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1.
J Vis ; 24(6): 5, 2024 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-38842835

RESUMEN

Ensemble processing allows the visual system to condense visual information into useful summary statistics (e.g., average size), thereby overcoming capacity limitations to visual working memory and attention. To examine the role of attention in ensemble processing, we conducted three experiments using a novel paradigm that merged the action effect (a manipulation of attention) and ensemble processing. Participants were instructed to make a simple action if the feature of a cue word corresponded to a subsequent shape. Immediately after, they were shown an ensemble display of eight ovals of varying sizes and were asked to report either the average size of all ovals or the size of a single oval from the set. In Experiments 1 and 2, participants were cued with a task-relevant feature, and in Experiment 3, participants were cued with a task-irrelevant feature. Overall, the task-relevant cues that elicited an action influenced reports of average size in the ensemble phase more than the cues that were passively viewed, whereas task-irrelevant cues did not bias the reports of average size. The results of this study suggest that attention influences ensemble processing only when it is directed toward a task-relevant feature.


Asunto(s)
Atención , Señales (Psicología) , Estimulación Luminosa , Humanos , Atención/fisiología , Adulto Joven , Masculino , Femenino , Estimulación Luminosa/métodos , Adulto , Memoria a Corto Plazo/fisiología , Tiempo de Reacción/fisiología , Percepción del Tamaño/fisiología , Percepción de Forma/fisiología , Desempeño Psicomotor/fisiología , Reconocimiento Visual de Modelos/fisiología
2.
Curr Neurol Neurosci Rep ; 21(10): 54, 2021 09 29.
Artículo en Inglés | MEDLINE | ID: mdl-34586544

RESUMEN

PURPOSE OF REVIEW: Historical and contemporary treatments of visual agnosia and neglect regard these disorders as largely unrelated. It is thought that damage to different neural processes leads directly to one or the other condition, yet apperceptive variants of agnosia and object-centered variants of neglect share remarkably similar deficits in the quality of conscious experience. Here we argue for a closer association between "apperceptive" variants of visual agnosia and "object-centered" variants of visual neglect. We introduce a theoretical framework for understanding these conditions based on "scale attention", which refers to selecting boundary and surface information at different levels of the structural hierarchy in the visual array. RECENT FINDINGS: We review work on visual agnosia, the cortical structures and cortico-cortical pathways that underlie visual perception, visuospatial neglect and object-centered neglect, and attention to scale. We highlight direct and indirect pathways involved in these disorders and in attention to scale. The direct pathway involves the posterior vertical segments of the superior longitudinal fasciculus that are positioned to link the established dorsal and ventral attentional centers in the parietal cortex with structures in the inferior occipitotemporal cortex associated with visual apperceptive agnosia. The connections in the right hemisphere appear to be more important for visual conscious experience, whereas those in the left hemisphere appear to be more strongly associated with the planning and execution of visually guided grasps directed at multi-part objects such as tools. In the latter case, semantic and functional information must drive the selection of the appropriate hand posture and grasp points on the object. This view is supported by studies of grasping in patients with agnosia and in patients with neglect that show that the selection of grasp points when picking up a tool involves both scale attention and semantic contributions from inferotemporal cortex. The indirect pathways, which include the inferior fronto-occipital and horizontal components of the superior longitudinal fasciculi, involve the frontal lobe, working memory and the "multiple demands" network, which can shape the content of visual awareness through the maintenance of goal- and task-based abstractions and their influence on scale attention. Recent studies of human cortico-cortical pathways necessitate revisions to long-standing theoretical views on visual perception, visually guided action and their integrations. We highlight findings from a broad sample of seemingly disparate areas of research to support the proposal that attention to scale is necessary for typical conscious visual experience and for goal-directed actions that depend on functional and semantic information. Furthermore, we suggest that vertical pathways between the parietal and occipitotemporal cortex, along with indirect pathways that involve the premotor and prefrontal cortex, facilitate the operations of scale attention.


Asunto(s)
Agnosia , Trastornos de la Percepción , Humanos , Vías Visuales , Percepción Visual
3.
J Vis ; 21(7): 11, 2021 07 06.
Artículo en Inglés | MEDLINE | ID: mdl-34269793

RESUMEN

Recent research has demonstrated that the parahippocampal place area represents both the shape and texture features of scenes, with the importance of each feature varying according to perceived scene category. Namely, shape features are predominately more diagnostic to the processing of artificial human-made scenes, while shape and texture are equally diagnostic in natural scene processing. However, to date little is known regarding the degree of interactivity or independence observed in the processing of these scene features. Furthermore, manipulating the scope of visual attention (i.e., globally vs. locally) when processing ensembles of multiple objects-stimuli that share a functional neuroanatomical link with scenes-has been shown to affect their cognitive visual representation. It remains unknown whether manipulating the scope of attention impacts scene processing in a similar manner. Using the well-established Garner speeded-classification behavioral paradigm, we investigated the influence of both feature diagnosticity and the scope of visual attention on potential interactivity or independence in the shape and texture processing of artificial human-made scenes. The results revealed asymmetric interference between scene shape and texture processing, with the more diagnostic feature (i.e., shape) interfering with the less diagnostic feature (i.e., texture), but not vice versa. Furthermore, this interference was attenuated and enhanced with more local and global visual processing strategies, respectively. These findings suggest that the scene shape and texture processing are mediated by shared cognitive mechanisms and that, although these representations are governed primarily via feature diagnosticity, they can nevertheless be influenced by the scope of visual attention.


Asunto(s)
Mapeo Encefálico , Imagen por Resonancia Magnética , Cognición , Humanos , Reconocimiento Visual de Modelos , Percepción Visual
4.
J Neurosci ; 39(39): 7737-7747, 2019 09 25.
Artículo en Inglés | MEDLINE | ID: mdl-31413074

RESUMEN

Extensive behavioral work has documented the ability of the human visual system to extract summary representations from face ensembles (e.g., the average identity of a crowd of faces). Yet, the nature of such representations, their underlying neural mechanisms, and their temporal dynamics await elucidation. Here, we examine summary representations of facial identity in human adults (of both sexes) with the aid of pattern analyses, as applied to EEG data, along with behavioral testing. Our findings confirm the ability of the visual system to form such representations both explicitly and implicitly (i.e., with or without the use of specific instructions). We show that summary representations, rather than individual ensemble constituents, can be decoded from neural signals elicited by ensemble perception, we describe the properties of such representations by appeal to multidimensional face space constructs, and we visualize their content through neural-based image reconstruction. Further, we show that the temporal profile of ensemble processing diverges systematically from that of single faces consistent with a slower, more gradual accumulation of perceptual information. Thus, our findings reveal the representational basis of ensemble processing, its fine-grained visual content, and its neural dynamics.SIGNIFICANCE STATEMENT Humans encounter groups of faces, or ensembles, in a variety of environments. Previous behavioral research has investigated how humans process face ensembles as well as the types of summary representations that can be derived from them, such as average emotion, gender, and identity. However, the neural mechanisms mediating these processes are unclear. Here, we demonstrate that ensemble representations, with different facial identity summaries, can be decoded and even visualized from neural data through multivariate analyses. These results provide, to our knowledge, the first detailed investigation into the status and the visual content of neural ensemble representations of faces. Further, the current findings shed light on the temporal dynamics of face ensembles and its relationship with single-face processing.


Asunto(s)
Encéfalo/fisiología , Reconocimiento Facial/fisiología , Adulto , Electroencefalografía , Femenino , Humanos , Masculino , Análisis Multivariante , Estimulación Luminosa , Procesamiento de Señales Asistido por Computador , Adulto Joven
5.
Neuroimage ; 211: 116629, 2020 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-32057998

RESUMEN

How are outliers in an otherwise homogeneous object ensemble represented by our visual system? Are outliers ignored because they are the minority? Or do outliers alter our perception of an otherwise homogeneous ensemble? We have previously demonstrated ensemble representation in human anterior-medial ventral visual cortex (overlapping the scene-selective parahippocampal place area; PPA). In this study we investigated how outliers impact object-ensemble representation in this human brain region as well as visual representation throughout posterior brain regions. We presented a homogeneous ensemble followed by an ensemble containing either identical elements or a majority of identical elements with a few outliers. Human participants ignored the outliers and made a same/different judgment between the two ensembles. In PPA, fMRI adaptation was observed when the outliers in the second ensemble matched the items in the first, even though the majority of the elements in the second ensemble were distinct from those in the first; conversely, release from fMRI adaptation was observed when the outliers in the second ensemble were distinct from the items in the first, even though the majority of the elements in the second ensemble were identical to those in the first. A similarly robust outlier effect was also found in other brain regions, including a shape-processing region in lateral occipital cortex (LO) and task-processing fronto-parietal regions. These brain regions likely work in concert to flag the presence of outliers during visual perception and then weigh the outliers appropriately in subsequent behavioral decisions. To our knowledge, this is the first time the neural mechanisms involved in outlier processing have been systematically documented in the human brain. Such an outlier effect could well provide the neural basis mediating our perceptual experience in situations like "one bad apple spoils the whole bushel".


Asunto(s)
Mapeo Encefálico , Corteza Cerebral/fisiología , Percepción de Color/fisiología , Reconocimiento Visual de Modelos/fisiología , Vías Visuales/fisiología , Adulto , Corteza Cerebral/diagnóstico por imagen , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Corteza Visual/diagnóstico por imagen , Corteza Visual/fisiología , Vías Visuales/diagnóstico por imagen , Adulto Joven
6.
Cereb Cortex ; 29(1): 253-264, 2019 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-29190332

RESUMEN

Social comparison plays an important role in our daily life. Several studies have investigated the neural mechanism of social comparison; however, their conclusions remain controversial. The present study explored the neural correlates of intelligence comparison and nonsocial size comparison using functional magnetic resonance imaging and a distance effect paradigm. We found that both intelligence and size comparisons obeyed the behavioral distance effect-longer response times for near than far distances and this effect involved an overlapping frontal network including the dorsomedial prefrontal cortex and insula. In addition, compared with size comparisons, intelligence comparisons elicited increased activity in the precuneus and angular gyrus, but decreased activity in the inferior parietal lobe. Furthermore, the analysis of seed-based functional connectivity complemented these neural commonalities and differences. Our findings suggest that social and nonsocial comparisons may rely on a common core mechanism, but this mechanism may be supplemented by different domain-specific cognitive components.


Asunto(s)
Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Inteligencia/fisiología , Red Nerviosa/diagnóstico por imagen , Red Nerviosa/fisiología , Conducta Social , Adolescente , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Estimulación Luminosa/métodos , Adulto Joven
7.
J Vis ; 19(5): 2, 2019 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-31058988

RESUMEN

Ensemble encoding refers to the visual system's ability to extract a summary representation from multiple items in a set-such as the mean identity of faces in a crowd-circumventing capacity limitations in visual working memory. In the present study we investigated face ensemble representations of higher level identity and lower level viewpoint with the aim of elucidating the extent of their overlap or independence. To this end, we used ensemble displays consisting of six face stimuli which could vary in identity, viewpoint, or both. Across three experiments, participants were asked to report an average identity, a single identity, an average viewpoint, or a single viewpoint, as cued by a central probe face following a stimulus display. In Experiment 1, we observed a dissociation between the processing of identity and viewpoint, as well as between average- and single-viewpoint extraction. Experiment 2 showed viewpoint-invariant identity processing across a wide range of mean viewpoints, spanning 120°. In Experiment 3, accuracy in reporting a response-relevant attribute was unaffected by changes in an irrelevant attribute. Participants were also capable of extracting both attributes simultaneously with little change in accuracy. Taken together, these results argue for the independence of identity and viewpoint in face ensemble processing.


Asunto(s)
Reconocimiento Facial/fisiología , Memoria a Corto Plazo/fisiología , Adolescente , Adulto , Señales (Psicología) , Retroalimentación Sensorial/fisiología , Femenino , Humanos , Masculino , Orientación Espacial/fisiología , Estimulación Luminosa/métodos , Adulto Joven
8.
J Cogn Neurosci ; 29(2): 398-412, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27676614

RESUMEN

Our visual system can extract summary statistics from large collections of objects without forming detailed representations of the individual objects in the ensemble. In a region in ventral visual cortex encompassing the collateral sulcus and the parahippocampal gyrus and overlapping extensively with the scene-selective parahippocampal place area (PPA), we have previously reported fMRI adaptation to object ensembles when ensemble statistics repeated, even when local image features differed across images (e.g., two different images of the same strawberry pile). We additionally showed that this ensemble representation is similar to (but still distinct from) how visual texture patterns are processed in this region and is not explained by appealing to differences in the color of the elements that make up the ensemble. To further explore the nature of ensemble representation in this brain region, here we used PPA as our ROI and investigated in detail how the shape and surface properties (i.e., both texture and color) of the individual objects constituting an ensemble affect the ensemble representation in anterior-medial ventral visual cortex. We photographed object ensembles of stone beads that varied in shape and surface properties. A given ensemble always contained beads of the same shape and surface properties (e.g., an ensemble of star-shaped rose quartz beads). A change to the shape and/or surface properties of all the beads in an ensemble resulted in a significant release from adaptation in PPA compared with conditions in which no ensemble feature changed. In contrast, in the object-sensitive lateral occipital area (LO), we only observed a significant release from adaptation when the shape of the ensemble elements varied, and found no significant results in additional scene-sensitive regions, namely, the retrosplenial complex and occipital place area. Together, these results demonstrate that the shape and surface properties of the individual objects comprising an ensemble both contribute significantly to object ensemble representation in anterior-medial ventral visual cortex and further demonstrate a functional dissociation between object- (LO) and scene-selective (PPA) visual cortical regions and within the broader scene-processing network itself.


Asunto(s)
Percepción de Forma/fisiología , Corteza Visual/fisiología , Percepción Visual/fisiología , Adaptación Psicológica/fisiología , Adulto , Mapeo Encefálico , Femenino , Humanos , Juicio/fisiología , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Estimulación Luminosa , Tiempo de Reacción , Corteza Visual/diagnóstico por imagen , Vías Visuales/diagnóstico por imagen , Vías Visuales/fisiología , Adulto Joven
9.
Neuroimage ; 157: 586-597, 2017 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-28647484

RESUMEN

Multiple cortical regions are crucial for perceiving the visual world, yet the processes shaping representations in these regions are unclear. To address this issue, we must elucidate how perceptual features shape representations of the environment. Here, we explore how the weighting of different visual features affects neural representations of objects and scenes, focusing on the scene-selective parahippocampal place area (PPA), but additionally including the retrosplenial complex (RSC), occipital place area (OPA), lateral occipital (LO) area, fusiform face area (FFA) and occipital face area (OFA). Across three experiments, we examined functional magnetic resonance imaging (fMRI) activity while human observers viewed scenes and objects that varied in geometry (shape/layout) and surface properties (texture/material). Interestingly, we found equal sensitivity in the PPA for these properties within a scene, revealing that spatial-selectivity alone does not drive activation within this cortical region. We also observed sensitivity to object texture in PPA, but not to the same degree as scene texture, and representations in PPA varied when objects were placed within scenes. We conclude that PPA may process surface properties in a domain-specific manner, and that the processing of scene texture and geometry is equally-weighted in PPA and may be mediated by similar underlying neuronal mechanisms.


Asunto(s)
Mapeo Encefálico/métodos , Lóbulo Occipital/fisiología , Giro Parahipocampal/fisiología , Percepción Espacial/fisiología , Lóbulo Temporal/fisiología , Percepción Visual/fisiología , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Lóbulo Occipital/diagnóstico por imagen , Giro Parahipocampal/diagnóstico por imagen , Lóbulo Temporal/diagnóstico por imagen , Adulto Joven
10.
Neuroimage ; 125: 681-692, 2016 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-26541082

RESUMEN

Scenes are constructed from multiple visual features, yet previous research investigating scene processing has often focused on the contributions of single features in isolation. In the real world, features rarely exist independently of one another and likely converge to inform scene identity in unique ways. Here, we utilize fMRI and pattern classification techniques to examine the interactions between task context (i.e., attend to diagnostic global scene features; texture or layout) and high-level scene attributes (content and spatial boundary) to test the novel hypothesis that scene-selective cortex represents multiple visual features, the importance of which varies according to their diagnostic relevance across scene categories and task demands. Our results show for the first time that scene representations are driven by interactions between multiple visual features and high-level scene attributes. Specifically, univariate analysis of scene-selective cortex revealed that task context and feature diagnosticity shape activity differentially across scene categories. Examination using multivariate decoding methods revealed results consistent with univariate findings, but also evidence for an interaction between high-level scene attributes and diagnostic visual features within scene categories. Critically, these findings suggest visual feature representations are not distributed uniformly across scene categories but are shaped by task context and feature diagnosticity. Thus, we propose that scene-selective cortex constructs a flexible representation of the environment by integrating multiple diagnostically relevant visual features, the nature of which varies according to the particular scene being perceived and the goals of the observer.


Asunto(s)
Reconocimiento Visual de Modelos/fisiología , Corteza Visual/fisiología , Adulto , Mapeo Encefálico , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino
11.
Cereb Cortex ; 25(11): 4226-39, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24964917

RESUMEN

Behavioral research has demonstrated that observers can extract summary statistics from ensembles of multiple objects. We recently showed that a region of anterior-medial ventral visual cortex, overlapping largely with the scene-sensitive parahippocampal place area (PPA), participates in object-ensemble representation. Here we investigated the encoding of ensemble density in this brain region using fMRI-adaptation. In Experiment 1, we varied density by changing the spacing between objects and found no sensitivity in PPA to such density changes. Thus, density may not be encoded in PPA, possibly because object spacing is not perceived as an intrinsic ensemble property. In Experiment 2, we varied relative density by changing the ratio of 2 types of objects comprising an ensemble, and observed significant sensitivity in PPA to such ratio change. Although colorful ensembles were shown in Experiment 2, Experiment 3 demonstrated that sensitivity to object ratio change was not driven mainly by a change in the ratio of colors. Thus, while anterior-medial ventral visual cortex is insensitive to density (object spacing) changes, it does code relative density (object ratio) within an ensemble. Object-ensemble processing in this region may thus depend on high-level visual information, such as object ratio, rather than low-level information, such as spacing/spatial frequency.


Asunto(s)
Adaptación Fisiológica/fisiología , Mapeo Encefálico , Reconocimiento Visual de Modelos/fisiología , Corteza Visual/fisiología , Vías Visuales/fisiología , Adulto , Análisis de Varianza , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Oxígeno/sangre , Estimulación Luminosa , Corteza Visual/irrigación sanguínea , Vías Visuales/irrigación sanguínea , Adulto Joven
12.
J Vis ; 16(6): 9, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27089064

RESUMEN

The scope of visual attention is known to affect conscious object perception, with recent studies showing that a global attentional scope boosts holistic face processing, relative to a local scope. Here we show that attentional scope settings can also modulate the availability of information for conscious visual awareness. In an initial experiment, we show that adopting a global attentional scope accelerates conscious detection of initially invisible faces, presented under continuous flash suppression (CFS). Furthermore, face detection time was not modulated by attentional scope in a nonrivalrous control condition, which emulated the experience of CFS without inducing binocular rivalry. In a follow-up experiment, we report an exact replication of the original effect, as well as data suggesting that this effect is specific to upright faces, and is abolished when using both inverted faces and images of houses in an otherwise identical task. Thus, attentional scope settings can modulate the availability of information to conscious awareness, fundamentally altering the contents of our subjective visual experience.


Asunto(s)
Estado de Conciencia/fisiología , Reconocimiento Facial/fisiología , Adolescente , Concienciación , Femenino , Humanos , Masculino , Adulto Joven
13.
J Vis ; 15(4): 12, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26360156

RESUMEN

Behavioral research has demonstrated that the shape and texture of single objects can be processed independently. Similarly, neuroimaging results have shown that an object's shape and texture are processed in distinct brain regions with shape in the lateral occipital area and texture in parahippocampal cortex. Meanwhile, objects are not always seen in isolation and are often grouped together as an ensemble. We recently showed that the processing of ensembles also involves parahippocampal cortex and that the shape and texture of ensemble elements are processed together within this region. These neural data suggest that the independence seen between shape and texture in single-object perception would not be observed in object-ensemble perception. Here we tested this prediction by examining whether observers could attend to the shape of ensemble elements while ignoring changes in an unattended texture feature and vice versa. Across six behavioral experiments, we replicated previous findings of independence between shape and texture in single-object perception. In contrast, we observed that changes in an unattended ensemble feature negatively impacted the processing of an attended ensemble feature only when ensemble features were attended globally. When they were attended locally, thereby making ensemble processing similar to single-object processing, interference was abolished. Overall, these findings confirm previous neuroimaging results and suggest that distinct cognitive mechanisms may be involved in single-object and object-ensemble perception. Additionally, they show that the scope of visual attention plays a critical role in determining which type of object processing (ensemble or single object) is engaged by the visual system.


Asunto(s)
Cognición/fisiología , Percepción de Forma/fisiología , Procesamiento Espacial/fisiología , Adolescente , Adulto , Mapeo Encefálico/métodos , Femenino , Humanos , Masculino , Corteza Visual/fisiología , Vías Visuales/fisiología , Adulto Joven
14.
J Exp Psychol Gen ; 153(1): 56-69, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37733008

RESUMEN

Ensemble coding (the brain's ability to rapidly extract summary statistics from groups of items) has been demonstrated across a range of low-level (e.g., average color) to high-level (e.g., average facial expression) visual features, and even on information that cannot be gleaned solely from retinal input (e.g., object lifelikeness). There is also evidence that ensemble coding can interact with other cognitive systems such as long-term memory (LTM), as observers are able to derive the average cost of items. We extended this line of research to examine if different sensory modalities can interact during ensemble coding. Participants made judgments about the average sweetness of groups of different visually presented foods. We found that, when viewed simultaneously, observers were limited in the number of items they could incorporate into their cross-modal ensemble percepts. We speculate that this capacity limit is caused by the cross-modal translation of visual percepts into taste representations stored in LTM. This was supported by findings that (a) participants could use similar stimuli to form capacity-unlimited ensemble representations of average screen size and (b) participants could extract the average sweetness of displays when items were viewed in sequence, with no capacity limitation (suggesting that spatial attention constrains the number of necessary visual cues an observer can integrate in a given moment to trigger cross-modal retrieval of taste). Together, the results of our study demonstrate that there are limits to the flexibility of ensemble coding, especially when multiple cognitive systems need to interact to compress sensory information into an ensemble representation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Asunto(s)
Señales (Psicología) , Memoria a Largo Plazo , Humanos , Atención , Expresión Facial , Percepción , Percepción Visual
15.
Neuropsychologia ; 192: 108745, 2024 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-38096982

RESUMEN

Ensemble coding refers to the brain's ability to rapidly extract summary statistics, such as average size and average cost, from a large set of visual stimuli. Although ensemble coding is thought to circumvent a capacity limit of visual working memory, we recently observed a VWM-like capacity limit in an ensemble task where observers extracted the average sweetness of groups of food pictures (i.e., they could only integrate information from four out of six available items), thus suggesting the involvement of VWM in this novel form of cross-modal ensemble coding. Therefore, across two experiments we investigated if this cross-modal ensemble capacity limit could be explained by individual differences in VWM processing. To test this, observers performed both an ensemble task and a VWM task, and we determined 1) how much information they integrated into their ensemble percepts, and 2) how much information they remembered from those displays. Interestingly, we found that individual differences in VWM capacity did not explain differences in performance on the ensemble coding task (i.e., high-capacity individuals did not have significantly higher "ensemble abilities" than low-capacity individuals). While our data cannot definitively state whether or not VWM is necessary to perform the ensemble task, we conclude that it is certainly not sufficient to support this cognitive process. We speculate that the capacity limit may be explained by 1) a bottleneck at the perceptual stage (i.e., a failure to process multiple visual features across multiple items, as there are no singular features that convey taste), or 2) the interaction of multiple cognitive systems (e.g., VWM, gustatory working memory, long term memory). Our results highlight the importance of examining ensemble perception across multiple sensory and cognitive domains to provide a clearer picture of the mechanisms underlying everyday behavior.


Asunto(s)
Memoria a Corto Plazo , Percepción Visual , Humanos , Recuerdo Mental , Memoria a Largo Plazo , Individualidad
16.
J Neurosci ; 32(22): 7685-700, 2012 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-22649247

RESUMEN

Our visual system can extract summary statistics from large collections of similar objects without forming detailed representations of the individual objects in the ensemble. Such object ensemble representation is adaptive and allows us to overcome the capacity limitation associated with representing specific objects. Surprisingly, little is known about the neural mechanisms supporting such object ensemble representation. Here we showed human observers identical photographs of the same object ensemble, different photographs depicting the same ensemble, or different photographs depicting different ensembles. We observed fMRI adaptation in anterior-medial ventral visual cortex whenever object ensemble statistics repeated, even when local image features differed across photographs. Interestingly, such object ensemble processing is closely related to texture and scene processing in the brain. In contrast, the lateral occipital area, a region involved in object-shape processing, showed adaptation only when identical photographs were repeated. These results provide the first step toward understanding the neural underpinnings of real-world object ensemble representation.


Asunto(s)
Adaptación Psicológica/fisiología , Mapeo Encefálico , Comprensión/fisiología , Reconocimiento Visual de Modelos/fisiología , Corteza Visual/fisiología , Adulto , Análisis de Varianza , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Oxígeno/sangre , Estimulación Luminosa , Tiempo de Reacción , Corteza Visual/irrigación sanguínea , Vías Visuales/irrigación sanguínea , Vías Visuales/fisiología , Adulto Joven
17.
Cognition ; 238: 105489, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37163952

RESUMEN

Some visual stimuli are consistently better remembered than others across individuals, due to variations in memorability (the stimulus-intrinsic property that determines ease of encoding into visual long-term memory (VLTM)). However, it remains unclear what cognitive processes give rise to this mnemonic benefit. One possibility is that this benefit is imbued within the capacity-limited bottleneck of VLTM encoding, namely visual working memory (VWM). More precisely, memorable stimuli may be preferentially encoded into VLTM because fewer cognitive resources are required to store them in VWM (efficiency hypothesis). Alternatively, memorable stimuli may be more competitive in obtaining cognitive resources than forgettable stimuli, leading to more successful storage in VWM (competitiveness hypothesis). Additionally, the memorability benefit might emerge post-VWM, specifically, if memorable stimuli are less prone to be forgotten (i.e., are "stickier") than forgettable stimuli after they pass through the encoding bottleneck (stickiness hypothesis). To test this, we conducted two experiments to examine how memorability benefits emerge by manipulating the stimulus memorability, set size, and degree of competition among stimuli as participants encoded them in the context of a working memory task. Subsequently, their memory for the encoded stimuli was tested in a VLTM task. In the VWM task, performance was better for memorable stimuli compared to forgettable stimuli, supporting the efficiency hypothesis. In addition, we found that when in direct competition, memorable stimuli were also better at attracting limited VWM resources than forgettable stimuli, supporting the competitiveness hypothesis. However, only the efficiency advantage translated to a performance benefit in VLTM. Lastly, we found that memorable stimuli were less likely to be forgotten after they passed through the encoding bottleneck imposed by VWM, supporting the "stickiness" hypothesis. Thus, our results demonstrate that the memorability benefit develops across multiple cognitive processes.


Asunto(s)
Memoria a Largo Plazo , Memoria a Corto Plazo , Humanos , Recuerdo Mental , Percepción Visual
18.
J Neurosci ; 31(22): 8248-58, 2011 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-21632946

RESUMEN

We used fMRI on neurologically intact humans to investigate whether or not there are different neural substrates for the different kinds of information that a visual surface signals (shape from texture vs material properties from texture). Participants attended to differences in the shape (flat/convex), texture and color (wood/rock), or material properties (soft/hard) of a set of circular surfaces. Attending to shape activated the contour-sensitive lateral occipital (LO) area, and attending to texture activated a region of the collateral sulcus (CoS) that overlaps with the parahippocampal place area (PPA). Interestingly, attending to material properties activated the same texture-sensitive region in the CoS. These results demonstrate the existence of different neural substrates for the different types of information that a visual surface signals. With regard to object shape, the organization of the LO area may be complex, with neurons tuned not only to the outline shape of objects, but also to their surface curvature independent of contour. Moreover, to our knowledge, this is the first study to demonstrate that processing surface texture, which occurs within the scene-sensitive PPA, is a route to accessing knowledge about an object's material properties. With this in mind, we propose that models of visual cortical organization should focus not only on the particular stimulus category to which a region maximally responds (e.g., objects, scenes), but also on the stimulus attributes that best support the processing of that category (e.g., shape, texture, material properties).


Asunto(s)
Percepción de Forma/fisiología , Lóbulo Occipital/fisiología , Giro Parahipocampal/fisiología , Percepción Visual/fisiología , Adulto , Mapeo Encefálico/métodos , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Estimulación Luminosa/métodos , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Propiedades de Superficie
19.
Atten Percept Psychophys ; 83(3): 1106-1128, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33506350

RESUMEN

Through ensemble encoding, the visual system compresses redundant statistical properties from multiple items into a single summary metric (e.g., average size). Numerous studies have shown that global summary information is extracted quickly, does not require access to single-item representations, and often interferes with reports of single items from the set. Yet a thorough understanding of ensemble processing would benefit from a more extensive investigation at the local level. Thus, the purpose of this study was to provide a more critical inspection of global-local processing in ensemble perception. Taking inspiration from Navon (Cognitive Psychology, 9(3), 353-383, 1977), we employed a novel paradigm that independently manipulates the degree of interference at the global (mean) or local (single item) level of the ensemble. Initial results were consistent with reciprocal interference between global and local ensemble processing. However, further testing revealed that local interference effects were better explained by interference from another summary statistic, the range of the set. Furthermore, participants were unable to disambiguate single items from the ensemble display from other items that were within the ensemble range but, critically, were not actually present in the ensemble. Thus, it appears that local item values are likely inferred based on their relationship to higher-order summary statistics such as the range and the mean. These results conflict with claims that local information is captured alongside global information in summary representations. In such studies, successful identification of set members was not compared with misidentification of items within the range, but which were nevertheless not presented within the set.

20.
J Exp Psychol Hum Percept Perform ; 47(5): 648-661, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33719468

RESUMEN

The process by which multiple items within an object grouping are rapidly summarized along a given visual dimension into a single mean value (i.e., perceptual averaging) has increasingly been shown to interact dynamically with visual working memory (VWM). Commonly, this interaction is studied with respect to the influence of perceptual averaging over VWM, but it is also the case that VWM can support perceptual averaging. Here, we argue that, in the presence of memory-matching elements, VWM exerts an obligatory influence over perceptual averaging even when it is detrimental to do so. Over four experiments, we tested our hypothesis by having individuals perform a mean orientation estimation task while concurrently maintaining a colored object in VWM. We anticipated that mean orientation reports would be attracted to the local mean of memory-matching items if such items are prioritized in perceptual average judgments. This was indeed the case as we observed a persistent bias in mean orientation judgments toward the subset mean of items matching the VWM item color, despite color being entirely irrelevant to the mean orientation task. Our results thus highlight a goal-invariant influence of VWM over perceptual averaging, which we attribute to amplification through memory-driven selection. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Asunto(s)
Juicio , Memoria a Corto Plazo , Humanos , Motivación , Percepción Visual
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