Nontarget objects can influence perceptual processes during object recognition

Previous experiments have shown that objects are recognized more readily in a semantically consistent visual context. However, the benefit from context could be explained by response bias, and may not reflect the influence of context on the perceptual processes of recognition. We conducted a six-alternative forced-choice experiment to measure semantic and perceptual errors. A target object appeared briefly, surrounded by four context objects. The target was more accurately identified when the context consisted of objects semantically related to the target. The large number of semantic errors, which increased when the context presentation preceded the target, showed that response bias did account for a proportion of the context effect. Nevertheless, significant facilitation was still present after a bias correction. Recognition of an object can be affected by context not only when it is embedded in a coherent naturalistic scene, but also when it is simply near other related objects. Materials associated with this article may be accessed at www.psychonomic.org/archive.     

Viewpoint dependence in visual and haptic object recognition

On the whole, people recognize objects best when they see the objects from a familiar view and worse when they see the objects from views that were previously occluded from sight. Unexpectedly, we found haptic object recognition to be viewpoint-specific as well, even though hand movements were unrestricted. This viewpoint dependence was due to the hands preferring the back "view" of the objects. Furthermore, when the sensory modalities (visual vs. haptic) differed between learning an object and recognizing it, recognition performance was best when the objects were rotated back-to-front between learning and recognition. Our data indicate that the visual system recognizes the front view of objects best, whereas the hand recognizes objects best from the back.     

The effects of temporal delay and orientation on haptic object recognition

We examined the effects of interstimulus interval (ISI) and orientation changes on the haptic recognition of novel objects, using a sequential shape-matching task. The stimuli consisted of 36 wedge-shaped plastic objects that varied along two shape dimensions (hole/bump and dip/ridge). Two objects were presented at either the same orientation or a different orientation, separated by either a short (3-sec) ISI or a long (15-sec) ISI. In separate conditions, ISI was blocked or randomly intermixed. Participants ignored orientation changes and matched on shape alone. Although performance was better in the mixed condition, there were no other differences between conditions. There was no decline in performance at the long ISI. There were similar, marginally significant benefits to same-orientation matching for short and long ISIs. The results suggest that the perceptual object representations activated from haptic inputs are both stable, being maintained for at least 15 sec, and orientation sensitive.     

Perceived arm posture and remote haptic perception of whether an object can be stepped over

The authors investigated whether the perceived posture of the arm plus a hand-held object influences remote haptic perception of whether an object can be stepped over. Blindfolded participants (N = 20) determined whether they could step over bars at different heights by exploring the bars with a T-shaped rod. The rod was weighted so that the perceived posture of the arm-plus-rod was shifted up, down, or left unchanged. Both the leg length of the participant and the perceived posture of the arm-plus-rod systematically influenced perception of whether the bar could be stepped over. The results highlight the role of perceived posture of the arm-plus-rod in remote haptic perception and have potential implications for the design of navigation aids for the visually impaired.     

Stages of manual exploration in haptic object identification

In a yes/no identification task using touch alone, subjects indicated whether an object belonged to a named category. Previously, we found that subjects explored in two stages—first grasping and lifting the object, then executing further exploratory procedures (Lederman & Klatzky, 1990b). We proposed that Stage 1 (grasp/lift) was sufficient to extract coarse information about multiple object properties, whereas Stage 2 was directed toward precise information about particularly diagnostic properties. the current study, subjects were initially constrained to grasping and lifting, after which they could explore further. Accuracy was above chance after Stage 1, confirming our assumption that the grasp/lift combination was broadly useful. Stage 2 increased accuracy and confidence. It primarily elicited exploratory procedures associated with object geometry, but exploration was also influenced by diagnostic object properties.     

Does emotion influence visual perception? Depends on how you look at it

ABSTRACT

One of the biggest challenges in the study of emotion–cognition interaction is addressing the question of whether and how emotions influence processes of perception as distinct from other higher-level cognitive processes. Most theories of emotion agree that an emotion episode begins with a sensory experience – such as a visual percept – that elicits a cascade of affective, cognitive, physiological, and/or behavioural responses (the ordering and inclusion of those latter components being forever debated). However, for decades, a subset of philosophers and scientists have suggested that the presumed perception → emotion relationship is in fact bidirectional, with emotion also altering the perceptual process. In the present review we reflect on the history and empirical support (or, some might argue, lack thereof) for the notion that emotion influences visual perception. We examine ways in which researchers have attempted to test the question, and the ways in which this pursuit is so difficult. As is the case with the ongoing debate about the cognitive penetrability of perception, we conclude that nothing is conclusive in the debate about the emotional penetrability of perception. We nonetheless don rose-coloured glasses as we look forward to the future of this research topic.     

The neural basis of haptic object processing.

We review the organization of the neural networks that underlie haptic object processing and compare that organization with the visual system. Haptic object processing is separated into at least two neural pathways, one for geometric properties or shape, and one for material properties, including texture. Like vision, haptic processing pathways are organized into a hierarchy of processing stages, with different stages represented by different brain areas. In addition, the haptic pathway for shape processing may be further subdivided into different streams for action and perception. These streams may be analogous to the action and perception streams of the visual system and represent two points of neural convergence for vision and haptics.     

Now you see it,now you don't: The context dependent nature of category-effects in visual object recognition

In two experiments, we test predictions regarding processing advantages/disadvantages for natural objects and artefacts in visual object recognition. Varying three important parameters—degree of perceptual differentiation, stimulus format, and stimulus exposure duration—we show how different category-effects can be provoked in normal subjects on the same task. We interpret the results in light of the Pre-semantic Account of Category Effects (PACE; Gerlach, 2009), and conclude that category-effects do not reflect absolute processing differences between categories. Rather, category-effects are products of common operations which are differentially affected by the structural similarity among objects (with natural objects being more structurally similar than artefacts). The potentially most important aspect of the present study is the demonstration that category-effects are very context dependent; an aspect which has been neglected in earlier literature on category-specificity. PACE provides a useful framework in this respect, as it specifies how category-effects are influenced by changes in task and stimulus characteristics.     

Imagined haptic exploration in judgments of object properties

In Experiment 1, each subject rated a single, named object for its roughness, hardness, temperature, weight, size, or shape. In Experiment 2, each subject compared one pair of objects along the same dimensions. In both studies, a substantial proportion of subjects who judged the first four dimensions imagined a hand making exploratory movements appropriate for the designated information. The proportion of hand-exploration images decreased substantially when judging size or shape, or when judgments could be made readily through general semantic knowledge. The results suggest that the incorporation of haptic exploration into visual imagery provides access to information about haptically accessible object properties.     

The influence of surface and edge-based visual similarity on object recognition

The role of 'visual similarity' has been emphasised in object recognition and in particular, for category-specific agnosias. [Laws and Gale, 2002] recently described a measure of pixel-level visual overlap for line drawings (Euclidean Overlap: EO[line]) that distinguished living and nonliving things and predicted normal naming errors and latencies ( [Laws et al., 2002]). Nevertheless, it is important to extend such analyses to stimuli other than line drawings. We therefore developed the same measure for greyscale versions of the same stimuli (EO[grey]), i.e., that contain shading and texture information. EO[grey], however, failed to differentiate living from nonliving things and failed to correlate with naming latencies to the greyscale images. By contrast, EO[line] did correlate with the naming latencies. This suggests that similarity of edge information is more influential than similarity of surface characteristics for naming and for categorically separating living and nonliving things (be they line drawings or greyscale images).     

Modulatory influence of dopamine receptors on consolidation of object recognition memory

The role of dopamine receptors in regulating the formation of recognition memory remains poorly understood. Here we show the effects of systemic administration of dopamine receptor agonists and antagonists on the formation of memory for novel object recognition in rats. In Experiment I, rats received an intraperitoneal (i.p.) injection of vehicle, the selective D1 receptor agonist SKF38393 (1.0 and 5.0mg/kg), or the D2 receptor agonist quinpirole (1.0 and 5.0mg/kg) immediately after training. In Experiment II, rats received an injection of vehicle, the dopamine receptor antagonist SCH23390 (0.1 and 0.05 mg/kg), or the D2 receptor antagonist raclopride (0.5 and 0.1mg/kg) before training, followed by an injection of vehicle or the nonselective dopamine receptor agonist apomorphine (0.05 mg/kg) immediately after training. SKF38393 at 5mg/kg produced an enhancement of novel object recognition memory measured at both 24 and 72 h after training, whereas the dose of 10mg/kg impaired 24-h retention. Posttraining administration of quinpirole did not affect 24-h retention. Apomorphine enhanced memory in rats given pretraining raclopride, suggesting that the effect was mediated by selective activation of D1 receptors. The results indicate that activation of D1 receptors can enhance recognition memory consolidation. Importantly, pharmacological activation of D1 receptors enhanced novel object recognition memory even under conditions in which control rats showed significant retention.     

Stages of manual exploration in haptic object identification.

In a yes/no identification task using touch alone, subjects indicated whether an object belonged to a named category. Previously, we found that subjects explored in two stages--first grasping and lifting the object, then executing further exploratory procedures (Lederman & Klatzky, 1990b). We proposed that Stage 1 (grasp/lift) was sufficient to extract coarse information about multiple object properties, whereas Stage 2 was directed toward precise information about particularly diagnostic properties. In the current study, subjects were initially constrained to grasping and lifting, after which they could explore further. Accuracy was above chance after Stage 1, confirming our assumption that the grasp/lift combination was broadly useful. Stage 2 increased accuracy and confidence. It primarily elicited exploratory procedures associated with object geometry, but exploration was also influenced by diagnostic object properties.     

An illusion you can sink your teeth into: haptic cues modulate the perceived freshness and crispness of pretzels

Eating is a multisensory experience involving more than simply the oral sensation of the taste and smell of foods. It has been shown that the way foods look, sound, and feel like in the mouth all affect food perception. The influence of haptic information available when handling food is relatively unknown. In this study, blindfolded participants bit-into fresh or stale pretzels while rating their freshness staleness and crispness-softness. Information provided to the hand was either congruent (whole pretzel fresh or stale) or incongruent (half pretzel fresh, half stale) with what was presented to the mouth. The results demonstrate that the perception of both freshness and crispness was systematically altered when incongruent information was provided: bit-into fresh pretzel tips were perceived as staler and softer when a stale pretzel tip was held in the hand and vice versa. Haptic information available when handling food thus plays a significant role in modulating food perception.     

The visual and haptic perception of natural object shape

In this study, we evaluated observers' ability to compare naturally shaped three-dimensional (3-D) objects, using their senses of vision and touch. In one experiment, the observers haptically manipulated 1 object and then indicated which of 12 visible objects possessed the same shape. In the second experiment, pairs of objects were presented, and the observers indicated whether their 3-D shape was the same or different. The 2 objects were presented either unimodally (vision-vision or haptic-haptic) or cross-modally (vision-haptic or haptic-vision). In both experiments, the observers were able to compare 3-D shape across modalities with reasonably high levels of accuracy. In Experiment 1, for example, the observers' matching performance rose to 72% correct (chance performance was 8.3%) after five experimental sessions. In Experiment 2, small (but significant) differences in performance were obtained between the unimodal vision-vision condition and the two cross-modal conditions. Taken together, the results suggest that vision and touch have functionally overlapping, but not necessarily equivalent, representations of 3-D shape.     

Infants' haptic perception of object unity in rotating displays

Four-month-old infants were allowed to manipulate, without vision, two rings attached to a bar that permitted each ring to undergo rotary motion against a fixed surface. In different conditions, the relative motions of the rings were rigid, independent, or opposite, and they circled either the same fixed point outside the zone of manipulation or spatially separated points. Infants' perception of the ring assemblies were affected by the nature of the rotary motion in two ways. First, infants perceived a unitary object when the felt ends of the object underwent a common, rigid rotary motion; perception of object unity was stronger in this condition than when the ends underwent either independent or opposite rotary motions. Second, infants perceived two distinct objects when the felt ends of the objects underwent independent rotary motions that centred on distinct fixed points. Perception of the distinctness of the objects was less clear when the ends underwent opposite or independent rotary motions that centred on a common fixed point. These findings provide the first evidence that infants are sensitive to rotary motion patterns and can extrapolate a global pattern of rigid motion from the distinct, local velocities that they produce and experience at their two hands.     

The influence of action perception on object recognition: a developmental study

Two experiments explored the existence and the development of relations between action representations and object representations. A priming paradigm was used in which participants viewed an action pantomime followed by the picture of a tool, the tool being either associated or unassociated with the preceding action. Overall, we observed that the perception of an action pantomime can facilitate the recognition of a corresponding tool. Experiment 1 was based on a naming task and was conducted with 9- to 12-year-old children and a group of young adults. While substantial priming effects were obtained for all age groups, they were especially important for the youngest participants. Smaller priming effects were obtained in Experiment 2, using a categorization task and conducted on 5- to 11-year-old children and young adults, but again the results suggest that these action priming effects diminish with increasing age. Implications of these results for the organization and development of conceptual knowledge are discussed.     

Odorization of a novel object can influence infant's exploratory behavior in unexpected ways

Although much is known about the development of object exploration during infancy, it remains to be understood whether and how olfaction can influence infants' interactions with novel objects. To address these issues, sixteen infants aged 7-15 months were videotaped during two consecutive 5-min free play sessions with a scented or an unscented version of visually similar objects. Results indicate that adding an odor to a novel object influenced the infants' behavior: the infants exhibited more and longer manipulations and mouthing of the unscented object than of the scented object. The differential responsiveness to the scented, relative to the unscented, object was noted after a 2-min delay following test onset, suggesting that in the present conditions infants do not immediately detect or react to the added odor. It may be concluded that infants do detect an odorant added on a novel object, show odor-based discrimination of visually similar objects, and express withdrawal of the scented, relative to the unscented, object. The implications of these findings for understanding how infants use their senses, namely their olfactory sense, in early exploratory behavior are discussed.