The forest, the trees, and the leaves across adulthood: Age-related changes on a visual search task containing three-level hierarchical stimuli

Selecting relevant visual information in complex scenes by processing either global information or local parts helps us act efficiently within our environment and achieve goals. A global advantage (faster global than local processing) and global interference (global processing interferes with local processing) comprise an evidentiary global precedence phenomenon in early adulthood. However, the impact of healthy aging on this phenomenon remains unclear. As such, we collected behavioral data during a visual search task, including three-levels hierarchical stimuli (i.e., global, intermediate, and local levels) with several hierarchical distractors, in 50 healthy adults (26 younger (mean age: 26 years) and 24 older (mean age: 62 years)). Results revealed that processing information presented at the global and intermediate levels was independent of age. Conversely, older adults were slower for local processing compared to the younger adults, suggesting lower efficiency to deal with visual distractors during detail-oriented visual search. Although healthy older adults continued exhibiting a global precedence phenomenon, they were disproportionately less efficient during local aspects of information processing, especially when multiple visual information was displayed. Our results could have important implications for many life situations by suggesting that visual information processing is impacted by healthy aging, even with similar visual stimuli objectively presented.

Broad scope of attention results in better temporal resolution: Evidence from a temporal order judgment study

The nature of spatiotemporal interactions in visual perception due to modulations of attention is still not well understood. Transient shifts of attention have been shown to induce a trade-off in spatiotemporal acuities at the cued location. Attention also can be varied in terms of scope and the evidence for the effects of scope on the spatiotemporal resolution for coupling or trade-offs have been equivocal. We predicted that scaling or changing the scope of attention would rather result in a spatiotemporal trade-off based on the complementary spatial and temporal frequency properties of the magnocellular and parvocellular channels. We manipulated the scope of attention by asking participants to perform a global or local target detection task with hierarchical stimuli. In addition, participants performed a temporal order judgment task with two discs presented alongside the hierarchical stimuli. We found higher temporal sensitivity with broad scope of attention or global processing compared to narrow scope of attention or local processing. The results provide evidence for a spatiotemporal processing trade-off when attention is scaled spatially. This result throws doubt on a general coupling or resource metaphor explanation irrespective of the spatial or temporal nature of the tasks. The results indicate the further need for carefully investigating the spatial and temporal properties of attention and its effect on spatiotemporal processing at different scales.

Individual Differences in Attentional Breadth Changes Over Time: An Event-Related Potential Investigation

Event-related potentials (ERPs) to hierarchical stimuli have been compared for global/local target trials, but the pattern of results across studies is mixed with respect to understanding how ERPs differ with local and global bias. There are reliable interindividual differences in attentional breadth biases. This study addresses two questions. Can these interindividual differences in attentional breadth be predicted by interindividual ERP differences to hierarchical stimuli? Can attentional breadth changes over time within participants (i.e., intraindividual differences) be predicted by ERPs changes over time when viewing hierarchical stimuli? Here, we estimated attentional breadth and isolated ERPs in response to Navon letter stimuli presented at two time points. We found that interindividual differences in ERPs at Time 1 did not predict attentional breadth differences across individuals at Time 1. However, individual differences in changes to P1, N1, and P3 ERPs to hierarchical stimuli from Time 1 to Time 2 were associated with individual differences in changes in attentional breadth from Time 1 to Time 2. These results suggest that attentional breadth changes within individuals over time are reflected in changes in ERP responses to hierarchical stimuli such that smaller N1s and larger P3s accompany a shift to processing the newly prioritized level, suggesting that the preferred level required less perceptual processing and elicited more attention.

The Influence of Inhibition of Return and Level-Priming on the Global Precedence Effect

The aim of the reported experiment was to investigate the effects of inhibition of return (IOR) and level-priming on the global precedence effect (GPE). The classical hierarchical stimuli combined with IOR and the level-priming paradigm were used. The participants selectively attended to the global or local features of compound numerals. The results showed that IOR inhibited the response to the global and local features; moreover, the inhibition effect on the perception of the global features was stronger than that of the local features in the stage of inhibitory processing, resulting in the disappearance of GPE. However, level-priming promoted the response to global and local features, and the promotion effect was stronger on local features, leading to the disappearance of GPE as well. These findings suggested that hierarchical processing was affected by IOR and level-priming, which were correlated with selective attention. Thus, it indicated that global precedence could be involved in attentional mechanisms.

How the forest interacts with the trees: Multiscale shape integration explains global and local processing

ABSTRACTHierarchical stimuli (such as a circle made of diamonds) have been widely used to study global and local processing. Two classic phenomena have been observed using these stimuli: the global advantage effect (that we identify the circle faster than the diamonds) and the incongruence effect (that we identify the circle faster when both global and local shapes are circles). Understanding them has been difficult because they occur during shape detection, where an unknown categorical judgement is made on an unknown feature representation.Here we report two essential findings. First, these phenomena are present both in a general same-different task and a visual search task, suggesting that they may be intrinsic properties of the underlying representation. Second, in both tasks, responses were explained using linear models that combined multiscale shape differences and shape distinctiveness. Thus, global and local processing can be understood as properties of a systematic underlying feature representation.

Involvement of the TPJ Area in Processing of Novel Global Forms

The neuropsychological syndrome “simultanagnosia” is characterized by the inability to integrate local elements into a global entity. This deficit in Gestalt perception is mainly apparent for novel global structures administered in clinical tests or unfamiliar visual scenes. Recognition of familiar complex objects or well-known visual scenes is often unaffected. Recent neuroimaging studies and reports from simultanagnosia patients suggest a crucial involvement of temporoparietal brain areas in processing of hierarchically organized visual material. In this study, we investigated the specific role of the TPJ in Gestalt perception. On the basis of perceptual characteristics known from simultanagnosia, we hypothesized that TPJ is dominantly involved in processing of novel object arrangements. To answer this question, we performed a learning study with hierarchical stimuli and tested behavioral and neuronal characteristics of Gestalt perception pre- and posttraining. The study included 16 psychophysical training sessions and two neuroimaging sessions. Participants improved their behavioral performance for trained global stimuli and showed limited transfer to untrained global material. We found significant training dependent neuronal signal modulations in anterior right hemispheric TPJ regions. These activation changes were specific to trained global stimuli, whereas no systematic neuronal response changes were observed for recognition of untrained global stimuli, local elements and regular objects that served as control stimuli. In line with perceptual characteristics in simultanagnosia, the results argue for an involvement of TPJ in processing of novel global structures. We discuss the signal modulations in the context of a more efficient or different neuronal strategy to process familiar global stimuli.

Priming atencional en patrones visuales jerárquicos: Efectos del nivel atendido, tamaño absoluto y congruencia estimular

<p>Previous studies on the visual processing of hierarchical stimuli showed that responses to targets presented either in the local or in the global level were faster when the target was presented at the same hierarchical level as the previous trial (sequential priming effect). In the present work, a new attentional priming paradigm was developed in order to explore this sequential effect by means of a within-trial design. For this purpose, two experiments were conducted manipulating attention (selective vs divided), congruency and stimulus size. Results suggested that the main factor underlying the sequential priming effect was the hierarchical level attended, at least in a selective attention task (Experiment 1). In addition, the stimulus size modulated the sequential priming effect in a divided attention task (Experiment 2). Interestingly, the sequential priming effect was only reliable when incongruent stimuli were presented.</p><p>Keywords: Priming, selective attention, divided attention, hierarchical stimuli, global/local processing.</p>