复合字母刺激心理旋转加工中的整体优先效应

采用复合字母材料结合正镜像判断任务,首次揭示了心理旋转加工中的整体优先效应。实验一延长复合字母材料的呈现时间,检验心理旋转实验常用的正/镜像判断任务中的视知觉整体优先效应;实验二将实验一的复合字母材料旋转一定角度,考察心理旋转加工中的整体优先效应。结果发现：（1）延长复合字母呈现时间后的字母正镜像判断任务中,被试判断大字母和判断小字母的时间没有显著差异,并且大小字母是否一致对大字母判断和小字母判断的影响无显著差异;（2）在排除了视知觉的整体优先效应存在的情况下,发现心理旋转加工中存在明显的整体优先效应,大字母（整体）旋转条件下的反应时显著短于小字母（局部）旋转条件下的反应时;（3）旋转角度一致性对大字母旋转和小字母旋转条件下的反应时均无显著影响,表明心理旋转的整体优先效应模式可能有别于视知觉加工的整体优先效应模式     

Do response time advantage and interference reflect the order of processing of global- and local-level information?

Navon's (1977) global precedence hypothesis was based primarily on the joint occurrence of two effects: a response time (RT) advantage for identifying global targets, and interference by global distractors on responding to local targets. Although the hypothesis has been questioned on the basis of experiments in which it has been shown that a local RT advantage and local interference can occur, it is still frequently assumed that these two effects are a valid measure of the order in which local and global levels of structure are processed. In the present experiment, this assumption was examined. Subjects identified target letters that occurred randomly at the global or local level in a divided-attention task. The visual angle subtended by the stimulus pattern was varied, a manipulation known to affect the relative speed of response to local- or global-level information. Local targets were identified faster than global targets at the larger visual angles, but there was no difference in RT at the smallest visual angle. Despite this change in RT advantage, the interference effect did not change as a function of the visual angle of the stimulus pattern. Moreover, global distractors interfered with responding to local targets but local targets had no effect on responding to global targets, which is exactly the opposite of the finding one would expect if RT advantage and interference reflected order of processing. These findings are not consistent with the assumption that RT advantage and interference reflect order of processing in a simple way.     

Beyond the forest and the trees: local and global interference in hierarchical visual stimuli containing three levels

Our visual world can be thought of as organised in a hierarchical manner. Studies on hierarchical letter stimuli (a large letter composed of smaller letters) suggest that processing of a visual scene is global to local, a phenomenon known as the global-precedence effect. Elaborating on this global-to-local hypothesis we tested whether global interference will increase with increasing level of globality. For this, we used three-level hierarchical letter stimuli with a global, middle, and local level. When attending to the local level of the stimulus, only the middle level showed an interference effect, whereas the global level did not interfere at all. We argue that, considering the perceptual and attentional contributions to this effect, the hypothesis of global-to-local processing of a visual scene may only hold within a limited spatial attentional window.     

Attentional zooming and the global-dominance phenomenon: Effects of level-specific cueing and abrupt visual onset

Summary In four experiments level-specific cueing of hierarchically structured stimuli was used to test the hypothesis that valid cues can reduce the global-dominance phenomenon. Compound stimuli (Experiments 1 and 2) or simple geometric forms (Experiments 3 and 4) were presented with different SOAs after a valid, an invalid, or a neutral level-specific cue (cue validity 80%). Costs for invalid cues and benefits for valid cues were produced in all experiments. However, a reduction of the global-local RT difference to about zero was achieved only after the reduction of the abrupt visual onset accompanying stimulus presentation in Experiments 2 (with compound stimuli) and 4 (with simple geometric forms). In addition, there was no longer the typical asymmetric-interference pattern (i. e., features of the global level interfere with local identification, but not vice versa) that was one of Navon's (1977) main arguments for assuming a perceptual precedence. It is concluded that the RT that is longer for local than for global identifications is produced by the time needed to refocus visual attention intentionally from the global level, which is focussed at first unintentionally, to the local level.     

Processing of global and local information in memory

The experiments reported in this paper were designed to test how global and local information are processed by the memory system. When subjects are required to match a given letter with either a previously presented large capital letter or the small capital letters comprising it, (1) responses to the global level (i.e. the big letter) are faster than responses to the local level (i.e. the small letters), and (2) responses to the latter level only are affected by the consistency between the large and the small letters (Experiment 2), a pattern similar to that obtained in perception (Experiment 1). Such results obtain when subjects are required to attend to only one level with a short ISI between the first and second stimulus, but not when a longer ISI is used (Experiment 5) or when subjects are required to attend to both levels at the same time (Experiments 3 and 4). The results are discussed in the light of a model that postulates a temporal precedence of the global information over the local one at the perceptual level.     

Interference in letter identification: A test of feature-specific inhibition

The role of perceptual interference in letter identification was investigated in three experiments designed to test the feature-specific inhibition model proposed by Bjork and Murray (1977). According to their extension of Estes’ (1972, 1974) interactive channels model, input channels leading to the same feature detector inhibit one another more than do channels leading to different detectors. The model therefore predicts perceptual interference between two letters to be a function of the degree of their feature overlap. Experiment 1 confirmed the feature-specific inhibition model and Bjork and Murray’s finding that the accuracy of report is lower when a briefly presented target letter is flanked by an identical letter than when flanked by another target letter or by a nontarget letter. Results from Experiment 2 indicated that single-target performance is a function of the degree of feature similarity between the target letter and background characters in a stimulus display. Experiment 3 ruled out a spatial-uncertainty explanation of feature-specific inhibition in a new paradigm that does not require subjects to process a poststimulus cue. The results of these experiments are discussed in relation to recent studies exhibiting strong effects of noise letters at the response stage of processing. It is suggested that discrepancies between feature-specific interference and response-interference studies may be a function of the particular mode of stimulus presentation and of the dependent measures that are used.     

Preconscious analysis of global structure: Evidence from masked priming

According to the global precedence hypothesis, the perceptual processing of complex objects proceeds from global structure to the analysis of local elements. In the present study, we used a masked priming paradigm to explore whether the global or the local level of hierarchical letters is analysed at preconscious processing stages. Experiment 1 found masked priming only after global prime letters in focused‐attention conditions. Experiment 2 used a divided‐attention task in which attention was not focused specifically on either level of hierarchy and did not find any priming. Experiment 3 used otherwise the same task as Experiment 2 but biased attention either to the global or the local level by manipulating the probability that targets appeared at one level. Priming was found after global prime letters in the global‐bias condition but not in the local‐bias condition. Experiments 4a and 4b suggest that the size of the local letters was not responsible for the lack of priming after local primes. The results suggest a priority for global processing already at a preconscious level and that attentional factors may modulate processes at this level.     

Forest before trees? It depends where you look

Because it may be deduced from the more elementary principles of visual processing, global precedence (Navon, 1977) is not a primary perceptual principle. Subjects were presented with a large letter made out of small ones and asked to make an identification response on the basis of either the large or small letter. When fixation was controlled to provide adequate stimulation from the small letter, there was no difference in reaction time (RT) between the large and small targets. Also, there was no difference in interference due to response incompatibility of the unattended letter based on target size. However, when the stimulus was presented peripherally, unpredictably to the right or left of fixation, RT was faster to the large target and interference was substantially greater for the small target. Functions for the development of associative strength and associative interference are presented. Global precedence is dependent on factors tending to degrade small stimuli more than large ones.     

The forest revisited: More on global precedence

Summary Several issues pertaining to the notion of global precedence, its testing, and its ecological validity are discussed. Global precedence is presented as a claim that, other things being equal, global structure is available in the percept earlier than local features are. It does not state that local processing starts only after global processing is terminated. Since global precedence is a hypothesis about temporal development of percepts, a natural way to test it is to limit exposure duration. Global precedence predicts that local features will be more sensitive to stimulus duration than global ones.An experiment is reported in which subjects were presented with 150 ms exposures of large letters made up of small ones, and had to discriminate either just the large letters or just the small ones. In addition, they had to respond to the presence of a concurrent tone. Local letters were responded to more slowly than global ones, and were associated with more tone errors. The variation of the global level as well as the consistency between the identities of the levels affected the latency to the local letter, but not vice versa. A single small-letter control-condition was used to rule out an explanation in terms of relative size. The effects, albeit weaker than some previous results, are compatible with the hypothesis tested.The results of this experiment are interpreted in the context of an extensive discussion of findings in the paradigm and the generality of the phenomenon assumed to underly them. Possible mechanisms which may mediate global precedence are evaluated. Among them are relative size, lateral masking, diffuse attention, and spatial uncertainty. The magnitude, or even the presence, of global precedence depends on some factors, most prominent of which are visual angle and retinal position. Ecological considerations suggest that proximal sizes and eccentricities which favor global features may be very frequent. Some further subtleties of, as well as problems with, the logic of compound letters are discussed.     

Haptic identification of letters using the left or right hand

The present study investigated the effects of the use of the right and left hands on haptic identification of letters of the alphabet. Each of the 64 right-handed subjects was given three series of randomly ordered presentations of the 26 letters of the alphabet. The subjects were asked to feel each letter and name correctly each letter as quickly but as accurately as possible. Analysis showed faster identification by those subjects using their left hands on Series 1 with no hand-differences appearing on Series 2 and 3. Significant over-all improvement in identification time occurred with practice. The results were interpreted in terms of a novelty hypothesis of right-hemisphere function and an explanation of perceptual learning of letter identification.     

The effect of psychological distance on perceptual level of construal

Three studies examined the effect of primed psychological distance on level of perceptual construal, using Navon's paradigm of composite letters (global letters that are made of local letters). Relative to a control group, thinking of the more distant future (Study 1), about more distant spatial locations (Study 2), and about more distant social relations (Study 3) facilitated perception of global letters relative to local letters. Proximal times, spatial locations, and social relations had the opposite effect. The results are discussed within the framework of Construal Level Theory of psychological distance ( Liberman & Trope, 2008 ; Trope & Liberman, 2003 ).     

New evidence for the perceptual precedence of global information

Two experiments are reported investigating the order in which global and local information of visual forms is processed. Subjects were presented with compound stimuli and were asked to identify the local level, always consisting of small letters. At the global level, the stimuli could be either large letters, consistent or inconsistent with the local level, or meaningless patterns derived from the large letters by modifying the spatial relations among segments. Results showed that inconsistent stimuli were responded to more slowly than both consistent stimuli and meaningless patterns, which did not differ from each other. This was true both when letters and patterns were presented intermixed, as in experiment 1 or separately, as in experiment 2. The pattern obtained accords well with predictions derived from the perceptual precedence hypothesis which states that global information becomes available at a faster rate than local information. No support for the alternative, post-perceptual, hypothesis was found.     

Does aging affect the allocation of visual attention in global and local information processing?

The earliest studies of Navon (1977) showed that in certain conditions the visual perception of hierarchical stimuli generates a global precedence effect. This hypothesis is based on the joint occurrence of two effects: a response time (RT) advantage for identifying global targets and interference by global distractors when responding to a local target. The aim of the present study was to determine the involvement of attentional mechanisms and whether certain aspects are specifically altered by normal aging. In a selective-attention task, a complete global precedence effect was found for young and old subjects. However, for the old subjects, global interference on local identification was more pronounced than for the young subjects. In a divided-attention task, the RT advantage was affected by attention shifts between global and local forms for both young and old subjects, but the global interference effect did not change.     

Gobal-local precedence in picture processing

Summary Previous investigations of the global precedence hypothesis (Navon, 1977) have utilized compound letter stimuli. In these stimuli there is no predictive relationship between the global and local levels. Pictorial stimuli, however, contain mutually predictable global and local levels. This study investigated the global precedence hypothesis with pictorial stimuli using a Stroop-like interference task similar to that used by Navon. Subjects were required to respond either to the global (e.g., beach or farm) or local (e.g., boat or tractor) level of a scene. The display size and consistency of the global and local levels were varied. Response latencies supported global precedence for small scenes (4°) but local precedence for large scenes (16°). The results are interpreted by a model in which the priority of processing is determined by a critical spatial frequency sampling bandwidth.Portions of this research were presented at the meeting of the Psychonomic Society, Minneapolis, November, 1982. The authors with to express their sincere appreciation to Tom Petros for his assistance in data analysis. Requests for reprints should be addressed to James R. Antes, Department of Psychology, University of North Dakota, Grand Forks, ND 58202.     

Global precedence in attended and nonattended objects

In four experiments we evaluated whether there is a priority in early perceptual analysis for the global aspect of a nonattended, visual, compound stimulus. In all experiments, two objects were distinguished by being enclosed in either a square or a circle, and each object consisted of a larger letter constructed from smaller letters. Attention was directed to one of the two objects on the basis of either the square/circle distinction (Experiments 1, 2, and 3) or a visual precue (Experiment 4). In agreement with previous findings, for attended objects, the global aspect was identified faster and was more difficult to ignore than the local aspect. However, for nonattended objects, no evidence was found for an overall priority in perceptual processing leading to identification of the global aspect. Rather, the results indicate that there is a priority in perceptual processing for the general category of the global information contained within nonattended objects. Although the results provide some support for the view that global information receives priority during early perceptual analysis, aspects of the results are more consistent with postidentification accounts of global precedence.     

Global predominance in object recognition: artefact or treatment rule?

This paper provides a critical evaluation of the idea that, relative to the identity of the parts (local aspect), the configuration of the parts (global aspect) is of special importance during perceptual analysis. The controversy surrounding the global precedence phenomenon (Navon, 1977) is reviewed. In particular, I evaluate and reject the hypothesis that global precedence is simply the product of the greater discriminability of the global aspect. Instead, I propose that one general rule characterizing preattentive perceptual processing is a broad categorization of global information. I present the empirical evidence supporting this model and suggest some direction for future studies.     

Changes in same-different laterality patterns as a function of practice and stimulus quality

Accuracy and reaction time (RT) of judgments about sameness vs. difference of (a) names of two letters and (b) shapes of two nonverbal forms were examined for stimuli presented to the center, left (LVF), and right (RVF) visual fields. For same-name letter pairs during Experiment I, responses were more accurate and faster for LVF than for RVF trials on an initial 90-trial block, but this difference was reversed by a third 90-trial block. The RVF advantage for RT was maintained over Trial Blocks 4 and 5, given during a second session, but had disappeared on Trial Blocks 6 through 9 as RT reached the same asymptotic level for both visual fields. No LVF-RVF differences were obtained at any level of practice for different-name letter pairs or for any of the form pairs. Experiment II replicated the shift from LVF toward RVF advantage that occurred over the first three trial blocks of Experiment I and demonstrated that such a shift does not occur when the letters are perceptually degraded. The results were discussed in terms of differences in cerebral hemisphere specialization for visuospatial vs. abstract stages of letter processing and changes with practice in the relative difficulty of these stages.     

A test of the Sophisticated Guessing Theory of word perception

Under difficult viewing conditions, a letter in a familiar word can be perceived more accurately than the same letter alone or in a string of unrelated letters. Sophisticated Guessing Theory asserts that perception is more accurate when a letter appears in a word because its identity is constrained by the identity of neighboring context letters. Experiment 1 tested the following prediction: A letter in a word should be perceived more accurately in strongly constraining word contexts than in weakly constraining word contexts. No such trend was found using a number of different measures of contextual constraint and perceptual accuracy. Experiment 2 verified that, with the same conditions used in Experiment 1 to test Sophisticated Guessing Theory, a strong perceptual advantage could be obtained for letters in words vs. letters alone or in unrelated-letter strings. Several alternative theories of word perception are discussed. The most attractive asserts that for words an additional higher-level perceptual code is formed that is more resistant to degradation than the code formed for letters.     

Cognitive precedence for local information in hierarchical stimulus processing by pigeons

Four experiments investigated the processing of hierarchical stimuli by pigeons. Using a 4 alternative divided-attention task, 4 pigeons were food-reinforced for accurately identifying letters arranged as either hierarchical global- or local-relevant stimuli or as size-matched filled stimuli. Experiment 1 found that task acquisition was faster with local-relevant than global-relevant stimuli. This difference was not due to letter size. Experiment 2 demonstrated successful transfer to a novel irrelevant letter configuration. Experiments 3 and 4 tested pigeons' responses to conflict probe stimuli composed of equally discriminable relevant letters at each level. These tests revealed that all of the pigeons showed a cognitive precedence for local information early in processing, with the pigeons using different cues to initiate the processing of global information. This local advantage contrasts with previously reported results for humans and pigeons but is similar to that reported for nonhuman primates. Alternatives attempting to reconcile these contrasting comparative results are considered.     

Perceptual versus postperceptual mediation of visual context effects: Evidence from the letter-superiority effect

Two experiments demonstrated letter-context effects that cannot easily be accounted for by post-perceptual theories based on structural redundancy, figural goodness, or memory advantage. In Experiment 1, subjects identified the color of a letter fragment more accurately in letter than in nonletter contexts. In Experiment 2, subjects identified the feature presented in a precued color more accurately in letters than in nonletters. We argue that these effects result from top-down perceptual processing.