Jacqueline C. Snow

• PhD / MPsych (Clinical Neuropsychology). University of Melbourne, Australia.
• Professor at University of Nevada, Reno

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 t...

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 ph...

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...

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....

Egocentric distance and real-world size are important cues for object perception and action. Nevertheless, most studies of human vision rely on two-dimensional pictorial stimuli that convey ambiguous distance and size information. Here, we use fMRI to test whether pictures are represented differently in the human brain from real, tangible objects t...

In experimental psychology and neuroscience, computerized image stimuli are typically used as artificial proxies for real-world objects to understand brain and behavior. Here, in a series of five experiments (n = 165), we studied human memory for objects presented as tangible solids versus computerized images. We found that recall for solids was su...

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 proble...

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...

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, littl...

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 play...

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

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. Six additional external electrod...

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...

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-dimensiona...

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...

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 t...

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 targe...

Hundreds of functional magnetic resonance imaging (fMRI) experiments have revealed the neural substrates of object processing using photos of objects. Here we used univariate and multivariate pattern analysis (MVPA) of fMRI responses to determine whether photos are represented similarly to real objects in the human brain. The stimuli were everyday...

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...

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, whic...

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 behavior...

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, th...

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...

Patients with visual form agnosia have difficulty recognizing pictures of objects but can show improved recognition for real-world exemplars – a phenomenon known as the 'Real Object Advantage'. For most everyday objects, visual size corresponds to real-world size, whereas in standard pictorial tests of object recognition stimuli can often be orders...

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...

Images of tools induce stronger activation than images of non-tool objects in a left-lateralized network of areas including the superior parietal lobe (SPL) and posterior medial temporal gyrus (pMTG). Importantly, however, graspable tools tend to be elongated rather than stubby, and so the tool-selective responses in these areas may reflect sensiti...

Humans typically rely upon vision to identify object shape, but we can also recognize shape via touch (haptics). Our haptic shape recognition ability raises an intriguing question: To what extent do visual cortical shape recognition mechanisms support haptic object recognition? We addressed this question using a haptic fMRI repetition design, which...

Past work from our lab found that participants are faster to use a real tool if they have been primed by a visual preview of that same real tool compared to a different real tool (Valyear et al., 2011, Exp Brain Res). Moreover the priming effect was larger when the task was to use the tool – which requires associating the visual form of the tool wi...

We investigated whether pictures of tools prime action as well as real tools. Participants previewed a tool or a photo of a tool and then performed a “grasp-to-move” (GTM) or “grasp-to-use” (GTU) action. The identity of prime and probe could be the same (congruent trials) or different (incongruent trials). Participants responded faster for congru...

The Judd variant of the Muller-Lyer figure consists of a horizontal shaft with an arrowhead at each end; one pointing inward with respect to the shaft (forming the "head" end) and the other pointing outward (forming the "tail"). The arrowhead inducers produce a visual illusion that consists of a displacement of the perceived midpoint towards the "t...

Accurate recognition of gender in another individual is integral to successful human social interaction and to mate selection. When we encounter another person, we are effortlessly able to identify their gender, most often through the information conveyed by their facial features. Faces comprise the most abundantly encountered cue used to classify...

The human ventral visual pathway represents object shape, color and category, but the degree to which shape and color are dissociable in occipito-temporal cortex is unknown. We examined color sensitivity in shape-sensitive visual cortex and shape-sensitivity in color-sensitive visual cortex. Shape-sensitivity was measured via fMRI-adaptation (fMR-A...

Facial features provide salient cues about the gender of another individual – information that is critical for human social interaction and mate selection. Although much is known about the neural representation of face and body information in ventral temporal cortex, surprisingly little is known about the neural circuitry supporting the recognition...

The orientation at which objects are most easily recognized — the perceptual upright (PU) — is influenced by body orientation with respect to gravity. To date, the influence of these cues on object recognition has only been measured within the visual system. Here we investigate whether objects explored through touch alone are similarly influenced b...

Our understanding of the neural underpinnings of perception is largely built upon studies employing 2-dimensional (2D) planar images. Here we used slow event-related functional imaging in humans to examine whether neural populations show a characteristic repetition-related change in haemodynamic response for real-world 3-dimensional (3D) objects, a...

Supplementary Table 1

Our understanding of the neural underpinnings of perception is largely built upon studies that have employed 2-dimensional (2D) planar images. When viewing a sequence of two 2D pictures of objects, a change in objects produces a characteristic release from adaptation within ventral visual object-selective areas. Here we use functional brain imaging...

The parietal cortex is considered to be part of a network of brain areas that modulates competitive interactions between targets and irrelevant distracters in early visual cortex, however there is currently little causal evidence to support this in human observers. It is also unclear as to whether parietal influences on visual perception in humans...

We examined the contributions of the human pulvinar to goal directed selection of visual targets in 3 patients with chronic, unilateral lesions involving topographic maps in the ventral pulvinar. Observers completed 2 psychophysical tasks in which they discriminated the orientation of a lateralized target grating in the presence of vertically-align...

In healthy individuals, filtering of distractors improves when the perceptual difficulty, or load, of a central task increases. Following an earlier study by Lavie and Robertson (2001), this study examined whether increasing the perceptual load of a visual discrimination task attenuates the influence of ipsilesional and contralesional distractors i...

In this review we address the question of whether selective attentional mechanisms within the ipsilesional field are intact in unilateral lesion patients with spatial neglect and extinction. We consider how a lesion-induced bias in the neural representation of salience critically disrupts the integration of goal-driven and stimulus-driven prioritiz...

Unconscious perception involves the processing of sensory information by the brain in the absence of subjective awareness. The physical properties of sensory stimuli, their meaning, and their emotional significance, may all be perceived unconsciously.

Patients with right hemisphere (RH) lesions often display a spatial bias in attention towards the ipsilesional hemifield. The behavioural manifestations of this spatial bias are typically interpreted as reflecting increased or enhanced attention for stimuli within the 'intact' ipsilesional field, and impaired attentional functioning within the cont...