Influence of aesthetic perception on visual event-related potentials

The aim of the study was to assess the effects of visual aesthetic perception on event-related potentials (ERPs). Eight subjects assigned an aesthetic judgment (beautiful, neutral, or ugly) and a 10-step beauty estimation to the target stimuli, consisting of famous artistic pictures and geometric shapes. In a further task, the subjects performed a motor response to the previously judged pictures and geometric shapes. ERPs were recorded through 54 scalp electrodes during both tasks. The P3b amplitude was increased during the categorization of the geometric shapes compared to the artistic figures and during the vision of the beautiful targets preceding the motor response. The categorization of the aesthetic qualities of geometrical shapes seems to induce a higher level of attention, while a higher arousal variation was elicited by the recognition of beauty, in any form that was presented.     

The influence of phonological neighborhood on visual word perception

In the research reported here, we investigated the influence of phonological neighborhood density on the processing of words in the visual lexical decision task. The results of the first experiment revealed that words with large phonological neighborhoods were verified more rapidly than words with small phonological neighborhoods. In the second experiment, we replicated this effect with a more tightly controlled set of stimuli. These results demonstrate the importance of phonological codes when processing visually presented letter strings. We relate this research to previous results on semantic and orthographic neighborhoods and discuss the results within the context of a model in which lexical decisions are based on stimulus familiarity.     

Expertise in pictorial perception: eye-movement patterns and visual memory in artists and laymen

In two sessions with free scanning and memory instructions, eye-movement patterns from nine artists were compared with those of nine artistically untrained participants viewing 16 pictures representing a selection of categories from ordinary scenes to abstraction: 12 pictures were made to accommodate an object-oriented viewing mode (selection of recognisable objects), and a pictorial viewing mode (selection of more structural features), and 4 were abstract. The artistically untrained participants showed preference for viewing human features and objects, while the artists spent more scanning time on structural/abstract features. A group by session interaction showed a change of viewing strategy in the artists, who viewed more objects and human features in the memory task session. A verbal test of recall memory showed no overall difference in the number of pictures remembered, but the number of correctly remembered pictorial features was significantly higher for artists than for the artistically untrained viewers, irrespective of picture type. No differences in fixation frequencies/durations were found between groups across sessions, but a significant task-dependent-group by session interaction of fixation frequency/duration showed that the artistically untrained participants demonstrated repetition effects in fewer, longer fixations with repeated viewing, while the opposite pattern obtained for the artists.     

The influence of eye movements and eye position on perception of the visual vertical

Summary Four experiments are reported which involved the adjustment of two points of light in an otherwise dark room to the visual vertical. In the first two experiments different point separations (corresponding to visual angles of about 2° and 23°) were employed in an attempt to control the degree of scanning eye movements. Binocular adjustments to the visual vertical during body tilt were influenced by the point separation (Exp. 1), but monocular adjustments with the head upright were not (Exp. 2). Using the larger point separation and fixating the top point the visual vertical using the right eye was counterclockwise of that with fixation of the bottom point when the head was upright (Exp. 3), but this difference was not found for judgments during tilt (Exp. 4). The results were discussed in terms of the rotational changes in eye position accompanying scanning eye movements and ocular elevation and depression.

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Zusammenfassung Es wird über vier Experimente berichtet, in denen es um die Einstellungen zweier Lichtpunkte in eine vertikale Richtung geht. In den ersten zwei Experimenten sollte der Einfluß der Fixierbewegungen der Augen geprüft werden. Der Winkelabstand der Lichtpunkte betrug 2° oder 23°. Bei seitwärts geneigtem Körper und binokularer Betrachtung wurde ein Unterschied gefunden (Exp. 1). Bei aufrecht gehaltenem Kopf und monokularer Betrachtung dagegen zeigte sich kein Unterschied (Exp. 2). Wurde in aufrechter Körperlage und bei einem Punktabstand von 23° der obere Punkt mit dem rechten Auge fixiert, so verschob sich die scheinbare Vertikale im Uhrzeigersinn; sie verschob sich noch weiter im Uhrzeigersinn, wenn der untere Punkt fixiert wurde (Exp. 3). Bei geneigtem Körper wurde dagegen kein Unterschied festgestellt (Exp. 4). Die Ergebnisse werden im Zusammenhang mit der Augendrehung diskutiert, die mit dem scanning sowie mit der Auf- und Abbewegung der Augen beim Fixieren verbunden ist.

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This research was carried out while I was a recipient of a Forschungsstipendium from the Alexander von Humboldt-Stiftung, appreciation for which is gratefully acknowledged. I also wish to thank the subjects who participated in the experiments.     

On a neglected variable in theories of pictorial perception: Truncation of the visual field

Theoretical analyses of pictorial perception have concentrated on the consequences of conflicting flatness and depth information in pictures, but have failed to consider the perceptual effects of the truncation of the visual field attendant on any pictorial display. The importance of this variable both for methods of testing pictorial information and for theory building was demonstrated. Under four different viewing conditions, adults were asked to scale the size and distance of five isoceles triangles at five different distances. The four conditions were unobstructed static monocular view, peephole view, view through a rectangular frame, and view of all the stimuli photographed in a slide. The slopes of the peephole, truncation, and slide conditions’ scaling functions were all significantly smaller than the slope of the untruncated Monocular condition, and the Y-intercepts were all greater. A decrease in over-constancy in the size functions indicated a similar effect for all three truncated conditions. Results are interpreted as supporting the hypothesis that truncation of the visual field, both in pictures and in peephole views of the real world, causes a frontal shift in the localization of the visible field, with a resultant compression of perceived size and distance.     

The role of pictorial convention in haptic picture perception

An investigation of tactile picture perception is reported. Blindfolded sighted subjects explored either 'line drawings' or 'textured' tactile pictures produced on Zytex swell paper. All pictures were 'two-dimensional', that is they depicted only one object face and so did not represent a third dimension. Both picture sets represented the same objects. Results revealed that the textured pictures, in which solid surfaces of depicted objects were uniformly textured, were recognised more often than tactile line drawings, in which surfaces of objects were simply bounded by lines. There were no significant correlations between imagery ability (visual, cutaneous, or kinaesthetic) and picture recognition success. Texture may be a form of 'uniform connectedness' (Palmer and Rock 1994 Psychonomic Bulletin & Review 1 29-55) or 'common region' (Palmer 1992 Cognitive Psychology 24 436-447), highlighting the global characteristics of stimuli. We argue that textured pictures may encourage the haptic system to take a more globally oriented approach to tactile picture perception, benefiting recognition.     

The visual perception of lines on the road

The present work demonstrates that observers grossly underestimate the length of lines parallel to their line of sight. In Experiment 1, observers, working from memory, estimated the length of a dashed line on the road to be 0.61 m. This result is consistent with observers' using an average visual angle converted to the physical length of visible lines on the road to estimate their length. In Experiment 2, observers gave verbal and matching estimates that significantly underestimated the length of a 3.05-m line on the ground that was parallel to their line of sight. In Experiment 3, observers significantly underestimated the length of dashed lines on the road while in a moving car. The results of Experiments 1 and 3 are described well by Euclidean geometry, whereas the tangle model that utilizes an increasing function of the visual angle to describe perceived extent best describes the results of Experiment 2.     

The influence of visual perception of self-motion on locomotor adaptation to unilateral limb loading

Self-perception of motion through visual stimulation may be important for adapting to locomotor conditions. Unilateral limb loading is a locomotor condition that can improve stability and reduce abnormal limb movement. In the present study, the authors investigated the effect of self-perception of motion through virtual reality (VR) on adaptation to unilateral limb loading. Healthy young adults, assigned to either a VR or a non-VR group, walked on a treadmill in the following 3 locomotor task periods--no load, loaded, and load removed. Subjects in the VR group viewed a virtual corridor during treadmill walking. Exposure to VR reduced cadence and muscle activity. During the loaded period, the swing time of the unloaded limb showed a larger increase in the VR group. When the load was removed, the swing time of the previously loaded limb and the stance time of the previously unloaded limb showed larger decrease and the swing time of the previously unloaded limb showed a smaller increase in the VR group. Lack of visual cues may cause the adoption of cautious strategies (higher muscle activity, shorter and more frequent steps, changes in the swing and stance times) when faced with situations that require adaptations. VR technology, providing such perceptual cues, has an important role in enhancing locomotor adaptation.     

The influence of lateral organization on the evaluation of paintings.

This study examines the influence of directional properties of lateral organization on evaluation of paintings. Lateral organization, as defined here, has two dimensions: (1) left or right location of the principal figure; and (2) left-to-right or right-to-left sequence of figures represented by the direction of suggested movement, action, or lines. That previous studies have failed to demonstrate consistently a relationship between evaluations and directional properties is attributed to methodological shortcomings involving lack of control of stimulus properties and exposure time. Here, on the basis of a well-defined judging procedure, paintings were distinguished according to whether each dimension of lateral organization depicted one or more than one direction. Under two exposure conditions, 5 and 20 s, three evaluations (general preference, balance, and dynamics) were made for paintings which were presented simultaneously in the artist-created, original view, and the mirror-image, reversed view. It was found that evaluations were influenced by directional properties (sequence of figures) with a 5 s exposure and by more inclusive formal features with a 20 s exposure. Implications of the findings for perception and aesthetics are considered.     

The influence of spatial reference frames on imagined object- and viewer rotations.

The human visual system can represent an object's spatial structure with respect to multiple frames of reference. It can also utilize multiple reference frames to mentally transform such representations. Recent studies have shown that performance on some mental transformations is not equivalent: Imagined object rotations tend to be more difficult than imagined viewer rotations. We reviewed several related research domains to understand this discrepancy in terms of the different reference frames associated with each imagined movement. An examination of the mental rotation literature revealed that observers' difficulties in predicting an object's rotational outcome may stem from a general deficit with imagining the cohesive rotation of the object's intrinsic frame. Such judgments are thus more reliant on supplementary information provided by other frames, such as the environmental frame. In contrast, as assessed in motor imagery and other studies, imagined rotations of the viewer's relative frame are performed cohesively and are thus mostly immune to effects of other frames.     

The effects of recoding and presentation format on recency and suffix effects

The primary linguistic theory of Shand and Klima (1981) hypothesizes that stimuli that cannot be directly processed without recoding are not in the primary linguistic mode of the subject and thus should lead to lesser recency and associated suffix effects. In three experiments, different normal hearing subjects learned to pair American Sign Language (ASL) stimuli, visual "quasivocables" (QVs), word-like letter strings, and auditory QVs with common English words. In the first experiment, the subjects were given sequences of ASL or QV stimuli and required to recall the associated words in strict serial order. In two other experiments involving auditory and visual presentation, respectively, subjects who had never been given paired associate training were required to recall the English words that had previously been associated with the ASL and QV stimuli, in a standard suffix paradigm. The results showed recency and suffix effects to be present only with auditorily presented QVs and words. Contrary to the predictions of the primary linguistic hypothesis, greater recency and larger suffix effects were present with the auditory QVs than with the auditory words, although the QVs were not primary linguistic and the task involved forced recoding. Previous results showing recency with ASL stimuli in normal subjects were not replicated. It is concluded that recency and suffix effects are not related either to the primary linguistic mode of the subject or to stimulus recoding, as we and Shand and Klima have defined them.     

Cognitive biases in the perception of discrimination: The importance of format

Previous work has shown that people seem less able to perceive sex discrimination on a personal level than on a societal level. The present experiment was performed to test the hypothesis that this phenomenon is in part an information-processing bias; that is, the perception of discrimination is more difficult when one makes case-by-case comparisons than when one encounters information in aggregate form. The experiment demonstrated the importance of formatting for the perception of discrimination. Among subjects with little or no emotional investment in the issue of sex discrimination, the format of the pertinent information has a large effect on information processing: subjects perceived less discrimination when they encountered the relevant information in little chunks than when they saw the total picture at a single shot.     

The combined influence of binocular disparity and shading on pictorial shape

The combined influence of binocular disparity and shading on pictorial shape was studied. Stimuli were several pairs of stereo photographs of real objects. The stereo base was 0, 7, or 14 cm, and the location of the light source was varied over three positions (one from about the viewpoint of the camera, one about perpendicular to the line of sight, and one in between the two). Therefore, in total, nine different combinations were studied. Subjects had to perform surface attitude settings at about 300 positions in the image plane. From the settings, depth maps were calculated on which a principal components analysis was performed. It was found that three components were enough to account for at least 97.8% of the variance in the data. The first component accounted for shape constancy. The effects of the two cues could be isolated as a linear combination of the other two components. The effects of the disparity and the shading cue variation were found to combine in almost linear fashion.     

The combined influence of binocular disparity and shading on pictorial shape

The combined influence of binocular disparity and shading on pictorial shape was studied. Stimuli were several pairs of stereo photographs of real objects. The stereo base was 0, 7, or 14 cm, and the location of the light source was varied over three positions (one from about the viewpoint of the camera, one about perpendicular to the line of sight, and one in between the two). Therefore, in total, nine different combinations were studied. Subjects had to perform surface attitude settings at about 300 positions in the image plane. From the settings, depth maps were calculated on which a principal components analysis was performed. It was found that three components were enough to account for at least 97.8% of the variance in the data. The first component accounted for shape constancy. The effects of the two cues could be isolated as a linear combination of the other two components. The effects of the disparity and the shading cue variation were found to combine in almost linear fashion.     

The influence of illumination direction on the pictorial reliefs of Lambertian surfaces

In order to assess the influence of illumination direction on shape constancy, we studied the pictorial relief of computer images of globular 3-D objects. We used two globally convex objects, one with a furrow and one with a dimple. Observers adjusted local surface attitude probes at 200-250 different locations in the image such that they seemed to lie on the pictorial surface. We manipulated the viewing direction and the illumination direction in a 2 x 2 orthogonal design. Viewing directions were chosen such that the image contained only a few, or no, contour singularities. Changes in the illumination direction were found to induce systematic changes in the settings for both viewing directions. Effects were especially pronounced for images that had no contour singularities. The results showed that a change in the illumination direction can change the local shape of the pictorial relief in addition to the bas-relief ambiguities of scaling and shearing in depth. We found that concavities in the pictorial relief are associated with the darker areas in the image. The deviation from shape constancy cannot be explained by bas-relief ambiguity since the required transformation between the shapes is nonlinear.     

The influence of camera angle on comprehension and retention of pictorial events

A subset of formal compositional principles was examined in the context of narrative pictorial events. Slide stories were constructed of six common events in which characters were depicted from three camera angles: low angle, eye-level, and high angle. After presentation, subjects evaluated the characters, recalled the stories, and engaged in a recognition task. Camera angle influenced subjects’ evaluation and retention of the stories in accordance with aesthetic principles. Camera angle had significant, predictable effects on judgments of the physical and personal characteristics of the characters, on recall of these characteristics, and on recall of the gist of the stories themselves. Recognition memory for camera angle was significantly less accurate than recognition memory for the characters. Subjects used the available visual information to construct coherent story representations, and, although camera angle strongly influenced the construction of these representations, specific camera angle information became less accessible.     

The effect of discrimination training on speech perception: Noncategorical perception

Three subjects were given extensive practice in discriminating syllables which differed in voice onset time. For these subjects, there were two major findings. First, discrimination of speech follows normal psychophysical laws: long-onset-time stimuli require larger differences than shorter ones for comparable discrimination. Second, the shape of the discrimination function for experienced subjects is more like a leaning W than an inverted V, the usual shape for naive subjects. The data support a model of speech perception with both an acoustic and a phonetic component. The phonetic component is best characterized as a prototype matching process, with the prototype including information on the simultaneity of formant onset.