Resisting change: The influence of luminance changes on visual marking and the preview benefit

Visual search can benefit when one set of distractors is presented as a preview, prior to the appearance the second set of distractors plus the target (Watson & Humphreys, 1997). It has been shown that changing the shape of the old, previewed stimuli when the new items appear causes the old stimuli to recompete for selection with the new ones. In contrast, changing the luminance or color of the old stimuli has no detrimental effects. Here, we present five experiments that reassessed the effect of luminance changes in preview search. We show (1) that preview search is remarkably resistant to large changes in the absolute luminance of the old stimuli, even when those changes would ordinarily be sufficient to signal the appearance of a new object and draw attention (Experiments 1 and 2), and (2) that resistance to luminance changes can be bolstered by feature-based inhibitory processes (Experiments 3–5). These findings are discussed in terms of the possible ecological properties of time-based visual selection and possible mechanisms underlying the preview benefit.     

Adolescent over-general memory,life events and mental health outcomes: Findings from a UK cohort study

Previous research suggesting that over-general memory (OGM) may moderate the effect of life events on depressive symptoms and suicidality has sampled older adolescents or adults, or younger adolescents in high-risk populations, and has been conducted over relatively short follow-up periods. The authors examined the relationship between OGM at age 13 and life events and mental health outcomes (depression, self-harm, suicidal ideation and planning) at age 16 years within a sample of 5792 adolescents participating in the Avon Longitudinal Study of Parents and Children (ALSPAC), approximately 3800 of whom had also provided data on depression and self-harm. There was no clear evidence of either direct or interactive effects of OGM at age 13 on levels of depression at age 16. Similarly there was no clear evidence of either direct or interactive effects of OGM on suicidal ideation and self-harm. Although there was some evidence that over-general autobiographical memory was associated with reduced risk of suicidal planning and increased risk of self-harm, these associations were absent when confounding variables were taken into account. The findings imply that although OGM is a marker of vulnerability to depression and related psychopathology in high-risk groups, this cannot be assumed to generalise to whole populations.     

The interaction of attention and action: From seeing action to acting on perception

We discuss evidence indicating that human visual attention is strongly modulated by the potential of objects for action. The possibility of action between multiple objects enables the objects to be attended as a single group, and the fit between individual objects in a group and the action that can be performed influences responses to group members. In addition, having a goal state to perform a particular action affects the stimuli that are selected along with the features and area of space that is attended. These effects of action may reflect statistical learning between environmental cues that are linked by action and/or the coupling between perception and action systems in the brain. The data support the argument that visual selection is a flexible process that emerges as a need to prioritize objects for action.     

Attending but not seeing: The "other race" effect in face and person perception studied through change blindness

We used a change blindness paradigm to examine the “other race” effect in perception. White Caucasian and Indian Asian participants viewed scenes in which White Caucasian and Indian Asian students were present. Changes were made either to the faces of the students, to their bodies or to an independent object in the background. Changes in faces were detected faster than changes in the bodies, which were in turn detected faster than changes in the background. For face detection there was a crossover interaction, with changes in White Caucasian faces detected faster than changes in Indian Asian faces by White Caucasian participants, whilst the opposite result occurred for changes in Indian Asian faces. In contrast, there was no effect of race on the detection of body-part changes or on the detection of changes to background objects. The results suggest that participants of both races attended equally well to subjects from the other race in the scene, but despite this they remained less sensitive to “other race” faces. Change blindness can provide a useful way of analysing attentional and memorial processes in social contexts.     

Quasireinforcement: Control of behavior by second-order interval schedules

Pigeons were trained on a variable-interval 66-sec schedule of reinforcement that was segmented into either fixed- or variable-interval 10-sec components. Three-second access to food followed some components according to the overall VI 66-sec schedule, but 3-sec periods of nonreinforcement followed the other components. With both FI 10-sec and VI 10-sec segments, overall response rates were generally higher when the completion of unreinforced segments was signaled by a red key (never paired with food) than when it was unsignaled. Response rates during the red-key periods dropped to zero. Brief presentations of the red key engendered the distinctive (FI or VI) patterns of responding which would be expected if each segment were followed by food. These data demonstrate behavioral control by brief stimuli which are not paired with primary reinforcement and show that such control may develop even when the sequences of behavior required to produce food or brief stimuli are variable in duration.     

The automatic and the expected self: separating self- and familiarity biases effects by manipulating stimulus probability

Attentional control over prepotent responses has previously been shown by manipulating the probability with which stimuli appear. Here, we examined whether prepotent responses to self-associated stimuli can be modulated by their frequency of occurrence. Participants were instructed to associate geometric shapes with the self, their mother, or a stranger before having to judge whether the sequential shape–label pairs matched or mismatched the instruction. The probability of the different shape–label pairs was varied. There was a robust advantage to self-related stimuli in all cases. Reducing the proportion of matched self pairs did not weaken performance with self-related stimuli, whereas reducing the frequency of either matched mother or stranger pairs hurt performance, relative to when the different match trials were equiprobable. In addition, while mother and stranger pairs jointly benefitted when they both occurred frequently, there were benefits only to self pairs when the frequency of self trials increased along with either mother or stranger trials. The results suggest that biases favoring self-related stimuli occur automatically, even when self-related stimuli have a low probability of occurrence, and that expectations to frequent, self-related stimuli operate in a relatively exclusive manner, minimizing biases to high-probability stimuli related to other people. In contrast, biases to high-familiarity stimuli (mother pairs) can be reduced when the items occur infrequently and they do not dominate expectations over other high-frequency stimuli.     

Dividing the self: distinct neural substrates of task-based and automatic self-prioritization after brain damage

Facial self-awareness is a basic human ability dependent on a distributed bilateral neural network and revealed through prioritized processing of our own over other faces. Using non-prosopagnosic patients we show, for the first time, that facial self-awareness can be fractionated into different component processes. Patients performed two face perception tasks. In a face orientation task, they judged whether their own or others' faces were oriented to the left or right. In the 'cross' experiment, they judged which horizontal or vertical element in a cross was relatively longer while ignoring a task-irrelevant face presented as background. The data indicate that impairments to a distinct task-based prioritization process (when faces had to be attended) were present after brain damage to right superior frontal gyrus, bilateral precuneus, and left middle temporal gyrus. In contrast, impairments to automatic prioritization processes (when faces had to be ignored) were associated only with left hemisphere damage (the cingulate gyrus, superior parietal lobe, and superior temporal gyrus). In addition, both automatic and task-based self-prioritizations were affected by damage to left supramarginal and angular gyrus. The results for the gray matter analyses also extended to the adjacent white matter fiber tracts including the inferior occipital-frontal fasciculus, cingulum, and optic radiation. The data provide the first empirical evidence for separate functional roles of the left and right hemispheres in different aspects of self-face perception and suggest distinct functional processes respectively for paying attention to and for ignoring self-related information.     

Action-related objects influence the distribution of visuospatial attention

Previous studies have shown that attention is drawn to the location of manipulable objects and is distributed across pairs of objects that are positioned for action. Here, we investigate whether central, action-related objects can cue attention to peripheral targets. Experiment 1 compared the effect of uninformative arrow and object cues on a letter discrimination task. Arrow cues led to spatial-cueing benefits across a range of stimulus onset asynchronies (SOAs: 0?ms, 120?ms, 400?ms), but object-cueing benefits were slow to build and were only significant at the 400-ms SOA. Similar results were found in Experiment 2, in which the targets were objects that could be either congruent or incongruent with the cue (e.g., screwdriver and screw versus screwdriver and glass). Cueing benefits were not influenced by the congruence between the cue and target, suggesting that the cueing effects reflected the action implied by the central object, not the interaction between the objects. For Experiment 3 participants decided whether the cue and target objects were related. Here, the interaction between congruent (but not incongruent) targets led to significant cueing/positioning benefits at all three SOAs. Reduced cueing benefits were obtained in all three experiments when the object cue did not portray a legitimate action (e.g., a bottle pointing towards an upper location, since a bottle cannot pour upwards), suggesting that it is the perceived action that is critical, rather than the structural properties of individual objects. The data suggest that affordance for action modulates the allocation of visual attention.     

Escaping capture: bilingualism modulates distraction from working memory

We ask whether bilingualism aids cognitive control over the inadvertent guidance of visual attention from working memory and from bottom-up cueing. We compare highly-proficient Catalan-Spanish bilinguals with Spanish monolinguals in three visual search conditions. In the working memory (WM) condition, attention was driven in a top-down fashion by irrelevant objects held in WM. In the Identify condition, attention was driven in a bottom-up fashion by visual priming. In the Singleton condition, attention was driven in a bottom-up fashion by including a unique distracting object in the search array. The results showed that bilinguals were overall faster than monolinguals in the three conditions, replicating previous findings that bilinguals can be more efficient than monolinguals in the deployment of attention. Interestingly, bilinguals were less captured by irrelevant information held in WM but were equally affected by visual priming and unique singletons in the search displays. These observations suggest that bilingualism aids top-down WM-mediated guidance of attention, facilitating processes that keep separate representations in WM from representations that guide visual attention. In contrast, bottom-up attentional capture by salient yet unrelated input operates similarly in bilinguals and monolinguals.