Attention

Learning to effectively execute goal-directed tasks generally requires guidance from knowledgeable experts that can direct the performer’s attention toward important environmental features. However, specifying the optimal attentional strategies is difficult due to the subjective nature of perceptions and the complexity of the underlying neural processes. The current skill acquisition literature emphasizes action-based contingencies through Predictive and Ecological models when examining attentional processes, while Perceptual Control Theory advocates for perceptual-based mechanisms. To evaluate the efficacy of these models, this study implicitly primed one hundred fifteen participants to focus on action-based or perceptual-based aspects during an interceptive task. It was predicted that the perceptual-based priming condition would result in faster learning and greater resilience to environmental disturbances. However, the highly variable results did not show significant differences in learning rate or resilience between the action and perceptual-based conditions. Ultimately, the variability in the findings suggests that a superior performance depends on numerous factors unique to each performer. Consequently, instructional methods cannot rely on a single optimal attentional strategy for gathering environmental information. Instead, the dynamic interplay between the individual and the environment must be considered to foster the skill development of novice performers.

Working memory (WM) enables the flexible representation of information over short intervals. It is established that WM performance can be enhanced by a retrospective cue presented during storage, yet the neural mechanisms responsible for this benefit are unclear. Here, we tested several explanations for retrospective cue benefits by quantifying changes in spatial WM representations reconstructed from alpha-band (8 - 12 Hz) EEG activity recorded from human participants before and after the presentation of a retrospective cue. This allowed us to track cue-related changes in WM representations with high temporal resolution. Our findings suggest that retrospective cues engage several different mechanisms such as recovery of information previously decreased to baseline after being cued as relevant and protecting the cued item from temporal decay to mitigate information loss during WM storage. Our EEG findings suggest that participants can supplement active memory traces with information from other memory stores. We next sought to better understand these additional store(s) by asking whether they are subject to the same temporal degradation seen in active memory representations during storage. We observed a significant increase in the quality of location representations following a retrocue, but the magnitude of this benefit was linearly and inversely related to the timing of the retrocue such that later cues yielded smaller increases.

In everyday life, we come across visual distractors such as crossing the street or driving down the highway, but what properties of distractors determine whether they will affect cognitive processing? Relatively little is known about how the strength of a distractor or changing it over time affects the ability to deploy attention. Previous studies have shown that suprathreshold stimuli interfere more in the Simon Effect than near threshold stimuli. However, it is unknown whether this effect is due simply to motor inhibition or generalizes to tasks without a motor component. To test the generalizability of this effect, an attentional blink task was presented in which a coherent motion stimulus surrounded a rapid serial visual presentation stream. The study demonstrated that the highest coherence condition presented first had the greatest effect on performance accuracy. This is suggestive of a diffused attentional state.

Spatial-based attention is shown to vary in strength over short intervals of time. Whether object-based selection also has similar temporal variability is not known. Egly, Driver and Rafal (1994) demonstrated using 2-rectangle displays how both spatial and object-based selection engages in processing of a visual scene. In Experiment-1 using the 2-rectangle paradigm we measured temporal variability of target detection by presenting targets at a variable SOA. In Experiment-2, we used 4-squares to preclude any object-based selection and measured temporal variability in target detection at similar locations as in Experiment-1. We found target detection to be periodic in delta and theta hertz rhythm in both Experiment-1 and Experiment-2 upon comparing corresponding cue-valid and same-object locations. Similar spectral profiles across experiments indicate a split-spotlight of spatial attention that rhythmically monitors cue-valid and other invalid locations. Future experiments are needed to determine whether object-based selection is periodic in nature.

Deciding what information we attend to has implications on our ability to remain
valuable and productive in our respective academic and economic domains. This study
investigated if attentional switching due to information technology interruptions would
deplete resources in a unique way and impair performance on a response inhibition task.
Three groups were compared on the Simon task after participants either did or did not
receive interruptions during a self-regulation task. Unexpectedly, a larger Simon effect
was found for participants who did not receive interruptions.
These results conform to previous evidence showing sustained directed attention
may result in depletion and effect subsequent inhibitory control. Although not supporting
predictions, these results may provide a basis for further research, particularly because
younger generations are developing in a more connected world than preceding
generations. By understanding these differences, younger generations may better adapt to
technological advances and leverage them to their advantage.

The present study examined whether differential motion could influence the spread of attention across an object. In particular, we examined whether the type of motion exhibited by an object would impact the reaction time in which a participant made a judgement on the location of a target or the accuracy of their judgment. We did not find significant effects of motion type upon reaction time. We did find that accuracy was significantly greater for validly cued targets than for invalidly cued targets. Further investigation may be needed to demonstrate the impact of motion upon the spread of attention across an object.

When perceivers examine a visual scene, they can control the extent to which their attention is either narrowly focused or spread over a larger spatial area. The experiments reported in this dissertation explore the consequences of narrow vs. broad attention for simple spatial discriminations as well as more complex cooperative interactions that are the basis for the self-organization of coherent motion patterns. Subjects' attentional spread (narrow or broad) is manipulated by means of a primary, luminance detection task. In conjunction with the luminance detection task is a secondary, spatial discrimination or detection task, which differs in the four reported experiments. In Experiment 1, the discrimination of misalignment of two visual elements is enhanced by narrowly focused attention. In Experiment 2, discrimination of horizontal spatial separation of two visual elements is improved for small inter-element distances by narrow attention and for relatively large inter-element distances by broad attention. Experiment 3 shows that the inter-element distance among counterphase-presented visual elements for which unidirectional and oscillatory motion patterns are observed with equal frequency depends on subjects' attentional spread. Narrow attention favors the oscillatory pattern and broad attention favors the unidirectional pattern. Experiment 4 shows that attentional spread has a minimal effect on the detection of motion, and, additionally that attentional effects on simple spatial judgments (Experiments 1 and 2) are too small to account for the large shift in the equi-probable boundary of reported unidirectional and oscillatory motion patterns found in Experiment 3. Therefore, it is concluded in conjunction with Hock and Balz's (1994) differential gradient model, that attentional spread influences the self-organization of unidirectional and oscillatory motion patterns through its effects on the relative strength of facilitating and inhibiting interactions among directionally selective motion detectors.

Contemporary understanding of human visual spatial attention rests on the hypothesis of a top-down control sending from cortical regions carrying higher-level functions to sensory regions. Evidence has been gathered through functional Magnetic Resonance Imaging (fMRI) experiments. The Frontal Eye Field (FEF) and IntraParietal Sulcus (IPS) are candidates proposed to form the frontoparietal attention network for top-down control. In this work we examined the influence patterns between frontoparietal network and Visual Occipital Cortex (VOC) using a statistical measure, Granger Causality (GC), with fMRI data acquired from subjects participated in a covert attention task. We found a directional asymmetry in GC between FEF/IPS and VOC, and further identified retinotopically specific control patterns in top-down GC. This work may lead to deeper understanding of goal-directed attention, as well as the application of GC to analyzing higher-level cognitive functions in healthy functioning human brain.