Visual Selective Research Articles

Visual selective attention in individuals with age-related hearing loss

Evidence from epidemiological studies suggests that hearing loss is associated with an accelerated decline in cognitive function, but the underlying pathophysiological mechanism remains poorly understood. Studies using auditory tasks have suggested that degraded auditory input increases the cognitive load for auditory perceptual processing and thereby reduces the resources available for other cognitive tasks. Attention-related networks are among the systems overrecruited to support degraded auditory perception, but it is unclear how they function when no excessive recruitment of cognitive resources for auditory processing is needed. Here, we implemented an EEG study using a nonauditory visual attentional selection task in 30 individuals with age-related hearing loss (ARHLs, 60–73 years) and compared them with aged (N = 30, 60–70 years) and young (N = 35, 22–29 years) normal-hearing controls. Compared with their normal-hearing peers, ARHLs demonstrated a significant amplitude reduction for the posterior contralateral N2 component, which is a well-validated index of the allocation of selective visual attention, despite the comparable behavioral performance. Furthermore, the amplitudes were observed to correlate significantly with hearing acuities (pure tone audiometry thresholds) and higher-order hearing abilities (speech-in-noise thresholds) in aged individuals. The target-elicited alpha lateralization, another mechanism of visuospatial attention, demonstrated in control groups was not observed in ARHLs. Although behavioral performance is comparable, the significant decrease in N2pc amplitude in ARHLs provides neurophysiologic evidence that may suggest a visual attentional deficit in ARHLs even without extra-recruitment of cognitive resources by auditory processing. It supports the hypothesis that constant degraded auditory input in ARHLs has an adverse impact on the function of cognitive control systems, which is a possible mechanism mediating the relationship between hearing loss and cognitive decline.

Verbal instructions as selection bias that modulates visual selection

ABSTRACTResearch has shown that in addition to top-down and bottom-up processes, biases produced by the repetition priming effect and reward play a major role in visual selection. Action control research argues that bidirectional effect-response associations underlie the repetition priming effect and that such associations are also achievable through verbal instructions. This study evaluated whether verbally induced effect-response instructions bias visual selective attention in a visual search task in which these instructions were irrelevant. In two online experiments (Exp.1, N = 100; Exp. 2, N = 100), participants memorized specific verbal instructions before completing speeded visual-search classification tasks. In critical trials of the visual search task, a priming stimulus specified in the verbal instructions matched the target stimulus (positive priming). In addition, the design of Experiment 2 accounted for the repetition priming effect caused by frequent appearance of the target object. Reaction time analysis showed that verbal instructions inhibited visual search. Response error analysis showed that verbal effect-response formed an effect-response association between verbally specified stimulus and response. The results also showed that the target object’s frequent appearance strongly affected visual search. The overall findings showed that verbal instructions extended the list of selection biases that modulate visual selective attention.

Updating the dual-mechanism model for cross-sensory attentional spreading: The influence of space-based visual selective attention.

Selective attention to visual stimuli can spread cross‐modally to task‐irrelevant auditory stimuli through either the stimulus‐driven binding mechanism or the representation‐driven priming mechanism. The stimulus‐driven attentional spreading occurs whenever a task‐irrelevant sound is delivered simultaneously with a spatially attended visual stimulus, whereas the representation‐driven attentional spreading occurs only when the object representation of the sound is congruent with that of the to‐be‐attended visual object. The current study recorded event‐related potentials in a space‐selective visual object‐recognition task to examine the exact roles of space‐based visual selective attention in both the stimulus‐driven and representation‐driven cross‐modal attentional spreading, which remain controversial in the literature. Our results yielded that the representation‐driven auditory Nd component (200–400 ms after sound onset) did not differ according to whether the peripheral visual representations of audiovisual target objects were spatially attended or not, but was decreased when the auditory representations of target objects were presented alone. In contrast, the stimulus‐driven auditory Nd component (200–300 ms) was decreased but still prominent when the peripheral visual constituents of audiovisual nontarget objects were spatially unattended. These findings demonstrate not only that the representation‐driven attentional spreading is independent of space‐based visual selective attention and benefits in an all‐or‐nothing manner from object‐based visual selection for actually presented visual representations of target objects, but also that although the stimulus‐driven attentional spreading is modulated by space‐based visual selective attention, attending to visual modality per se is more likely to be the endogenous determinant of the stimulus‐driven attentional spreading.

Visual selective attention and the control of tracking eye movements: a critical review.

People's eyes are directed at objects of interest with the aim of acquiring visual information. However, processing this information is constrained in capacity, requiring task-driven and salience-driven attentional mechanisms to select few among the many available objects. A wealth of behavioral and neurophysiological evidence has demonstrated that visual selection and the motor selection of saccade targets rely on shared mechanisms. This coupling supports the premotor theory of visual attention put forth more than 30 years ago, postulating visual selection as a necessary stage in motor selection. In this review, we examine to which extent the coupling of visual and motor selection observed with saccades is replicated during ocular tracking. Ocular tracking combines catch-up saccades and smooth pursuit to foveate a moving object. We find evidence that ocular tracking requires visual selection of the speed and direction of the moving target, but the position of the motion signal may not coincide with the position of the pursuit target. Further, visual and motor selection can be spatially decoupled when pursuit is initiated (open-loop pursuit). We propose that a main function of coupled visual and motor selection is to serve the coordination of catch-up saccades and pursuit eye movements. A simple race-to-threshold model is proposed to explain the variable coupling of visual selection during pursuit, catch-up and regular saccades, while generating testable predictions. We discuss pending issues, such as disentangling visual selection from preattentive visual processing and response selection, and the pinpointing of visual selection mechanisms, which have begun to be addressed in the neurophysiological literature.

Irrelevant reward and selection histories have different influences on task-relevant attentional selection.

Task-relevant and physically salient features influence visual selective attention. In the present study, we investigated the influence of task-irrelevant and physically nonsalient reward-associated features on visual selective attention. Two hypotheses were tested: One predicts that the effects of target-defining task-relevant and task-irrelevant features interact to modulate visual selection; the other predicts that visual selection is determined by the independent combination of relevant and irrelevant feature effects. These alternatives were tested using a visual search task that contained multiple targets, placing a high demand on the need for selectivity, and that was data-limited and required unspeeded responses, emphasizing early perceptual selection processes. One week prior to the visual search task, participants completed a training task in which they learned to associate particular colors with a specific reward value. In the search task, the reward-associated colors were presented surrounding targets and distractors, but were neither physically salient nor task-relevant. In two experiments, the irrelevant reward-associated features influenced performance, but only when they were presented in a task-relevant location. The costs induced by the irrelevant reward-associated features were greater when they oriented attention to a target than to a distractor. In a third experiment, we examined the effects of selection history in the absence of reward history and found that the interaction between task relevance and selection history differed, relative to when the features had previously been associated with reward. The results indicate that under conditions that demand highly efficient perceptual selection, physically nonsalient task-irrelevant and task-relevant factors interact to influence visual selective attention.

Brain mechanisms underlying behavioral specificity and generalization of short-term texture discrimination learning.

In this study, we used high-density event-related potentials (ERPs) to investigate the brain mechanisms underlying behavioral specificity and generalization of short-term learning of texture discrimination task (TDT). Human adults were trained with TDT for a single session of 1.5 h and their ERPs were measured on the following day. Behavioral performance showed that, after a same amount of exposure of the trained and untrained conditions during EEG session, learning effects were specific to the trained background orientation but generalized across target locations. ERP data, however, revealed both target-location and background-orientation specific changes. While the behavioral background-orientation specificity mainly involved amplitude enhancement of early N2pc over occipital cortex, behavioral target-location generalization was associated with modulation of tempo-spatial configurations of the N2pc component (early-occipital vs. late-parietal/temporal pattern) and decrease of frontal P2 amplitudes for the trained relative to the untrained condition. The earliest visual component C1 did not show specific effects for either background orientation or target location. These results indicated different brain mechanisms underlying the behavioral specificity and generalization of TDT learning. Based on the present findings and literatures, we propose that perceptual learning may induce not only enhancement of relatively early visual selection of the trained target among distractors but also decreases of top-down attention originating from high-level brain center. The reactivation of top-down attention control in some conditions (e.g., the untrained target-location condition) may compensate for the specific effect induced by the early visual selective attention mechanism, leading to generalization or less specificity of perceptual learning in behavioral performance.

Failing to Ignore: Paradoxical Neural Effects of Perceptual Load on Early Attentional Selection in Normal Aging

We examined visual selective attention under perceptual load--simultaneous presentation of task-relevant and -irrelevant information--in healthy young and older adult human participants to determine whether age differences are observable at early stages of selection in the visual cortices. Participants viewed 50/50 superimposed face/place images and judged whether the faces were male or female, rendering places perceptible but task-irrelevant. Each stimulus was repeated, allowing us to index dynamic stimulus-driven competition from places. Consistent with intact early selection in young adults, we observed no adaptation to unattended places in parahippocampal place area (PPA) and significant adaptation to attended faces in fusiform face area (FFA). Older adults, however, exhibited both PPA adaptation to places and weak FFA adaptation to faces. We also probed participants' associative recognition for face-place pairs post-task. Older adults with better place recognition memory scores were found to exhibit both the largest magnitudes of PPA adaptation and the smallest magnitudes of FFA adaptation on the attention task. In a control study, we removed the competing perceptual information to decrease perceptual load. These data revealed that the initial age-related impairments in selective attention were not due to a general decline in visual cortical selectivity; both young and older adults exhibited robust FFA adaptation and neither group exhibited PPA adaptation to repeated faces. Accordingly, distracting information does not merely interfere with attended input in older adults, but is co-encoded along with the contents of attended input, to the extent that this information can subsequently be recovered from recognition memory.

Dimension-based attention modulates feed-forward visual processing

In his position paper, Theeuwes (2010) makes a challenge to a number of current theories of visual selective attention, which assume that what we select in the first instance is not simply bottom-up driven by properties of the stimulus, but also influenced (at least to some extent) by internal system settings that are under top-down control. In essence, Theeuwes (2010) puts forward a strong stimulusdriven view of visual selection, maintaining that the first sweep of information through the visual system is entirely driven by bottom-up stimulus salience and that top-down settings can bias visual processing only after selection of the most salient item, based on recurrent, feed-back processing. This view represents one pole of how we can conceive of visual selection. The other pole is given by a strong version of the contingent-capture hypothesis (e.g., Folk, Remington, & Johnston, 1992), which assumes that unless a bottom-up computed signal matches the top-down (goal) settings of the system, it will not ‘capture attention’; in other words, only signals that match these settings will engage selective attention—so that what is selected is entirely under two-down control. The dimension-weighting account (DWA; e.g., Found M Muller, Heller, & Ziegler, 1995) that we have developed over the past 15 years or so takes a position inbetween these extremes: consistent with Theeuwes (2010) and computational theories (e.g., Itti & Koch, 2000; Koch & Ullman, 1985; Wolfe, 1994), the DWA assumes that attentional selection is driven by an ‘overall-saliency’ or ‘master’ map of the visual array, that is: humans attend with priority to the stimulus (location) that achieves the highest activation on this map. However, we argue that this map is not simply computed in a bottom-up, stimulus-driven manner; but rather, saliency computations may be biased, in a spatially parallel manner, by top-down signals reflecting expectations of particular stimulus attributes. We refer to this account as dimension-weighting account (see Fig. 1 for an illustration of the processing architecture;

Linguistic control of visual attention: Differential access and focus or just confusion?

Investigation of the linguistic control of visual selective attention has shown that spatial language cues produce a cued-location effect (increased RTs in response to “left” and “right” when compared to “Above” and “Below”; Logan, 1995; Gibson & Kingstone, 2006). The cued-location effect is generally interpreted as representing differential access to spatial locations. In addition, an opposite-compatibility effect (distractors at uncued locations opposite the target decrease RTs when compatible and increase RTs when incompatible; Gibson, Scheutz, & Davis, in press) has been demonstrated that is unique to the cues “Left” and “Right.” The opposite-compatibility effect has been interpreted as representing a differential focus of attention. The present experiment explored an alternative explanation that confusion about locations along the horizontal axis is the underlying cause of these effects by separating cue processing from the visual selection task. In this experiment, subjects were presented with the spatial cues “Above,” “Below,” “Left,” and “Right” and asked to move a joystick in the corresponding direction. Immediately following their response, subjects engaged in color discrimination task where the target was indicated by the preceding word cue. Results of the joystick task showed that subjects were both slower in responding to “Left” and “Right” and also made significantly more errors when compared to “Above” and “Below.” Results of the selection task demonstrate a significant cued-location effect but not a significant opposite-compatibility effect. These results suggest that left/right confusion cannot explain the differential efficiency of accessing spatial locations across the axes but may influence attentional focus. An alternative “embodied cognition” interpretation of the non-significant opposite-compatibility effect is also discussed.

Are spatial and dimensional attention separate? Evidence from Posner, Stroop, and Eriksen tasks

Do various operational definitions of visual attention tap the same underlying process? To address this question, we probed visual selective attention using orientation of attention, flanker, and Stroop tasks. These were embedded in combined designs that enabled assessment of each effect, as well as their interaction. For the orientation task, performance was poorer at unexpected than at expected locations. The flanker effects also differed across the two locations. In contrast, the Stroop effects were comparable at expected and unexpected locations. We conclude that spatial attention (tapped by the orientation and the flanker tasks) and dimensional attention (tapped by the Stroop task) engage separate processes of visual selection, both of which are needed in normal attention processing.

Learning by selection: Visual search and object perception in young infants.

The authors examined how visual selection mechanisms may relate to developing cognitive functions in infancy. Twenty-two 3-month-old infants were tested in 2 tasks on the same day: perceptual completion and visual search. In the perceptual completion task, infants were habituated to a partly occluded moving rod and subsequently presented with unoccluded broken and complete rod test stimuli. In the visual search task, infants viewed displays in which single targets of varying levels of salience were cast among homogeneous static vertical distractors. Infants whose posthabituation preference indicated unity perception in the completion task provided evidence of a functional visual selective attention mechanism in the search task. The authors discuss the implications of the efficiency of attentional mechanisms for information processing and learning.

Selection and inhibition in infancy: evidence from the spatial negative priming paradigm

We used a spatial negative priming (SNP) paradigm to examine visual selective attention in infants and adults using eye movements as the motor selection measure. In SNP, when a previously ignored location becomes the target to be selected, responses to it are impaired, providing a measure of inhibitory selection. Each trial consisted of a prime and a probe, separated by 67, 200, or 550 ms interstimulus intervals (ISIs). In the prime, a target was accompanied by a distractor. In the probe, the target appeared either in the location formerly occupied by the distractor (ignored repetition) or in another location (control). Adults exhibited the SNP effect in all three ISI conditions, producing slower saccade latencies on ignored repetition versus control trials. The SNP effect obtained for infants only under 550 and 200 ms ISI conditions. These results suggest that important developments in visual selection are rooted in emerging inhibitory mechanisms.

Dipole source localization of event-related brain activity indicative of an early visual selective attention deficit in ADHD children

Objective This study was aimed at investigating whether attention-deficit hyperactivity disorder (ADHD) children suffer from specific early selective attention deficits in the visual modality with the aid of event-related brain potentials (ERPs). Furthermore, brain source localization was applied to identify brain areas underlying possible deficits in selective visual processing in ADHD children. Methods A two-channel visual color selection task was administered to 18 ADHD and 18 control subjects in the age range of 7–13 years and ERP activity was derived from 30 electrodes. Results ADHD children exhibited lower perceptual sensitivity scores resulting in poorer target selection. The ERP data suggested an early selective-attention deficit as manifested in smaller frontal positive activity (frontal selection positivity; FSP) in ADHD children around 200 ms whereas later occipital and fronto-central negative activity (OSN and N2b; 200–400 ms latency) appeared to be unaffected. Source localization explained the FSP by posterior-medial equivalent dipoles in control subjects, which may reflect the contribution of numerous surrounding areas. Conclusions ADHD children have problems with selective visual processing that might be caused by a specific early filtering deficit (absent FSP) occurring around 200 ms. The neural sources underlying these problems have to be further identified. Source localization also suggested abnormalities in the 200–400 ms time range, pertaining to the distribution of attention-modulated activity in lateral frontal areas.

Is there more to visual attention than meets the eye?

Models of saccade generation and visual selective attention must explain how and why particular targets are selected. Findlay & Walker do an excellent job of explaining the how of visual selection, but not the why. For a salience map to be more than a description of the relative importance of potential targets, there must be some account of the learning and inheritance that fashion its peaks and troughs. Point of gaze is not necessarily region of attention, and it may be premature to downgrade the role of covert attention in models of visual selection.

Neural representation of objects in space: a dual coding account.

I present evidence on the nature of object coding in the brain and discuss the implications of this coding for models of visual selective attention. Neuropsychological studies of task-based constraints on: (i) visual neglect; and (ii) reading and counting, reveal the existence of parallel forms of spatial representation for objects: within-object representations, where elements are coded as parts of objects, and between-object representations, where elements are coded as independent objects. Aside from these spatial codes for objects, however, the coding of visual space is limited. We are extremely poor at remembering small spatial displacements across eye movements, indicating (at best) impoverished coding of spatial position per se. Also, effects of element separation on spatial extinction can be eliminated by filling the space with an occluding object, indicating that spatial effects on visual selection are moderated by object coding. Overall, there are separate limits on visual processing reflecting: (i) the competition to code parts within objects; (ii) the small number of independent objects that can be coded in parallel; and (iii) task-based selection of whether within- or between-object codes determine behaviour. Between-object coding may be linked to the dorsal visual system while parallel coding of parts within objects takes place in the ventral system, although there may additionally be some dorsal involvement either when attention must be shifted within objects or when explicit spatial coding of parts is necessary for object identification.

Visual Selective Attention: Outlines of a Choice Model, a Race Model and a Computational Theory

A computational theory of visual selective attention is presented. The theory developed out of a choice and a race model for visual selection from multi-elementdisplays. The choice model (Bundesen, Pedersen, & Larsen, 1984) provides a rule for computation of selection probabilities, which accounts for effects of the selection criterion and the numbers of targets and distractors in the stimulus. The race model (Shibuya & Bundesen, 1988) provides a process interpretation of the choice model and accounts for effects of the exposure duration of the stimulus. The computational theory (TVA; Bundesen, 1990) was constructed by integrating the race model with a biased-choice model for single-stimulus recognition (Luce, 1963). TVA describes two mechanisms (filtering and pigeonholing) by which selection is assumed to be carried out, and it organizes a large body of empirical data on human performance in visual recognition and attention tasks. A recent theoretical development (CTVA; Logan, 1996; Logan & Bundesen, 1996) combines TVA with a theory of perceptual grouping by proximity. CTVA explains effects of spatial separation between items in multi-element displays. The neural localization of the operations described in TVA is considered in the final section.

Spatial extinction on double asynchronous stimulation

Despite the fact that visual extinction is widely considered a space-based disturbance of selective attention, there has been little theoretical consensus about the nature of its pathogenic mechanism. A specific disruption in the ability to disengage attention from ipsilesional stimuli, or a loss of weight with which contralesional objects compete for visual selection, have been hypothesized to account for the disorder. We tested the merits of these two explanations in a right-hemisphere-lesioned patient. FB, who failed to recognize a contralesional target only when it was shown concurrently to an ipsilesional target (i.e. visual extinction). His task was to report two target letters presented in rapid succession to the left and right of the fixation point. The order of stimulus presentation (Left-First vs Right-First), and the intertarget interval (stimulus onset asynchrony) were varied systematically. We showed that contralesional extinction may occur for successively presented targets, not just for stimuli displayed at the same time. Of most importance, FB was seriously and equally impaired in dealing with a contralesional stimulus when this either preceded the ipsilesional stimulus or followed it by an interval less than about 600 msec. The data appear to contradict the disengagement hypothesis, which predicted a substantial reduction of extinction when a stimulus was displayed first into the lesioned side of space. We suggest that a competitive model of visual selective attention fits the data quite well.

Visual selective attention: A theoretical analysis

The present paper outlines a framework which allows a consistent interpretation of data regarding visual selection in visual search tasks. It organizes and reviews visual search tasks in which the target is defined by primitive features, by conjunctions of features and when the target is categorically different from non-targets. The special role of spatial attention is reviewed and different theoretical accounts are discussed. Because visual selection depends principally on the outcome of the early parallel preattentive stage of processing, the main focus will be on this stage. It is concluded that visual selection is to a large extent determined by the physical characteristics of the stimuli present in the visual field. The early preattentive parallel process computes how different each object is from each of the other objects within a particular stimulus dimension. Attention is automatically drawn to the location having the highest activation, implying that the object at that location is automatically selected irrespective of the intentions of the subject. The model also assumes some top-down control. It is well known that attention can be voluntarily directed to nonfixated locations in visual space, varying from a uniform distribution over the visual field to a highly focused concentration. The model assumes that the endogenous direction of attention to an area in the visual field is the only top-down manner of affecting visual selection. Within the area of directed attention, no top-down control is possible: selection is completely determined by the physical properties of the stimuli.

SLAM: A connectionist model for attention in visual selection tasks

SLAM, the SeLective Attention Model, performs visual selective attention tasks, an analysis of which shows that two processes, object and attribute selection, are both necessary and sufficient. It is based upon the McClelland and Rumelhart (1981) model for visual word recognition, with the addition of a response selection and evaluation mechanism. The responses may be correct or incorrect and, in particular conditions, SLAM may not make a response at all. Moreover, it allows for the generation of specific responses in time. SLAM's main characteristics are parallelism restricted by competition within modules, heterarchical processing in a hierarchical structure, and generation of responses as a result of relaxation given the conjoint constraints of stimulation, object, and attribute selection. The model is considered to represent an individual subject performing filtering tasks and demonstrates appropriate selective behavior. It is also tested quantitatively using a single tentative set of model parameters. The study reports simulations of four different filtering experiments, modeling response latencies, and error proportions. Specifications are made to take account of instructions, previous trials, and the effect of a barmarker cue and of asynchronies in stimulus and cue onsets. The model is then extended in order to provide simulations of a number of Stroop experiments, which can be regarded as filtering tasks with nonequivalent stimuli. The extension required for Stroop simulations is the addition of direct connections between compatible stimulus and response aspects. The direct connections do not affect the simulation of simpler filtering tasks. A variety of different experiments carried out by different authors is simulated. The model is discussed in terms of how modular architecture and the interaction of excitation and inhibition generate facilitation or inhibition of response latencies.

The understanding of industrial melanism in the peppered moth (Biston betularia) (Lepidoptera: Geometridae)

Melanic polymorphism in B. betularia has been extensively studied. Correlations between high melanic frequency and high levels of air pollution have been demonstrated. Kettlewell and others have shown that differential bird predation has an important effect on the maintenance of the polymorphism, and coefficients of visual selection have been obtained on the assumption that the moth habitually rests on tree trunks. Computer models based on these selective coefficients show that they are not sufficient accurately to explain observed melanic frequencies. Other non-visual selective factors and weak frequency-dependent selection have been invoked to improve fits. Analysis of the resting positions of moths recorded in the wild demonstrates that B. betularia does not usually rest in exposed positions on tree trunks, but rather rests on the underside of branches, on trunks in shaded positions just below major branch joints or on foliate twigs. The results of a pilot selection experiment, while agreeing qualitatively with Kettlewell's results, suggest that fitness estimates that assume trunk-resting are quantitively incorrect. The error is greatest for melanic moths in rural areas. It is suggested that visual selective coefficients based on a true assessment of the resting behaviour of the moths may considerably improve the fit between computer predictions and observed phenotype frequency distributions.