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    Exploring the relationship between working memory capacity and task switching : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University, Manawatū, New Zealand
    (Massey University, 2019) Knapp, Katie
    Tests of task switching and working memory capacity are both thought to assess executive attentional control. Given that they are purported to measure the same underlying cognitive construct, one would expect a relationship between performance on these tasks. However, preliminary research has largely failed to find such an association. This thesis explored the association between task switching and working memory capacity to determine why previous research has failed to find this expected relationship. Experiment 1 examined this relationship across three commonly used task switching paradigms which differed in the amount of environmental support available to participants as they completed the task. Experiment 2 explored the role of task difficulty on the switching paradigm because working memory capacity and cognitive control are most related under particularly taxing conditions. Both of these Experiments failed to find a clear relationship between task switching and working memory capacity. These findings replicated much of the previous research in this area and suggested that task difficulty and paradigm choice could not explain the failure of previous research to find a relationship between these two constructs. Experiment 3 explored the role of cue switch costs. The task switching paradigm confounds cue switching and task switching, and it has been argued that switch costs may largely be explained by the cost of the cue switching. If this is the case, and cue switch costs do not index attentional control, then it is not surprising that previous research has failed to find a relationship between task switching and working memory capacity. Experiment 3 found evidence of cue switch costs, but ‘true’ task switch costs remained. After the confounding effect of cue switching was controlled for, the expected negative linear relationship between working memory capacity and task switching was found. Participants with higher working memory capacity had smaller switch costs, indicative of better performance. The results of this thesis point to the importance of making careful experimental design decisions when using the task switching paradigm. This is particularly important when the goal of such research is to index attentional control, especially in the context of individual differences research.
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    The blue brain : hemispheric asymmetry in depression as an explanation for working memory impairment : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University, Manawatu, New Zealand
    (Massey University, 2015) Campbell, Kathryn
    Due to substantial variability in past research regarding the cognitive and neurobiological correlates of depression, the current study investigated whether taking the possible relationship between asymmetric brain activity and cognitive impairment into account would help to clarify the matter. A total of 78 participants including 36 currently depressed, 11 previously depressed, and 31 never depressed participants, completed three mood questionnaires (Beck Depression Inventory, Hamilton Depression Inventory Short-Form, and the State-Trait Anxiety Inventory), and four working memory tasks (a spatial and verbal variant of both the N-back and complex span task). All participants had their resting brain activity recorded using an electroencephalogram. It was hypothesised that depressed participants would show relatively reduced left frontal activity, since left frontal activity is linked to positive affect and approach motivation, and that participants with depression but low levels of anxiety would show reduced right parietal activity while those with high anxiety would show increased right parietal activity due to the role of the right parietal area in arousal. These hypotheses were not supported as there were no differences in asymmetry scores between the currently depressed and the never depressed groups. However, investigation of this hypothesis was hindered by the high comorbidity of anxiety and depression making it impossible to disentangle the effects of depression and anxiety on parietal activity. It was also hypothesised that participants with depression would show impaired working memory with disproportionate impairment in the verbal working memory tasks that are thought to utilise left frontal brain activity. There was no clear support for this hypothesis. In fact, there was a trend toward improved performance possibly related to increased attention to detail due to activation of stress systems signalling a potential threat in the environment. A final hypothesis was that there would be an association between different patterns of brain activity and WM impairment but no association was found. These results highlight problems with research in this field including the conceptualisation and measurement of depression and cognitive performance as well as problems distinguishing between anxiety and depression. Future research needs to address these issues.
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    Investigating working memory and metamemory in old age : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University
    (Massey University, 2002) Craighead, Cheryll L
    An investigation of metamemory for working memory was conducted in a group of older adults aged 60 to 74 years using a variation of the Daneman and Carpenter (1980) reading span task. There were twelve trials in each experiment, with each trial containing six sentences. Participants had to assess whether each sentence was true or false as well as remembering the last word of each sentence in correct order. In Experiment 1 words were phonologically similar (rhyming) and dissimilar (non-rhyming), whereas Experiment 2 presented one syllable (short) words and two syllable (long) words Half the participants were asked to predict how well they would remember the words and half were asked to postdict how well they had recalled the words. Participants were also asked to complete the Metamemory Functioning Questionnaire (Gilewski, Zelinski & Schaie, 1990) for a self-assessment of memory and this was compared to their memory performance on the recall task. Results indicated that older adults recalled more rhyming words than non-rhyming words, and more short words than long words. They overestimated the number of non-rhyming words they would remember but their estimates fluctuated in the same pattern as actual recall for the rhyming and non-rhyming words showing some accuracy in their metamemory. However, people unexpectedly estimated that they would do better with long than short words. For long words postdictions matched recall better than predictions which showed that older adults were able to gather information about their performance during the task. There was no correlation between the MFQ scores and the recall accuracy of the memory task probably because the questionnaire measured more general aspects of everyday memory, whereas the recall task involved a single and very specific aspect of memory. When compared to the younger adults the older adults showed poorer recall performance and overestimation was larger for older adults. These results showed us that to some extent, older adults are able to estimate their memory performance, using metamemory in a complex memory task.
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    Cross-sectional and longitudinal analyses of the effects of aging on memory in healthy young, middle-aged, and oldest-old adults : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University, Palmerston North, New Zealand
    (Massey University, 2006) Lamont, Allison
    While a growing body of research indicates that older adults typically perform more poorly on many types of memory tasks than do younger adults, relatively little research has addressed the question of whether this trend continues unchanged into the late ninth and tenth decades of life. Such decrements in memory have been reported as linear declines from early adulthood up until about 80 years of age. Questions arise as to whether such memory declines slow or accelerate in very advanced aging, and to what extent differences are due to aging, per se, or variables that intervene between age and memory.To address these two questions, six memory types - verbal recall, nonverbal recall, short-term memory, working memory, face recognition, and prospective memory - were examined using both cross-sectional and longitudinal methodologies. The six types of memory and the influence of verbal processing speed, nonverbal processing speed, and intelligence were examined in mixed-gender groups of 20 - 40 (n = 40, M = 30.7, SD = 5.52), 50 - 70 (n = 44, M = 59.2, SD = 4.94), and 85+ year olds (n = 42, M = 87.8, SD = 2.43), at two points, the second occurring two years after the first. Each participant completed tests of word recall, geometric shapes recall, short-term memory (digit span), working memory (letter-number sequencing), face recognition, and prospective memory. Additionally, there were two processing speed tasks (Identical Pictures and Finding As), and the National Adult Reading Test of verbal fluency was used to estimate intelligence. The Mini-Mental State Examination and the Beck Depression Inventory (BDI-II) were used to screen for dementia and depression, respectively.At Time 1 testing the 85+ participants showed declines in all memory types (compared to the 20 - 40 year olds). Nonverbal recall (66.2% lower than the young group), working memory (46.2%), verbal recall (45%), and prospective memory (38.2%) produced the largest differences, short-term memory (12.3%) and face recognition (14.7%) the least. Two years later, the 85+ years old participants had shown further declines, relative to the 20 - 40 years group. Nonverbal recall (72.3% lower than the young group), prospective memory (63.2%), working memory (55.3%), and verbal recall (54.7%) continued to produce the largest decrements, with short-term memory (18.9%) and face recognition (19.8%) the least. The results for the young and middle participants did not change appreciably between Time 1 and Time 2. The difference between unadjusted scores and scores adjusted for intelligence, verbal processing speed, and nonverbal processing speed, increased markedly between Time 1 and Time 2 testing for the oldest-old participants.These findings support the view that while memory declines may be approximately linear from age 20 to 80 years, there is a sharp decline in most types of memory after the age of 85 years, recall and working memory suffering the most. Intelligence and processing speed have an effect on some types of memory, but age is by far the largest contributor to memory decline. Furthermore, as expected, all memory types declined over the two-year period, with prospective memory, verbal recall, nonverbal recall, and working memory showing the greatest declines. Short-term memory and face recognition declined at a noticeably slower rate.
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    When prudence is reckless : rethinking the role of project risk management : a 152.785 (25 point) research report presented in partial fulfilment of the requirements for the degree of Master of Management at Massey University
    (Massey University. Department of Management, 2005) Busch, Adrian
    Despite the widespread use of project risk management, the results of such efforts are often underwhelming. Do project risk management practices somehow miss the point? To explore this idea I use a critical management studies framework to study project risk management. The approach prescribed in the Project Management Institute's Project Management Body of Knowledge is compared to the very different approach of a professional project manager. A theorised analysis of the difference between these approaches finds that they employ the logic of different knowledge-constitutive interests thereby making them suitable for different purposes. The study concludes with a discussion of how the results of this analysis can be presented to practitioners in a way consistent with the emancipatory agenda of critical management studies.