The purpose of this study was to compare and contrast within and between participant performance on three different measures of listening effort: a dual-task paradigm, pupillometry, and skin conductance; participants also subjectively rated the difficulty of their experience. A repeated measures design was used to address the reliability and validity of each measure. 20 participants were recruited and attended two sessions; the second occurred a minimum of one week after the first. Participants listened to sentences presented in stationary noise at four different signal-to-noise ratios: quiet, 0, -3, and -5 dB SNR. The variables of interest were: change in peak-to-peak pupil diameter, change in reaction time from baseline, skin conductance response amplitude, and skin conductance response quantity. The results indicated that as SNR decreased, speech perception performance decreased and subjective listening effort increased. Participants accurately and consistently rated the more difficult conditions as requiring more listening effort. The change in reaction time from baseline, peak-to-peak pupil diameter, and skin conductance response quantity increased as SNR decreased; skin conductance response amplitude did not vary as task difficulty increased, but skin conductance response amplitude was larger for incorrect responses than it was for correct responses. There was a significant practice effect observed for the reaction time data. The dual-task paradigm and pupillometry measures had the greatest reliability and validity. This study demonstrated that listening effort can successfully be quantified both subjectively and objectively by using a variety of tasks. Future studies may be able to use these measures to further assess listening effort in the clinic and in the real-world.

The process of generating a phonological code from print is widely described as automatic. This claim is tested in Chapter 1 by assessing whether phonological recoding uses central attention in the context of the Psychological Refractory Period (PRP) paradigm. Task 1 was a tone discrimination task and Task 2 was reading aloud. Nonword letter length and grapheme-phoneme complexity yielded additive effects with SOA in Experiments 1 and 2 suggesting that <em>assembled phonology</em> uses central attention. Neighborhood density (N) yielded additive effects with SOA in Experiments 3 and 4, suggesting that one form of lexical contribution to phonological recoding also uses central attention. Taken together, the results of these experiments are <em>inconsistent</em> with the widespread claim that phonological codes are computed automatically. Chapter 2 begins by reconsidering the utility of ?automaticity? as an explanatory framework. It is argued that automaticity should be replaced by accounts that make more specific claims about how processing unfolds. Experiment 5 yielded underadditivity of long-lag word repetition priming with decreasing SOA, suggesting that an early component of the lexical contribution to phonology does not use central attention. There was no evidence of Task 1 slowing with decreasing SOA in Experiments 6 and 7, suggesting that phonological recoding processes are postponed until central attention becomes available. Theoretical development in this field (and others) will be facilitated by abandoning the idea that skilled performance inevitably means that all the underlying processes are automatic.

Student engagement is a critical component of effective classroom instruction. Many socio-constructive pedagogies, including active learning and peer instruction, depend upon students not only paying attention to, but actively shaping, the learning environment. Student response devices, such as clickers, are thought to increase student engagement by providing students with regular opportunities to check their comprehension or express their opinions. Claims of increased student engagement due to clicker use are often based upon student self-reports and have only a small correlation with observed learning gains or other measures of attentiveness. This paper compared self-report data, pre- and post-test scores, and a direct test of attentiveness to investigate what effect clicker use has on student engagement. Analyses showed that subjects using clickers were significantly slower to respond to tests of attentiveness than subjects in other conditions. This suggests that using clickers affects what students are able or willing to attend to during a lecture. / text

The multiple object tracking task (Pylyshyn and Storm, 1988) has long been a standard tool for use in understanding how we attend to multiple moving points in the visual field. In the current experiments, it is first demonstrated that this classical task can be adapted for use in a simulated driving environment, where it is commonly thought to apply. Standard requirements of driving (steering, maintaining headway) are shown to reduce tracking ability. Subsequent experiments (2a, 2b, 2c) investigate the way in which participants respond to events at target and distractor locations, and have bearing on Pylyshyn’s (1989) “indexing” hypothesis. The final experiment investigates the effect of the colour-composition of the tracking set on performance, and may have implications for our theoretical understanding of how tracking is performed. / AUTO21, NSERC, CANDrive

The purposes of this study were to: 1) evaluate the effect of walking speed on gait, balance and cognitive task performance and 2) examine the effect of dual task (cognitive load) on gait balance and cognitive task performance. Twenty young healthy adults (24+6 years of age) were recruited and each participant walked on a motorised treadmill at two speeds(0.5m/s and 0.8m/s), first without performing cognitive tasks, then while performing three types of cognitive loaded tasks. The speed had a significant effect on average and coefficient of variation of temporal gait parameters (P<0.001), cognitive task performance (P<0.001) and center of pressure excursion (P<0.001). No statistically significant effect of speed was found ML trunk displacement. However, dual task (cognitive load) had significant effect on COV of temporal gait (P<0.001), cognition (P<0.001) and trunk motion (P<0.001). In conclusion, the speed and dual task had significant effect on locomotors rhythm, balance, and cognitive performances.

This study investigated dual-task processing in younger and older adults using a psychological refractory period procedure. The first task was to name the color framing a picture; the second task was to either press a button or tilt their body in the direction of the tilt of the picture. In the body-tilt condition, electromyography was used to determine the reaction time. The stimulus-onset asynchrony (SOA) between the onset of the color and tilting of the picture varied from 50 to 1000 ms. In contrast with the response selection bottleneck model, which claims that processing of a second task cannot be completed until the first task is finished, the mode of response for the two tasks directly impacted the ability to avoid the bottleneck. In the body-tilt condition the increase in reaction time to the second task with decreasing SOA was less than in the button press condition, suggesting that processing of the second task could begin before processing of the first task was completed. This was true for both younger and older adults. Contrary to previous findings that older adults cannot engage in simultaneous processing of two tasks, evidence was found that older adults, like younger adults, could bypass the cognitive bottleneck if the second task has a reflexive component.

As the popularity of digitally based communication devices increases, so does the propensity for individuals to find clever ways to convey messages in a shorter amount of space and time. Often, individuals use word or phrase shortening techniques known collectively as text-speak. A majority of investigations into the topic of text-speak have only focused on the potential impact text-speak may have on literacy or scholastic achievement (Crystal, 2008; Pinker 1994; Thurlow, 2003). However, there is a void in empirical investigation into how individuals create text-speak and more importantly how they process it (Farrell & Lyddy, 2012). The primary aim of this dissertation is to systematically investigate text-speak using various methodological techniques to gain a better understanding of how people create text-speak and explore how it elicits meaningful comprehension. An additional aim of this dissertation is to determine whether processing text-speak comes at a cognitive cost.

The interaction between exercise and cognitive task performance has been previously examined using cycle ergometer and treadmill running tasks. The interaction between natural (non-constrained) exercise and cognitive task performance has, however, been well less examined. An example of a natural exercise task would be running outdoors on a steep trail where route selection and foot placement are critical for the runner. The performance of runners is examined in a dual trail-running and working memory task. The working memory task involved counting tones, and was performed at both a low workload, in which they were asked to count every fourth low frequency tone and a high workload in which they were asked to count every fourth low, medium and high frequency tone. In experiment 1, runners performed the tone-counting tasks both while running on a steep trail with uneven terrain and while seated (control conditions). In addition, they ran the trail without a cognitive task load. Running distance and counting accuracy significantly decreased during the dual task trials, there was a linear trend the run distance decreased as the task got harder. As the secondary cognitive task demand increased running performance decreased (linear trend). Cognitive performance was only significantly impaired while running for the hard cognitive task (for the easy cognitive task there was no statistically significant difference). Participants reported an increased workload in the dual run-counting task conditions when compared with the seated task conditions. Reports of task focus and feeling of being spent (exhausted) also varied across task conditions. In experiment 2 unconstrained running was conducted in the same manner, on a flat-even terrain track to establish if the route selection and scanning required to negotiate uneven terrain was causing the dual-task interference, or if there is a general interference effect caused by the self-regulatory demands of running, or the direct demands of running itself (exercise). The linear trend of decreased running performance with increased secondary cognitive demand was similar to experiment 1 - the more cognitive load the less distance traveled. The effect on the cognitive task was, however, not evident in experiment 2; there was no statistically significant difference between cognitive task performance in the dual and single-task conditions. The findings outlined in these experiments, demonstrate dual cognitive tasks have a negative effect on running performance, and the cognitive task may also be affected depending on running intensity, particularly where self-paced natural running over terrain is coupled with complex cognitive tasks.

The purposes of this study were to: 1) evaluate the effect of walking speed on gait, balance and cognitive task performance and 2) examine the effect of dual task (cognitive load) on gait balance and cognitive task performance. Twenty young healthy adults (24+6 years of age) were recruited and each participant walked on a motorised treadmill at two speeds(0.5m/s and 0.8m/s), first without performing cognitive tasks, then while performing three types of cognitive loaded tasks. The speed had a significant effect on average and coefficient of variation of temporal gait parameters (P<0.001), cognitive task performance (P<0.001) and center of pressure excursion (P<0.001). No statistically significant effect of speed was found ML trunk displacement. However, dual task (cognitive load) had significant effect on COV of temporal gait (P<0.001), cognition (P<0.001) and trunk motion (P<0.001). In conclusion, the speed and dual task had significant effect on locomotors rhythm, balance, and cognitive performances.

Numerous theories have been developed in explanation of object perception, such as Feature Integration Theory, which posits that an object is perceived after two stages: a pre-attentive stage and a focused attention stage. It is during the focused attention stage that a representation of the perceived object is formed. Theories such as object file theory account for the maintenance of these object representations following their creation. Evidence for object file theory has been provided by studies of the object specific preview benefit. This thesis seeks to examine the effect that dividing attention has on the maintenance of object representations. Using the tenets of object file theory and the cortical field hypothesis for dual task interference, it is hypothesized that by presenting participants with two simultaneous tasks which make use of overlapping cortical areas the object representation initially formed will be lost resulting in the loss of the object specific preview benefit. Whereas presenting participants with two simultaneous tasks which are associated with spatially separate, or non-overlapping, cortical regions will not result in the loss of the object specific preview benefit.