We continually encounter different ground terrain such as slippery, compliant, uneven, rocky, and irregular terrain when walking, yet we know very little about how individuals safely negotiate this type of complex environment. Furthermore, we know little about how aging affects stability in these situations despite the increased risk of falls and fall-related injuries among older adults. Paramount to our comprehension of how individuals safely traverse challenging ground terrain is to understand how visual information is utilized as vision is the first line of defense for preparing for and/or avoiding potentially hazardous terrain or obstacles. Thus, the objective of this thesis was to provide a better understanding towards how individuals negotiate different ground terrain in the environment to maintain dynamic stability and prevent the occurrence of a fall. In particular, the role of vision and the effects of aging were investigated. Three studies focused on the role of vision while negotiating varying ground terrain while two studies examined stability across these surfaces. Two main conclusions can be drawn from the results of the three studies on the role of vision. First, regardless of age individuals fixate on highly task-relevant areas (i.e. surfaces eventually stepped on) in an on-line manner and by fixating approximately two steps ahead. Second, visual information from the lower visual field is important for negotiating varying ground terrain. This latter finding has implications for older adults who wear multi-focal glasses and suggests that these individuals should be cautious when wearing these glasses in complex environments. In terms of stability, the results suggest that young and older adults demonstrate greater instability when walking across varying unstable ground terrain compared to solid level ground. Older adults are particularly more unstable in the medial-lateral direction when negotiating the challenging terrain, which may explain the frequency of laterally directed falls and increased hip-fracture risk with advancing age. Interestingly, older adults appear more stable in the anterior-posterior direction; although, this can largely be explained by the cautious gait strategy (i.e. slower walking speed and shorter steps) adopted by these individuals. The results of the studies of my thesis provide valuable insight into how individuals safely negotiate different types of challenging ground terrain when walking. Importantly, this knowledge can serve as an initial step in attempting to reduce falling among those at risk.

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.

Background: Planning has long been assumed to be an important element of any successful quit smoking strategy. However, recent research findings indicate that unplanned, or spontaneous quit attempts, may lead to more successful and longer cessation periods than planned attempts. This calls into question continued advice to plan and the validity of planning based behaviour change theories. Objectives: To: 1) assess the prevalence of planning; 2) identify the attributes of planners; 3) examine the association of planning and intentions to quit; 4) examine the association of planning and use of quit aids; and 5) examine the impact of planning on smoking cessation outcomes. Methods: Data from the longitudinal Ontario Tobacco Survey (OTS) were examined. Analyses consisted of 418 smokers who made a planned or unplanned quit attempt between their waves 4 and 5 survey response. Descriptive, bivariate, and multivariate analyses were conducted using specialized survey analysis procedures to account for the complex sampling and design features of the OTS. Multiple Imputation (MI) was used to fill in missing data to reduce bias. Results: The prevalence of planning among Ontario smokers who made a quit attempt in the past six months was 70%. Regression models indicated that women, smokers who felt that it would be “very hard to quit”, and those with intentions to quit in the next 6 months had higher odds of making a planned quit attempt. Individuals who made a planned quit attempt had increased odds for using a quit aid compared to those making unplanned attempts. Univariate regression models indicated that planned attempts did not result in higher odds ratios for being abstinent for at least one week and at least one month. Conclusions: The present results suggest that a majority of smokers who made a quit attempt did so with a plan. Planned quit attempts had higher odds use of any quit aid compared with unplanned attempts. Planning was not found to increase the odds of being abstinent compared to unplanned attempts. Although more research is needed, the current study contributes to the dialogue of planning and smoking cessation.

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.

The neural correlates that underpin fine motor control of the hand and their connections with the primary motor cortex (M1) require further investigation. Brodmann’s area 5 located in the superior parietal lobule (SPL) is suggested to be an important cortical area involved in the processing of somatosensory input important for precision movements. Area 5 is present in monkey species capable of opposable thumb movements and it is proposed that this area evolved with the ability to execute manual behaviours such as pinch grip. Further, area 5 is dominated by the representation of the hand and forelimb, and has direct connectivity with M1 implicating its role in the control of hand movements. Few studies have investigated the function of area 5 in humans and none have examined the connectivity between area 5 and ipsilateral M1. This thesis presents a novel approach to study the influence of area 5 on M1 output in healthy and awake humans during the processing of somatosensory inputs and during performance of motor tasks involving the hand. Using paired pulse transcranial magnetic stimulation over left area 5 and ipsilateral M1, the connections between the two cortical loci was probed. It was hypothesized that area 5 would facilitate M1 output at short and long latencies during the processing of tactile inputs and during the performance of motor tasks compared to rest. The current results demonstrate that changes in M1 output are task and temporally specific. Facilitation of the motor evoked potential (MEP) was present at short latency of 6 ms during the processing of somatosensory input whereas inhibition was present during conditions where the hand was performing a task with the thumb and index finger. Further, an inhibitory effect was seen at 40 ms during cutaneous stimulation. In experiments 1 and 2, there was no net influence of area 5 on M1 output observed at rest. The findings presented may have revealed a novel path with which to alter the motor output, and possibly movement of hand muscles.

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.

Functional recovery of the upper limb after stroke is influenced by many factors, one being amount of affected arm and hand use following stroke. In the healthy population, amount of hand use is influenced by degree of hand dominance. Depending on side of stroke and previous hand dominance, these preferences may be altered, consequently affecting the amount of upper limb use. Determining hand preference in patients after stroke, when measured, is commonly assessed with questionnaires; however, these reports are subjective and patients may have difficulty recalling from memory which hand they use for the numerous activities on the questionnaire. A preferential reaching task has been shown to correlate with the degree of hand dominance as determined by the Waterloo Handedness Questionnaire, providing an objective performance-based method to assess the continuum of hand dominance in healthy subjects. A modified version of this preferential reaching task, with varying degrees of proximal to distal control, was used to investigate the influence of impairment, pre-stroke dominance and task difficulty on affected arm reach percentage. Results of the study revealed that it is feasible to administer a modified preferential reaching task in the stroke population, as the test could be completed in less than 10 minutes with no adverse effects reported from the patients. Heterogeneity made it difficult to detect statistical effects of task difficulty and pre-stroke dominance on post-stroke preference; however, there were trends observed indicating that patients with their dominant arm affected may have greater preference for the affected arm compared to those with their non-dominant arm affected. This was despite similar impairment levels between these patient groups. Preference for the dominant arm (whether affected or unaffected) was stronger when the task was at midline or in contralateral space, and when tasks required the greatest degree of distal control. In future, the degree of hand preference measured with this tool will have important implications for identifying areas in therapy requiring greater focus as well as identifying individuals who would most benefit from therapies that promote affected arm use, such as constraint induced movement therapy

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.

Denna uppsats har skrivits i syfte att undersöka om finansiella aktörers information angående risk i fondsparande är förenlig med investerares riskuppfattning. Idag följer finansiella institutioner EU-direktiv och svensk lagstiftning när de riskklassificerar sina fonder. Konkret används 5-årig historisk volatilitet mätt med standardavvikelse. Vi har därför ämnat undersöka om det riskmått och teorierna som ligger till grund för det är tillfredställande i sin nuvarande form. Vi har undersökt detta med hjälp av så väl traditionell som behovsfokuserad finansieringsteori. Genomförandet har gjorts med hjälp av en enkätundersökning som skickats ut till ett urval av medlemmar i Sveriges Aktiesparares riksförbund. Vi har i och med detta urval undersökt en investerare som är något mer kunnig än en småsparare. Resultaten av undersökningen visar på att det finns en brist i kommunikationen mellan finansiella institut och investerare. Likheten mellan de begrepp som idag används och de som reflekterar investeras riskuppfattning är visserligen inte helt olika. Dock visar undersökningen på att det trots detta finns ett antal problem. För det första finns svagheter i förståelse för de akademiska begrepp som förklarar de definitioner som används hos de finansiella instituten. För det andra har investerare en mycket bredare riskdefinition än vad som förmedlas genom nuvarande praxis. Resultaten visar också på problematiken med de psykologiska aspekter som påverkar mänskligt beteende. I fondinformationens nuvarande form tas detta inte i beaktning vilket leder till en asymmetri mellan teori och verklighet. Undersökningen pekar därför på att de riskmått och teorier som ligger till grund för information om risk i fondsparande idag ej är tillräcklig. Slutsatsen är därför att det behövs förbättring från den finansiella sfären för att uppnå bättre kundkommunikation, kundskydd och konkurrenskraft.

Finance taught in schools generally starts with the efficient market hypothesis, which holds the assumptions of rational investors and markets where all information available is reflected. In recent years however, a lot of critique has been given to efficient markets and its assumptions of rationality. The greatest reason to this is because of crashes and irregularities in the market. The field of behavioural finance has been in existence for many years but is not as established as the efficient market hypothesis. It says that investors may act irrational and are mostly trying to explain the reasons why. People’s behaviour is being closely studied in order to see patterns of behaviour and this has resulted in different heuristics and biases. Heuristics are instances that come to mind when making a decision and differ a lot depending on what kind of decision you are making. Since there are many different heuristics, this thesis only focused on one: the affect heuristic. The method was constructed in a specific way in order to show if the students showed affect in their answers. Also, a check for home bias was made. This thesis presents the behaviour of two different groups of students, finance students from Sweden and MBE-students from Germany. It was proved that both of the groups were acting irrational in their investment decisions. The reason to their irrationality is both because the method was constructed in a way to strategically mislead them but also because of the data collection. There were also some differences noticed depending on age groups, former studies in finance and work experience in finance. The affect heuristic was clearly shown in the answers by both groups of students. A home bias was also noticed in the answers. It was proven that 10,3 percent of the Swedish students invested in Swedish companies in both their first and second choice, even though the three best companies were German. None of the German Students decided to invest in a Swedish company in both the first and second choice.