Perceiving the present and a systematization of illusions

Over the history of the study of visual perception there has been great success at discovering countless visual illusions. There has been less success in organizing the overwhelming variety of illusions into empirical generalizations (much less explaining them all via a unifying theory). Here, this article shows that it is possible to systematically organize more than 50 kinds of illusion into a 7 × 4 matrix of 28 classes. In particular, this article demonstrates that (1) smaller sizes, (2) slower speeds, (3) greater luminance contrast, (4) farther distance, (5) lower eccentricity, (6) greater proximity to the vanishing point, and (7) greater proximity to the focus of expansion all tend to have similar perceptual effects, namely, to (A) increase perceived size, (B) increase perceived speed, (C) decrease perceived luminance contrast, and (D) decrease perceived distance. The detection of these empirical regularities was motivated by a hypothesis, called "perceiving the present," that the visual system possesses mechanisms for compensating neural delay during forward motion. This article shows how this hypothesis predicts the empirical regularity.     

Perceiving distance: a role of effort and intent

Perceiving egocentric distance is not only a function of the optical variables to which it relates, but also a function of people's current physiological potential to perform intended actions. In a set of experiments, we showed that, as the effort associated with walking increases, perceived distance increases if the perceiver intends to walk the extent, but not if the perceiver intends to throw. Conversely, as the effort associated with throwing increases, perceived distance increases if people intend to throw to the target, but not if they intend to walk. Perceiving distance combines the geometry of the world with our behavior goals and the potential of our body to achieve these goals.     

Perceiving verbal and vocal emotions in a second language

Emotional inferences from speech require the integration of verbal and vocal emotional expressions. We asked whether this integration is comparable when listeners are exposed to their native language and when they listen to a language learned later in life. To this end, we presented native and non-native listeners with positive, neutral and negative words that were spoken with a happy, neutral or sad tone of voice. In two separate tasks, participants judged word valence and ignored tone of voice or judged emotional tone of voice and ignored word valence. While native listeners outperformed non-native listeners in the word valence task, performance was comparable in the voice task. More importantly, both native and non-native listeners responded faster and more accurately when verbal and vocal emotional expressions were congruent as compared to when they were incongruent. Given that the size of the latter effect did not differ as a function of language proficiency, one can conclude that the integration of verbal and vocal emotional expressions occurs as readily in one's second language as it does in one's native language.     

Perceiving verbal and vocal emotions in a second language

Emotional inferences from speech require the integration of verbal and vocal emotional expressions. We asked whether this integration is comparable when listeners are exposed to their native language and when they listen to a language learned later in life. To this end, we presented native and non-native listeners with positive, neutral and negative words that were spoken with a happy, neutral or sad tone of voice. In two separate tasks, participants judged word valence and ignored tone of voice or judged emotional tone of voice and ignored word valence. While native listeners outperformed non-native listeners in the word valence task, performance was comparable in the voice task. More importantly, both native and non-native listeners responded faster and more accurately when verbal and vocal emotional expressions were congruent as compared to when they were incongruent. Given that the size of the latter effect did not differ as a function of language proficiency, one can conclude that the integration of verbal and vocal emotional expressions occurs as readily in one's second language as it does in one's native language.     

Perceiving and re-perceiving objects.

A number of experiments exploring priming effects and automatization in the perception of novel objects are described, and a framework for understanding the benefits and costs of re-perceiving previously seen objects is proposed. The suggestion is that perceiving an object creates a temporary representation in an object file that collects, integrates, and updates information about its current characteristics. The contents of an object file may be stored as an object token and retrieved next time the object appears. This facilitates its re-perception when all of the attributes match and may impair it if some are changed. Thus, the world molds our minds to capitalize on earlier experiences but at the same time leaves us able readily to detect and represent any novel or unexpected objects and events.     

Perceiving children's behavior and reaching limits in a risk environment

The purpose of this study was to investigate the accuracy of parents' perception of children's reaching limits in a risk scenario. A sample of 68 parents of 1- to 4-year-olds were asked to make a prior estimate of their children's behavior and action limits in a task that involved retrieving a toy out of the water. The action modes used for reaching, accuracy of estimates, and error tendency were investigated. Several morphological variables, walking experience, and swimming program experience were analyzed as predictors of maximum and estimated maximum reachability. Most children sat to retrieve the toy out of the water and fell in while attempting to grasp beyond their reaching limit. Nearly 80% of the parents correctly predicted their children's behavior when the toy was unreachable. Parents were cautious in predicting their children's maximum reachability (>50% underestimates). Mothers were more accurate than fathers in estimating their children's reaching limit. The prediction of children's capabilities was based partially on body dimensions and proportions.     

Perceiving the centroid of configurations on a rolling wheel

Undergraduates observed configurations of point-lights undergoing wheel-generated motions and judged how wheel-like the movement of each stimulus appeared on a 7-point scale. Viewer judgments were predicted by a metric defining the variable parameters for the motion path of each configuration’s geometric center—the centroid. The effects on judgments of eye movement and the stimulus characteristics of rotation, translation, and configuration were explored in six experiments. First, a strain operation on the dynamic stimuli did not affect the ability of the metric to predict perceptual judgments. Second, the predictive strength of the metric did not interact with the type of eye movements used in viewing the stimuli, though judged wheel-likeness was greater under pursuit vision than under static fixation. Third, variations in the extent of translation yielded little, if any, effect on observers’ judgments, nor did translation in a circular path. Finally, for stimuli having two lights extremely close together in the configuration, the metric’s predictive value was slightly lessened but only at the limits of visual acuity. Thus, within a wide range of presentation conditions, and for a wide variety of configurations, a metric that defined the variable parameters for the motion path of the centroid was an accurate predictor of observers’ judgments of goodness of perceived rotary motion.     

Standardization and norms for a Hebrew naming test

This paper describes a Hebrew naming test that consists of 48 line drawings ordered by word frequency. The initial validation phase included 48 young adults (ages 20-28), 48 old adults (ages 67-85), and 27 individuals with Alzheimer's disease (ages 68-87). Results indicated a modest odd-even internal consistency effect, word frequency effect, and sensitivity to neurological disease. The normative population included 365 participants, aged 18-85. Means of correct answers (responses provided spontaneously and those following a functional cue), of spontaneous responses alone, and of responses provided after a functional and after a phonemic cue are presented, along with cumulative percentiles for the total score. Results show that age had the greatest effect on naming performance with age at immigration accounting for a significant share of the variance as well.     

Toward a functional classification of naming impairments

Three experiments involving confrontation naming and nonverbal classification tasks establish that impaired naming is relatively common in elderly cardiac patients, but that it can be distinguished functionally from aphasic dysnoia. The results suggest that while the aphasics' failures often reflected failure to retrieve the verbal labels of objects which were appropriately perceived, naming failures in cardiac patients were frequently precipitated by failure to éstablish the semantic identity of the target and were more sentitive to reductions in visual quality of the target picture.     

Perceiving binocular depth with reference to a common surface

A common surface is a spatial regularity of our terrestrial environment. For instance, we walk on the common ground surface, lay a variety of objects on the table top, and display our favorite paintings on the wall. It has been proposed that the visual system utilizes this regularity as a reference frame for coding objects' distances. Presumably, by treating the common surface as such--i.e. an anticipated constant--the visual system can reduce its coding redundancy, and divert its resources to representing other information. For intermediate-distance space perception, it has been found that absolute distance judgment is most accurate when a common ground surface is available. Here we explored if the common surface also serves as the reference frame for the processing of binocular-disparity information, which is a predominant cue for near-distance space perception. We capitalized on an established observation where the perceived slant of a surface with linear binocular-disparity gradient is underestimated. Clearly, if the visual system utilizes this incorrectly represented slant surface as a reference frame for coding the objects' locations, the perceived depth separation between the objects will be adversely affected. Our results confirm this, by showing that the depth judgment of objects (two laterally separated vertical lines) on, or in the vicinity of, the surface is underestimated. Furthermore, we show that the impact of the common surface on perceived depth separation most likely occurs at the surface-representation level where the visual surface has been explicitly delineated, rather than at the earlier disparity-processing level.     

Parallel processing of objects in a naming task

The authors investigated whether speakers who named several objects processed them sequentially or in parallel. Speakers named object triplets, arranged in a triangle, in the order left, right, and bottom object. The left object was easy or difficult to identify and name. During the saccade from the left to the right object, the right object shown at trial onset (the interloper) was replaced by a new object (the target), which the speakers named. Interloper and target were identical or unrelated objects, or they were conceptually unrelated objects with the same name (e.g., bat [animal] and [baseball] bat). The mean duration of the gazes to the target was shorter when interloper and target were identical or had the same name than when they were unrelated. The facilitatory effects of identical and homophonous interlopers were significantly larger when the left object was easy to process than when it was difficult to process. This interaction demonstrates that the speakers processed the left and right objects in parallel.