A dual-task paradigm was used to infer the processes critical for episodic memory retrieval by measuring susceptibility to memory interference from different distracting tasks. Research suggests that retrieval interference occurs due to material-specific overlap between concurrent tasks. I tested whether interference could instead arise from processing-specific overlap. In Experiment 1, I took advantage of individual differences in how verbal materials could be represented in those with different language backgrounds. I compared recognition of studied information in English and Chinese speakers under full attention (FA) or under one of two different divided attention (DA) conditions. Participants viewed simplified Chinese characters or English words, and later completed recognition while simultaneously performing distracting tasks requiring phonological (DAP) or visuospatial (DAV) processing of auditorily presented letters. I found an interaction such that Chinese speakers were more susceptible to interference from the visuospatial than phonological distracting task, whereas the reverse pattern was shown in English speakers. These results suggest that interference with memory retrieval is processing-, not material-, specific, as both distracting tasks used the same materials. Next I sought to determine whether processing-specific interference could be observed within the visuo-spatial domain. Accordingly, in Experiments 2 and 3, I examined whether face recognition would be disrupted more by a distracting task requiring configural than featural processing. In Experiment 2, participants studied faces under FA and subsequently performed a recognition task under either FA or each of two different DA conditions in which a distracting face was presented alongside, requiring either a featural (DAF) or configural (DAC) decision. In line with a material-specific account of interference, face memory accuracy was disrupted in both DA conditions relative to the FA condition, although no processing-specific differences in interference were found between the DA conditions, likely because both distracting tasks engaged configural processing. To better isolate the different processing streams in Experiment 3, some faces were inverted to offset configural processing and to engage featural processing. I compared patterns of memory interference when target faces were presented upright (configural) or inverted (featural). I found a crossover interaction: memory for upright faces was worse in the DAC than in the DAF condition, whereas the reverse was true for inverted target faces, supporting a processing-specific account of memory interference. In Experiment 4, I sought to rule out task difficulty as an alternative explanation for the pattern of interference effects. I measured whether each distracting task produced similar slowing, which provides an indirect assessment of resource requirements of a task, on a simultaneously performed auditory tone discrimination task. Results showed that my distracting tasks were not differentially attention demanding, as indexed by similar accuracy rates for tone classification and response times on the tone discrimination task when performed concurrently with each distracting task. Findings suggest that the magnitude of memory interference under DA conditions at retrieval is influenced by material-specificity but that, critically, it also depends on the extent to which the processing demands of the distracting and retrieval tasks overlap. I have shown here that retrieval is not automatic or obligatory as others have suggested, but instead is subject to disruption. This thesis specifies that retrieval interference can occur due to competition for a limited pool of common processing resources across target and distracting tasks. Thus, when trying to recall studied information, one should avoid distracting conditions, especially those that overlap significantly not only with the type of materials tested but also with the mental processes required to retrieve that target information.

Thesis (Ph.D.)--University of Wollongong, 2003. / Typescript. Bibliographical references: leaf 285-306.

Thesis (Ph. D.)--University of Kentucky, 2002. / Title from document title page. Document formatted into pages; contains ix, 111p. : ill. Includes abstract. Includes bibliographical references (p. 103-108).

Thesis (M. Phil.)--University of Hong Kong, 1990.

<p> Numerous studies have shown retrieval practice to be an effective strategy for improving memory. One account proposed to explain this benefit is the episodic context account (Karpicke et al., 2014). This account proposes that contextual information is reinstated and updated when an item is retrieved. This updated context is then used to aid in retrieval. Examining memory for contextual information, in addition to item memory, may provide additional insight into retrieval practice and what contextual cues are relevant in retrieval. The current study examined memory for temporal-contextual information at 2 different grain sizes: (a) memory for which list a word occurred in, and (b) memory for when an item occurred within a list. Previous research has shown that retrieval practice enhances memory for list temporal contextual information, as assessed by a list discrimination task (Brewer et al., 2010; Chan & McDermott, 2007). In contrast, Karpicke and Zaromb (2010) found worse memory following retrieval practice (relative to restudy) for within-list temporal-contextual information, as assessed by an order reconstruction task. In both experiments of the current study, participants studied multiple lists of words and either engaged in a word stem completion cued recall task, or restudied the words. Our results were partially consistent with previous research. We found no difference in performance between the retrieval practice and restudy groups when assessed on a list discrimination test. However, performance was worse for the retrieval practice group relative to restudy when assessed on an order reconstruction task. Finally, in both experiments, there was no difference in recognition accuracy. Overall, our results suggest that certain retrieval practice tasks may differentially affect memory for various grain sizes of temporal-contextual information. </p>

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Interpersonal power, defined as the asymmetrical control over valued outcomes, has important effects on the way cognitive processing unfolds. This work explores the effect of power on basic cognitive processes, in addition to broader processes that appear at the level of social behaviour. I begin this thesis with an introductory chapter, followed by a chapter describing the theory and practice behind electro-encephalogram recordings. In Chapter 3, I explore the effect of power on attention selection using a task that requires the ability to focus or divide attention in space, while varying the amount of distractors. The results suggest that low-power participants (subordinates) are more susceptible to the presence of distractors, regardless of whether the task necessitates focused or divided attention. In this context, inhibition accounts for the results to a greater extent than spatial orienting. In Chapter 4, I explore the effect of power on early inhibition processes in the context of executive control, in a task which allows participants to allegedly observe each others’ performance and receive feedback. The results show that high power is associated with reduced behavioural accuracy on trials that require executive control. Event-related potential analyses show that power-holders devote reduced motivational resources to their targets compared to subordinates, but do not differ at the level of early conflict detection. Their feedback potential results show a greater expectation of rewards, but reduced subjective magnitude attributed to losses. Subordinates, on the other hand, are asymmetrically sensitive to power-holders’ targets. They expect fewer rewards, but attribute greater significance to losses. In Chapter 5, I show that subordinates are asymmetrically competent at remembering diagnostic choices made by power-holders. In a final general discussion chapter, I integrate the findings of the experiments, which point to multi-layered effects of power, conferring those who possess it and those who lack it with distinct cognitive processing styles that suit their adaptive needs. The results are consistent with a hypothesized link between subordination and up-regulation of vigilance and environmental sensitivity. Limitations and future directions are discussed.

<p>One of the most important aspects of visual perception is inference of 3D shape from a 2D retinal image of the real world. The existence of several valid mapping functions from object to data makes this inverse problem ill-posed and therefore computationally difficult. In human vision, the retinal image is a 2D projection of the 3D real world. The visual system imposes certain constraints on the family of solutions in order to efficiently solve this inverse problem. This project specifically focuses on the aspect of minimization of standard deviation of all 3D angles (MSDA) for 3D perception. Our goal is to use a Deep Convolutional Neural Network based on biological principles derived from visual area V4 to solve 3D reconstruction using constrained minimization of MSDA. We conduct an experiment with novel shapes with human participants to collect data to test our model.</p>