How to construct liquid-crystal spectacles to control vision of real-world objects and environments.

A major challenge in studying naturalistic vision lies in controlling stimulus and scene viewing time. This is especially the case for studies using real-world objects as stimuli (rather than computerized images) because real objects cannot be "onset" and "offset" in the same way that images can be. Since the late 1980s, one solution to this problem has been to have the observer wear electro-optic spectacles with computer-controlled liquid-crystal lenses that switch between transparent ("open") and translucent ("closed") states.

Using High-Density Electroencephalography to Explore Spatiotemporal Representations of Object Categories in Visual Cortex.

Visual object perception involves neural processes that unfold over time and recruit multiple regions of the brain. Here, we use high-density EEG to investigate the spatiotemporal representations of object categories across the dorsal and ventral pathways. In , human participants were presented with images from two animate object categories (birds and insects) and two inanimate categories (tools and graspable objects).

Graspability Modulates the Stronger Neural Signature of Motor Preparation for Real Objects vs. Pictures.

The cognitive and neural bases of visual perception are typically studied using pictures rather than real-world stimuli. Unlike pictures, real objects are actionable solids that can be manipulated with the hands. Recent evidence from human brain imaging suggests that neural responses to real objects differ from responses to pictures; however, little is known about the neural mechanisms that drive these differences.

The Treachery of Images: How Realism Influences Brain and Behavior.

Although the cognitive sciences aim to ultimately understand behavior and brain function in the real world, for historical and practical reasons, the field has relied heavily on artificial stimuli, typically pictures. We review a growing body of evidence that both behavior and brain function differ between image proxies and real, tangible objects. We also propose a new framework for immersive neuroscience to combine two approaches: (i) the traditional build-up approach of gradually combining simplified stimuli, tasks, and processes; and (ii) a newer tear-down approach that begins with reality and compelling simulations such as virtual reality to determine which elements critically affect behavior and brain processing.

What Does Dorsal Cortex Contribute to Perception?

According to the influential "Two Visual Pathways" hypothesis, the cortical visual system is segregated into two pathways, with the ventral, occipitotemporal pathway subserving object perception, and the dorsal, occipitoparietal pathway subserving the visuomotor control of action. However, growing evidence suggests that the dorsal pathway also plays a functional role in object perception. In the current article, we present evidence that the dorsal pathway contributes uniquely to the perception of a range of visuospatial attributes that are not redundant with representations in ventral cortex.

Object responses are highly malleable, rather than invariant, with changes in object appearance.

Theoretical frameworks of human vision argue that object responses remain stable, or 'invariant', despite changes in viewing conditions that can alter object appearance but not identity. Here, in a major departure from previous approaches that have relied on two-dimensional (2-D) images to study object processing, we demonstrate that changes in an object's appearance, but not its identity, can lead to striking shifts in behavioral responses to objects. We used inverse multidimensional scaling (MDS) to measure the extent to which arrangements of objects in a sorting task were similar or different when the stimuli were displayed as scaled 2-D images, three-dimensional (3-D) augmented reality (AR) projections, or real-world solids.

How the brain represents mass.

New fMRI experiments and machine learning are helping to identify how the mass of objects is processed in the brain.

Methods for Presenting Real-world Objects Under Controlled Laboratory Conditions.

Our knowledge of human object vision is based almost exclusively on studies in which the stimuli are presented in the form of computerized two-dimensional (2-D) images. In everyday life, however, humans interact predominantly with real-world solid objects, not images. Currently, we know very little about whether images of objects trigger similar behavioral or neural processes as do real-world exemplars.

Dataset of 24-subject EEG recordings during viewing of real-world objects and planar images of the same items.

Here we present a collection of electroencephalographic (EEG) data recorded from 24 observers (14 females, 10 males, mean age: 25.4) while observing individually-presented stimuli comprised of 96 real-world objects, and 96 images of the same items printed in high-resolution. EEG was recorded from 128 scalp channels.

Real-world size coding of solid objects, but not 2-D or 3-D images, in visual agnosia patients with bilateral ventral lesions.

Patients with visual agnosia show severe deficits in recognizing two-dimensional (2-D) images of objects, despite the fact that early visual processes such as figure-ground segmentation, and stereopsis, are largely intact. Strikingly, however, these patients can nevertheless show a preservation in their ability to recognize real-world objects -a phenomenon known as the 'real-object advantage' (ROA) in agnosia. To uncover the mechanisms that support the ROA, patients were asked to identify objects whose size was congruent or incongruent with typical real-world size, presented in different display formats (real objects, 2-D and 3-D images).

Distinct visuo-motor brain dynamics for real-world objects versus planar images.

Ultimately, we aim to generalize and translate scientific knowledge to the real world, yet current understanding of human visual perception is based predominantly on studies of two-dimensional (2-D) images. Recent cognitive-behavioral evidence shows that real objects are processed differently to images, although the neural processes that underlie these differences are unknown. Because real objects (unlike images) afford actions, they may trigger stronger or more prolonged activation in neural populations for visuo-motor action planning.

Preserved Object Weight Processing after Bilateral Lateral Occipital Complex Lesions.

Object interaction requires knowledge of the weight of an object, as well as its shape. The lateral occipital complex (LOC), an area within the ventral visual pathway, is well known to be critically involved in processing visual shape information. Recently, however, LOC has also been implicated in coding object weight before grasping-a result that is surprising because weight is a nonvisual object property that is more relevant for motor interaction than visual perception.

Towards a unified perspective of object shape and motion processing in human dorsal cortex.

Although object-related areas were discovered in human parietal cortex a decade ago, surprisingly little is known about the nature and purpose of these representations, and how they differ from those in the ventral processing stream. In this article, we review evidence for the unique contribution of object areas of dorsal cortex to three-dimensional (3-D) shape representation, the localization of objects in space, and in guiding reaching and grasping actions. We also highlight the role of dorsal cortex in form-motion interaction and spatiotemporal integration, possible functional relationships between 3-D shape and motion processing, and how these processes operate together in the service of supporting goal-directed actions with objects.

The real deal: Willingness-to-pay and satiety expectations are greater for real foods versus their images.

Laboratory studies of human dietary choice have relied on computerized two-dimensional (2D) images as stimuli, whereas in everyday life, consumers make decisions in the context of real foods that have actual caloric content and afford grasping and consumption. Surprisingly, few studies have compared whether real foods are valued more than 2D images of foods, and in the studies that have, differences in the stimuli and testing conditions could have resulted in inflated bids for the real foods. Moreover, although the caloric content of food images has been shown to influence valuation, no studies to date have investigated whether 'real food exposure effects' on valuation reflect greater sensitivity to the caloric content of real foods versus images.

Graspable Objects Grab Attention More Than Images Do.

The opportunity an object presents for action is known as an affordance. A basic assumption in previous research was that images of objects, which do not afford physical action, elicit effects on attention and behavior comparable with those of real-world tangible objects. Using a flanker task, we compared interference effects between real graspable objects and matched 2-D or 3-D images of the items.

What Role Does "Elongation" Play in "Tool-Specific" Activation and Connectivity in the Dorsal and Ventral Visual Streams?

Images of tools induce stronger activation than images of nontools in a left-lateralized network that includes ventral-stream areas implicated in tool identification and dorsal-stream areas implicated in tool manipulation. Importantly, however, graspable tools tend to be elongated rather than stubby, and so the tool-selective responses in some of these areas may, to some extent, reflect sensitivity to elongation rather than "toolness" per se. Using functional magnetic resonance imaging, we investigated the role of elongation in driving tool-specific activation in the 2 streams and their interconnections.

Action properties of object images facilitate visual search.

There is mounting evidence that constraints from action can influence the early stages of object selection, even in the absence of any explicit preparation for action. Here, we examined whether action properties of images can influence visual search, and whether such effects were modulated by hand preference. Observers searched for an oddball target among 3 distractors.

Attentional capture for tool images is driven by the head end of the tool, not the handle.

Tools afford specialized actions that are tied closely to object identity. Although there is mounting evidence that functional objects, such as tools, capture visuospatial attention relative to non-tool competitors, this leaves open the question of which part of a tool drives attentional capture. We used a modified version of the Posner cueing task to determine whether attention is oriented towards the head versus the handle of realistic images of common elongated tools.

Priming tool actions: Are real objects more effective primes than pictures?

Humans are faster to grasp an object such as a tool if they have previewed the same object beforehand. This priming effect is strongest when actors gesture the use of the tool rather than simply move it, possibly because the previewed tool activates action-specific routines in dorsal-stream motor networks. Here, we examined whether real tools, which observers could physically act upon, serve as more potent primes than two-dimensional images of tools, which do not afford physical action.

Contribution of Bodily and Gravitational Orientation Cues to Face and Letter Recognition.

Sensory information provided by the vestibular system is crucial in cognitive processes such as the ability to recognize objects. The orientation at which objects are most easily recognized--the perceptual upright (PU)--is influenced by body orientation with respect to gravity as detected from the somatosensory and vestibular systems. To date, the influence of these sensory cues on the PU has been measured using a letter recognition task.

Preserved Haptic Shape Processing after Bilateral LOC Lesions.

Unlabelled: The visual and haptic perceptual systems are understood to share a common neural representation of object shape. A region thought to be critical for recognizing visual and haptic shape information is the lateral occipital complex (LOC). We investigated whether LOC is essential for haptic shape recognition in humans by studying behavioral responses and brain activation for haptically explored objects in a patient (M.

Real-world objects are more memorable than photographs of objects.

Research studies in psychology typically use two-dimensional (2D) images of objects as proxies for real-world three-dimensional (3D) stimuli. There are, however, a number of important differences between real objects and images that could influence cognition and behavior. Although human memory has been studied extensively, only a handful of studies have used real objects in the context of memory and virtually none have directly compared memory for real objects vs.

Are visual texture-selective areas recruited during haptic texture discrimination?

Shape and texture provide cues to object identity, both when objects are explored using vision and via touch (haptics). Visual shape information is processed within the lateral occipital complex (LOC), while texture is processed in medial regions of the collateral sulcus (CoS). Evidence indicates that the LOC is recruited during both visual and haptic shape processing.