汉字间空格大小对青年人和老年人阅读的影响：眼动研究

拼音文字阅读的眼动研究发现,老年人会采取一种“风险”阅读策略来弥补因视力和认知的自然老化所造成的阅读困难。本研究通过控制字间空格的大小对青年人和老年人汉语阅读过程的眼动模式进行了比较,结果发现,相比青年人,老年人读得更慢,有更长的注视时间和更多的回视,这些研究结果与拼音文字一致;但更为重要的发现是,相比青年人,老年人有更短的向前眼跳距离,缩小汉语字间空格给老年人阅读造成了更为显著的困难,但扩大字间空格两组被试表现出相似的阅读眼动模式。结果说明,汉语阅读中老年人并不使用拼音文字研究中发现的“风险”阅读策略,反而采用了更为谨慎的策略,原因可能在于,作为拼音文字阅读中的重要视觉线索,空格是影响两种语言下老年人阅读加工策略不同的重要因素。     

Not fixating at the line of text comes at a cost

Previous research on eye guidance in reading has investigated systematic tendencies with respect to horizontal fixation locations on letters within words and the relationship between fixation location in a word and the duration of the fixation. The present study investigates where readers place their eyes vertically on the line of text and how vertical fixation location is related to fixation duration. Analyses were based on a large corpus of eye movement recordings from single-sentence reading. The vertical preferred viewing location was found to be within the vertical extent of the font, but fixations beyond the vertical boundaries of the text also frequently occurred. Analyzing fixation duration as a function of vertical fixation location revealed a vertical optimal viewing position (vOVP) effect: Fixations were shortest when placed optimally on the line of text, and fixation duration gradually increased for fixations that fell above or below the line of text. The vOVP effect can be explained by the limits of visual resolution along the vertical meridian. It is concluded that vertical and horizontal landing positions in single-sentence reading are associated with differences in fixation durations in opposite ways.     

Working memory and individual differences in the encoding of vertical, horizontal and diagonal symmetry

Previous studies, using a modified version of the sequential Corsi block task to examine the impact of symmetry on visuospatial memory, showed an advantage of vertical symmetry over non-symmetrical sequences, but no effect of horizontal or diagonal symmetry. The present four experiments investigated the mechanisms underlying the encoding of vertical, horizontal and diagonal configurations using simultaneous presentation and a dual-task paradigm. Results indicated that the recall of vertically symmetric arrays was always better than that of all other patterns and was not influenced by any of the concurrent tasks. Performance with horizontally or diagonally symmetrical patterns differed, with high performing participants showing little effect of concurrent tasks, while low performers were disrupted by concurrent visuospatial and executive tasks. A verbal interference had no effect on either group. Implications for processes involved in the encoding of symmetry are discussed, together with the crucial importance of individual differences.     

Coactivation, pop-out, and symmetry affect line discrimination

17 college students discriminated between vertical and horizontal target lines flanked by vertical and horizontal distractors. Large displays with 3.0-cm lines and small displays half this size were used. The distractors were positioned above and below the target or to the left and right of it, forming vertical and horizontal global orientations. The number of flankers sharing the target's orientation was varied. Vertical targets and small display sizes were processed more quickly. Speed of responding did not differ for the two global orientations. There was no advantage for target lines consistent with global orientation. The results were replicated in Exp. 2 with diagonal flankers. This supports an explanation using stimulus compatibility, since diagonal lines do not correspond to either of the response options and cannot induce a tendency to respond more to one target than another. Displays with multiple symmetry were responded to faster than those with a single symmetry which were faster than asymmetrical displays, supporting the idea that symmetrical axes parallel and perpendicular to the target orientation provide a facilitative frame of reference. Coactivation from same-oriented flankers, pop-out from differences in orientation, and symmetry all influenced responding in these patterns.     

Perceived path of oblique motion: horizontal-vertical and stimulus-orientation effects

Subjects adjusted the path of moving stimuli to produce apparent slopes of 45 degrees with respect to horizontal. The stimulus was either a single moving dot or a vertical or horizontal bar. In separate experiments either the stimuli were tracked or fixation was maintained on a stationary fixation target positioned 8 deg to the right of the center of stimulus motion. In both experiments the selected path slopes were in general more horizontal than 45 degrees. This pattern indicates that subjects overestimate the vertical component of motion along an oblique path, and is interpreted as a manifestation of the spatial anisometropy generally termed the 'horizontal-vertical illusion'. Additionally, paths selected for horizontal bars were more vertical than those for vertical bars. This finding is interpreted in the context of a previous report of the influence of stimulus orientation on perceived velocity.     

Integration of local features as a function of global goodness and spacing

In two experiments, the accuracy with which subjects detected a conjunction of features was examined as a function of the spacing between items and the goodness of the axis along which they were located. In each array, two items were arranged along a vertical, a horizontal, or a diagonal axis. Based on the well-established oblique effect, the vertical and horizontal axes were considered to be good global patterns and the diagonals were considered to be poor. In Experiment 1, the two items in an array could be two horizontal lines, two vertical lines, a vertical and a horizontal line, or a plus sign with one of the single lines. In Experiment 2, a positive- and a negative-diagonal line were used as the individual features, and an "X" was used as the conjunction. The results from Experiment 1 indicated that global goodness influenced only the rate of illusory conjunctions, and not of feature errors. Illusory conjunctions of vertical and horizontal line segments were more likely to occur in vertical and horizontal arrangements. The results from Experiment 2 revealed a reversal of the effect of global goodness on the rate of illusory conjunctions: Illusory conjunctions of negative- and positive-diagonal line segments were more likely to occur in diagonal arrangements. The results of both experiments taken together showed the existence of an important and new factor that influences the likelihood that features of shape will be conjoined: the ease with which line segments conjoin when they are translated along their extent toward each other. In both experiments, greater spacing between items produced more feature-identification errors and fewer feature-integration errors than did less spacing.     

The effects of adaptation to square-wave gratings as a function of grating orientation

An adaptation technique was used to measure the selectivity or tuning for grating orientation in the visual system for different orientations of the inspection stimulus. Duration thresholds for grating patterns of constant luminance were determined for 13 test gratings oriented from ±5 to 90 deg away from each of five adaptation gratings: 0, 22, 45, 67, and 90 deg. Threshold data obtained for test gratings without prior adaptation indicated higher sensitivity for gratings oriented along the horizontal and vertical axis than along the oblique axis. After adaptation, thresholds increased (sensitivity was reduced) for gratings having similar orientations as the test gratings. However, the functions relating sensitivity reduction to degree of angular disparity between test and adaptation grating did not vary across the five inpsection orientations, i.e., selectivity or tuning for grating orientation appeared to be independent of the orientation of the adapting stimulus.     

Visual field differences in recognizing letters

Differences due to visual field location were examined for single letters placed at one of 12 clockface positions 3° and 6° from fixation. Results compared closely with established findings using simple light stimuli, showing best recognition on the horizontal meridian, poorest on the vertical and intermediate on oblique meridians. Subjects’ confidence ratings followed the same pattern. There was evidence for a specific right superiority along the horizontal meridian, as found in previous studies, but no evidence for a general right hemifield superiority. The difficulty of arguing from these findings to available dominance or scanning explanations is pointed out. It is proposed that effects due to visual field variability may have a pervasive yet largely unrecognized influence in visual perception research.     

An orientation anisotropy in induced brightness

It is shown that an orientation anisotropy exists for the magnitude of induced brightness in a cruciform stimulus consisting of a grey test patch positioned at the intersection of two inducing bars, one black and one white, oriented at right angles to each other. When the cruciform was oriented such that the white bar was horizontal, the grey patch appeared darker than when the same cruciform was oriented such that the white bar was vertical. The contribution of the black and white inducing bars towards the brightness of the test patch was investigated. A simple mathematical function, which took into account both the contribution of the two component inducing bars and the orientation anisotropy, was fitted to the data. No consistent orientation anisotropy was found with inducing stimuli at oblique orientations.     

Orientation,length and exposure duration in the identification of line segments

Summary Single line segments titled with 0, 45, 90, and 135 degrees orientation were briefly exposed as stimuli and the subjects had to identify the orientation of a presented line segment. The length of the lines and the exposure duration were varied. The multicomponent theory (Rumelhart, 1970, 1971) was applied to the observed frequencies of a correct response and of some incorrect responses given to a stimulus with a particular orientation, length, and exposure duration. Within the framework of this theory several hypotheses concerning the effects of orientation, length and exposure duration in identification were tested. The main results are: (1) The rate of component detection was higher for the horizontal and vertical orientations than for the two oblique orientations. (2) The number of components in a line segment quite accurately followed a linear function of the line's physical length, and the negatively valued additive constant in this function could not be neglected. (3) The information in the visual information store decayed more rapidly after longer exposure durations and more slowly after shorter exposure durations. These findings are discussed in relation to other research on the subject.     

Disparity minimisation, cyclovergence, and the validity of nonius lines as a technique for measuring torsional alignment

Frisby et al (1993 Perception 22 Supplement, 115) proposed that the visual system might make cyclovergent eye movements in order to minimise the overall pattern of both vertical and horizontal disparities when an observer views an inclined stereoscopic surface. Their measurements of cyclovergence, which used vertically oriented nonius lines, were found to be consistent with that proposal. In our experiment 1, we measured torsional eye movements objectively, using scleral coils, and found no evidence of a cyclovergent response to either a real inclined surface or to a simulated inclined surface in which the two stereoscopic images were related by a horizontal shear transformation. These results are inconsistent with the disparity minimisation hypothesis. In order to account for the discrepant findings of the two studies, we propose that vertically oriented nonius lines may not be a valid method for assessing cyclovergence because the lines can be seen as lying 'within' the inclined surface. In experiment 2, we tested the predictions of the cyclovergence hypothesis of Frisby et al against our own 'within surface' explanation, using both horizontally and vertically oriented nonius lines and dichoptic images related by either a horizontal or a vertical shear. If cyclovergence were the cause of the misalignment, both horizontal and vertical nonius lines should appear misaligned to the same extent. This was not found to be the case. We conclude that vertical nonius lines may not be a valid technique for measuring cyclovergence when the lines are seen against a background of an inclined surface.     

Perception of objects oriented downward from a vertical position

In the present work we investigated people’s perceptions of orientation for surfaces that are conceived of as being sloped downward from vertical against a vertical reference frame. In the three conditions of Experiment 1, participants either (1) placed a ladder against a wall at what they thought was the most stable position, and then estimated its orientation; (2) gave a verbal (conceptual) estimate of what the most stable position of a ladder leaned against a wall would be; or (3) drew a line representing the most stable position of a ladder to be placed against a wall, and then gave a verbal estimate of the ladder’s orientation. Ladder placement was shallower than the most stable position, as were the verbal estimations of both the positioned and drawn orientations and the verbal (conceptual) estimates of the most stable position for a ladder to be leaned against a wall, relative to the actual orientations. In Experiment 2, participants verbally estimated various ladder orientations. The estimates were again shallower than the actual orientations. For orientations between 60° and 90°, the estimates showed a scale compression effect from horizontal. This perceived exaggeration of the orientation of an object typically oriented down from vertical is similar to the perceived exaggeration of the orientation of hills and ramps, typically thought of as oriented up from horizontal. This may point to a generic perceived exaggeration of slant whose direction depends on the conceptual or actual reference frame being used.     

Orientation and spatial frequency effects on linear afterimages: The retinal reference for selectivity — A supplementary report

Afterimages of gratings oriented vertically or at 45 deg relative to gravity were generated with the head upright or tilted so that the retinal meridian was inclined 45 deg. The duration of visibility of the whole afterimage was longer for the vertical grating when the head was upright and for the 45-deg grating when the head was tilted. It was concluded that this orientation selectivity of afterimages is dependent upon the orientation of the grating with respect to the retinal meridian rather than to the direction of gravity.     

Orientation tuning of shape from shading

Four experiments were performed to assess the effect of different orientations and direction of lighting on the visual processing of shaded or bipartite disks. In the first two experiments, observers were presented with nine different shading orientations from 0 degree to 180 degrees. Targets were detected in a rapid and parallel fashion for shaded disks when the orientation of the shading gradient was not horizontal (90 degrees) or oriented at 67.5 degrees. Search asymmetries favoring the detection of "pock" targets over "ball" targets were found for all orientations. The search rates for bipartite disks were similar to the shaded disks at 0 degree, 22.5 degrees, and 90 degrees but not for intermediate orientations, and no search asymmetries were found. These differences suggest that shaded displays and bipartite displays are processed by different underlying mechanisms. The third experiment showed that the direction of the light source (left or right) had no influence on search asymmetries around the 90 degrees point. Shading gradient orientation affected magnitude estimates of depth in the fourth experiment. These experiments show that the visual system's "assumption" of overhead lighting is broadly tuned.     

Spatial asymmetries in tactile discrimination of line orientation: a comparison of the sighted, visually impaired, and blind

Thresholds for tactile discrimination of stimulus orientation discrepancy from standard or referent vertical, horizontal, and diagonal orientations were determined for sighted, visually impaired, and blind subject groups. The stimuli were presented to the ventral distal portion of the tip of the subject's left index finger via an Optacon. Although the subject groups did not differ in overall discrimination accuracy, for each group the deviations from vertical and horizontal standard orientations were discriminated reliably more accurately than the deviations from standard diagonals, ie the oblique effect was obtained. The bases for this tactual spatial anisotrophic effect appear to reflect both sensory--neurological and experiential factors.     

Eye movements of second language learners when reading spaced and unspaced Chinese text

The effect of spacing in relation to word segmentation was examined for four groups of non-native Chinese speakers (American, Korean, Japanese, and Thai) who were learning Chinese as second language. Chinese sentences with four types of spacing information were used: unspaced text, word-spaced text, character-spaced text, and nonword-spaced text. Also, participants' native languages were different in terms of their basic characteristics: English and Korean are spaced, whereas the other two are unspaced; Japanese is character based whereas the other three are alphabetic. Thus, we assessed whether any spacing effects were modulated by native language characteristics. Eye movement measures showed least disruption to reading for word-spaced text and longer reading times for unspaced than character-spaced text, with nonword-spaced text yielding the most disruption. These effects were uninfluenced by native language (though reading times differed between groups as a result of Chinese reading experience). Demarcation of word boundaries through spacing reduces non-native readers' uncertainty about the characters that constitute a word, thereby speeding lexical identification, and in turn, reading. More generally, the results indicate that words have psychological reality for those who are learning to read Chinese as a second language, and that segmentation of text into words is more beneficial to successful comprehension than is separating individual Chinese characters with spaces.     

What guides a search for food that has disappeared? Experiments on cotton-top tamarins (Saguinus oedipus).

When food is launched down a vertically positioned S-shaped opaque tube, cotton-top tamarins (Saguinus oedipus) search for the food in the position directly beneath the release point, even though over several trials it never appears in this position (B. M. Hood et al., 1999). Experiment 1 showed that when the trajectory of the food shifts from the vertical to the horizontal plane, tamarins no longer show systematic perseverative errors and, in general, perform better on this invisible displacement task. Experiment 2 showed that tamarins with experience on the horizontal task show less of a bias when tested on the vertical task but nonetheless fail overall to solve this invisible displacement problem; their performance is substantially worse than it was on the horizontal task. Experiment 3 revealed that when the vertically positioned tube is replaced by an occluded ramp, tamarins consistently search in the compartment below the release point, even though most of the tamarins had experience in Experiments 1 and 2. Overall, results indicate that tamarins have a significant gravity bias when searching for food that has disappeared along the vertical plane but also have more general problems finding food that has moved out of sight.     

Reading rotated words

Hebrew-speaking students performed lexical decisions on Hebrew letter strings that appeared at different orientations. Response times evidenced a strong interaction between string length and orientation. At angular deviations of less than 60 degrees from the upright, neither orientation nor string length had any effect, suggesting that words were directly, and probably holistically, recognized. The results for the 60 degrees deviation, while also exhibiting no effects of word length, yielded slower response times, suggesting a holistic rectification process. For deviations between 60 degrees and 120 degrees, the effects of disorientation increased sharply with increasing string length, suggesting piecemeal processing that may be due to the utilization of reading units smaller than the whole word or to piecemeal rectification. In this region, stimulus disorientation appears to impair word recognition by disrupting transgraphemic information rather than by interfering with letter identification. Extreme disorientations, 120 degrees or more, exhibited no further impairment with increased disorientation, and all evidenced strong and similar length effects, suggesting letter-by-letter reading. The implications of the results for the reading of normal and transformed text are discussed.