Many of our daily activities are achieved through goal-oriented routines which illustrates the adaptability and efficiency of information processing. Nevertheless, slips of action do occur. This study was designed to determine if slips of action can be induced in a well learned task and if so, how these slips affect specific indicators of task performance. Thirty (12 male) right-handed undergraduate participants were taught, with arrow cues, a sequence of dominant hand movements. Following this learning phase, a portion of the sequences were altered by either changing the spatial location of the arrow cue or by changing the actual movement goal. Results revealed that participants made numerous action slips which were most prevalent when the movement goal was altered. This suggests that participants were unable to disengage their expected movement plan and thus were vulnerable to errors. In addition to exploring the frequency of action slips we also looked at participants’ reaction and movement times on trials that preceded and followed errors and found that a speed-accuracy trade-off could not account for the slips. We also showed that frequency of slips on our task could reliably predict performance on the SART, a measure of inhibitory control, and the frequency of attention failures in daily living on the ARCES. Overall, the results of this study reveal that action slips can be induced by manipulating a well learned action routine and that the frequency of these induced slips reflects a participant’s tendency to commit action slips in everyday life.

Recently, researchers have found evidence that after a concussion, residual visuomotor control deficits may linger longer than working memory or psychomotor speed deficits. All of the major computer administered test batteries currently in use for concussion management rely on examination of the latter tasks, and lack any measure of visuomotor control. The present research set out to develop a task to measure visuomotor performance. Using a touch-screen computer, the task required participants to point towards or away from (i.e., antipointing) a target in a design simmilar to an anti-saccade task. The task required participants to use visual information to execute controlled movements, and is designed to measure movement planning, execution performance and accuracy. The task was delivered to a large sample of healthy individuals to develop a normative performance data set. A self-report questionnaire was used to identify a small group of individuals from the normative population who were identified with a prior history of concussion. These individuals were directly contrasted with the healthy individuals. While only a few reported moderate or severe concussions, and information about recency and number of occurrences was unavailable, performance differences were observed --providing evidence of residual deficits. In particular, while concussed individuals were not slower, or less accurate overall than the healthy population on the task, they demonstrated unusual hand and spatial asymmetries. Future research will compare recently concussed individuals with the normative set developed here, and will make direct comparisons with existing computer administered test batteries to determine the efficacy of visuomotor tasks for detecting the long-term effects of concussion.

Many of our daily activities are achieved through goal-oriented routines which illustrates the adaptability and efficiency of information processing. Nevertheless, slips of action do occur. This study was designed to determine if slips of action can be induced in a well learned task and if so, how these slips affect specific indicators of task performance. Thirty (12 male) right-handed undergraduate participants were taught, with arrow cues, a sequence of dominant hand movements. Following this learning phase, a portion of the sequences were altered by either changing the spatial location of the arrow cue or by changing the actual movement goal. Results revealed that participants made numerous action slips which were most prevalent when the movement goal was altered. This suggests that participants were unable to disengage their expected movement plan and thus were vulnerable to errors. In addition to exploring the frequency of action slips we also looked at participants’ reaction and movement times on trials that preceded and followed errors and found that a speed-accuracy trade-off could not account for the slips. We also showed that frequency of slips on our task could reliably predict performance on the SART, a measure of inhibitory control, and the frequency of attention failures in daily living on the ARCES. Overall, the results of this study reveal that action slips can be induced by manipulating a well learned action routine and that the frequency of these induced slips reflects a participant’s tendency to commit action slips in everyday life.

Recently, researchers have found evidence that after a concussion, residual visuomotor control deficits may linger longer than working memory or psychomotor speed deficits. All of the major computer administered test batteries currently in use for concussion management rely on examination of the latter tasks, and lack any measure of visuomotor control. The present research set out to develop a task to measure visuomotor performance. Using a touch-screen computer, the task required participants to point towards or away from (i.e., antipointing) a target in a design simmilar to an anti-saccade task. The task required participants to use visual information to execute controlled movements, and is designed to measure movement planning, execution performance and accuracy. The task was delivered to a large sample of healthy individuals to develop a normative performance data set. A self-report questionnaire was used to identify a small group of individuals from the normative population who were identified with a prior history of concussion. These individuals were directly contrasted with the healthy individuals. While only a few reported moderate or severe concussions, and information about recency and number of occurrences was unavailable, performance differences were observed --providing evidence of residual deficits. In particular, while concussed individuals were not slower, or less accurate overall than the healthy population on the task, they demonstrated unusual hand and spatial asymmetries. Future research will compare recently concussed individuals with the normative set developed here, and will make direct comparisons with existing computer administered test batteries to determine the efficacy of visuomotor tasks for detecting the long-term effects of concussion.

Synaesthesia is a fascinating condition whereby individuals report extraordinary experiences when presented with ordinary stimuli. In this thesis, we examine an individual (L) who experiences time units (i.e., months and hours) and numbers as occupying specific spatial locations (e.g., January is 30º to the left). This type of spatial-form synaesthesia has been recently investigated by Smilek et al. (2007), demonstrating that synaesthetic time-space associations are highly consistent, occur regardless of intention, and can direct spatial attention. We extended this work in Chapter 2 by showing that for L, her time-space vantage point changed depending on whether the time units were seen or heard. For example, when L saw the word JANUARY, she reported experiencing January on her left side, however when she heard the word "January" she experienced the month on her right side. In this thesis, we validated L’s subjective reports using a spatial cueing task. The names of months were centrally presented followed by targets on the left or right. L was faster at detecting targets in validly cued locations relative to invalidly cued locations both for visually presented cues (January orients attention to the left) and for aurally presented cues (January orients attention to the right). We replicated these vantage-point dependent cueing effects also using hours of day. In Chapter 3, we further explored whether synaesthetic number forms could bias spatial attention using a spatial cueing and SNARC-type task. Two synaesthetes (L and B) both described experiencing the numbers 1 through 10 running vertically from bottom to top. Both experiments confirmed their synaesthetic number forms, such that when making odd-even judgments for the numbers 1, 2, 8, and 9, they showed SNARC-compatibility effects for up-down movements (aligned with their number form), but not left-right (misaligned) movements. Likewise in the spatial cueing task, both synaesthetes showed significantly faster response times to detect targets on the bottom of the display if preceded by a low number (1,2) and the top of the display if preceded by a high number (8,9), whereas they showed no cueing effects when targets appeared on the left or right (misaligned with their number forms). Both synaesthetes were, however, reliably faster to detect left targets following the presentation of numbers 10, and 11, and right targets following numbers 19 and 20 (running from left to right). Hence, we demonstrated that cueing and SNARC tasks could be used to empirically verify synaesthetic number forms. Moreover, we showed that numbers could direct spatial attention to idiosyncratic locations similar to time-units, replicating and extending our findings from Chapter 2. Lastly, Chapter 4 was aimed to explore the automaticity and involuntary nature of L’s number-forms. We continued to use the spatial cueing task and sought to eliminate any influence of strategy on L’s performance by: (1) shortening the interval between the cue and target onset to only 150 ms and (2) having the targets only fall in synaesthetically cued locations on 14.2% of trials. As a result, these manipulations should eliminate any cuing effects if L’s performance was attributable to intentionally using the cue to predict target location. However, our findings still showed an attentional bias consistent with L’s synaesthesia. We attributed L’s resilient cueing effects to the automaticity of her number-forms, thus demonstrating one of the hallmark attributes of synaesthesia. Overall, this series of studies convincingly demonstrated the reality of time-space and number-form synaesthesia and Chapter 5 concludes by discussing how this work has significantly contributed to the synaesthesia literature and to the study of perception overall.

The thesis introduces a novel search paradigm, and explores a previously unreported behavioural error detectable in this paradigm. In particular, the ‘Unpacking Task’ is introduced – a search task in which participants use a computer mouse to sort through random heaps of items in order to locate a unique target. The task differs from traditional search paradigms by including an active motor component in addition to purely perceptual inspection. While completing this task, participants are often found to select and move the unique target item without recognizing it, at times continuing to make many additional moves before correcting the error. This ‘unpacking error’ is explored with perceptual, memory load, and instructional manipulations, evaluating eye-movements and motor characteristics in additional to traditional response time and error rate metrics. It is concluded that the unpacking error arises because perceptual and motor systems fail to adequately coordinate during completion of the task. In particular, the motor system is found to ‘process’ items (i.e., to select and discard them) more quickly than the perceptual system is able to reliably identify those same items. On those occasions where the motor system selects and rejects the target item before the perceptual system has had time to resolve its identity, the unpacking error results. These findings have important implications for naturalistic search, where motor interaction is common, and provide further insights into the conditions under which perceptual and motor systems will interact in a coordinated or an uncoordinated fashion.

Synaesthesia is a fascinating condition whereby individuals report extraordinary experiences when presented with ordinary stimuli. In this thesis, we examine an individual (L) who experiences time units (i.e., months and hours) and numbers as occupying specific spatial locations (e.g., January is 30º to the left). This type of spatial-form synaesthesia has been recently investigated by Smilek et al. (2007), demonstrating that synaesthetic time-space associations are highly consistent, occur regardless of intention, and can direct spatial attention. We extended this work in Chapter 2 by showing that for L, her time-space vantage point changed depending on whether the time units were seen or heard. For example, when L saw the word JANUARY, she reported experiencing January on her left side, however when she heard the word "January" she experienced the month on her right side. In this thesis, we validated L’s subjective reports using a spatial cueing task. The names of months were centrally presented followed by targets on the left or right. L was faster at detecting targets in validly cued locations relative to invalidly cued locations both for visually presented cues (January orients attention to the left) and for aurally presented cues (January orients attention to the right). We replicated these vantage-point dependent cueing effects also using hours of day. In Chapter 3, we further explored whether synaesthetic number forms could bias spatial attention using a spatial cueing and SNARC-type task. Two synaesthetes (L and B) both described experiencing the numbers 1 through 10 running vertically from bottom to top. Both experiments confirmed their synaesthetic number forms, such that when making odd-even judgments for the numbers 1, 2, 8, and 9, they showed SNARC-compatibility effects for up-down movements (aligned with their number form), but not left-right (misaligned) movements. Likewise in the spatial cueing task, both synaesthetes showed significantly faster response times to detect targets on the bottom of the display if preceded by a low number (1,2) and the top of the display if preceded by a high number (8,9), whereas they showed no cueing effects when targets appeared on the left or right (misaligned with their number forms). Both synaesthetes were, however, reliably faster to detect left targets following the presentation of numbers 10, and 11, and right targets following numbers 19 and 20 (running from left to right). Hence, we demonstrated that cueing and SNARC tasks could be used to empirically verify synaesthetic number forms. Moreover, we showed that numbers could direct spatial attention to idiosyncratic locations similar to time-units, replicating and extending our findings from Chapter 2. Lastly, Chapter 4 was aimed to explore the automaticity and involuntary nature of L’s number-forms. We continued to use the spatial cueing task and sought to eliminate any influence of strategy on L’s performance by: (1) shortening the interval between the cue and target onset to only 150 ms and (2) having the targets only fall in synaesthetically cued locations on 14.2% of trials. As a result, these manipulations should eliminate any cuing effects if L’s performance was attributable to intentionally using the cue to predict target location. However, our findings still showed an attentional bias consistent with L’s synaesthesia. We attributed L’s resilient cueing effects to the automaticity of her number-forms, thus demonstrating one of the hallmark attributes of synaesthesia. Overall, this series of studies convincingly demonstrated the reality of time-space and number-form synaesthesia and Chapter 5 concludes by discussing how this work has significantly contributed to the synaesthesia literature and to the study of perception overall.

The thesis introduces a novel search paradigm, and explores a previously unreported behavioural error detectable in this paradigm. In particular, the ‘Unpacking Task’ is introduced – a search task in which participants use a computer mouse to sort through random heaps of items in order to locate a unique target. The task differs from traditional search paradigms by including an active motor component in addition to purely perceptual inspection. While completing this task, participants are often found to select and move the unique target item without recognizing it, at times continuing to make many additional moves before correcting the error. This ‘unpacking error’ is explored with perceptual, memory load, and instructional manipulations, evaluating eye-movements and motor characteristics in additional to traditional response time and error rate metrics. It is concluded that the unpacking error arises because perceptual and motor systems fail to adequately coordinate during completion of the task. In particular, the motor system is found to ‘process’ items (i.e., to select and discard them) more quickly than the perceptual system is able to reliably identify those same items. On those occasions where the motor system selects and rejects the target item before the perceptual system has had time to resolve its identity, the unpacking error results. These findings have important implications for naturalistic search, where motor interaction is common, and provide further insights into the conditions under which perceptual and motor systems will interact in a coordinated or an uncoordinated fashion.

The fornical tract, a major input-output pathway of the hippocampus, of the primate brain makes crucial contributions to visual memory, as effects after surgical or aetiological lesions of this tract are widely documented in the monkey and human literature. Here, a series of experiments sought to further elucidate the functions of this structure with a battery of novel tasks in macaque monkeys, conducted either on a touchscreen or in an ambulatory chamber, so as to offer a more global view of the mnemonic role accomplished by it. After receiving bilateral transection of the fornix, monkeys are impeded in the 'fast learning' phase of a large number of new visuospatial conditional problems, with major impairments seen in eliminating non-perseverative errors. These fornix transected monkeys are however facilitated in the initial acquisition of a visuovisual conditional task, with facilitation seen in their improved ability in eliminating perseverative errors. It is also demonstrated in an ambulatory apparatus, in comparison to control monkeys, these monkeys are impaired in the new learning of visuospatial context of environments, albeit still displaying intact locomotor and exploratory behaviour patterns. Contrary to the relatively clear role in new learning, the involvement of the fornix in memory retention over the very long-term is unknown. It is shown here that once some visuospatial information is learnt; the fornix is no longer implicated in the retention of the material. The effects of fornix transection are also found to be detrimental on a spatial recognition task, with impairments observed in acquisition of the more demanding stages of the task. The overall results covered in this thesis support previous work suggesting that the fornix mediates the new learning of visual information, and I further propose that this fornical involvement lies primarily in the learning of spatio-temporal contexts, particularly during 'fast learning', as well as in task-sets acquisition. I also argue for dissociation in the contributions of the fornix and hippocampus to some memory processes in the macaque.

In our pilot study investigating Texas Hold ‘em poker, we found that players bluffing (with a losing hand) elicits a similar physiological arousal response (as measured by skin conductance levels) to those in a position of strength and poised to win. Since arousal has been suggested to be a reinforcing factor in problematic gambling behaviour, we sought to replicate the findings of our pilot study in the current investigation. We aimed to extend our previous findings further by: isolating truthful betting (strong betting) to disambiguate deception when players are in positions of strength (i.e. trapping), measuring subjective excitement levels and risk assessments, investigating the physiological arousal responses following wins versus losses, and finally, exploring group differences (i.e. problem gambling status, experience levels). 71 participants played 20 naturalistic rounds of Texas Hold ‘em poker for monetary rewards. We were able to replicate our previous findings that bluffing triggers a physiological arousal (as measured by skin conductance responses) similar to truthful strong betting. Trapping was also found to elicit a skin conductance response similar to both bluffing and strong betting. Measures of subjective excitement revealed a pattern that converged with physiological data. Furthermore, wins were found to be more arousing than losses. Finally, our exploratory analysis of group differences (i.e. problem gambling status, experience) proved to be an insignificant factor with all measures. We conclude that the effect of bluffing on physiological arousal is so powerful that it pervades all participants; which is problematic due to its risky nature and potential to be self-triggered. With its ever increasing popularity and availability, more research on Texas Hold ‘em poker is warranted for treatment implications.