Emergent features and feature combination

Pomerantz, James R.; Cragin, Anna

doi:10.1093/oxfordhb/9780199686858.013.021

Cited by 29 publications

(7 citation statements)

References 24 publications

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“…As an example of the things class of models, some theories of texture segmentation represent texture by a set of discrete features, called textons. Whether segmentation occurs depends on whether two abutting textures contain the same number of attributes, like vertical lines, endstops, closed curves, and arrow junctions (Julesz, 1981; Julesz & Bergen, 1983; Pomerantz & Cragin, 2015). On the other hand, filter–nonlinearity–filter models of texture segmentation (Landy & Bergen, 1991; Malik & Perona, 1990; Rosenholtz, 2000), as well as texture representations based on image statistics (Heeger & Bergen, 1995; Portilla & Simoncelli, 2000), fall into the class of stuff models of texture perception.…”

Section: Introductionmentioning

confidence: 99%

Pooling of continuous features provides a unifying account of crowding

Keshvari¹,

Rosenholtz²

2016

Journal of Vision

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Visual crowding refers to phenomena in which the perception of a peripheral target is strongly affected by nearby flankers. Observers often report seeing the stimuli as “jumbled up,” or otherwise confuse the target with the flankers. Theories of visual crowding contend over which aspect of the stimulus gets confused in peripheral vision. Attempts to test these theories have led to seemingly conflicting results, with some experiments suggesting that the mechanism underlying crowding operates on unbound features like color or orientation (Parkes, Lund, Angelucci, Solomon, & Morgan, 2001), while others suggest it “jumbles up” more complex features, or even objects like letters (Korte, 1923). Many of these theories operate on discrete features of the display items, such as the orientation of each line or the identity of each item. By contrast, here we examine the predictions of the Texture Tiling Model, which operates on continuous feature measurements (Balas, Nakano, & Rosenholtz, 2009). We show that the main effects of three studies from the crowding literature are consistent with the predictions of Texture Tiling Model. This suggests that many of the stimulus-specific curiosities surrounding crowding are the inherent result of the informativeness of a rich set of image statistics for the particular tasks.

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Section: Introductionmentioning

confidence: 99%

Pooling of continuous features provides a unifying account of crowding

Keshvari¹,

Rosenholtz²

2016

Journal of Vision

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“…In Experiment 2 , we investigated whether emergent features could explain the advantage of uniform tilts (present versus absent) for target discrimination when all lines were of the same contrast polarity. An emergent feature refers to the salient property of a spatial configuration resulting from the combination of basic features ( Pomerantz & Cragin, 2014 ). Previous studies have already shown that specific line configurations may elicit emergent features such as parallelism or collinearity ( Pomerantz, Chapman, Flynn, Noe, & Yingxue, 2017 ; Stupina, 2011 ).…”

Section: Discussionmentioning

confidence: 99%

Multidimensional feature interactions in visual crowding: When configural cues eliminate the polarity advantage

Rummens

Sayim

2022

Journal of Vision

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Crowding occurs when surrounding objects (flankers) impair target perception. A key property of crowding is the weaker interference when target and flankers strongly differ on a given dimension. For instance, identification of a target letter is usually superior with flankers of opposite versus the same contrast polarity as the target (the “polarity advantage”). High performance when target-flanker similarity is low has been attributed to the ungrouping of target and flankers. Here, we show that configural cues can override the usual advantage of low target-flanker similarity, and strong target-flanker grouping can reduce – instead of exacerbate – crowding. In Experiment 1 , observers were presented with line triplets in the periphery and reported the tilt (left or right) of the central line. Target and flankers had the same (uniform condition) or opposite contrast polarity (alternating condition). Flanker configurations were either upright (||), unidirectionally tilted (\\ or //), or bidirectionally tilted (\/ or /\). Upright flankers yielded stronger crowding than unidirectional flankers, and weaker crowding than bidirectional flankers. Importantly, our results revealed a clear interaction between contrast polarity and flanker configuration. Triplets with upright and bidirectional flankers, but not unidirectional flankers, showed the polarity advantage. In Experiments 2 and 3 , we showed that emergent features and redundancy masking (i.e. the reduction of the number of perceived items in repeating configurations) made it easier to discriminate between uniform triplets when flanker tilts were unidirectional (but not when bidirectional). We propose that the spatial configurations of uniform triplets with unidirectional flankers provided sufficient task-relevant information to enable a similar performance as with alternating triplets: strong-target flanker grouping alleviated crowding. We suggest that features which modulate crowding strength can interact non-additively, limiting the validity of typical crowding rules to contexts where only single, independent dimensions determine the effects of target-flanker similarity.

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“…The goal of the present study was to examine how flexible emergent features are, that is, to determine the extent to which the perception of emergent features is tolerant to changes in the arrangement of their constituent local elements. We manipulated the arrangement of local elements within stimulus arrays, and assessed the extent to which the CSE, an index of stimulus configurality (Pomerantz and Cragin, 2015), can be obtained across a range of deviations from an ideal configuration. We used behavioral performance to establish whether increasing configurality produces faster and more accurate responses; we used neuroimaging to determine where increasing configurality produces increased activation along the ventral visual pathway.…”

Section: Discussionmentioning

confidence: 99%

“…A set of stimuli were developed that continuously and parametrically varied the deviation of their constituent features from symmetric and parallel orientations. We chose to focus on symmetry and parallelism, as they are two prime examples of emergent features often discussed in the context of the CSE (e.g., Pomerantz and Garner, 1973; Pomerantz et al, 1977; Mersch, 2014; Pomerantz and Cragin, 2015). This allowed us to explore the extent to which emergent features are continuously perceived, and correspondingly, how behavioral outcomes (response times, accuracy) are impacted by degrees of configurality (e.g., continuous degradation or a dichotomous break?…”

Section: Introductionmentioning

confidence: 99%

How Configural Is the Configural Superiority Effect? A Neuroimaging Investigation of Emergent Features in Visual Cortex

2017

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The perception of a visual stimulus is dependent not only upon local features, but also on the arrangement of those features. When stimulus features are perceptually well organized (e.g., symmetric or parallel), a global configuration with a high degree of salience emerges from the interactions between these features, often referred to as emergent features. Emergent features can be demonstrated in the Configural Superiority Effect (CSE): presenting a stimulus within an organized context relative to its presentation in a disarranged one results in better performance. Prior neuroimaging work on the perception of emergent features regards the CSE as an “all or none” phenomenon, focusing on the contrast between configural and non-configural stimuli. However, it is still not clear how emergent features are processed between these two endpoints. The current study examined the extent to which behavioral and neuroimaging markers of emergent features are responsive to the degree of configurality in visual displays. Subjects were tasked with reporting the anomalous quadrant in a visual search task while being scanned. Degree of configurality was manipulated by incrementally varying the rotational angle of low-level features within the stimulus arrays. Behaviorally, we observed faster response times with increasing levels of configurality. These behavioral changes were accompanied by increases in response magnitude across multiple visual areas in occipito-temporal cortex, primarily early visual cortex and object-selective cortex. Our findings suggest that the neural correlates of emergent features can be observed even in response to stimuli that are not fully configural, and demonstrate that configural information is already present at early stages of the visual hierarchy.

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Emergent features and feature combination

Cited by 29 publications

References 24 publications

Pooling of continuous features provides a unifying account of crowding

Pooling of continuous features provides a unifying account of crowding

Multidimensional feature interactions in visual crowding: When configural cues eliminate the polarity advantage

How Configural Is the Configural Superiority Effect? A Neuroimaging Investigation of Emergent Features in Visual Cortex

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