Browsing by Subject "Attention"
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Item Open Access A Philosophical Examination of Working Memory(2019) Beninger, Max HansonWorking memory—the mental capacity to “hold on to” information after it ceases to be perceptually available—is one of the most discussed topics in psychology and neuroscience. Despite the importance of working memory in the sciences, however, there is only a small amount of philosophical research on the topic. The aim of my dissertation is to provide a philosophically-informed account of working memory, and to assess its relationship to other mental phenomena, including attention and consciousness.
In chapter one, I provide a broad historical overview of working memory. I begin by outlining William James’ original distinction between “primary” and “secondary” memory, and work my way up to present-day neuroscientific investigations of working memory. One of the main conclusions of this chapter is that there is no single working memory “module” in the brain. Instead, working memory is best conceptualized as a functionally-defined process that is potentially realized by multiple neural mechanisms.
In chapter two, I explore the link between working memory and attention. Recent evidence from psychology and neuroscience indicates that attention is (to some extent) involved in the process of working memory maintenance. However, it remains unclear whether the contents of working memory are always attended, or if working memory representations can be dynamically shifted in and out of the focus of attention. Drawing on empirical and phenomenological data, I argue that the second view is correct. Although attention plays an important role in working memory maintenance, working memory representations can persist—at least temporarily—outside the focus of attention.
Chapter three addresses a related question: namely, how working memory relates to consciousness. I distinguish three possible positions on this score: (i) working memory representations are always conscious; (ii) working memory representations can be either conscious or unconscious, but they are all accessible to consciousness; and (iii) working memory representations can be either conscious or unconscious, and some are inaccessible to consciousness. Based on the available empirical data, I argue in favor of position (ii). Evidence suggests that working memory representations can be unconscious, but such unconscious representations still appear to be consciously accessible, in the sense that they can be brought to consciousness at will.
Finally, in chapter four, I provide a critique of Peter Carruthers’ recent sensory-based account of working memory. According to Carruthers, attention only targets “mid-level” sensory areas, and thus the representations held in working memory will necessarily be sensory based in nature. I disagree. I point out that there is some evidence for attentional modulation outside of modality-specific sensory areas. I also highlight several empirical studies which provide preliminary support for the existence of non-sensory (i.e., amodal) working memory representations.
Item Open Access A Refined Neuronal Population Measure of Visual Attention.(PloS one, 2015-01) Mayo, J Patrick; Cohen, Marlene R; Maunsell, John HRNeurophysiological studies of cognitive mechanisms such as visual attention typically ignore trial-by-trial variability and instead report mean differences averaged across many trials. Advances in electrophysiology allow for the simultaneous recording of small populations of neurons, which may obviate the need for averaging activity over trials. We recently introduced a method called the attention axis that uses multi-electrode recordings to provide estimates of attentional state of behaving monkeys on individual trials. Here, we refine this method to eliminate problems that can cause bias in estimates of attentional state in certain scenarios. We demonstrate the sources of these problems using simulations and propose an amendment to the previous formulation that provides superior performance in trial-by-trial assessments of attentional state.Item Open Access Action video game playing is associated with improved visual sensitivity, but not alterations in visual sensory memory.(Atten Percept Psychophys, 2013-08) Appelbaum, L Gregory; Cain, Matthew S; Darling, Elise F; Mitroff, Stephen RAction video game playing has been experimentally linked to a number of perceptual and cognitive improvements. These benefits are captured through a wide range of psychometric tasks and have led to the proposition that action video game experience may promote the ability to extract statistical evidence from sensory stimuli. Such an advantage could arise from a number of possible mechanisms: improvements in visual sensitivity, enhancements in the capacity or duration for which information is retained in visual memory, or higher-level strategic use of information for decision making. The present study measured the capacity and time course of visual sensory memory using a partial report performance task as a means to distinguish between these three possible mechanisms. Sensitivity measures and parameter estimates that describe sensory memory capacity and the rate of memory decay were compared between individuals who reported high evels and low levels of action video game experience. Our results revealed a uniform increase in partial report accuracy at all stimulus-to-cue delays for action video game players but no difference in the rate or time course of the memory decay. The present findings suggest that action video game playing may be related to enhancements in the initial sensitivity to visual stimuli, but not to a greater retention of information in iconic memory buffers.Item Open Access Activation in mesolimbic and visuospatial neural circuits elicited by smoking cues: evidence from functional magnetic resonance imaging.(Am J Psychiatry, 2002-06) Due, Deborah L; Huettel, Scott A; Hall, Warren G; Rubin, David COBJECTIVE: The authors sought to increase understanding of the brain mechanisms involved in cigarette addiction by identifying neural substrates modulated by visual smoking cues in nicotine-deprived smokers. METHOD: Event-related functional magnetic resonance imaging (fMRI) was used to detect brain activation after exposure to smoking-related images in a group of nicotine-deprived smokers and a nonsmoking comparison group. Subjects viewed a pseudo-random sequence of smoking images, neutral nonsmoking images, and rare targets (photographs of animals). Subjects pressed a button whenever a rare target appeared. RESULTS: In smokers, the fMRI signal was greater after exposure to smoking-related images than after exposure to neutral images in mesolimbic dopamine reward circuits known to be activated by addictive drugs (right posterior amygdala, posterior hippocampus, ventral tegmental area, and medial thalamus) as well as in areas related to visuospatial attention (bilateral prefrontal and parietal cortex and right fusiform gyrus). In nonsmokers, no significant differences in fMRI signal following exposure to smoking-related and neutral images were detected. In most regions studied, both subject groups showed greater activation following presentation of rare target images than after exposure to neutral images. CONCLUSIONS: In nicotine-deprived smokers, both reward and attention circuits were activated by exposure to smoking-related images. Smoking cues are processed like rare targets in that they activate attentional regions. These cues are also processed like addictive drugs in that they activate mesolimbic reward regions.Item Open Access Aerobic exercise and neurocognitive performance: a meta-analytic review of randomized controlled trials.(Psychosom Med, 2010-04) Smith, Patrick J; Blumenthal, James A; Hoffman, Benson M; Cooper, Harris; Strauman, Timothy A; Welsh-Bohmer, Kathleen; Browndyke, Jeffrey N; Sherwood, AndrewOBJECTIVES: To assess the effects of aerobic exercise training on neurocognitive performance. Although the effects of exercise on neurocognition have been the subject of several previous reviews and meta-analyses, they have been hampered by methodological shortcomings and are now outdated as a result of the recent publication of several large-scale, randomized, controlled trials (RCTs). METHODS: We conducted a systematic literature review of RCTs examining the association between aerobic exercise training on neurocognitive performance between January 1966 and July 2009. Suitable studies were selected for inclusion according to the following criteria: randomized treatment allocation; mean age > or =18 years of age; duration of treatment >1 month; incorporated aerobic exercise components; supervised exercise training; the presence of a nonaerobic-exercise control group; and sufficient information to derive effect size data. RESULTS: Twenty-nine studies met inclusion criteria and were included in our analyses, representing data from 2049 participants and 234 effect sizes. Individuals randomly assigned to receive aerobic exercise training demonstrated modest improvements in attention and processing speed (g = 0.158; 95% confidence interval [CI]; 0.055-0.260; p = .003), executive function (g = 0.123; 95% CI, 0.021-0.225; p = .018), and memory (g = 0.128; 95% CI, 0.015-0.241; p = .026). CONCLUSIONS: Aerobic exercise training is associated with modest improvements in attention and processing speed, executive function, and memory, although the effects of exercise on working memory are less consistent. Rigorous RCTs are needed with larger samples, appropriate controls, and longer follow-up periods.Item Open Access Age mediation of frontoparietal activation during visual feature search.(Neuroimage, 2014-11-15) Madden, David J; Parks, Emily L; Davis, Simon W; Diaz, Michele T; Potter, Guy G; Chou, Ying-hui; Chen, Nan-kuei; Cabeza, RobertoActivation of frontal and parietal brain regions is associated with attentional control during visual search. We used fMRI to characterize age-related differences in frontoparietal activation in a highly efficient feature search task, detection of a shape singleton. On half of the trials, a salient distractor (a color singleton) was present in the display. The hypothesis was that frontoparietal activation mediated the relation between age and attentional capture by the salient distractor. Participants were healthy, community-dwelling individuals, 21 younger adults (19-29 years of age) and 21 older adults (60-87 years of age). Top-down attention, in the form of target predictability, was associated with an improvement in search performance that was comparable for younger and older adults. The increase in search reaction time (RT) associated with the salient distractor (attentional capture), standardized to correct for generalized age-related slowing, was greater for older adults than for younger adults. On trials with a color singleton distractor, search RT increased as a function of increasing activation in frontal regions, for both age groups combined, suggesting increased task difficulty. Mediational analyses disconfirmed the hypothesized model, in which frontal activation mediated the age-related increase in attentional capture, but supported an alternative model in which age was a mediator of the relation between frontal activation and capture.Item Open Access Age-related differences in frontoparietal activation for target and distractor singletons during visual search.(Attention, perception & psychophysics, 2023-04) Merenstein, Jenna L; Mullin, Hollie A; Madden, David JAge-related decline in visual search performance has been associated with different patterns of activation in frontoparietal regions using functional magnetic resonance imaging (fMRI), but whether these age-related effects represent specific influences of target and distractor processing is unclear. Therefore, we acquired event-related fMRI data from 68 healthy, community-dwelling adults ages 18-78 years, during both conjunction (T/F target among rotated Ts and Fs) and feature (T/F target among Os) search. Some displays contained a color singleton that could correspond to either the target or a distractor. A diffusion decision analysis indicated age-related increases in sensorimotor response time across all task conditions, but an age-related decrease in the rate of evidence accumulation (drift rate) was specific to conjunction search. Moreover, the color singleton facilitated search performance when occurring as a target and disrupted performance when occurring as a distractor, but only during conjunction search, and these effects were independent of age. The fMRI data indicated that decreased search efficiency for conjunction relative to feature search was evident as widespread frontoparietal activation. Activation within the left insula mediated the age-related decrease in drift rate for conjunction search, whereas this relation in the FEF and parietal cortex was significant only for individuals younger than 30 or 44 years, respectively. Finally, distractor singletons were associated with significant parietal activation, whereas target singletons were associated with significant frontoparietal deactivation, and this latter effect increased with adult age. Age-related differences in frontoparietal activation therefore reflect both the overall efficiency of search and the enhancement from salient targets.Item Open Access At the Threshold with Simone Weil: A Political Theory of Migration and Refuge(2012) Gonzalez Rice, David LaurenceThe persistent presence of refugees challenges political theorists to rethink our approaches to citizenship and national sovereignty. I look to philosopher Simone Weil (1909-1943), who brings to the Western tradition her insight as a refugee who attended to other refugees. Deploying the tropes of Threshold, Refuge, and Attention (which I garner and elaborate from her writings) I read Weil as an eminently political theorist whose practice of befriending political strangers maintains the urgent, interrogative insight of the refugee while tempering certain "temptations of exile." On my reading, Weil's body of theory travels physically and conceptually among plural, intersecting, and conflicting bodies politic, finding in each a source of limited, imperfect, and precious Refuge.
I then put Weil into conversation with several contemporary scholars - Michael Walzer, Martha Nussbaum, and Kwame Anthony Appiah - each of whom takes up a problematic between duties to existing political community and the call to engagements with political strangers. Bringing Weilian theory to bear on this conversation, I argue that polity depends deeply on those who heed the call to assume variously particular, vocational, and unenforceable duties across received borders.
Finally, by way of furthering Weil's incomplete experiments in Attention to the other, I look to "accompaniment" and related strategies adopted by human rights activists in recent decades in the Americas. These projects, I suggest, display many traits in common with Weil's political sensibility, but they also demonstrate possibilities beyond those imagined by Weil herself. As such, they provide practical guidance to those of us confronting political failures and refugee flows in the Western hemisphere today. I conclude that politico-humanitarian movements' own bodies of theory and practice point the way to sustained, cross-border, political relations.
Item Open Access Attention to Suffering in the Work of Simone Weil and Käthe Kollwitz(2018) Gehring, StephanieThis dissertation traces the ethical and conceptual connections between Weil’s account of attention and Kollwitz’s artistic practice of attention, especially attention to suffering. Attention, in Weil’s view, is a strenuous surrender to things as they are, which involves the difficult work of letting those things be other than we desire (or even need) them to be. For both Weil and Kollwitz, attention is the only meaningful way of engaging human suffering, one’s own or that of others. My dissertation explores their ethically risky claim, and argues that attention is not only interesting or valuable but necessary when it comes to suffering: any genuine attempt to engage with suffering must begin with a discipline substantially similar to the one Weil writes about as attention and Kollwitz practices in her art. I show how Kollwitz visually extends Weil’s philosophy and theology of attention to suffering in two distinct ways: first, by attending in her art to her own suffering as well as the suffering of others; and second, by investing her art with a wholehearted and tactile focus on the human body.
For Weil, it is attention (as opposed to the will) that is at the heart of human agency. Meaningful action is, for her, impossible without attention. This means that actions intended to alleviate suffering cannot be effective unless they begin (and remain grounded) in attention. This is true especially because one of the effects of suffering (especially the extreme suffering Weil calls malheur, or affliction) is to disfigure the sufferer so much that she is no longer recognizable (even to herself) as a human being, and becomes invisible. Weil writes that attention, which is a form of love, is able to see sufferers even when suffering has made them invisible. Because attention is an exercise of the image of God in human beings, and is a participation in God’s work in the world, it can restore to those whom suffering has reduced to the status of objects a sense of their own human value and dignity. When it comes to our own suffering, the discipline of attention involves accepting it rather than attempting to evade it by passing it on to others. Weil argues that because of the way God entered into suffering in Christ’s incarnation and passion, the nature of suffering has changed: suffering is no longer empty, but is instead a place where we can meet God.
Kollwitz’s two first series of prints (A Weavers’ Revolt and Peasants’ War) show her drawing on many of the strands of modern art that surround her in pursuit of one central goal: to attend to human beings, and to help her viewers learn such attention through her work. The many states of her prints show the rigor of her revisions and the resonance between her artistic process and Weil’s account of attention. Over the course of her career, her aim of seeing humans accurately becomes more and more an aim to see those who suffer. On the one hand, Kollwitz turns toward the industrial poor among whom she lived, whose sufferings tended to make them invisible to others. On the other hand, she turns toward her own suffering, particularly her grief over the death of her son in WWI. In a late series of woodcuts called War, and in her bronze sculpture Mother with Dead Son, she connects the two. Both the print series and the sculpture serve as an invitation to hesitate in a way that lets us attend to the crushing and disorienting reality of suffering. I argue that the series War shows humans meeting their own exposure to the possibility of affliction, and that Kollwitz’s self-described calling “to voice the sufferings of people” fits into a theological account of lament, which presents human suffering in the context of God’s hearing and care.
My dissertation contributes to theological aesthetics by proposing attention as a generally commendable practice of perception, and by offering Weil and Kollwitz’s way of engaging with suffering as an alternative to theodicy.
Item Open Access Attentional Biases in Value-Based Decision-Making(2014) San Martin Ulloa, ReneHumans make decisions in highly complex physical, economic and social environments. In order to adaptively choose, the human brain has to learn about- and attend to- sensory cues that provide information about the potential outcome of different courses of action. Here I present three event-related potential (ERP) studies, in which I evaluated the role of the interactions between attention and reward learning in economic decision-making. I focused my analyses on three ERP components (Chap. 1): (1) the N2pc, an early lateralized ERP response reflecting the lateralized focus of visual; (2) the feedback-related negativity (FRN), which reflects the process by which the brain extracts utility from feedback; and (3) the P300 (P3), which reflects the amount of attention devoted to feedback-processing. I found that learned stimulus-reward associations can influence the rapid allocation of attention (N2pc) towards outcome-predicting cues, and that differences in this attention allocation process are associated with individual differences in economic decision performance (Chap. 2). Such individual differences were also linked to differences in neural responses reflecting the amount of attention devoted to processing monetary outcomes (P3) (Chap. 3). Finally, the relative amount of attention devoted to processing rewards for oneself versus others (as reflected by the P3) predicted both charitable giving and self-reported engagement in real-life altruistic behaviors across individuals (Chap. 4). Overall, these findings indicate that attention and reward processing interact and can influence each other in the brain. Moreover, they indicate that individual differences in economic choice behavior are associated both with biases in the manner in which attention is drawn towards sensory cues that inform subsequent choices, and with biases in the way that attention is allocated to learn from the outcomes of recent choices.
Item Open Access Attentional Effects on Conditioned Inhibition of Discrete and Contextual Stimuli(2013) Kutlu, Munir GunesIn the present study, we examined the predictions of an attentional-associative model (Schmajuk, Lam, & Gray Journal of Experimental Psychology: Animal Behavior Processes, 22, 321-349, 1996) regarding the effect of attentional manipulations on both discrete and contextual conditioned inhibitors.
The SLG model assumes that non-reinforced presentations of an inhibitory conditioned stimulus (CS) do not decrease its inhibitory associations. However, the model predicts that extended presentations will decrease attention to the inhibitor, thereby, decreasing both the expression of its inhibitory power in a summation test and the rate of acquisition in a retardation test. The model also predicts that subsequent presentations of the inhibitory CS with a novel CS will increase both its inhibitory power in a summation test and the rate of acquisition in a retardation test. Using a predictive learning design in humans, Experiment 1 examined the predictions involving the summation tests, whereas Experiments 2 and 3 examined the predictions involving the retardation tests. Experimental results were in agreement with the predictions of the model.
The SLG model also predicts that a salient extinction context (CX) becomes inhibitory and prevents extinction of the excitatory CS-unconditioned stimulus (US) association. Although some data seem to contradict that prediction (e.g., Bouton and King, 1983, Bouton and Swartzentruber, 1986, 1989), Larrauri and Schmajuk (2008) indicated that the CX might not appear inhibitory in a summation test because attention to the CX decreases with many but not few extinction trials. In a human predictive learning experiment, we confirmed the model's predictions that the inhibitory power of the extinction CX can be detected after a few extinction trials when attention to the CX is still high, but not after many extinction trials once attention to the CX has decreased (Experiment 4), and even after many extinction trials by presenting novel CSs to increase attention to the unattended CX (Experiment 5). Furthermore, using an eye-tracker, we confirmed the model's explanation of Experiment 4 results by showing decreased overt attention to the CX after many but not after few extinction trials (Experiment 6).
Importantly, the view that the extinction CX becomes inhibitory allows the model to explain spontaneous recovery (because attention to the excitatory CS increases before attention to the inhibitory CX), renewal (because the inhibition provided by the extinction CX disappears), and reinstatement (the inhibitory CX becomes neutral or excitatory), as well as a very large number of other experimental results related to extinction. Based on the prediction of the SLG, model the implications of our results for the treatments of anxiety disorders were discussed.
Item Open Access Brain connectivity and visual attention.(Brain connectivity, 2013-01) Parks, Emily L; Madden, David JEmerging hypotheses suggest that efficient cognitive functioning requires the integration of separate, but interconnected cortical networks in the brain. Although task-related measures of brain activity suggest that a frontoparietal network is associated with the control of attention, little is known regarding how components within this distributed network act together or with other networks to achieve various attentional functions. This review considers both functional and structural studies of brain connectivity, as complemented by behavioral and task-related neuroimaging data. These studies show converging results: The frontal and parietal cortical regions are active together, over time, and identifiable frontoparietal networks are active in relation to specific task demands. However, the spontaneous, low-frequency fluctuations of brain activity that occur in the resting state, without specific task demands, also exhibit patterns of connectivity that closely resemble the task-related, frontoparietal attention networks. Both task-related and resting-state networks exhibit consistent relations to behavioral measures of attention. Further, anatomical structure, particularly white matter pathways as defined by diffusion tensor imaging, places constraints on intrinsic functional connectivity. Lastly, connectivity analyses applied to investigate cognitive differences across individuals in both healthy and diseased states suggest that disconnection of attentional networks is linked to deficits in cognitive functioning, and in extreme cases, to disorders of attention. Thus, comprehensive theories of visual attention and their clinical translation depend on the continued integration of behavioral, task-related neuroimaging, and brain connectivity measures.Item Open Access Challenges in measuring the effects of pharmacological interventions on cognitive and adaptive functioning in individuals with Down syndrome: A systematic review.(American journal of medical genetics. Part A, 2017-11) Keeling, Lori A; Spiridigliozzi, Gail A; Hart, Sarah J; Baker, Jane A; Jones, Harrison N; Kishnani, Priya SWe systematically reviewed the measures used in pharmaceutical trials in children/adults with Down syndrome without dementia. Our purpose was to identify developmentally appropriate outcome measures capable of detecting changes in cognitive and adaptive functioning in this population. Eleven studies were included and used diverse outcome measures across the domains of language, memory, attention, behavior, and executive/adaptive functioning. Our results highlight the challenges in selecting measures capable of capturing improvements in pharmaceutical trials in individuals with DS. We offer suggestions to enhance future research, including: conducting studies with larger samples of participants with a range of developmental abilities; modifying existing/developing novel outcome measures; incorporating advances from related areas and DS observational studies; and considering alternative analytic techniques to characterize treatment effects.Item Open Access Cortical Brain Activity Reflecting Attentional Biasing Toward Reward-Predicting Cues Covaries with Economic Decision-Making Performance.(Cereb Cortex, 2016-01) San Martín, René; Appelbaum, Lawrence G; Huettel, Scott A; Woldorff, Marty GAdaptive choice behavior depends critically on identifying and learning from outcome-predicting cues. We hypothesized that attention may be preferentially directed toward certain outcome-predicting cues. We studied this possibility by analyzing event-related potential (ERP) responses in humans during a probabilistic decision-making task. Participants viewed pairs of outcome-predicting visual cues and then chose to wager either a small (i.e., loss-minimizing) or large (i.e., gain-maximizing) amount of money. The cues were bilaterally presented, which allowed us to extract the relative neural responses to each cue by using a contralateral-versus-ipsilateral ERP contrast. We found an early lateralized ERP response, whose features matched the attention-shift-related N2pc component and whose amplitude scaled with the learned reward-predicting value of the cues as predicted by an attention-for-reward model. Consistently, we found a double dissociation involving the N2pc. Across participants, gain-maximization positively correlated with the N2pc amplitude to the most reliable gain-predicting cue, suggesting an attentional bias toward such cues. Conversely, loss-minimization was negatively correlated with the N2pc amplitude to the most reliable loss-predicting cue, suggesting an attentional avoidance toward such stimuli. These results indicate that learned stimulus-reward associations can influence rapid attention allocation, and that differences in this process are associated with individual differences in economic decision-making performance.Item Open Access Culture moderates the relationship between self-control ability and free will beliefs in childhood(Cognition, 2021-05) Zhao, Xin; Wente, Adrienne; Flecha, María Fernández; Galvan, Denise Segovia; Gopnik, Alison; Kushnir, TamarWe investigate individual, developmental, and cultural differences in self-control in relation to children's changing belief in "free will" - the possibility of acting against and inhibiting strong desires. In three studies, 4- to 8-year-olds in the U.S., China, Singapore, and Peru (N = 441) answered questions to gauge their belief in free will and completed a series of self-control and inhibitory control tasks. Children across all four cultures showed predictable age-related improvements in self-control, as well as changes in their free will beliefs. Cultural context played a role in the timing of these emerging free will beliefs: Singaporean and Peruvian children's beliefs changed at later ages than Chinese and U.S. children. Critically, culture moderated the link between self-control abilities and free will beliefs: Individual differences in self-control behaviors were linked to individual differences in free will beliefs in U.S. children, but not in children from China, Singapore or Peru. There was also evidence of a causal influence of self-control performance on free will beliefs in our U.S. sample. In Study 2, a randomly assigned group of U.S. 4- and 5-year-olds who failed at two self-control tasks showed reduced belief in free will, but a group of children who completed free will questions first did not show changes to self-control. Together these results suggest that culturally-acquired causal-explanatory frameworks for action, along with observations of one's own abilities, might influence children's emerging understanding of free will.Item Open Access Data-driven and memory-driven selective attention in visual search.(Journal of gerontology, 1984-01) Madden, DJThe present experiment investigated Rabbitt's (1979) hypothesis that age differences in selective attention occur when memory-driven processing must be employed. Young and older adults performed a visual search task, which, on some trials, provided advance information (a cue) regarding the particular target letter most likely to appear in the display. The nature of the selectivity required by the cue was either data-driven (Condition 1) or memory-driven (Condition 2). Analyses of the benefit in search performance associated with the cued trials and of the cost in performance resulting from the presentation of misleading advance information yielded limited support for Rabbitt's hypothesis. The older adults, but not the young, did exhibit a smaller cuing benefit in Condition 2 than in Condition 1. Both age groups, however, demonstrated substantial benefits and costs within each condition. Age differences in selective attention are thus not determined completely by the requirement to use memory-driven processing.Item Open Access Determinants of Distractibility in the Rhesus Macaque(2013) Ebitz, Robert B.The visual world is full of potentially important information, but only a subset of the world can be evaluated at any time. An essential function of the central nervous system is to rapidly and adaptively select which stimuli warrant attention. Much of the time, attention is directed towards stimuli that are relevant for current goals. However, things that have proven important in an organisms' personal or evolutionary past effectively compete with goal-relevant targets for attention. In humans, one example of this attentional superset is faces: faces attract attention even when they are in competition with immediate goals. Using a combination of behavioral, pharmacological, and electrophysiological techniques in the rhesus macaque, I investigated the physiological, neurobiological, and evolutionary determinants of the attentional capture of faces. First, I show that the prioritization of faces is evolutionarily conserved in primates. Face distractors also capture attention in rhesus macaques, a species of old world monkey, successfully competing with task goals for limited attentional resources. Importantly, the same classes of faces have the greatest attentional effects in both monkeys and humans. Further, I describe behavioral evidence that subcortical systems contribute to the attentional salience of faces in this species, proving an initial characterization of the neural mechanisms that may mediate this effect. Next, I examine the interaction between pupil size and vigilance for faces. A focal increase in luminance has long been known to provoke pupil constriction, but here I show that the pupil response to a flashed distractor is proportional to the allocation of attention to that image. Pupil constriction may provide a novel implicit metric of stimulus attention. In particular, face images provoked greater pupil constriction than non-face images. Moreover, I also find that baseline pupil size is a strong predictor of distractor interference, suggesting that arousal may modulate social vigilance. Therefore, I next examined the activity of single neurons within dorsal anterior cingulate cortex (dACC), a region implicated in task performance across a wide variety of tasks, but which also has strong connections to subcortical neuromodulatory centers responsible for regulating arousal. I find that the dACC discriminates between social and nonsocial distractors, scales with distractor attention, and predicts adjustments in arousal and vigilance state on upcoming trials. This is consistent with a model in which dACC supports task performance through regulating arousal. Finally, I turn to oxytocin (OT), a neuromodulatory hormone released during affiliative social interactions that is also implicated in regulating arousal. Though typically thought to generally enhance social attention, I report multiple circumstances in which OT suppresses, rather than enhances, vigilance for faces. This suggests a mechanism through which affiliative social interactions can reduce social vigilance, permitting more relaxed social interactions. Together, these results highlight an evolutionarily conserved neural circuit important for the adaptive, contextual modulation of reflexive face attention, a behavior that is compromised in both anxiety disorders and autism.
Item Open Access Distribution of important and word-cued autobiographical memories in 20-, 35-, and 70-year-old adults.(Psychol Aging, 1997-09) Rubin, DC; Schulkind, MDFor word-cued autobiographical memories, older adults had an increase, or bump, from the ages 10 to 30. All age groups had fewer memories from childhood than from other years and a power-function retention for memories from the most recent 10 years. There were no consistent differences in reaction times and rating scale responses across decades. Concrete words cued older memories, but no property of the cues predicted which memories would come from the bump. The 5 most important memories given by 20- and 35-year-old participants were distributed similarly to their word-cued memories, but those given by 70-year-old participants came mostly from the single 20-to-30 decade. No theory fully accounts for the bump.Item Open Access Does Mindfulness Affect Subsystems of Attention?(2011) Cozza, CarolineAttention is considered a fundamental component of mindfulness and current theory suggests that it is a primary mechanism of change that contributes to the substantive improvements in physical and psychological functioning attributed to mindfulness-based interventions including Mindfulness Based Stress Reduction (MBSR) and Mindfulness Based Cognitive Therapy (MBCT). Using the Attention Network Test (ANT) and an Inattentional Blindness (IB) task, the current study assessed differences in subsystems of attention in a group of experienced MBSR practitioners and a group of meditation naïve controls. MBSR practitioners demonstrated superior conflict monitoring performance relative to the control participants; however, groups did not differ with regards to their performance on the alerting and orienting components of the ANT. Additionally, although the MBSR practitioners were nearly half as likely as their control counterparts to evidence IB, this difference was not significant. Finally, self-reported mindfulness was higher in meditators relative to meditation naïve control participants, though scores did not correlate with performance on the attention tasks. The implications of these findings and directions for future research are discussed.
Item Open Access Effects of Expectation, Experience, and Environment on Visual Search(2009) Fleck, Mathias SamuelA pervasive aspect of daily life is searching for a specific target amongst an array of distracting items. Studying such visual searches offers a useful and powerful tool for revealing the underlying aspects of visual attention. Understanding how factors influence accurate target detection serves to both enhance real-world search tasks and inform basic cognitive psychology. The goal of the research presented herein is to examine the effects of expectation, experience, and environment on search behavior. The experiments are conducted in controlled laboratory environments, but are designed to simulate real-world searches, with the express goal of informing the implementation of search tasks in everyday life. First, expectation is explored by manipulating target prevalence and measuring the resultant change in behavior as participants' biases shift. Second, experience is tested by comparing individuals with and without extensive video game exposure, specifically on their susceptibility to the pressures of rare target search. Lastly, environment is examined by utilizing multiple simultaneous targets. This manipulation has been shown to induce errors in radiology, and here the generality of this effect is explored to establish the various pressures to which it is sensitive. Collectively, these data serve to inform how different influences modulate visual search performance, and the results can directly inform the training, recruitment, and execution of real-world search tasks such as those in radiology, cytology, and airport security.