Segregation by color and stereoscopic depth in three-dimensional visual space

Two experiments were conducted to investigate how color and stereoscopic depth information are used to segregate objects for visual search in three-dimensional (3-D) visual space. Eight observers were asked to indicate the alphanumeric category (letter or digit) of the target which had its unique color and unique depth plane. In Experiment 1, distractors sharing a common depth plane or a common color appeared in spatial contiguity in thexy plane. The results suggest that visual search for the target involves examination of kernels formed by homogeneous items sharing the same color and depth. In Experiment 2, thexy contiguity of distractors sharing a common color or a common depth plane was varied. The results showed that when target-distractor distinction becomes more difficult on one dimension, the other dimension becomes more important in performing visual search, as indicated by a larger effect on search time. This suggests that observers can make optimal use of the information available. Finally, color had a larger effect on search time than did stereoscopic depth. Overall, the results support models of visual processing which maintain that perceptual segregation and selective attention are determined by similarity among objects in 3-D visual space on both spatial and nonspatial stimulus dimensions.     

Apparent Distortions in Photography and the Geometry of Visual Space

In this paper I contrast the geometric structure of phenomenal visual space with that of photographic images. I argue that topologically both are two-dimensional and that both involve central projections of scenes being depicted. However, I also argue that the metric structures of the spaces differ inasmuch as two types of “apparent distortions”—marginal distortion in wide-angle photography and close-up distortions—which occur in photography do not occur in the corresponding visual experiences. In particular, I argue that the absence of marginal distortions in vision is evidence for a holistic metric of visual space that is spherical, and that the absence of close-up distortions shows that the local metric structure possesses a dynamic variable curvature which is dependent upon the distance away of objects being viewed at a given time.     

Alleys in visual space

Geometry of frameless visual space is dealt with. First, parallel and equidistant alleys, horopters in the horizontal plane of eyes' level are discussed within the framework of the Luneburg's model that the frameless visual space is a Riemannian space of constant curvature. That basic postulate and the specific mapping functions assumed by Luneburg between the euclidean map of visual space and the physical space are kept separate, and efforts are directed to make the model applicable to more natural conditions of our visual space. A possibility is pointed out to remove the constraint “frameless” in the sense that perceptual geometrical properties are primarily determined by the convergence of optic axes. So far, only alleys in the horizontal plane extending from us toward infinity have been studied, but more often we perceive parallel lines, horizontal or vertical, in front of us like shelves of a bookcase. Hence, equations are derived for horopter plane appearing fronto-parallel in the three-dimensional visual space and alleys running horizontally or vertically on the horopter plane. It is shown that parallel and equidistant alleys are not the same in the horopter plane as in the horizontal plane, if the visual space is not euclidean. A method to evaluate the discrepancy between the two alleys without using any mapping functions is stated with some numerical examples.     

A physicalist reinterpretion of ‘phenomenal’ spaces

This paper argues that phenomenal or internal metrical spaces are redundant posits. It is shown that we need not posit an internal space-time frame, as the physical space-time suffices to explain geometrical perception, memory and planning. More than the internal space-time frame, the idea of a phenomenal colour space has lent credibility to the idea of internal spaces. It is argued that there is no phenomenal colour space that underlies the various psychophysical colour spaces; it is parasitic upon physical and psychophysical colour spaces. The argumentation is further extended to other sensory spaces and generalised quality spaces.     

Visual space as physical geometry

The geometrical incongruence between patterns in visual space and structures and patterns of activity in the visual cortex, long known to investigators, serves as a criterion for evaluating physical theories of visual space. The problem of determining the geometry of the visual world (visual geometry) is compared with that of determining the geometry of the physical world (physical geometry). Theories as to the possible physical locus of visual space, whether in the brain or elsewhere, are reviewed, analyzed, and criticized accordingly. It is concluded that on the basis of congruence alone it would be predicted that visual space is not to be found in the brain, even though it is seemingly linked to it causally, as experimental neurology and neurophysiology demonstrate. Alternative theories as to the nature of visual space are considered, but are also found to be inadequate in explaining visual space in terms acceptable to contemporary science.     

特征整合与加工深度对道德概念容器隐喻联结的影响

提出了隐喻提取假说将隐喻联结的形成和提取进行分离, 并通过3个实验探究了道德概念与容器空间的隐喻联结及其受知觉加工深度和特征整合程度的影响。实验1采用空间Stroop范式, 实验2a和实验2b均采用启动范式, 实验3a和实验3b均采用加入任务要求的Stroop范式。结果发现：(1)在经典Stroop范式中未发现道德概念与容器空间的隐喻联结; (2)在启动范式中发现, 较深知觉加工深度下道德概念与容器空间存在较弱的隐喻联结; (3)在较高特征整合程度的Stroop任务中, 道德概念与容器空间存在较强的隐喻联结。结果表明：道德概念与容器空间存在道德为内、不道德为外的隐喻联结, 这种隐喻联结在映射上表现为双向性, 并且受到特征整合程度和知觉加工深度的影响, 同时也为隐喻提取假说提供了证据支持。     

Visual span of detection and recognition of a kanji character embedded in a horizontal row of random hiragana characters

Two experiments were conducted to determine the visual span of detection and recognition of the kanji character embedded in a horizontal row of random hiragana characters. An independent variable was the visual complexity of the kanji characters: simple and complex. In Experiment 1, visual spans of detection were determined by a staircase method. Values of visual spans were more than 15 character spaces for the complex kanji characters, and ranged from 4 to 10 character spaces (mean 7.6) for the simple kanji characters. In Experiment 2, visual spans of recognition were determined by an ascending series of limits method. Values of visual spans ranged from 0 to 4 character spaces (mean 2.3) for the complex kanji characters and from 3 to 7 character spaces (mean 4.8) for the simple kanji characters. These results are discussed in relation to reading of Japanese kanji-kana mixed texts.     

What do graded effects of semantic transparency reveal about morphological processing?

We examined the influence of semantic transparency on morphological facilitation in English in three lexical decision experiments. Decision latencies to visual targets (e.g., CASUALNESS) were faster after semantically transparent (e.g., CASUALLY) than semantically opaque (e.g., CASUALTY) primes whether primes were auditory and presented immediately before onset of the target (Experiment 1a) or visual with an stimulus onset asynchrony (SOA) of 250 ms (Experiment 1b). Latencies did not differ at an SOA of 48 ms (Experiment 2) or with a forward mask at an SOA of 83 ms (Experiment 3). Generally, effects of semantic transparency among morphological relatives were evident at long but not at short SOAs with visual targets, regardless of prime modality. Moreover, the difference in facilitation after opaque and transparent primes was graded and increased with family size of the base morpheme.     

Is this a dax which I see before me? Use of the logical argument disjunctive syllogism supports word-learning in children and adults

Many authors have argued that word-learning constraints help guide a word-learner's hypotheses as to the meaning of a newly heard word. One such class of constraints derives from the observation that word-learners of all ages prefer to map novel labels to novel objects in situations of referential ambiguity. In this paper I use eye-tracking to document the mental computations that support this word-learning strategy. Adults and preschoolers saw images of known and novel objects, and were asked to find the referent of known and novel labels. Experiment 1 shows that adults systematically reject a known distractor (e.g. brush) before mapping a novel label (e.g. "dax") to a novel object. This is consistent with the proposal that participants worked through a Disjunctive Syllogism (i.e. Process-of-Elimination) to motivate the mapping of the novel label to the novel object. Experiment 2 shows that processing is similar for adults performing an implicit Disjunctive Syllogism (e.g. "the winner is the dax") and an explicit Disjunctive Syllogism (e.g. "the winner is not the iron"). Experiment 3 reveals that similar processes govern preschoolers' mapping of novel labels. Taken together, these results suggest that word-learners use Disjunctive Syllogism to motivate the mapping of novel labels to novel objects.     

Bouncing a ball: tuning into dynamic stability

Rhythmically bouncing a ball with a racket was investigated and modeled with a nonlinear map. Model analyses provided a variable defining a dynamically stable solution that obviates computationally expensive corrections. Three experiments evaluated whether dynamic stability is optimized and what perceptual support is necessary for stable behavior. Two hypotheses were tested: (a) Performance is stable if racket acceleration is negative at impact, and (b) variability is lowest at an impact acceleration between -4 and -1 m/s2. In Experiment 1 participants performed the task, eyes open or closed, bouncing a ball confined to a 1-dimensional trajectory. Experiment 2 eliminated constraints on racket and ball trajectory. Experiment 3 excluded visual or haptic information. Movements were performed with negative racket accelerations in the range of highest stability. Performance with eyes closed was more variable, leaving acceleration unaffected. With haptic information, performance was more stable than with visual information alone.     

Intact visual discrimination of complex and feature-ambiguous stimuli in the absence of perirhinal cortex

The perirhinal cortex is known to be important for memory, but there has recently been interest in the possibility that it might also be involved in visual perceptual functions. In four experiments, we assessed visual discrimination ability and visual discrimination learning in severely amnesic patients with large medial temporal lobe lesions that included complete lesions of perirhinal cortex. Experiment 1 tested complex visual object perception. Experiments 2a and 2b tested in two different ways the ability to discriminate between feature-ambiguous images, which was reported to be impaired in monkeys with perirhinal lesions. Experiment 3 involved images that were successfully discriminated in Experiment 2a and asked patients to learn across 20 trials which of the images had been designated as "correct." Patients performed as well as controls in Experiments 1, 2a, and 2b, but one of the patients had difficulty in Experiment 3 when the task required remembering from trial to trial which image was "correct." These findings indicate that perirhinal cortex is not needed for visual perception across a wide range of visual perceptual tasks.     

Repetition blindness and illusory conjunctions: errors in binding visual types with visual tokens.

Repetition blindness (Kanwisher, 1986, 1987) has been defined as the failure to detect or recall repetitions of words presented in rapid serial visual presentation (RSVP). The experiments presented here suggest that repetition blindness (RB) is a more general visual phenomenon, and examine its relationship to feature integration theory (Treisman & Gelade, 1980). Experiment 1 shows RB for letters distributed through space, time, or both. Experiment 2 demonstrates RB for repeated colors in RSVP lists. In Experiments 3 and 4, RB was found for repeated letters and colors in spatial arrays. Experiment 5 provides evidence that the mental representations of discrete objects (called "visual tokens" here) that are necessary to detect visual repetitions (Kanwisher, 1987) are the same as the "object files" (Kahneman & Treisman, 1984) in which visual features are conjoined. In Experiment 6, repetition blindness for the second occurrence of a repeated letter resulted only when the first occurrence was attended to. The overall results suggest that a general dissociation between types and tokens in visual information processing can account for both repetition blindness and illusory conjunctions.     

One-dimensional and multi-dimensional studies of the exocentric distance estimates in frontoparallel plane, virtual space, and outdoor open field

The aim of this study is twofold: on the one hand, to determine how visual space, as assessed by exocentric distance estimates, is related to physical space. On the other hand, to determine the structure of visual space as assessed by exocentric distance estimates. Visual space was measured in three environments: (a) points located in a 2-D frontoparallel plane, covering a range of distances of 20 cm; (b) stakes placed in a 3-D virtual space (range = 330 mm); and (c) stakes in a 3-D outdoors open field (range = 45 m). Observers made matching judgments of distances between all possible pairs of stimuli, obtained from 16 stimuli (in a regular squared 4 x 4 matrix). Two parameters from Stevens' power law informed us about the distortion of visual space: its exponent and its coefficient of determination (R2). The results showed a ranking of the magnitude of the distortions found in each experimental environment, and also provided information about the efficacy of available visual cues of spatial layout. Furthermore, our data are in agreement with previous findings showing systematic perceptual errors, such as the further the stimuli, the larger the distortion of the area subtended by perceived distances between stimuli. Additionally, we measured the magnitude of distortion of visual space relative to physical space by a parameter of multidimensional scaling analyses, the RMSE. From these results, the magnitude of such distortions can be ranked, and the utility or efficacy of the available visual cues informing about the space layout can also be inferred.     

Semantic and phonological codes interact in single word production

The relationship between semantic-syntactic and phonological levels in speaking was investigated using a picture naming procedure with simultaneously presented visual or auditory distractor words. Previous results with auditory distractors have been used to support the independent stage model (e.g., H. Schriefers, A. S. Meyer, & W. J. M. Levelt, 1990), whereas results with visual distractors have been used to support an interactive view (e.g., P.A. Starreveld & W. La Heij, 1996b). Experiment 1 demonstrated that with auditory distractors, semantic effects preceded phonological effects, whereas the reverse pattern held for visual distractors. Experiment 2 indicated that the results for visual distractors followed the auditory pattern when distractor presentation time was limited. Experiment 3 demonstrated an interaction between phonological and semantic relatedness of distractors for auditory presentation, supporting an interactive account of lexical access in speaking.     

The time course of gaze bias in visual decision tasks

In three experiments, we used eyetracking to investigate the time course of biases in looking behaviour during visual decision making. Our study replicated and extended prior research by Shimojo, Simion, Shimojo, and Scheier (2003), and Simion and Shimojo (2006). Three groups of participants performed forced-choice decisions in a two-alternative free-viewing condition (Experiment 1a), a two-alternative gaze-contingent window condition (Experiment 1b), and an eight-alternative free-viewing condition (Experiment 1c). Participants viewed photographic art images and were instructed to select the one that they preferred (preference task), or the one that they judged to be photographed most recently (recency task). Across experiments and tasks, we demonstrated robust bias towards the chosen item in either gaze duration, gaze frequency or both. The present gaze bias effect was less task specific than those reported previously. Importantly, in the eight-alternative condition we demonstrated a very early gaze bias effect, which rules out a postdecision response-related explanation.     

Eye movements to pictures reveal transient semantic activation during spoken word recognition

Two experiments explore the activation of semantic information during spoken word recognition. Experiment 1 shows that as the name of an object unfolds (e.g., lock), eye movements are drawn to pictorial representations of both the named object and semantically related objects (e.g., key). Experiment 2 shows that objects semantically related to an uttered word's onset competitors become active enough to draw visual attention (e.g., if the uttered word is logs, participants fixate on key because of partial activation of lock), despite that the onset competitor itself is not present in the visual display. Together, these experiments provide detailed information about the activation of semantic information associated with a spoken word and its phonological competitors and demonstrate that transient semantic activation is sufficient to impact visual attention.     

Double Skew-Dual Scaling: A Conjoint Scaling of Two Sets of Objects Related by a Dominance Matrix

Consider two sets of objects, {alpha(1), em leader, alpha(n)} and {beta(1), em leader, beta(m), such as n subjects solving m tasks, or n stimuli presented first and m stimuli presented second in a pairwise comparison experiment. Let any pair (alpha(i), beta(j)) be associated with a real number a(ij), interpreted as the degree of dominance of alpha(i) over beta(j) (e.g., the probability of alpha(i) relating in a certain way to beta(j)). Intuitively, the problem addressed in this paper is how to conjointly, in a "naturally" coordinated fashion, characterize the alpha-objects and beta-objects in terms of their overall tendency to dominate or be dominated. The gist of the solution is as follows. Let A denote the nxm matrix of a(ij) values, and let there be a class of monotonic transformations straight phi with nonnegative codomains. For a given straight phi, a complementary matrix B is defined so that straight phi(a(ij))+straight phi(b(ij))=const, and one computes vectors D(alpha) and D(beta) (the dominance values for alpha-objects and beta-objects) by solving the equations straight phi(A) straight phi(D(beta))/Sigma;straight phi(D(beta))=straight phi(D(alpha)) and straight phi(B(T)) straight phi(D(alpha))/Sigmastraight phi(D(alpha))=straight phi(D(beta)), where (T) is transposition, Sigma is the sum of elements, and straight phi applies elementwise. One also computes vectors S(alpha) and S(beta) (the subdominance values for alpha-objects and beta-objects) by solving the equations straight phi(B) straight phi(S(beta))/Sigmastraight phi(S(beta))=straight phi(S(alpha)) and straight phi(A(T)) straight phi(S(alpha))/Sigmastraight phi(S(alpha))=straight phi(S(beta)). The relationship between S-vectors and D-vectors is complex: intuitively, D(alpha) characterizes the tendency of an alpha-object to dominate beta-objects with large dominance values, whereas S(alpha) characterizes the tendency of an alpha-objects to fail to dominate beta-objects with large subdominance values. For classes containing more than one straight phi-transformation, one can choose an optimal straight phi as the one maximizing some measure of discrimination between individual elements of vectors straight phi(D(alpha)), straight phi(D(beta)), straight phi(S(alpha)), and straight phi(S(beta)), such as the product or minimum of these vectors' variances. The proposed analysis of dominance matrices has only superficial similarities with the classical dual scaling (Nishisato, 1980). Copyright 1999 Academic Press.     

Reorientation in a rhombic environment: No evidence for an encapsulated geometric module

Reorientation behavior of young children has been described as dependent upon a geometric module that is incapable of interacting with landmark information. Whereas previous studies typically used rectangular spaces that provided geometric information about distance, we used a rhombic space that allowed us to explore the way children use geometric information about angles. Reorientation was studied in manipulatory space (Experiment 1) and locomotor space (Experiment 2) in the presence and absence of a salient landmark. In the absence of salient landmarks, 4- to 6-year-olds used geometric features to reorient in both spaces. When a salient landmark was available in manipulatory space, 4-year-olds used the landmark and ignored the geometry. Five- and 6-year-olds used the geometry, but in combination with the landmark. In locomotor space, this combined use was already seen at age 4, and increased with age. Taken together, these results offer no support for the notion that reorientation behavior in young children depends on an informationally encapsulated geometric module.     

Does monocular visual space contain planes?

The issue of the existence of planes—understood as the carriers of a nexus of straight lines—in the monocular visual space of a stationary human observer has never been addressed. The most recent empirical data apply to binocular visual space and date from the 1960s (Foley, 1964). This appears to be both the first and the last time this basic issue was addressed empirically. Yet the question is of considerable conceptual interest. Here we report on a direct empirical test of the existence of planes in monocular visual space for a group of sixteen experienced observers. For the majority of these observers monocular visual space lacks a projective structure, albeit in qualitatively different ways. This greatly reduces the set of viable geometrical models. For example, it rules out all the classical homogeneous spaces (the Cayley-Klein geometries) such as the familiar Luneburg model. The qualitatively different behavior of experienced observers implies that the generic population might well be inhomogeneous with respect to the structure of visual space.     

Interference in Visual Working Memory

This paper uses the theoretical distinction that has recently developed between the passive visual store and the active spatial rehearsal mechanism of the visuo-spatial component of working memory (VSSP). It examines the circumstances under which visual fields gain functional access to the passive visual store and seeks to cast light on the circumstances under which irrelevant visual fields interfere with concurrent visual processing. Experiment 1 contrasts a dynamic visual noise field with a static noise field and shows that the static field, in contrast to the dynamic noise field, causes no interference when presented concurrently with a visual task. Experiment 2 investigates the reason for this contrast and concludes that the static field is susceptible to decay and so fails to cause interference. Experiment 3 investigates further the circumstances under which dynamic visual noise causes interference and shows that manipulation of the number of changes within the noise field is also of importance in causing interference. The results allow further consideration of the characteristics of the VSSP.