement was complete or by constraining hand movements along a channel, so the cursor always went straight to the target. The goal was to investigate if and to what extent these error signals affected the timecourse of proprioceptive recalibration. Despite this reduction, we could not detect a decrease in the rate or size of shifts in felt hand position, indicating the robustness and invariance of these visually-induced changes in proprioceptive estimates. In the third and final experiment, we reduced certainty in the rotation by changing it every 12 trials and still measured estimates of felt hand position on a trial-by-trial basis. We once again found shifts in felt hand position in the expected size and direction that peaked just as fast as the previous experiments, indicating that proprioceptive recalibration is a consistent aspect of reach adaptation to altered visual feedback. The rapid speed by which saturation is attained may also suggest that shifts in proprioceptive recalibration may be a driving factor in reach adaptation, as it saturates far earlier than adaptation does.
  • ItemOpen Access
    Visuomotor Learning and Proprioception Across Development
    (2023-03-28) Clayton, Holly Ann; Henriques, Denise
    Being able to adapt our motor repertoire to novel contexts is crucial for completing even the simplest daily tasks. This can be examined in visuomotor adaptation paradigms where the motor system is challenged to compensate for changes in vision, such as learning to reach to targets on a screen with a misaligned hand-cursor, which our brains do through trial-and-error. A motor command is sent to the arm and a prediction of the outcome is sent back into the brain. This prediction is compared with sensory feedback from proprioceptors and is thought to generate one of the error signals that drives motor learning. This begs the question of whether adaptation processes might differ across development if proprioception is less reliable, as proprioceptive impairments have been found to occur alongside normal aging (children and older adults differ from young adults) and in several neurological disorders. Proprioception is suspected to be impaired in Ehlers-Danlos syndrome (EDS), a group of inherited connective tissue diseases where the most common symptoms are joint hypermobility and chronic pain. In Chapter 2 I explored sensitivity of hand proprioception in EDS as a function of disease severity. In Chapter 3 I further explored proprioceptive sensitivity in EDS by comparing patients’ estimates of hand position to those of controls, and changes in their estimates after participants underwent visuomotor adaptation. Finally, in Chapter 4, I examined whether visuomotor adaptation differs across the lifespan, by looking at several characteristics of learning and comparing them across groups of children, young adults, and older adults that I tested in familiar settings. Together, these findings provide further insight into how the sensorimotor system functions under special developmental circumstances, such as with connective tissue disease, or during early/late stages of life.
  • ItemOpen Access
    Differentiating Visual Search Efficiencies for Symmetry Type and Texture Regularity
    (2023-03-28) Moreau, Rachel Carmen Earleen; Kohler, Peter
    Symmetry is believed to be a fundamental gestalt that aides in our day-to-day ability to interact with the visual world. The goal of this thesis was to investigate the differential processing of types of symmetry when embedded in texture or when viewed as individual objects. Across four experiments, I used the behavioural paradigm of the visual search task to measure processing efficiency across types of symmetry and texture regularity. I used stimuli called “wallpaper groups” which allowed for manipulations of symmetry type while holding constant low and midlevel visual cues. My results indicated that reflection symmetry was processed more efficiently than rotation symmetry and when these symmetries are embedded in a regular texture, they are processed more efficiently than not. The results of this research extend previous findings across behavioural psychology and visual neuroscience.
  • ItemOpen Access
    Sex and Sexual Orientation Differences in Perceptual and Cognitive Processing
    (2023-03-28) Andrinopoulos, Katerina Deanna; Steeves, Jennifer
    Sex differences have been found in some visual perception and cognitive abilities, and male and female brains have been shown to have differences in functional activation. These abilities include mental rotation, face recognition and face detection. One way to measure mental rotation is by using the mental rotation task (MRT), with males outperforming females (Voyer, 2011). Face perception tasks show differences favouring females (McBain et al., 2009; Brewster et al., 2012). Same-sex attracted males tend to perform at the level of females in face recognition ability (Brewster et al., 2012). This thesis seeks to further examine the effect sexual orientation has on these visual and perceptual abilities that have previously shown sex differences. A male advantage was found for mental rotation ability, with heterosexual males outperforming heterosexual females. Within the same-sex attracted groups, this difference was not found, with same-sex attracted females performing at the level of same-sex attracted males.
  • ItemOpen Access
    Effects of the Brain Derived Neurotrophic Factor Val66met Polymorphism on the Structural and Functional Architecture of the Human Brain
    (2022-12-14) Alba Suarez, Vicente Alejandro; Stevens, Dale
    Brain Derived Neurotrophic Factor (BDNF) is an important neurotrophin enabling synaptogenesis at the dendrites of neurons. Several studies have implicated the Val66Met single nucleotide polymorphism of the BDNF gene as a factor affecting cortical thickness and resting-state functional connectivity (RSFC) of the human brain. In this thesis, I investigated the effects of Val66Met on cortical thickness and RSFC among individual cortical regions and at the level of large-scale functional networks in all genotype groups (Val/Val, Val/Met, Met/Met, and Met carriers). Cutting-edge techniques were used to individually localize anatomical and functional brain regions in a large sample of healthy young adults from the Human Connectome Project. A comprehensive series of analyses revealed no significant group differences in cortical thickness or RSFC across the brain. These results suggest that, contrary to previous reports, the Met allele does not confer differences in structural or functional integrity of the healthy young adult brain.
  • ItemOpen Access
    Perceived Depth in Virtual and Physical Environments
    (2022-12-14) Hartle, Brittney Ann; Wilcox, Laurie
    Theoretically, stereopsis provides accurate depth information if information regarding absolute distance is accurate and reliable. However, assessments of stereopsis often report depth distortions, particularly for virtual stimuli. These distortions are often attributed to misestimates of viewing distance caused by limited distance cues and/or the presence of conflicts between ocular distance cues in virtual displays. To understand how these factors contribute to depth distortions, I conducted a series of experiments in which depth was estimated under a range of viewing conditions and cue combinations. In the first series (Chapter 2), I evaluated if conflicts between oculomotor distance cues drive depth underconstancy observed in virtual environments by comparing judgments of virtual and physical objects. The results showed that depth judgments of physical stimuli were accurate and exhibited depth constancy, but judgments of virtual stimuli failed to achieve depth constancy. This failure was due in part to the presence of the vergence-accommodation conflict. Further, prior experience with each environment had a profound effect on depth judgments, e.g., performance in virtual environments was enhanced by limited exposure to a similar task using physical objects. In Chapter 3, I assessed if limitations of virtual environments contributed to previous failures of linear combination models to account for the integration of stereopsis and motion cues. I measured the perceived depth of virtual and physical objects defined by motion parallax, binocular disparity, or their combination. Accuracy was remarkedly similar for both environments, but estimates were more precise when depth was defined by binocular disparity than motion parallax. A linear combination model did not adequately describe performance in either physical or virtual conditions. In Chapter 4, I evaluated if reaching to virtual objects provides distance information that can be used to scale stereopsis using an interactive ring game. Brief experience reaching to virtual objects improved the accuracy and scaling of subsequent depth judgements. Overall, experience with physical objects or reaching-in-depth enhanced performance on tasks dependent on distance perception. To fully understand how binocular depth perception is used to interact with objects in the real world, it is important to assess these cues in a rich, full-cue natural scenes.
  • ItemOpen Access
    The Effect of Frequent Cannabis Use on the Main Components of Executive Functioning
    (2022-12-14) Al-Bayati, Assel; Henriques, Denise
    The legalization of recreational cannabis use in Canada has raised many questions regarding its immediate and sustained effect on performance of various critical daily tasks (e.g., driving). To investigate the sustained effect, we created an online battery of tasks that assess the main components of executive functioning that are involved in all aspects of daily activities. The performance of healthy, young frequent cannabis users, infrequent users, and non-users was compared. Selective visual attention, response inhibition, visuospatial working memory, and cognitive flexibility and set shifting ability was analyzed. No meaningful differences in performance were found on any of the measures of executive functioning components between frequent users, infrequent users, and non-users. Additionally, secondary analyses in frequent users on the effect of sex, last occasion of cannabis use, age of cannabis-use onset, length of cannabis use (years), and reason for cannabis use (medical or recreational) on executive functioning performance are also reported.
  • ItemOpen Access
    The Impact Of Color on Response Inhibition
    (2022-12-14) Asare, Gifty; Fallah, Mazyar
    Response inhibition is an important cognitive function that affects decision-making and action selection. Impairments in it occur in neurodegenerative diseases therefore, ways to support response inhibition are important for quality of life. One possibility is the use of color, as color has been shown to modulate inhibitory processes. The overall objective of this work was to determine the prefrontal networks underlying response inhibition that can be modulated through an automatic attentional process such as color. A series of three studies were performed whereby young adults performed a stop-signal task (SST) or a Go/No-go task (GNGT) with colored stimuli. In our first study, the SST, a reactive response inhibition task, was performed to determine whether the effect of color on response inhibition was due to color opponency, attentional color hierarchy, or visual associations. We found that while red stop signals produced faster response inhibition compared to green, blue and yellow stop signals did not differ from each other. This pattern of results was not consistent with color opponency or the attentional color hierarchy of red > green > yellow > blue. Therefore, red facilitating and green impairing response inhibition suggested that response inhibition was modulated by visual color associations where red means stop and green means go. In our second study, we tested if the color modulations between red and green extended beyond countermanding to more general inhibitory control by using a proactive response inhibition task, the GNGT. Indeed, participants were more successful on red in comparison to green No-go trials. Based on these results, a modified accumulator model and putative neural circuitry of color modulation response inhibition was proposed. In our third study, event-related potentials (ERPs) were recorded while participants performed a GNGT to test the putative underlying neural network. While the P300 was not modulated by color, we observed reduced N200 amplitudes and earlier N200 latencies over the prefrontal areas proposed in study 2 in response to red No-go stimuli over green, yellow, and blue. The increased accuracy was argued to be an advantage conferred by learned and evolutionary associations to the colour red. The decreased N200 amplitudes suggested reduced conflict on No-go trials with red No-go stimuli compared to other colours. These findings bring us a step closer to mapping out the differential colour modulated neural circuitry involved in response inhibition and such research will help pave the way for efficient decision-making and staving off cognitive decline.
  • ItemOpen Access
    Atypical Lateralization of Language and Face Processing in Autism Spectrum Disorder
    (2022-08-08) Solomon-Harris, Lily Marissa; Stevens, Dale
    Autism spectrum disorder (ASD) is characterized by persistent deficits in communication and social interaction, as well as repetitive behaviours and restricted interests. Language and face processing are areas of domain-specific dysfunction impacting social interaction in ASD. Brain function associated with these cognitive domains is typically lateralized across the cerebral hemispheres, such that language and face processing are dominant within the left and right hemispheres, respectively. Furthermore, the degree of lateralization is related to behavioural proficiency in both domains. Converging evidence suggests that the development of lateralization in these separate domains is typically interrelated. Neuroimaging literature demonstrates reduced leftward lateralization of language in ASD, but the existing literature on face processing is inconsistent. Mixed findings are partly due to discrepancies in how regions of interest (ROIs) are localized for neuroimaging analyses. The present work aims to test the hypothesis that ASD is related to atypical lateralization of both language and face processing. First, a quantitative fMRI meta-analysis was conducted to resolve inconsistencies in the literature by identifying the most reliable, concordant patterns of differences in language and face processing in the brain associated with ASD across previous fMRI studies. The findings of the meta-analysis were then used to inform a rigorous analysis of category-related brain activation using individually localized ROIs and task-related fMRI data. However, the question remains regarding whether brain activation differences demonstrate a sustained, fundamental difference in the way language and faces are processed in the brain, rather than reflecting moment-to-moment differences in attention to these stimuli, motivating the final analysis of intrinsic functional connectivity between category-related brain regions. The findings from the meta-analysis, task-related fMRI analyses, and RSFC analysis of intrinsic functional connectivity converged, demonstrating that ASD is indeed related to reduced functional specialization and hemispheric lateralization of both language and face processing, particularly in posterior lateral temporal cortex. This is an important contribution to the mixed existing literature, and further demonstrates the importance of individual ROI localization when studying neurodiverse populations. Atypical development of hemispheric asymmetry for language and face processing in posterior lateral temporal cortex might be a fundamental factor underlying the behavioural presentation of ASD.
  • ItemOpen Access
    Understanding Lightness and Brightness in Different Media
    (2022-03-03) Patel, Jaykishan Yogeshbhai; Murray, Richard F.
    This thesis aimed to study how lightness and brightness perception relate to each other. We used a simple task to study whether observers perceive lightness and brightness to be different percepts and what cues they use to make these judgments. In Experiment 1, we used a custom-built apparatus to present two reflectance patches, each with independent illuminance. In the lightness and brightness conditions, observers judged which patch had a higher reflectance or luminance, respectively. In Experiment 2, we repeated the same procedure using a computer rendering of the apparatus on a monitor. Finally, we simulated computational models of lightness and brightness to evaluate their performance with respect to observer performance. We conclude that (a) lightness and brightness judgments are more similar than expected from previous work, (b) brightness is nothing like an estimate of luminance, and (c) current computational models can fail on even simple lightness and brightness judgments.
  • ItemOpen Access
    A Novel Neurorehabilitation Model Designed to Examine the Neural Plasticity Involved in Disease
    (2022-03-03) Bearss, Karolina Anna; DeSouza, Joseph FX
    Parkinson's disease (PD) is a progressive neurodegenerative disorder that that is most often characterised for its motor impairments. However, people with PD (PwPD) often experience a range of mental health and non-motor issues alongside their physical symptoms. Exercise has shown to positively impact and improve PD motor symptoms, less research observations have been shown in PD mental health and non-motor symptoms. Dance is a great form of exercise which provides both aerobic and anaerobic movements. Dance is constantly changing providing a creative outlet, dance provides flexibility and balance/coordination, develops social skills thereby improving mental health, and lastly dance with music combination allows this form of exercise to be unique in that it encompasses a multisensory component that exercise alone cannot provide. My dissertation aims to understand how dance impacts PD motor, non-motor symptoms and if the changes are associated to specific brain related alterations. Using behavioral, motor and EEG approaches, I will present three separate experiments to test the effects of dance on people with PD by first studying the potential impacts of dance on short-term behavioral changes in PwPD and their overall Quality of Life (QoL) after a 12-week dance intervention. Second I will present a novel examination of the interaction of dance on both behavioural measures and electroencephalography (EEG) activity before and after the short-term (1.25 hour) course of a single dance class. The third study is a novel examination of the interaction of dance on the progression of both behavioural measures and non-motor symptoms over the long-term course of participating in multiple dance classes over a 3-year period of time. Finally, EEG activity changes over the long-term course of participating in multiple dance classes over a 3-year period of time is presented. The results of these studies strengthen the idea of dance being an alternative or additional therapy for PwPD and also provides putative neuroplastic changes in the diseased brain.
  • ItemOpen Access
    Explicit Attention to Allocentric Landmarks Improves Memory-Guided Reaching
    (2021-11-15) Musa, Lina; Crawford, John Douglas
    The presence of an allocentric landmark can have both explicit (instruction-dependent) and implicit influences on reaching performance However, it is not known how the instruction itself (to rely either on egocentric versus allocentric cues) influences memory-guided reaching. Here, 13 participants performed a task with two instruction conditions (egocentric vs. allocentric), but with similar sensory and motor conditions. In the allocentric condition, participants were instructed to remember the initial location of the target relative to a landmark, and to reach relative to a shifted landmark. In the egocentric condition, participants were instructed to ignore the landmark and point toward the remembered location of the target. The allocentric instructions yielded significantly more accurate pointing than the egocentric instruction, despite identical visual and motor conditions and regardless of the final pointing side. This suggests that explicit attention to a visual landmark better recruits allocentric coding mechanisms that can augment implicit egocentric visuomotor transformations.
  • ItemOpen Access
    Perceived Depth Modulates Perceptual Resolution
    (2021-11-15) Ahsan, Tasfia; Freud, Erez
    The goal of this thesis was to investigate whether changes to perceived depth affects the resolution of object perception. In a series of four experiments, I used psychophysical methods to examine how perceived depth, defined by 2D pictorial cues in the Ponzo Illusion, modulated perceptual resolution even when it was independent to the task at hand. For Experiments 1-2, participants completed size and orientation discrimination tasks with a pair of lines, where the stimuli were placed either on the "close" or "far" portion of the Ponzo Illusion, as well as a non-Illusory "flat" portion. Across both experiments, more precise and faster discrimination abilities were found for lines perceived as closer to the observer. To rule out a potential confound of surface size, a follow up control experiment was conducted on the orientation task (Experiment 2b) using two size-matched non-illusory version of the Ponzo illusion. The results continued to show a persistent enhancement of close objects even when surface size was controlled for. Lastly, in agreement with previous findings, results of Experiment 3 showed that this close benefit extends even to high level perceptual processing such as a face identification task. Together these findings support the idea that the human visual system may have dedicated processes for closer things.
  • ItemOpen Access
    Movement-Based Cues Aid the Formation and Retrieval of Multiple Motor Memories
    (2021-11-15) Ayala, Maria Nadine; Henriques, Denise
    The ability to switch between different visuomotor mapping accurately and efficiently is an invaluable feature to a flexible and adaptive human motor system. This can be examined in dual adaptation paradigms where the motor system is challenged to perform under randomly switching, opposing perturbations. Typically, dual adaptation doesnt proceed unless each mapping is trained in association with a predictive contextual cue. To investigate this, in Experiment 1 I explored whether dual adaptation occurs if cued by distinct movement types (ballistic or pursuit/tracking reaches), and how adaptation to a perturbation while tracking an object generalize to ballistic reaches. Next, motivated by Experiment 1 findings that support the idea that "intrinsic" or motor-based cues (i.e., pertaining to a distinct goal) is key to dual adaptation along with recent work that shows the critical role of motor planning in dual adaptation, in Experiment 2 I looked at whether movement skew as elicited by distinct visual obstacles can facilitate dual adaptation. Next, in Experiment 3 I look at whether intrinsic cues need to be actively produced to elicit dual adaptation. Additionally, to better understand the underlying components of dual learning, I implement a Process Dissociation Procedure borrowed from cognitive sciences literature to understand the underlying explicit and implicit processes contributing to dual adaptation. In Experiment 4 I give participants an explicit strategy to drive learning where it otherwise would not occur due to an insufficient extrinsic visual cue. Finally, to understand dual adaptation in the most ecologically valid manner, in Experiment 5 I implemented the conventional virtual reality paradigm in Head-mounted VR, while also answering how the brain attributes error in this novel setup. Together, these findings provide further insight as to how the motor system plans movements and learns to adapt to an ever-changing environment, and the underlying mechanisms that drive it.
  • ItemOpen Access
    Do Great Apes Choose to Choose?: An Investigation of Preference for Computer-Provided Choice in Orangutans (Pongo abelii)
    (2021-03-08) Ritvo, Sarah Elizabeth; MacDonald, Suzanne
    This dissertation examined orangutans preference for computer touchscreen-provided choice and their capacity to recognize the content of 2-D pictures. Investigation of these factors is important for advancing our understanding of orangutan cognition and the development of Animal-Computer Interaction systems that provide captive great apes environmental enrichment through provision of choice. Using a concurrent chain procedure presented on a touchscreen computer, the first experiment examined three orangutans intrinsic valuation of choice by assessing preference for free- or forced- choice when neither choice options nor outcomes vary. Initial results indicated a preference for free-choice across all participants. However, in two control conditions, preferences varied, suggesting a weaker tendency to exercise choice than species previously tested. Motivated by subjects difficulty learning associations between application icons and food rewards, a series of three experiments investigated five orangutans capacity to spontaneously recognize the content of novel pictorial stimuli by assessing if they demonstrated the same hierarchical preferences for food and pictures of food. Results indicated that orangutans only recognized picture content in certain formats and that they were more proficient in print than in digital mediums. Having confirmed that orangutans could recognize digital food images in a single format, this format was employed in the final pair of experiments to examine whether increasing the fidelity of the experimental choice paradigm elicited stronger free-choice preferences. This research question was investigated in a stepwise manner: Experiment 1 provided varied choices options that led to a single outcome and Experiment 2 varied both the choice options and outcomes. Results indicated a preference for free-choice in orangutans, but one that can be overwhelmed by competing factors and depend on the advantage afforded by it. Moreover, findings indicated that for orangutans, the strength and quality of preference for free-choice can be affected by the fidelity of the choice paradigm and vary between individuals. In light of these results, I suggest that preference for choice may be more accurately conceptualized along a spectrum rather than a dichotomy of preference for choice or lack thereof.