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Our study investigated the effect of preparatory selective attention on encoding two target items (T1 and T2), causing an attentional blink effect (AB), as observed in previous studies. We altered participants' readiness state on a trial-to-trial basis using informative or uninformative cues for selective attention. Additionally, we varied their overall state of readiness by randomly mixing cue types (mixed cue-context) or presenting them in separate blocks (blocked cue- context). Our findings demonstrated a clear advantage in performance when participants received informative cues compared to uninformative ones in the mixed cue-condition, regardless of the lag between T1 and T2. Notably, in the blocked cue-context condition, cueing benefits were limited to the shortest T1-T2 lag. This suggests that participants proactively prepared to focus on T1 when anticipating conflict, but the extent of this preparation varied between cue-contexts. A heightened state of preparation led to an overinvestment of resources to T1 encoding, which negatively affected T2 encoding. / Thesis / Master of Science (MSc)

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An inhibition-based fan effect was explored with two different negative priming tasks. Experiment 1 used a modified flanker-type colour blob task in both children and adults (Pritchard & Neumann, 2004), where two additional conditions were included (C2 and IR2). Each set of the colour blobs for the additional conditions consist of two distractor colours instead of one distractor colour. Experiment 2 used Navon’s (1977) global-local letter task, where a global letter contains one, two, or three local letters as distractors to see if an inhibitory fan effect operated on the should-be-ignored local letters. Results from both experiments did not support for the inhibition-based fan effect hypothesis. However, in line with Pritchard and Neumann (2004) and Frings et al. (2007), there was evidence for the claim that selective control mechanism are developed much earlier in young children than previously thought.

archives@tulane.edu / Learning environments are complex, dynamic settings that contain multiple sources of information that compete for our attention resources. Researchers and practitioners argue that selective attention control is critical for effective learning, as selective attention allows individuals to stay focused on primary task goals and ignore task-irrelevant competing information. However, research with older adults has shown that increased attention to competing information can also benefit learning when this competing information is relevant to ongoing learning tasks. We examined the extent to which individual differences in selective attention skills influenced individuals’ learning from task-relevant competing information. Across three experiments we examined these effects at multiple developmental time points in the context of an experimental learning task and in computer-based learning environments. In Experiment 1, 4- to 8-year-old children completed a selective attention task that included competing information that was relevant for an ongoing learning and memory task. Children with better selective attention skills showed enhanced learning from the task-relevant competing information when they could efficiently complete the attention task and visually sample the relevant information. Experiment 2 examined 3- to 5-year-old children’s learning from science video lessons that varied in the amount of lesson-relevant vs. -irrelevant competing information available. Children with better selective attention skills preferentially attended to lesson-relevant competing information when both relevant and irrelevant information was present during the lessons, which promoted enhanced learning of lesson content. Finally, Experiment 3 examined the impact of multiple competing visual features (i.e., instructor videos, visual cues) on young adults’ learning from pre-recorded video lessons. Adults’ learning depended on both their selective attention skills and their perception about the relevance of these visuals for their learning. Individuals with better selective attention showed enhanced learning from lessons that included multiple competing visual features considered task-relevant by the learner. Attention control is typically equated with the ability to focus on primary target information while ignoring competing information. However, the current results suggest that selective attention control also involves the ability to efficiently shift across multiple relevant inputs in the environment, allowing for effective learning from both target material and task-relevant competing information. / 1 / Jill L King

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Master of Science / Department of Psychology / Lester C. Loschky / The effect of blur/clarity contrast on selective attention was investigated in terms of how unique blur and/or clarity guides attention. Visual blur has previously been suggested to be processed preattentively using a dual-task paradigm (Loschky et al., 2014). Experiments 1 and 2 used rotated L and T visual search tasks with blur/clarity contrast being manipulated such that it was non-predictive of the target’s location. Each experiment was preceded by a legibility control study such that blurred and clear letters had similar accuracy and reaction times. This allowed for the results to be interpreted as changes in attention rather than difficulty identifying the letters because they were blurry. Results suggest that when non-predictive of target location, unique blur plays a passive role in selective attention in which it is ignored, neither capturing nor repelling attention to its spatial location, whereas unique clarity captures attention. The findings provide insight to the role that blur/clarity contrast plays in guiding visual attention, which can be implemented in visual software to help guide selective attention to critical regions of interest displayed on a computer screen.

This study examined the changes that occur in spontaneous speech when speakers are distracted by background audio. Forty young adults answered open ended questions under five audio conditions (pink noise, movie dialogue, heated debate, classical music, and contemporary music) and a silent condition. Acoustic parameters assessed during the sessions included mean and variability of the fundamental frequency (F0), mean and variability of intensity, speaking time ratio, and disfluency ratio. It was hypothesized that there would be significant increases in the mean and variability of F0 as well as the mean and variability of intensity. There were statistically significant increases in mean and variability of intensity and mean F0 across most audio conditions. There were no significant changes in variability of intensity in the pink noise condition and no significant changes in variability of F0 in any audio condition. We hypothesized that the speaking time ratio would decrease in the presence of background audio compared to the silent baseline. Results demonstrate significant increases in speaking time ratio except for the classical music condition. It was expected that the disfluency ratio of speech production for each participant would increase in the presence of background audio, with informational masking demonstrating the most increase. Results revealed a significant increase in disfluency ratios across background audio conditions except for the pink noise and classical music conditions. Participants reported the heated debate and contemporary music to be the most distracting. These results have potential clinical implications regarding the type of environment where therapy is given, and what type of everyday situations might cause the most difficulties with fluency as well as the processing and production of speech.

Cognition is dynamic and complex, requiring specific sets of brain areas to cooperate for specific tasks. Neural synchronization is a proposed mechanism for transient functional integration of specific neural populations, enabling feature flexible binding and dynamic assignment of functional connectivity in the brain according to task demands. This thesis addresses the role of neural synchronization in selective attention and perceptual consciousness. The goals of this thesis are to test the hypothesis that synchronization between brain regions is relevant to network dynamics in selective attention and for perceptual organization, and to elucidate the function of synchronization in different frequency ranges. Using a selective visuospatial cuing paradigm it is shown that deploying attention to one visual hemifield yields transient long-distance gamma-band synchronization between contralateral visual cortex and other, widespread, brain regions. This is interpreted as a mechanism for establishing anticipatory biasing of communication in the cortex. Long-distance gamma synchrony, moreover, is periodically 'refreshed' at a theta rate, possibly serving to maintain this gamma network. While local alpha-band activity was found to be greater ipsilateral to the attended visual hemifield, alpha-band synchronization between primary visual cortex and higher visual areas was greater contralateral to attended locations. This suggests that local alpha synchrony is relevant for inhibition, while long-range alpha synchronization enacts functional coupling. The onset of a new conscious percept during binocular rivalry coincides with large-scale gamma-band synchronization which recurs at a theta rate. This suggests that gamma synchronization integrates features into a unified conscious percept while the theta cycle maintains that network. Using an audiovisual speech integration paradigm it is shown that large-scale gamma synchronization is greater when incongruence is detected between auditory and visual streams. This highlights an important distinction: neural synchronization reflects neural integration, not perceptual integration. Perceptual integration typically requires neural integration (feature binding), however, in this case detection of audiovisual mismatches requires cooperation within a distributed network, whereas audiovisual speech integration is largely accomplished in superior temporal cortex. These studies indicate that long-distance gamma synchronization establishes neural integration, the theta cycle maintains gamma synchronous networks, and local and long-range alpha synchrony reflect sustained inhibition and functional coupling mechanisms, respectively.