The objectives of the present study were 1) to examine the effects of noise exposure on recall and recognition of orally presented text and 2) to examine the relation between working memory capacity and the performance of recall and recognition of orally presented text in noisy conditions. A total of 32 subjects, age 20-33, with no known hearing impairment, were paid to participate in the experiment. The hearing ability of all subjects was tested using recorded sentences with and without background noise. Their working memory capacity was tested using listening span, reading span and operation span tests measuring a) correctly recalled words of all three tests, b) the response latency in the reading span test and c) the processing time of the arithmetical operations in the operation span test. Finally all subjects took recall and recognition tests on texts presented orally with and without broadband background noise (white noise). The test results showed that 1) noise had no significant main effect on recall or recognition of the spoken texts, 2) ) the capacity of the central executive component of working memory, measured as the processing time of the arithmetical operations of the operation span test, correlated significantly with recall and recognition of the orally presented text in the noise condition, but not in the control condition, 3) noise exposure had a negative effect on the recognition performance of subjects with lower capacity of the central executive component of working memory.

The efficiency of human visual information processing is supported by numerous attentional resources. These resources ensure that behaviourally relevant information within visual scenes is selected for detailed processing, while behaviourally irrelevant information is ignored. One of these attentional resources—reflexive visuospatial attention—operates by prioritising locations in visual space in response to the appearance of salient stimuli. The purpose of the present dissertation was to examine how this type of attention contributes to the efficiency of visual processing by asking: How is processing altered for information presented at the location of attention? To develop some initial evidence of the stage of processing affected by reflexive visuospatial attention, Chapters 1 to 6 assessed whether this attentional resource is related to four other stimulus-driven effects that are each associated with a specific stage of visual processing: identity processing, object filtering, visual working memory (VWM), and response generation. Based on the observation that only the stimulus-driven effects on VWM are related to reflexive visuospatial attention (i.e., only those effects were contingent on attentional control settings), a VWM model of reflexive visuospatial attention was proposed in Chapter 7, and tested in Chapters 8 to 11. According to this model, reflexive visuospatial attention alters visual processing by triggering VWM to update. Thus, the effect of reflexive visuospatial attention is to speed the encoding of attended information into VWM. As a result, this information is more likely than unattended information to bias our behaviour, in particular those behaviours that depend on VWM. Further, by biasing VWM, reflexive visuospatial attention can interact with other attentional resources that have also been associated with VWM. In this way, these attentional resources can coordinate in optimising the process of selection, thus, contributing to the efficiency of the human visual system.

The efficiency of human visual information processing is supported by numerous attentional resources. These resources ensure that behaviourally relevant information within visual scenes is selected for detailed processing, while behaviourally irrelevant information is ignored. One of these attentional resources—reflexive visuospatial attention—operates by prioritising locations in visual space in response to the appearance of salient stimuli. The purpose of the present dissertation was to examine how this type of attention contributes to the efficiency of visual processing by asking: How is processing altered for information presented at the location of attention? To develop some initial evidence of the stage of processing affected by reflexive visuospatial attention, Chapters 1 to 6 assessed whether this attentional resource is related to four other stimulus-driven effects that are each associated with a specific stage of visual processing: identity processing, object filtering, visual working memory (VWM), and response generation. Based on the observation that only the stimulus-driven effects on VWM are related to reflexive visuospatial attention (i.e., only those effects were contingent on attentional control settings), a VWM model of reflexive visuospatial attention was proposed in Chapter 7, and tested in Chapters 8 to 11. According to this model, reflexive visuospatial attention alters visual processing by triggering VWM to update. Thus, the effect of reflexive visuospatial attention is to speed the encoding of attended information into VWM. As a result, this information is more likely than unattended information to bias our behaviour, in particular those behaviours that depend on VWM. Further, by biasing VWM, reflexive visuospatial attention can interact with other attentional resources that have also been associated with VWM. In this way, these attentional resources can coordinate in optimising the process of selection, thus, contributing to the efficiency of the human visual system.

Prior research has shown that visual working memory (VWM) performance can be improved via retrospective cues (“retro-cues”) that spatially indicate which item currently being held in working memory will be probed at test. These studies have utilized electroencephalography (EEG) methods to monitor contralateral delay activity (CDA) event related potentials (ERPs) and assert that retro-cues benefit memory by reducing effective memory load. Here, we investigated the potential relationship between CDA amplitude and future long-term memory (LTM) performance. Emerging evidence from ERP and fMRI studies suggest that working memory maintenance can contribute to LTM formation, which suggests that memory systems are not as discrete as some models suggest. We investigated the hypotheses that A) the benefits afforded by the retro-cue in VWM will carry over into LTM, and B) CDA amplitude will be modulated by subsequent LTM performance. Results revealed that retro-cuing improved item accuracy at both VWM and LTM delays, suggesting that the two memory systems are interactive. Due to an insufficient amount of subsequent LTM misses, we were unfortunately too underpowered to detect a CDA depending on long-term memory performance. However, we found that posterior slow-wave potentials during the maintenance period did differ by subsequent LTM performance, which further suggests an interactive systems account of memory. We also sought to investigate what exactly the retro-cue cues. Prior research has focused on memory for items, but no study has questioned if the retro-cue also enhances memory for item location. To this end, the present study investigated the effect of retro-cueing on both item identity and item location. LTM Behavioral results revealed a retro-cue benefit for item accuracy but no benefit for item location, suggesting that the retro-cue selectively cues item identity.

This thesis evaluates the effectiveness of study components in order to aid in design refinements for a larger randomized controlled trial (RCT). A total of 38 post-secondary students with Attention-Deficit/Hyperactivity Disorder (ADHD) were randomized into a waitlist control group, or standard-length (45 minute) or shortened-length (15 minute) WM training group. Criterion measures included the WAIS-IV Digit Span (auditory-verbal WM), CANTAB Spatial Span (visual-spatial WM) and WRAML Finger Windows (visual-spatial WM). Transfer-of-training effects were assessed using indices of everyday cognitive functioning. Participants in the standard- and shortened-length groups showed greater improvements at post-test on auditory-verbal WM and reported fewer cognitive failures in everyday life than waitlist controls. Participants in the standard-length group showed greater improvements in visual-spatial WM at post-test than participants in the other two groups. Preliminary findings suggest that shorter training may have similar beneficial outcomes as documented for the standard-length training, indicating that a larger-scale RCT is warranted.

This thesis evaluates the effectiveness of study components in order to aid in design refinements for a larger randomized controlled trial (RCT). A total of 38 post-secondary students with Attention-Deficit/Hyperactivity Disorder (ADHD) were randomized into a waitlist control group, or standard-length (45 minute) or shortened-length (15 minute) WM training group. Criterion measures included the WAIS-IV Digit Span (auditory-verbal WM), CANTAB Spatial Span (visual-spatial WM) and WRAML Finger Windows (visual-spatial WM). Transfer-of-training effects were assessed using indices of everyday cognitive functioning. Participants in the standard- and shortened-length groups showed greater improvements at post-test on auditory-verbal WM and reported fewer cognitive failures in everyday life than waitlist controls. Participants in the standard-length group showed greater improvements in visual-spatial WM at post-test than participants in the other two groups. Preliminary findings suggest that shorter training may have similar beneficial outcomes as documented for the standard-length training, indicating that a larger-scale RCT is warranted.

Working memory provides us with the capacity to both store and process information. It is a fundamental ability that we use throughout our daily lives to interpret, make sense of and understand the world around us. In particular, verbal working memory capacity has long been recognised as foundational to children’s ability to learn, and is especially implicated in language development, reading, comprehension and mathematics abilities. Recognising the fundamental importance of working memory, seminal research has recently demonstrated that repeated practice on computerised training programmes can lead to increases in children’s working memory capacity. However, while these programmes are promising, there are some inherent difficulties which are likely to restrict their application and uptake within the school context, both for the individual child or whole class. To overcome these limitations, the present research aimed to develop and evaluate a practical, whole-class working memory training programme. Achieving this could potentially offer every teacher and child a viable, effective way to improve their working memory capacity and, in doing so, increase their fundamental learning ability. The first phase of the research aimed to create a theoretically effective and practical programme which was grounded in the needs and preferences of teachers and children. This was achieved by first developing prototype materials based on the theoretical literature of what would make an effective programme, before drawing upon the experiences and expertise of teachers within a focus group, and children within a playtest exploration. A wide range of proposals were made which had implications for the final design and implementation procedures. The final working memory training programme involved pairs of children engaging in a series of five different card-based working memory activities, each with three levels of difficulty. The second phase of the research involved the implementation and evaluation of the programme within a mainstream primary school classroom for fifteen minutes a day for six weeks. Measures of children’s working memory demonstrated that they made significant gains in their working memory, and verbal short-term memory. These improvements were significant both immediately following the programme and at a two month follow up. Children’s responses on a questionnaire, as well as interviews with the children and class teacher demonstrated that the programme proved easy to use in the classroom to the extent that it was run almost autonomously by the children. Reports also indicated that children found the programme to be an engaging and enjoyable experience. The demonstration of a practical and effective whole class working memory training programme holds considerable potential to increase children’s capacity to learn and achieve. The wide range of factors which potentially enable a WM training programme to be effective, enjoyable and practical are discussed, and the future implications of this research are explored.

Most prior investigations of visual working memory (VWM) presented the to-be-remembered items simultaneously in a static configuration (e.g., Luck & Vogel, 1997). However, in everyday situations, such as driving on a busy multilane highway, items (e.g., cars) are presented sequentially and must be retained to support later actions (e.g., knowing if it’s safe to change lanes). In a simultaneous presentation, the relative positions of items are apparent but for sequential presentation, relative positions must be inferred in relation to the background structure (e.g., highway lane markings). To examine sequential encoding in VWM, we developed a novel task in which dots were presented slowly, one at a time, with each dot appearing in one of six boxes (Experiment 1), or in invisible boxes within a visible encompassing outer frame (Experiment 2). Experiment 1 found strong recency effects for judgments of color at the end of the sequence but not for the location of dots. In contrast, without dividing lines, Experiment 2 found strong recency effects for both color and location judgments. These results held true for accuracy, reaction time, and an integrated measure of speed and accuracy. We hypothesize that background structure allows the updating of VWM, slotting each new item into that structure to provide a new configuration that retains both old and new items, whereas in the absence of structure, VWM suffers from severe retroactive interference.

No description available.

This research explores auditory short-term memory (STM) capacity for non-linguistic sounds in 10-month-old infants. Infants were presented with auditory streams composed of repeating sequences of either 2 or 4 unique instruments (e.g., flute, piano, cello; 350 or 700. ms in duration) followed by a 500-ms retention interval. These instrument sequences either stayed the same for every repetition (Constant) or changed by 1 instrument per sequence (Varying). Using the head-turn preference procedure, infant listening durations were recorded for each stream type (2- or 4-instrument sequences composed of 350- or 700-ms notes). Preference for the Varying stream was taken as evidence of auditory STM because detection of the novel instrument required memory for all of the instruments in a given sequence. Results demonstrate that infants listened longer to Varying streams for 2-instrument sequences, but not 4-instrument sequences, composed of 350-ms notes (Experiment 1), although this effect did not hold when note durations were increased to 700. ms (Experiment 2). Experiment 3 replicates and extends results from Experiments 1 and 2 and provides support for a duration account of capacity limits in infant auditory STM.