The structure of visual pattern associates and pattern goodness

Two tasks were used with a total set of 126 dot patterns. In one task Ss rated the goodness of each pattern. In another task they produced a dot pattern as an associate to each of the patterns used as a stimulus. The distributions of the associates suggest that the total set of patterns is both partitioned and nested. Groups defined by rotation and reflection are partitioned, thus kept intact. These groups in turn form a series of nested subsets., Both partitioning and nesting produce subsets of different size. The size of these subsets is related to pattern goodness, with good patterns coming from small subsets.     

The factorial structure of individual differences in visual perception

Although at first glance the way we perceive the world is similar for most individuals and resembles a veridical interpretation of the environment, the persistent individual differences found in many perceptual processes continue to inspire and confuse researchers. Despite numerous attempts to map out the reliable factors and correlates of individual variance in perception, the factorial structure of vision has remained elusive. The current article reviews recent developments in the study of individual differences in perception with a focus on work that has applied latent variable techniques for analysing performance across multiple visual paradigms. As this overview reveals, studies that have attempted to answer the question whether one general or several specific factors best describe vision tend to reject the monolithic view. Some general notes are also provided regarding pitfalls that should be taken into account when designing such research in the future.     

Useful visual field size for pattern perception

The useful visual field size at each fixation in a pattern was investigated by artificially supplying various visual field sizes on a TV display. The degree of pattern perception was measured in terms of recognition memory for pictures, and the speed of processing pictures was determined as a function of field size. A serious deterioration in the perception of pictures occurred as the visual field was limited to a small area around the fovea (about 3.3° × 3.3°), processing speed becoming extremely slow. Speed increased gradually as visual field size became larger, to reach a certain level beyond which no further increase was observed. The visual field size at this asymptotic speed was called the useful visual field and was found to be about 50% of the entire pattern size. Analysis of eye-movement records demonstrated that in terms of the useful visual field, the scanning characteristics of the eye over the pattern occurred in a heavily overlapping manner to assure good perception of the pattern.     

The role of structural redundancy in the perception of visual targets

Most visual images contain “gross shapes” which are highly correlated with less perceptable “details,” e.g., the gross outline of a head and details such as eyes, ears, etc. The role of such structural redundancy in perception is considered both from a “syntactical” and “spatial-frequency” view of structure. An experiment is reported and evaluated in terms of a simple mathematical model which allows one to isolate the influence of several factors in the perceptual process, particularly the observer’s actual sensitivity to specific details and the influence of the redundant (correlated) information in “higher order forms,” The basic idea is that one decides whether a particular (target) detail is present in a briefly presented image by integrating impressions from various parts of the image in a weighted manner, with the weights determined by redundant information in “higher order forms.” Furthermore, the results are generally consistent with the notion that an increase in the number of attended letters does not reduce the information extracted from each letter.     

The role of central processes in the perception of visual after-images

Three experiments are reported in which part of the stimulus to be after-imaged was presented to each eye, producing simultaneous, binocular, after-images. In each case the monocular stimuli were complementary to each other, so that the binocular combination constituted a meaningful whole. The subjects' reports on the appearances and fragmentations of their after-images suggest the existence of some central, integrative, mechanism.     

Linear systems analysis of infant visual pattern preferences

Karmel's check-pattern preference data for 13-week-old infants were reanalyzed using linear systems analysis. The two-dimensional Fourier amplitude spectrum was calculated for each of his eight checkerboard and random check patterns. The mean contrast sensitivity data for 3-month-old infants of Banks and Salapatek and the spatial frequency amplitudes of the patterns were used to derive three metrics to predict the looking times observed by Karmel. One was based on the sensitivity of the visual system to the single pattern component highest above threshold (maximum amplitude), the second was based on the total amount of pattern energy above threshold (total summation), and the third was based on the maximum amplitude with summation over nearby spatial frequency components (limited summation). The predictive power of the maximum amplitude and the total summation metrics depended on whether the pattern type was checkerboard or random check. The limited summation metric predicted looking times well for both pattern types. A linear function of the logarithm of the limited summation metric accounted for 91% of the total variance in looking time.     

Auditory spatial pattern perception aided by visual choices

Summary Thirty-six human subjects, facing a panel of 100 loud-speakers, were requested to match sounds outlining geometrical and alphabetical patterns with visual pattern choices, which were given to them on a folder. The listeners' correct responses were found to be above chance. Geometrical patterns were better perceived when transmitted at the sound frequency of 800 cps as compared to 6400 cps. The number of visual pattern choices given with the sound pattern presentations affected the number of correct responses. The results indicate that the perception of acoustic spatial patterns depends on mechanisms different from those defining the spatial localization of single acoustic signals.This work was supported by the Swiss National Science Foundation, Grants 3.74.68, 4.0120.70 and 4.0860.73 to E. Perret.     

The role of visual and body movement information in infant search

Three experiments investigated the use of visual input and body movement input arising from movement through the world on spatial orientation. Infants between 9 1/2 and 18 months participated in a search task in which they searched for a toy hidden in 1 of 2 containers. Prior to beginning search, either the infants or the containers were rotated 180 degrees; these rotations occurred in a lit or dark environment. These experiments were distinguished by the environmental cues for object location; Experiment 1 used a position cue, Experiment 2 a color cue, and Experiment 3 both position and color cues. Accuracy was better in Experiments 2 and 3 than in Experiment 1. All studies found that search was best after infant movement in the light; all other conditions led to equivalently worse performance. These results are discussed relative to a theoretical characterization of spatial coding focusing on the uses of spatial information.     

Common mechanisms in apparent motion perception and visual pattern matching

There are close functional similarities between apparent motion perception and visual pattern matching. In particular, striking functional similarities have been demonstrated between perception of rigid objects in apparent motion and purely mental transformations of visual size and orientation used in comparisons of objects with respect to shape but regardless of size and orientation. In both cases, psychophysical data suggest that differences in visual size are resolved as differences in depth, such that transformation of size is done by translation in depth. Furthermore, the process of perceived or imagined translation appears to be stepwise additive such that a translation over a long distance consists of a sequence of smaller translations, the durations of these steps being additive. Both perceived and imagined rotation also appear to be stepwise additive, and combined transformations of size and orientation appear to be done by alternation of small steps of pure translation and small steps of pure rotation. The functional similarities suggest that common mechanisms underlie perception of apparent motion and purely mental transformations. In line with this suggestion, functional brain imaging has isolated neural structures in motion area MT used in mental transformation of size.     

The role of convexity in perception of symmetry and in visual short-term memory

Visual perception of shape is affected by coding of local convexities and concavities. For instance, a recent study reported that deviations from symmetry carried by convexities were easier to detect than deviations carried by concavities. We removed some confounds and extended this work from a detection of reflection of a contour (i.e., bilateral symmetry), to a detection of repetition of a contour (i.e., translational symmetry). We tested whether any convexity advantage is specific to bilateral symmetry in a two-interval (Experiment 1) and a single-interval (Experiment 2) detection task. In both, we found a convexity advantage only for repetition. When we removed the need to choose which region of the contour to monitor (Experiment 3) the effect disappeared. In a second series of studies, we again used shapes with multiple convex or concave features. Participants performed a change detection task in which only one of the features could change. We did not find any evidence that convexities are special in visual short-term memory, when the to-be-remembered features only changed shape (Experiment 4), when they changed shape and changed from concave to convex and vice versa (Experiment 5), or when these conditions were mixed (Experiment 6). We did find a small advantage for coding convexity as well as concavity over an isolated (and thus ambiguous) contour. The latter is consistent with the known effect of closure on processing of shape. We conclude that convexity plays a role in many perceptual tasks but that it does not have a basic encoding advantage over concavity.     

婴儿的痛觉

婴儿痛觉对婴儿的生长发育有重要意义, 已经日益引发研究者的兴趣。痛觉本质上是一种不愉悦的感官和情绪体验, 是通过早年与伤害有关的经历习得的。在心理学角度, 在介绍婴儿痛觉概念、神经生理机制、评估工具的基础上, 系统梳理痛觉对婴儿生长发育的影响及其影响因素十分必要。后续研究需继续完善婴儿痛觉的测量方法, 考察疼痛反应在不同文化和不同群体间的差异。     

The role of self-produced movement and visual tracking in infant spatial orientation

In two longitudinal studies, infants were trained at 12 and 18 months to find an object hidden in one of two identical wells in a Plexiglas box. On the test trial, normal access was blocked and infants were either guided by their mother or allowed to move on their own to another opening on the opposite side. In Experiment 1 significantly more correct responding occurred after active movement than after passive at 12 months, with correct responding related to high visual tracking. In contrast, at 18 months correct search without tracking predominated among both movement conditions. A difference between the conditions in the position of the mother on the test trial was ruled out as a contributor to performance on the basis of data from Experiment 2. When opaque sides were inserted to prevent tracking in Experiment 3, active movement no longer facilitated correct search at 12 months, thus indicating that the tracking and not the active movement per se was the critical factor.     

The role of facial colour and luminance in visual and audiovisual speech perception

We conducted four experiments to investigate the role of colour and luminance information in visual and audiovisual speech perception. In experiments 1a (stimuli presented in quiet conditions) and 1b (stimuli presented in auditory noise), face display types comprised naturalistic colour (NC), grey-scale (GS), and luminance inverted (LI) faces. In experiments 2a (quiet) and 2b (noise), face display types comprised NC, colour inverted (CI), LI, and colour and luminance inverted (CLI) faces. Six syllables and twenty-two words were used to produce auditory and visual speech stimuli. Auditory and visual signals were combined to produce congruent and incongruent audiovisual speech stimuli. Experiments 1a and 1b showed that perception of visual speech, and its influence on identifying the auditory components of congruent and incongruent audiovisual speech, was less for LI than for either NC or GS faces, which produced identical results. Experiments 2a and 2b showed that perception of visual speech, and influences on perception of incongruent auditory speech, was less for LI and CLI faces than for NC and CI faces (which produced identical patterns of performance). Our findings for NC and CI faces suggest that colour is not critical for perception of visual and audiovisual speech. The effect of luminance inversion on performance accuracy was relatively small (5%), which suggests that the luminance information preserved in LI faces is important for the processing of visual and audiovisual speech.     

When believing is seeing: The role of predictions in shaping visual perception

The study investigated the influence of predictions on perception—in particular, how strong but erroneous prediction coupled with poor sensory data can trigger misperceptions. Using signal detection, we tested whether predictions induced by a semantic cue change the recognition threshold (criterion) or the subjectively perceived differences between stimuli (sensitivity). In a series of 3 experiments, participants observed pictures of (a) real objects distorted to various extents (targets), (b) noise with elements corresponding to meaningful objects (foils), or (c) nonsense images (noise). Stimuli were preceded either by a semantic cue or by a blank screen with equal probability. Presence of the cue resulted in a more liberal criterion, but only for targets and foils. The cue decreased sensitivity between the distorted targets, but increased sensitivity between the targets and noise—that is, the cue increased between-class differences, but decreased within-class differences. When there was no correspondence between prediction and the sensory input, prediction actually increased the chances of correctly rejecting noise. The influence of the cue was strongest for the moderately distorted targets and foils—when uncertainty related to the bottom-up input was the highest.     

The role of visible persistence for perception of visual bilateral symmetry1

Abstract: Although the detection of visual bilateral symmetry has been claimed to be highly efficient, the possible involvement and function of visual memory in such efficient mechanisms has rarely been examined. We hypothesized that symmetry perception is rapid, as it can be achieved from rapidly decaying information of visible persistence. To test this hypothesis, we employed a temporal integration paradigm. A symmetric dot pattern was randomly divided into two asymmetric patterns and presented successively with a blank screen presented between patterns. Observers could detect symmetry when the two patterns were presented close in time (Experiment 1), indicating that observers perceived symmetry presumably utilizing visible persistence. In addition, the inverse‐intensity effect of visible persistence (Di Lollo & Bischof, 1995) was evident in our temporal integration task of symmetry (Experiment 2). The results of the current study clearly demonstrate that the detection of symmetry can be achieved based on the visible persistence. The large capacity and high spatial precision of visible persistence might be adequate for the rapid and spatially global encoding of visual symmetry.     

The role of phenomenal displacement on the perception of the visual upright

Tilt invariably involves the factor of displacement. A clockwise rotation of a rod, for example, results in the top being displaced to the right and the bottom to the left. The question was raised as to which is primary, displacement or tilt. Through a series of experiments, apparent tilt was found to be the perceptual outcome of phenomenal displacement. In addition, gravity seemed to play no significant role in determining the visual upright. Therefore, the conventionally accepted field theory of apparent verticality was rejected and the visual upright was interpreted according to principles which govern the perception of motion and radial direction.