Blowing in the wind: Perceiving structure in trees and bushes

When lights are mounted at the ends of the limbs of a tree and the surround darkened such that branches and trunk are not visible, viewers can nonetheless make systematic and precise judgments about the unseen structure of the tree through its motion. They seem to perform this task by picking up information about the relative arborization of the tree through the vector paths of the lights on the limbs. Theoretically speaking, the focus of this study is on the perception of second-order centers of moment; previous studies have focused on the perception of first-order centers. A second-order center in a tree-like structure is the location where limb meets trunk, and it is these that perceivers can infer from the dynamic display. The importance of this study is to demonstrate further that the study of centers of moment makes possible a detailed and differential study of event perception.     

Perceiving minority members as individuals: the effects of relative group size in social categorization

According to the account by comparative distinctiveness, minorities draw attention by virtue of their relative size, leading to more individuation and more stereotyping of their members. Using the ‘Who said what?’ paradigm by Taylor, Fiske, Etcoff, and Ruderman ( 1978 ) in Klauer and Wegener's ( 1998 ) modified version, relative group size of gender categories and age categories was varied in a pilot study and a main experiment, respectively. In the pilot study, memory for discussion statements and in both studies, memory for individuating information increased as subgroup size decreased. Rating measures obtained in the main experiment revealed most stereotyping of minority members. The findings thereby support major predictions of the account by comparative distinctiveness, but demonstrate dissociations between different modes of category‐based processing, i.e. category memory, reconstructive category use, and stereotyping. Copyright © 2002 John Wiley & Sons, Ltd.     

Background surface and horizon effects in the perception of relative size and distance

The projected height of an object in a scene relative to a ground surface influences its perceived size and distance, but the effect of height should change when the object is moved above the horizon. In four experiments, observers judged relative size or relative distance for pairs of objects varying in height with respect to the horizon. Higher objects equal in projected size were judged larger below the horizon, but the relative size effect was reversed either when one object was on the horizon and one was above the horizon or when both objects were above the horizon. With the real horizon not explicitly present in the display, relative size judgements were affected both by the boundary of the visible surface and the vanishing point implied by the converging lines. For relative distance judgements, the higher object was judged more distant regardless of the height of the objects relative to the perceptual horizon, resulting in a reversal of the relation between size and distance judgements for objects above the horizon.     

Perceiving discrimination: Psychological and sociopolitical barriers

Recognizing discrimination is not always an easy thing to do. This is particularly true in North America where perpetrators’ fears of being labelled have resulted in a shift in the type of discrimination experienced. Incidents may be subtle and ambiguous. As a country of immigration, Canada provides a template for the world community. While conditions for minorities in Canada may rival other countries, improvement is needed. In this paper, narratives of East and Central African Asian Ismailis in Québec are analyzed to demonstrate that understanding the way people perceive discrimination requires not only knowledge of the psychological processes involved but also of the reasons for immigrating, the beliefs about the country of destination prior to migration, and the socio-political conditions in host and sending, societies. The results of this analysis provide policy-relevant information in order to address problems of racism and discrimination more effectively.     

Category size and judgments of variability: The effects of seeing the trees in the forest1

Abstract: Competing predictions about the effects of category size on judgments of category variability were examined in two studies involving the presentation of exemplars of two artificial social groups. In contrast to predictions of some exemplar-based models, Experiment 1 demonstrated that a numerically smaller group was perceived to be more variable than a larger group on the standard deviation measure of frequency distribution estimates. The result was interpreted to be an effect of differential information load. Experiment 2 revealed that variability judgments were influenced by prior expectations about the central tendencies as well as by practice in retrieving information about category exemplars. When frequency distribution estimates were made subsequent to abstract tasks, expectations about the numerical majority reduced perceived variability, while this influence was mitigated when memory measures preceded the frequency estimates.     

Perceiving the intensity of light

The relationship between luminance (i.e., the photometric intensity of light) and its perception (i.e., sensations of lightness or brightness) has long been a puzzle. In addition to the mystery of why these perceptual qualities do not scale with luminance in any simple way, "illusions" such as simultaneous brightness contrast, Mach bands, Craik-O'Brien-Cornsweet edge effects, and the Chubb-Sperling-Solomon illusion have all generated much interest but no generally accepted explanation. The authors review evidence that the full range of this perceptual phenomenology can be rationalized in terms of an empirical theory of vision. The implication of these observations is that perceptions of lightness and brightness are generated according to the probability distributions of the possible sources of luminance values in stimuli that are inevitably ambiguous.     

群体印象形成与个体印象形成：反基准比率效应

采用 “反基准比率效应”范式考察在群体印象形成与个体印象形成两种认知加工过程中, 基准比率对印象形成过程及其结果的影响。被试分别为39名19~25岁大学生(实验1：男生17名, 女生22名, 均为右利手)以及46名19~25岁大学生(实验2：男生21名, 女生25名, 均为右利手)。结果发现：无论是群体印象形成还是个体印象形成, 在学习阶段, 知觉者都能准确认知各类事件间的关系, 但会优先建构高频事件间的联结。而在测试阶段, 当低频事件与高频事件同时出现时, 知觉者发生明显关系误判, 即以反基准比率的倾向高估低频事件间的联结强度。实验表明群体与个体印象形成过程中都会产生反基准比率效应这样的加工偏差, 进而初步揭示反基准比率现象在社会信息加工领域具有一定的普遍性。     

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 the language of films.

Children appear to be familiar with the language of film makers or at least to perceive and remember films less well when the rules of this cinematic language are broken. In this experiment a simple action sequence filmed from a static viewpoint was made up into two films of four shots. One film was edited according to the rules of directional continuity specified by Hollywood cinema, that is the four shots were presented so as to preserve the subject's direction of movement across cuts. The other film was edited disregarding these rules. Apart from this difference both films were identical. Children aged seven, nine, and thirteen years watched either of these films and reconstructed the action using pictures representing the four shots. The children who saw the conventional version were better able to reconstruct what they had seen than those who saw the unconventional version.     

Perceiving the sequence of speech and non-speech stimuli

The task is to estimate on which syllable of a spoken sentence a click was superimposed. Experiment I confirms Ladefoged and Broadbent's finding of a systematic tendency to prepose the click (negative displacement), but shows also that the tendency is decreased when prior knowledge of the sentence is provided. Experiment II shows that acoustic prior knowledge is not necessary to produce the decrease and that it occurs also with textual prior knowledge. Experiment III shows that the negative displacement is not eliminated by short-term practice on the task, as Fodor and Bever contended. The effect of prior knowledge is inconsistent with the explanation of negative displacement in terms of attention demands suggested by Ladefoged and Broadbent. It is argued that this explanation was unnecessary, and that negative displacement can be expected in a system which analyses speech by discrete units.     

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 personal discrimination: the role of group status and legitimizing ideology

It was hypothesized that relative group status and endorsement of ideologies that legitimize group status differences moderate attributions to discrimination in intergroup encounters. According to the status-legitimacy hypothesis, the more members of low-status groups endorse the ideology of individual mobility, the less likely they are to attribute negative outcomes from higher status group members to discrimination. In contrast, the more members of high-status groups endorse individual mobility, the more likely they are to attribute negative outcomes from lower status group members to discrimination. Results from 3 studies using 2 different methodologies provide support for this hypothesis among members of different high-status (European Americans and men) and low-status (African Americans, Latino Americans, and women) groups.     

Perceiving affect from the voice and the face

This experiment examines how emotion is perceived by using facial and vocal cues of a speaker. Three levels of facial affect were presented using a computer-generated face. Three levels of vocal affect were obtained by recording the voice of a male amateur actor who spoke a semantically neutral word in different simulated emotional states. These two independent variables were presented to subjects in all possible permutations—visual cues alone, vocal cues alone, and visual and vocal cues together—which gave a total set of 15 stimuli. The subjects were asked to judge the emotion of the stimuli in a two-alternative forced choice task (either HAPPY or ANGRY). The results indicate that subjects evaluate and integrate information from both modalities to perceive emotion. The influence of one modality was greater to the extent that the other was ambiguous (neutral). The fuzzy logical model of perception (FLMP) fit the judgments significantly better than an additive model, which weakens theories based on an additive combination of modalities, categorical perception, and influence from only a single modality.     

Discriminability of fixed-ratio schedules for pigeons: effects of absolute ratio size

In a discrete-trial choice situation, 12 pigeons were trained to discriminate which of two different fixed ratios they had completed. Psychometric functions were obtained at three ratio requirements (i.e., with the larger ratio set at 10, 20, or 30 responses) by gradually reducing the size of the smaller value. Although different response biases developed across subjects, in each case accuracy decreased systematically with ratio difference regardless of absolute ratio requirements. Above-chance performances were maintained even at relative ratio differences of 10% or less. Estimates of the Weber fraction showed that, in general, discriminability improved with absolute ratio size up to 30 responses, and beyond, when the results of other studies are considered. A similar trend held for rats studied by other investigators in fixed-ratio “counting” tasks at lower requirements. In terms of a signal-detection analysis, performance was similar to that reported for other species and dimensions. Taken together, the results suggest that for this somewhat novel dimension the same psychophysical relations hold as are commonly observed for exteroceptive stimuli.     

Perceiving vocal age and gender: An adaptation approach

Aftereffects of adaptation have revealed both independent and interactive coding of facial signals including identity and expression or gender and age. By contrast, interactive processing of non-linguistic features in voices has rarely been investigated. Here we studied bidirectional cross-categorical aftereffects of adaptation to vocal age and gender. Prolonged exposure to young (~ 20 yrs) or old (~ 70 yrs) male or female voices biased perception of subsequent test voices away from the adapting age (Exp. 1) and the adapting gender (Exp. 2). Relative to gender-congruent adaptor-test pairings, vocal age aftereffects (VAAEs) were reduced but remained significant when voice gender changed between adaptation and test. This suggests that the VAAE relies on both gender-specific and gender-independent age representations for male and female voices. By contrast, voice gender aftereffects (VGAEs) were not modulated by age-congruency of adaptor and test voices (Exp. 2). Instead, young voice adaptors generally induced larger VGAEs than old voice adaptors. This suggests that young voices are particularly efficient gender adaptors, likely reflecting more pronounced sexual dimorphism in these voices. In sum, our findings demonstrate how high-level processing of vocal age and gender is partially intertwined.     

Perceiving and Understanding Religion: A task for RE in the classroom

Given conventional refusals of sense perception in RE pedagogics, this article tries to take a fresh approach. To provide new insight into the essence and function of perception for religion and RE, it draws on a phenomenological concept of the human senses. Finally, it presents two elements of RE classroom practice.     

The form of analog size information in memory

The information used to choose the larger of two objects from memory was investigated in two experiments that compared the effects of a number of variables on the performance of subjects who either were instructed to use imagery in the comparison task or were not so instructed. Subjects instructed to use imagery could perform the task more quickly if they prepared themselves with an image of one of the objects at its normal size, rather than with an image that was abnormally big or small, or no image at all. Such subjects were also subject to substantial selective interference when asked to simultaneously maintain irrelevant images of digits. In contrast, when subjects were not specifically instructed to use imagery to reach their decisions, an initial image at normal size did not produce significantly faster decisions than no image, or a large or small image congruent with the correct decision. The selective interference created by simultaneously imaging digits was reduced for subjects not told to base their size comparisons on imagery. The difficulty of the size discrimination did not interact significantly with any other variable. The results suggest that subjects, unless specifically instructed to use imagery, can compare the size of objects in memory using information more abstract than visual imagery.