规则多边图形的离散度与图形信号认知绩效的关系

用实验方法研究规则多边图形的离散度与图形信号认知绩效的关系。实验的自变量是图形的离散度参数,因变量是单位时间图形信号的视觉通道信息传递量。实验的刺激材料是２５个离散度为０．３～０．７的规则多边图形。刺激材料的呈现与被试的反应记录都由计算机控制。结果表明：离散度适中（０．５左右）及偏小的图形信号认知绩效较高,离散度从０．５增大到０．６,认知绩效迅速下降,离散度继续增大,认知绩效仍有下降,但趋势平缓。     

Angular homeostasis: IV. Polygonal orbits

Some properties are discussed of regular polygons that may result from angular homeostatic processes in stable orbit. To characterize these homeostatic polygons we need to discuss the winding number, the sidedness (integer, fractional and irrational), multiplicity, envelopes, and density. A regular (i.e., equilateral, equiangular) polygon may be closed in one revolution about its unique center, in multiple revolutions, or not at all. A homeostatic polygon can be generated only if all vertices are included in a single polygon, which occurs if and only if the number of vertices and the number of revolutions required to complete the polygon are relatively prime. For the homeostatic polygon to have a finite number of sides (without repeating itself) the angle subtended by any two successive vertices at the center must be a rational multiple of 2. Biological implications of these properties are illustrated.     

The perception of continuous curves in dot stimuli

Two categorisation experiments are reported in which the perceptual phenomenon that some simple arrays of discrete dots appear as a continuous curve whereas others are perceived as an angular contour or as consisting of separate groups of dots was investigated. Triplets of dots were presented in the first experiment, and complete or incomplete regular dot polygons (ie dots positioned on the vertices of imaginary regular polygons) in the second. In both experiments the perception of a curve versus an angle was determined mainly by the relative orientations of the dots, ie by the angles between successive virtual lines, whereas the lengths of the virtual lines had relatively little influence. In experiment 2 the number of displayed dots was shown to be a second independent factor for perceiving continuity. These results are in agreement with results from experiments on dipole textures discrimination, and suggest the psychological existence and importance of virtual lines in the visual processing of dot stimuli.     

Intra- and interindividual variation in the power law exponent for area summation

Subjects were required to indicate the magnitudes of subjective sums of areas of regular 20-sided polygons by three methods—generation of a polygon of matching area, estimation of the ratio of the subjective sum to a fixed area, and magnitude estimation. Power law exponents were estimated for each subject by maximum likelihood estimation. A very large amount of interindividual exponent variation was observed. Exponents resulting from magnitude estimation were consistent on the average with previous results, but exponents from area matching and ratio estimation were much larger and close to unity. When subjects were given feedback on the discrepancy between their responses and physical area summation, they readily shifted their exponents toward unity.     

Visual statistical learning at basic and subordinate category levels in real-world images

Visual statistical learning (VSL) has been proposed as a powerful mechanism underlying the striking ability of human observers to handle complex visual environments. Previous studies have shown that VSL can occur when statistical information is embedded at multiple levels of abstraction, such as at semantically different category levels. In the present study, we further examined whether statistical regularities at a basic category level (e.g., a regular sequence of a bird, then a car, and then a dog) could influence the ability to extract statistical regularities at the subordinate level (e.g., a regular sequence of a parrot, then a sports car, and then an Eskimo dog). In the familiarization phase, participants were exposed to a stream of real-world images whose semantic categories had temporal regularities. Importantly, the temporal regularities existed at both the basic and subordinate levels, or the regularities existed at only the subordinate level, depending on the experimental condition. After completing the familiarization, participants performed a surprise two-alternative forced choice (2AFC) task for a familiarity judgment between two triplets in which the temporal regularities were either preserved or not preserved. Our results showed that the existence of statistical regularities at the basic level did not influence VSL at the subordinate level. The subsequent experiments showed these results consistently even when the basic-level categories had to be explicitly recognized and when the stimuli were not easily categorized at their subordinate level. Our results suggest that VSL is constrained to learn a particular level of patterns when patterns are presented across multiple levels.     

Learning at a distance I. Statistical learning of non-adjacent dependencies

In earlier work we have shown that adults, young children, and infants are capable of computing transitional probabilities among adjacent syllables in rapidly presented streams of speech, and of using these statistics to group adjacent syllables into word-like units. In the present experiments we ask whether adult learners are also capable of such computations when the only available patterns occur in non-adjacent elements. In the first experiment, we present streams of speech in which precisely the same kinds of syllable regularities occur as in our previous studies, except that the patterned relations among syllables occur between non-adjacent syllables (with an intervening syllable that is unrelated). Under these circumstances we do not obtain our previous results: learners are quite poor at acquiring regular relations among non-adjacent syllables, even when the patterns are objectively quite simple. In subsequent experiments we show that learners are, in contrast, quite capable of acquiring patterned relations among non-adjacent segments-both non-adjacent consonants (with an intervening vocalic segment that is unrelated) and non-adjacent vowels (with an intervening consonantal segment that is unrelated). Finally, we discuss why human learners display these strong differences in learning differing types of non-adjacent regularities, and we conclude by suggesting that these contrasts in learnability may account for why human languages display non-adjacent regularities of one type much more widely than non-adjacent regularities of the other type.     

Laws, Regularities and Exceptions

Sentences of the form ' F s are G s' can express laws of nature, weaker Special Science laws, and also regularities which are not a part of any explicit science. These so-called generic sentences express nomic relationships which may have exceptions. I discuss the kinds of regularities expressed by generic sentences and argue that since they play a similar role in determining our ability to categorise and reason about the world, we should look for a unified treatment of them.     

Location memory for dots in polygons versus cities in regions: Evaluating the category adjustment model

We conducted 3 experiments to examine the category adjustment model (Huttenlocher, Hedges, & Duncan, 1991) in circumstances in which the category boundaries were irregular schematized polygons made from outlines of maps. For the first time, accuracy was tested when only perceptual and/or existing long-term memory information about identical locations was cued. Participants from Alberta, Canada and California received 1 of 3 conditions: dots-only, in which a dot appeared within the polygon, and after a 4-s dynamic mask the empty polygon appeared and the participant indicated where the dot had been; dots-and-names, in which participants were told that the first polygon represented Alberta/California and that each dot was in the correct location for the city whose name appeared outside the polygon; and names-only, in which there was no first polygon, and participants clicked on the city locations from extant memory alone. Location recall in the dots-only and dots-and-names conditions did not differ from each other and had small but significant directional errors that pointed away from the centroids of the polygons. In contrast, the names-only condition had large and significant directional errors that pointed toward the centroids. Experiments 2 and 3 eliminated the distribution of stimuli and overall screen position as causal factors. The data suggest that in the "classic" category adjustment paradigm, it is difficult to determine a priori when Bayesian cue combination is applicable, making Bayesian analysis less useful as a theoretical approach to location estimation. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

任务规律性对前瞻记忆的影响

采用混合实验设计,结合行为和眼动数据,探讨任务规律性对前瞻记忆的影响。行为结果显示规律已知条件下前瞻记忆成绩显著高于规律未知和无规律条件,规律未知条件下的前瞻记忆成绩在靶线索之后刺激上有高于无规律条件的趋势;眼动结果显示规律已知条件下的注视点最多,首次注视时间最长。结果说明:(1)任务规律性对前瞻记忆成绩具有促进作用;(2)任务规律性促进了对前瞻记忆任务的自动化加工;(3)在规律已知条件下前瞻记忆的加工过程呈现出动态交替的特点。     

Interrupted visual searches reveal volatile search memory

This study investigated memory from interrupted visual searches. Participants conducted a change detection search task on polygons overlaid on scenes. Search was interrupted by various disruptions, including unfilled delay, passive viewing of other scenes, and additional search on new displays. Results showed that performance was unaffected by short intervals of unfilled delay or passive viewing, but it was impaired by additional search tasks. Across delays, memory for the spatial layout of the polygons was retained for future use, but memory for polygon shapes, background scene, and absolute polygon locations was not. The authors suggest that spatial memory aids interrupted visual searches, but the use of this memory is easily disrupted by additional searches.     

Incidental learning of real-world regularities

The large literature on incidental learning relies almost exclusively on laboratory experiments. Whenever researchers have attempted to demonstrate incidental learning of real-world regularities, they have typically failed to show learning. For example, it is well established that people do not learn regularities in everyday objects, such as the left-right orientation of faces on coins, despite a very large exposure to them. In this report, we examine this apparent contradiction. We argue that most studies exploring real-life incidental learning use tests that are not as sensitive to low-confidence information as those traditionally used in laboratory tasks. Using more sensitive measures, we show that it is possible to learn regularities from British and Japanese cultural life as a direct result of exposure to these regularities. Further, confidence measures suggest that although the information may be acquired incidentally, it can be expressed with and without concomitant awareness of that knowledge.     

Does size rescaling require central attention?

The goal of the present experiment was to determine if object size rescaling in the shape-matching task requires central resources. Two polygons were presented side by side as the second task in a psychological refractory period paradigm. The polygons could be the same as each other or mirror images of each other and the size ratio between the two polygons was varied. In the first task, subjects were required to make a speeded response to the pitch of a tone. The polygon task followed at varying SOAs and the subjects then made a speeded same/mirror image judgement on the polygons. The size ratio effect was additive with SOA indicating that size rescaling is capacity demanding and that it requires central attention.     

Recognition of partly occluded objects by fish

The ability to visually complete partly occluded objects (so-called “amodal completion”) has been documented in mammals and birds. Here, we report the first evidence of such a perceptual ability in a fish species. Fish (Xenotoca eiseni) were trained to discriminate between a complete and an amputated disk. Thereafter, the fish performed test trials in which hexagonal polygons were either exactly juxtaposed or only placed close to the missing sectors of the disk in order to produce or not produce the impression (to a human observer) of an occlusion of the missing sectors of the disk by the polygon. In another experiment, fish were first trained to discriminate between hexagonal polygons that were either exactly juxtaposed or only placed close to the missing sectors of a disk, and then tested for choice between a complete and an amputated disk. In both experiments, fish behaved as if they were experiencing visual completion of the partly occluded stimuli. These findings suggest that the ability to visually complete partly occluded objects may be widespread among vertebrates, possibly inherited in mammals, birds and fish from early vertebrate ancestors.     

Investigating local and global effects of surface colours and contours in amodal completion

ABSTRACT

We studied interpretations of partly occluded shapes. Models that account for amodal completion mostly deal with local and global contour characteristics. In the current study, we were interested in the effects of colour on local and global contour completions. In our stimuli, local contour completions comprised simple linear extensions of the partly occluded contours, whereas global contour completions accounted for global shape regularities. Our stimuli were designed such that the visible surface colour could also be completed in a local or global fashion, being consistent or inconsistent with contour completions. We tested the preferred interpretations of the partly occluded shapes by using a sequential matching task. Participants had to judge whether a test shape could be a previously shown partly occluded shape. We found that interpretations of partly occluded shapes depend on both colour and contour characteristics. Additional time bin analyses revealed that for fast responses colour and contour completions already depend on the visible context of the partly occluded shapes, while for slow responses the congruency between colour and contour completions play a role as well.     

Statistical regularities modulate attentional capture independent of search strategy

An earlier study using the additional singleton task showed that statistical regularities regarding the distractor location can cause an attentional bias that affects the amount of attentional capture by distractors and the efficiency of selection of targets. The distractor singleton was systematically present more often in one location than in all other locations. The present study investigated whether this bias also occurs when observers adopt a feature search mode, i.e., when they search for a specific feature (circle) between elements with different shapes, while ignoring a colored distractor singleton. It is assumed that in feature search, observers can ignore distractors in a top-down way and as such one expects that statistical regularities about the distractor location should not play a role. Contrary to this prediction, we found that even in feature search, both attentional capture by the distractors and the efficiency of selecting the target were impacted by these statistical regularities. Moreover, statistical regularities regarding the feature value of the distractor (its color) had no effect on the amount of capture or the efficiency of selection. We claim that statistical regularities cause passive lingering biases of attention such that on the priority map, the location containing a high probability distractor competes less for attention than locations that are less likely to contain distractors.     

Local contour characteristics as determinants of pattern discrimination

Subjects were required to discriminate complex random polygons which had the same global shapes but differed in local contour characteristics. Discrimination was most often successful when local contour features comprised a few long line segments or when they were relatively complex. Local contour features of intermediate sized elements and intermediate complexity played a smaller role in discrimination. Presentation time and interstimulus interval effects, and their interaction were observed. A two-factor explanation was offered for the effect of the contour variable.     

Implications of measurement of eye fixations for a psychophysics of form perception

It was suggested that insights into feature analysis of processes involved in form identification might be gained from an analysis of eye movements made by Ss as they identified patterns. Fixations were measured during identifications of histoforms, polygons, and Vargus 10 figures. Eye fixations were measured, and Ss rated sections of the figures in terms of their importance. Eye fixations were measured in terms of number of changes and duration of fixations. The number of changes in fixation were found to reflect only individual differences. Duration of fixation was found to vary significantly with location within figures, with fixations being longest where changes of contour occurred. There was also a tendency to look longer at the top of polygons and Vargus 10 figures and at the center of histoforms. Ratings of importance were highest for sections of figures fixated for longer duration-generally areas in which changes of contour were present.     

The paradox of the universal triangle: Concepts,language, and prototypes

For over 300 years, the humble triangle has served as the paradigmatic example of the problem of abstraction. How can we have the idea of a general triangle even though every experience with triangles is with specific ones? Classical cognitive science seemed to provide an answer in symbolic representation. With its easily enumerated necessary and sufficient conditions, the triangle would appear to be an ideal candidate for being represented in a symbolic form. I show that it is not. Across a variety of tasks—drawing, speeded recognition, unspeeded visual judgments, and inference—representations of triangles appear to be graded and context dependent. I show that using the category name “triangle” activates a more prototypical representation than using an arguably coextensive cue, “three-sided polygon”. For example, when asked to draw “triangles” people draw more typical triangles than when asked to draw “three-sided polygons”. Altogether, the results support the view that (even formal) concepts have a graded and flexible structure, which takes on a more prototypical and stable form when activated by category labels.     

Form identification in peripheral vision

Outlined and solid-surfaced metric histoforms and polygons we;e employed in an identification task where choice forms were fixed at 0 deg and target forms at six points along the temporal horizontal meridian in the periphery (nasal retina). Accuracy in the identification of solid-surfaced polygons in the far periphery (80 deg from the fovea) was much higher than has been previously reported. Polygons were identified more quickly than histaforms, but a significant difference was not obtained between the speed of identification of outlined and solid shapes. Combined speed and error data indicated that shape (histoform or polygon) is the most salient dimension of a form less than 50 deg from the fovea. whereas beyond 50 deg from the fovea the surface (outlined or solid) of a form is its most salient dimension. Finally. comparisons of the functional relations provided by these performance data with anatomical and physiological data produced the following hypothesis: Spatial summation of rod receptors beyond 20 deg of angular eccentricity in the nasal retina is directly proportional to the density of rod receptors.