Attentional Capture of Objects Referred to by Spoken Language

Participants saw a small number of objects in a visual display and performed a visual detection or visual-discrimination task in the context of task-irrelevant spoken distractors. In each experiment, a visual cue was presented 400 ms after the onset of a spoken word. In experiments 1 and 2, the cue was an isoluminant color change and participants generated an eye movement to the target object. In experiment 1, responses were slower when the spoken word referred to the distractor object than when it referred to the target object. In experiment 2, responses were slower when the spoken word referred to a distractor object than when it referred to an object not in the display. In experiment 3, the cue was a small shift in location of the target object and participants indicated the direction of the shift. Responses were slowest when the word referred to the distractor object, faster when the word did not have a referent, and fastest when the word referred to the target object. Taken together, the results demonstrate that referents of spoken words capture attention

Purely endogenous capture of attention by task-defining features proceeds independently from spatial attention.

Attention can be focused voluntarily and effectively on spatial locations in order to enhance the processing of task-relevant events. However, work on 'attentional capture' has demonstrated that spatial biases can be temporarily reset by transient and salient stimuli, especially if they share defining characteristics with the targets of a task goal. In the current study, we investigated whether the appearance of stimuli containing task-defining features at an unattended location was sufficient to capture attention, even when these were not perceptually salient. We used event-related-potential (ERP) markers to test whether the selection of task-defining features was modulated by top-down spatial attention, and to test whether the appearance of 'unattended targets' transiently disrupted the spatial bias. Surprisingly, the results revealed that ERP markers of selection of task-defining features were equivalent for stimuli appearing at spatially attended and unattended locations. In addition, the presentation of task-defining stimuli at the spatially unattended location induced a short-lived redistribution of the pre-established spatial attention bias toward the 'capture' side. These findings show that task-defining features of a stimulus are automatically processed independently from spatial attention, and suggest the co-existence of multiple sources of top-down biasing signals, which might in part sustain the capture mechanism

Space-based and feature-based attentional selection in perception and working memory

In order to manage the high amount of sensory input we experience, attention processes enable the selective prioritization of goal-relevant information over irrelevant distractions. Two fundamental ways in which this is accomplished is by focusing attention at particular locations in the environment (spatial attention) or by focusing on specific forms of information (feature-based attention). Despite many decades of research examining these mechanisms, however, they have been seldom directly compared particularly in relation to their underlying neural mechanisms. In this thesis, the neural correlates of spatial and feature-based attentional selection for perception and working memory maintenance processes are contrasted. Event-related potential (ERP) components from electroencephalography (EEG) recordings are used as markers of such processes. The N2pc component is used to measure lateralised attentional selection to targets defined by one or a combination of spatial locations and features in perceptual tasks, whilst the CDA component is used to measure the active maintenance of target objects/locations in working memory tasks. In total, this thesis contains three lines of investigation. The first line compares these ERP components for attentional selection to targets defined by spatial locations and features and reveals that in many contexts, spatial attention is processed similarly to featural attention with a few notable exceptions (Chapter 2). The second line of enquiry examines how spatial configural information affects feature-based attentional selection when it is a critical component for successful goal-directed search, revealing that such information can guide attentional selection for some feature dimensions (Chapter 3). Finally, the third line of enquiry compares how spatial and feature-based attention influences visual perceptual and post-perceptual working memory processes (Chapters 4 and 5). This investigation lead to the observations that spatial attentional templates are quicker to guide attention when there is no SOA between the cue and target display onset, and that the two types of attention have similar working memory capacity limitations These findings culminate to provide one of the first direct comparisons of the neural correlates of attention to spatially or featurally-defined information, thereby expanding the current understanding of how spatial/feature-based attention operates. By measuring real-time event-related responses during these task contexts, the present thesis highlights the independent nature of spatial and feature-based attention and their qualitative similarities, but also how they interact upon one another under some circumstances. The findings aid the literature by shedding light on the argument perceptual and post-perceptual processes involved in spatial attention are qualitatively different from featural attention processes

Attention, psychology and pluralism

There is an overriding orthodoxy amongst philosophers that attention is a ‘unified phenomenon’, subject to explanation by one monistic theory. In this paper, I examine whether this philosophical orthodoxy is reflected in the practice of psychology. I argue that the view of attention that best represents psychological work is a variety of conceptual pluralism. When it comes to the psychology of attention, monism should be rejected and pluralism should be embraced. 1. The Monistic Consensus 2. The Varieties of Pluralism 3. Three Concepts 3.1 Blindsight 3.2 Executive attention 3.3 Alerting 4. Pluralism 4.1 Methodological conceptual pluralism 4.2 Three monist interpretations 5. Philosophical Monism? 6. ConclusionI am grateful to the Royal Institute of Philosophy for a Jacobsen Fellowship, which supported me while research for the paper was carried out , and during the initial writing phase. I am also grateful to the Leverhulme Trust and Isaac Newton Trust for an Early Career Fellowship (ECF-2015-088), which supported me while the paper was revised

Attention Psychology and Pluralism

There is an overriding orthodoxy amongst philosophers that attention is a ‘unified phenomenon’, subject to explanation by one monistic theory. In this paper, I examine whether this philosophical orthodoxy is reflected in the practice of psychology. I argue that the view of attention that best represents psychological work is a variety of conceptual pluralism. When it comes to the psychology of attention, monism should be rejected and pluralism should be embraced. 1. The Monistic Consensus 2. The Varieties of Pluralism 3. Three Concepts 3.1 Blindsight 3.2 Executive attention 3.3 Alerting 4. Pluralism 4.1 Methodological conceptual pluralism 4.2 Three monist interpretations 5. Philosophical Monism? 6. ConclusionI am grateful to the Royal Institute of Philosophy for a Jacobsen Fellowship, which supported me while research for the paper was carried out , and during the initial writing phase. I am also grateful to the Leverhulme Trust and Isaac Newton Trust for an Early Career Fellowship (ECF-2015-088), which supported me while the paper was revised

Attention capture by multiple events using dynamic displays

Being able to select relevant visual information from among irrelevant information is critical for the successful accomplishment of many day to day activities. However, the locus of attentional selection is not always under the control of the observer. Certain events and stimuli in the visual environment have been shown to control selection against observers’ intentions and goals. These are said to capture attention in an automatic and stimulus driven manner. The events and stimuli that capture attention can be static (colour, shape, size, etc.) or dynamic (motion, flicker, etc.). This thesis examines the effect of dynamic stimuli on attentional selection by using a visual search paradigm. The findings suggest that neither motion per se nor the onset of motion captures attention. They also suggest that when low refresh rate motion is used, capture occurs, but this effect cannot be attributed to capture by motion onset (Chapter 3). Further, the second study suggests that attention capture is observed using low refresh rate motion onsets because they are not masked as compared with the static items in the display. Thus capture is put down to a relatively better visual quality and stimulus encoding rather than motion (Chapter 4). The findings from this thesis also suggests that when back and forth oscillatory motion is used, capture re-emerges, but this effect is best attributed to a change in direction that happens to be temporally unique (Chapter 5). Another important finding is that in attention capture by abrupt onset, only one onset is prioritised in search (Chapter 6). The findings overall argue for a strong role of low level factors in attention capture by dynamic stimuli

Perceptual organization and its influence upon attention

Humans are able to control so much of their environment not through brute strength or enhanced sensory receptors, but through our ability to understand the world around us. In order to make sense of the world around us we need to organize the information that our sensory systems receive. One of the most fundamental steps in this organizational process lies in the construction of objects. By breaking down our sensory input into objects the mind provides a basis upon which it can begin to scaffold our understanding of the world. This thesis therefore explores the basic stages at which the visual system organizes our sensory input into distinct objects. It explores these stages by exploiting the fact that the brain’s limited processing resources can be selectively allocated on the basis of ‘object-hood’. This allocation of processing resources, or attention, on the basis of these early stages of segmentation is commonly referred to as ‘object based attention’. ‘Object based attention’ and perceptual organisation are explored in three sections in this thesis: Understanding the Phenomenon of Object Based Attention. The first three chapters of this thesis seeks to further our understanding of the phenomenon of ‘object based attention’, for example, chapter 3 explores whether the visual system can simultaneously parse several objects as potential units of attention, or whether it can only segment one or two objects at a time. Object Based Attention, a Tool to Explore the Nature of Perceptual Organisation The second section of this thesis attempts to use the phenomenon of ‘object based attention’ as a tool to explore the nature of perceptual representations, for example chapter 5 tests whether different modalities (in particular vision and touch) are able to directly share information about objects in order to build up an integrated model of the external world. Object Based Attention, Perceptual Organisation and Shape Processing Area LO. In the final section of this thesis the nature of perceptual organization is explored in a patient with a very specific form of brain damage that enables us to ask what areas of the brain are critically required for different aspects of perceptual organization

Punishment-related memory-guided attention: Neural dynamics of perceptual modulation

Remembering the outcomes of past experiences allows us to generate future expectations and shape selection in the long-term. A growing number of studies has shown that learned positive reward values impact spatial memory-based attentional biases on perception. However, whether memory-driven attentional biases extend to punishment-related values has received comparatively less attention. Here, we manipulated whether recent spatial contextual memories became associated with successful avoidance of punishment (potential monetary loss). Behavioural and electrophysiological measures were collected from 27 participants during a subsequent memory-based attention task, in which we tested for the effect of punishment avoidance associations. Punishment avoidance significantly amplified effects of spatial contextual memories on visual search processes within natural scenes. Compared to non-associated scenes, contextual memories paired with punishment avoidance lead to faster responses to targets presented at remembered locations. Event-related potentials elicited by target stimuli revealed that acquired motivational value of specific spatial locations, by virtue of their association with past avoidance of punishment, dynamically affected neural signatures of early visual processing (indexed by larger P1 and earlier N1 potentials) and target selection (as indicated by reduced N2pc potentials). The present results extend our understanding of how memory, attention, and punishment-related mechanisms interact to optimize perceptual decision in real world environmentsThis research was supported by a Project Grant to S.D. from the Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia, Spain (EM2012/017). S.S-S was supported by a grant for predoctoral contracts from the Spanish Ministry of Economy and Competitiveness, Spain (BES-2016-076298). A.C.N. is supported by Wellcome Trust Senior Investigator Award, United Kingdom (104571/Z/14/Z)S