Developmental differences in cognitive scanning and encoding of visual information

Report accuracy of horizontally arranged letter sequences was measured for second-grade children and adults using a tachistoscopic single report procedure. Results indicated age differences in both the amount of information encoded out of visual sensory store and in the magnitude of left-right visual field differences. However, large age differences in amount of encoded information were also present under conditions which served to reduce left-right visual-field asymmetries in report accuracy. These findings are discussed in terms of their implications for using a left-to-right cognitive trace scanning explanation to account for age differences in encoding efficiency.     

Imageability does not interact with visual field in lateral word recognition with oral report

Four lateral tachistoscopic experiments are reported which tested the hypothesis that the right hemisphere has a selective ability to process highly imageable words (the RH imageability hypothesis). The prediction that performance asymmetry would vary as a function of word imageability, in a lateral recognition task with oral report, was not fulfilled. Results suggested that several previously published studies which hitherto have been regarded as supporting the RH imageability hypothesis may be discounted on artifactual grounds. The implications of these findings for the overall status of the hypothesis were discussed.     

Role of input factors in visual-field asymmetries

This paper examines the implications of lateral tachistoscopic presentation of information for the processing efficiency of the intact cerebral hemispheres. Considering that the understanding of the processes underlying the particular competences of each hemisphere may require, as a preliminary step, the specification of the characteristics of the input on which the brain operates, anatomical, physiological, and psychophysical consequences of briefly stimulating the retinal periphery for the representation of information in the brain are outlined, with special reference to the spatial-frequency spectral composition of the stimuli. Retinal eccentricity and brief exposure duration converge to making the representation of information qualitatively different from the information that the brain normally operates on, which constrains the interpretation of findings with respect to the normal functions of the cerebral hemispheres. A review and discussion of empirical findings relevant to these issues suggest that manipulation of procedural variables may differentially affect the processing efficiency of the cerebral hemispheres and indicate that a given pattern of visual-field asymmetry may be overdetermined by a multitude of variables interacting in complex ways.     

Multitask investigation of individual differences in hemispheric asymmetry

Right-handed subjects (N = 120) participated in four different laterality tasks designed to measure aspects of cerebral hemisphere asymmetry: identification of dichotically presented consonant-vowel syllables (CVs), examination of the effects of concurrent repetition of CVs and concurrent anagram solution on finger-tapping by the right and left hands, lateralized identification of CVs presented tachistoscopically to the left and right visual fields, and left/right biases on a free-vision face task involving judgments of emotion. Ear differences in the dichotic listening task were related to the pattern of lateralized interference in the dual-task finger-tapping paradigm. There were no other significant relations between pairs of tasks, but when the present results are considered in the light of other recent experiments, there appears to be a relation between lateral bias on the free-vision face task and visual field differences in tachistoscopic identification. The pattern of results has implications for hypothesized individual differences among right-handers in cerebral dominance for verbal processes, input pathway dominance, and asymmetric arousal of the two cerebral hemispheres.     

Recognition of Facial Expression in Diverging Socioeconomic Levels

Cerebral organization has been seen to vary in different social or ethnic groups; also, sociocultural retardation is a serious obstacle to development in poorer countries. The ability of the right hemisphere to recognize facial emotions in a tachistoscopic task was tested in university and low-socioeconomic-level subjects. All were male and right-handed. The university students recognized facial emotions projected to their left field-right hemisphere significantly better than with their right field-left hemisphere; the low-socioeconomic-level subjects showed no differences in hemispheric performance. The explanation of laterality as a function of social class may be of importance in dealing with sociocultural retardation.     

A novel contact-lens system to assess visual hemispheric asymmetries.

A soft contact-lens system for achieving unilateral visual stimulation in a free vision format is described. Initial testing with light transmittance and visual perimetry indicated that the lenses created artificial visual-field deficits. The efficacy of the lenses as a technique for lateralizing visual input was evaluated by examining within-subject differences in performance on two visuospatial tasks. Speed and accuracy of performance were greater with visual input directed to the right hemisphere. These data support the lens design as a useful alternative to tachistoscopic procedures and previous lens systems.     

Laterality of cerebral function: relations with anxiety, repression, and perception

Based on two factor analyses of data from 67 right-handed undergraduates, a laterality quotient based on forward memory spans, spatial minus digit, divided by their sum, was devised. The hemispheric balance factor for which this quotient served as the principal marker had significant positive loadings by the laterality quotient for the Edinburgh Handedness Questionnaire and by a measure of repressive tendencies, the Marlowe-Crowne Social Desirability Scale. Scores from this factor were positively related to global as opposed to analytic perception as measured by the Navon tachistoscopic task. This factor was unrelated to the trait anxiety and working short-term memory factors which also emerged. Trait anxiety was negatively related to global perception. The results raise the possibility that greater degrees of right-handedness may be related to the release of the nondominant right hemisphere from inhibition and that working short-term memory may not be lateralized.     

A hemispheric asymmetry for the unconscious perception of emotion

Previous research has demonstrated that hemispheric asymmetries for conscious visual perception do not lead to asymmetries for unconscious visual perception. These studies utilized emotionally neutral items as stimuli. The current research utilized both emotionally negative and neutral stimuli to assess hemispheric differences for conscious and unconscious visual perception. Conscious perception was measured using a subjective measure of awareness reported by participants on each trial. Unconscious perception was measured by an "exclusion task," a form of word-stem-completion task. Consistent with predictions, negative stimuli were consciously perceived most often when presented to the right hemisphere. Negative stimuli presented to the right hemisphere showed no evidence of unconscious perception, suggesting that the hemispheric asymmetry for the conscious perception of negative information occurs at the expense of unconscious perception.     

Absence of exposure time influence on lateralized face recognition and object naming latency tasks

J. Sergent (1982, Perception & Psychophysics, 31, 451-461; 1983, Psychological Bulletin, 93, 481-512) postulates that the left cerebral hemisphere preferentially extracts higher spatial frequency information, while the right hemisphere preferentially extracts lower frequency spatial information, from the visual scene. According to this view, shorter exposure times favor better right than left hemisphere performance, while longer exposure times favor better left than right hemisphere performance on tachistoscopic laterality tasks. We studied the effects of a threefold variation (40 msec versus 120 msec) in exposure duration, with constant 3-mL luminance, on face recognition and on object naming latency task performances. These are the same stimulus parameters employed by J. Sergent (1983, Psychological Bulletin, 93, 481-512) to demonstrate exposure duration effects in a task requiring the judgment of the sex of models from face photographs. We found the expected LVF superiority on the face recognition task and RVF superiority on the object naming task. There was, however, no influence of exposure duration on the performances. It is concluded that these tasks, which tap established lateralized processing asymmetries, are quite robust in their resistance to exposure time influence.     

The influence of age, sex, and specialized training on the vertical-horizontal illusion

With the aim of investigating the perceptual processes responsible for perceptual illusions, we have studied the influence of age, sex and specialized training on two forms of the vertical-horizontal illusion. In Figure A, the vertical is a short distance away from the horizontal; in Figure B, the vertical meets the horizontal segment at its mid-point. Both figures were presented in brief (0-2 second) and long (I-o second) tachistoscopic exposure, and in unlimited exposure.

When time is unlimited. Illusion A increases up to 9-10 years and then remains constant and Illusion B decreases as a function of age and chiefly as a function of the degree of scientific training. The illusions are stronger in tachistoscopic perception than under conditions of umlimited exposure. Both illusions also increase in tachistoscopic perception with age except for science students. Under condition of unlimited time, women have stronger illusions than men. This difference does not occur in tachistoscopic perception.

These results may be interpreted in terms of the interaction of three processes: interaction among the elements of a figure (field effects); perceptual activity which makes possible the passing from syncretism or multiplicity to organized perception; and the activity of measuring the elements relatively to each other. This latter activity develops with cultural level and especially with scientific training. It is more effective with men than with women, due, it is suggested, to the spatial factor being higher in men.     

Studies of letter identification using qualitative error analysis: effects of speed stress, tachistoscopic presentation, and word context

In Experiment 1 subjects named letters under a response deadline chosen so that an appreciable number of errors would be produced. The stimulus confusions were analyzed via the same mathematical models of stimulus recognition that have been applied to the confusion matrices generated in tachistoscopic experiments. Both the Luce choice model and the informed guessing model (a new model having a simple and elegant process interpretation) provided excellent fits to the data. The parameter values of the informed guessing model changed in logical and interpretable ways with changes in the response deadline. In Experiment 2 a direct comparison was made of the types of errors produced in the data-limited tachistoscopic situation and the resource-limited response deadline situation. It was found that, relative to the response deadline task, identification in the tachistoscopic task is much more likely to be based on partial information. In Experiments 3 and 4 the same research methodology was applied to the problem of the effect of a word context on letter perception. The methodology allowed this problem to be addressed in the context of both response deadline and tachistoscopic tasks. Several advantages of the methodology for investigating other issues of interest to cognitive psychologists are discussed.     

Sex Differences in Right Hemisphere Tasks

We tested the hypothesis that sex differences in spatial ability and emotional perception are due to sex differences in intrahemispheric organization of the right hemisphere. If the right hemisphere is differently organized by sex—primarily specialized for spatial ability in men, but primarily specialized for emotional perception in women—then there should be a negative correlation between spatial ability and emotional perception within sex, and the greatest disparity between abilities should be found in people with characteristic arousal of the right hemisphere. Undergraduate men (N= 86) and women (N= 132) completed tests of Mental Rotation, Surface Development, Profile of Nonverbal Sensitivity, Progressive Matrices, and Chimeric Faces. Although the expected pattern of sex differences was observed, there was no evidence for the hypothesized negative correlation between spatial ability and emotional perception, even after statistical control of general intelligence.     

The bilateral effect: callosal inhibition or intrahemispheric competition?

The magnification of visual field asymmetry observed with bilateral compared to unilateral tachistoscopic presentation of homologous stimuli (bilateral effect) can be explained by two hypothetical processes: homologous activation with subsequent inhibition of callosal information transfer or intrahemispheric competition for processing resources. A lexical decision task with unilateral and bilateral stimulation and response with the right or left hand was used in an attempt to decide between these hypotheses. Analysis of response time data revealed a bilateral effect, superimposed on a right visual field advantage, and no interaction between visual field and response hand. Results are consistent with the hypothesis of intrahemispheric competition in the left hemisphere.     

Hemispheric specialization for processing of visually presented verbal and spatial stimuli

Two “same-different” reaction time experiments, analogous in task demands made on the S, were designed to test laterality differences in. perception. Ten normal right-handed Ss performed a verbal task in which they decided whether or not two three-letter words belonged to the same conceptual class. Ten different Ss performed a spatial task in which they decided whether two 16-cell matrices with 3 blackened cells were identical. Reaction times were found to be sensitive to laterality differences in perception. Verbal stimuli were processed faster when presented in the right visual field, and thus projected directly to the left cerebral hemisphere; spatial stimuli were processed faster when presented in the left visual field, and thus projected directly to the right cerebral hemisphere. These results were analyzed in terms of implications regarding hemispheric asymmetries for processing of verbal and spatial material and the nature of interhemispheric transfer of information.     

A theory of visual interpolation in object perception

We describe a new theory explaining the perception of partly occluded objects and illusory figures, from both static and kinematic information, in a unified framework. Three ideas guide our approach. First, perception of partly occluded objects, perception of illusory figures, and some other object perception phenomena derive from a single boundary interpolation process. These phenomena differ only in respects that are not part of the unit formation process, such as the depth placement of units formed. Second, unit formation from static and kinematic information can be treated in the same general framework. Third, spatial and spatiotemporal discontinuities in the boundaries of optically projected areas are fundamental to the unit formation process. Consistent with these ideas, we develop a detailed theory of unit formation that accounts for most cases of boundary perception in the absence of local physical specification. According to this theory, discontinuities in the first derivative of projected edges are initiating conditions for unit formation. A formal notion of relatability is defined, specifying which physically given edges leading into discontinuities can be connected to others by interpolated edges. Intuitively, relatability requires that two edges be connectable by a smooth, monotonic curve. The roots of the discontinuity and relatability notions in ecological constraints on object perception are discussed. Finally, we elaborate our approach by discussing related issues, some new phenomena, connections to other approaches, and issues for future research.     

Hemispheric differences in the perception of words and faces in deaf and hearing children

The purpose of this study was to investigate hemispheric functional asymmetry in 18 normal hearing children and 18 congenitally deaf children aged 13-14 years. The task was identification of a visual stimulus (3-letter word or photograph of a face) presented in either the left or right visual field. The children responded by pointing to the target stimulus on a response card which contained four different words or three different faces. The percentage of errors for presentations to the two visual fields were analysed to determine hemispheric dominance. The pattern of hemispheric differences for the hearing children was consistent with that from previous investigations. The results for the deaf children differed from those of the normals. In word perception we observed a right hemisphere advantage and in the face recognition a lack of hemispheric differences. These results point to a lack of auditory experiences which is affecting the functional organization of the two hemispheres. It is suggested that the necessity to make use of visuo-spatial information in the process of communication causes right hemisphere dominance in verbal tasks. This may influence the perception of other visuo-spatial stimuli which may yield a lack of hemispheric asymmetry in face recognition.     

Structural factors in figure perception

In this report, we examine tachistoscopic perception of lines in structured figures. Previous research has shown that perception of lines is facilitated when the lines occur as parts of coherent three-dimensional figures. Experiment 1 demonstrates that it is not necessary for the figure to be three-dimensional to obtain facilitation. Experiments 2 and 3 show that three-dimensionality is not sufficient either. What is important is that the target lines be structurally relevant to the figure. However, structural relevance of a target segment to the figure as perceived with unlimited viewing time is not perfectly correlated with perceptibility under tachistoscopic conditions; it appears that the targets which fall on the external contour of a figure may be facilitated even without a high degree of structural relevance. In view of this, we suggest a model in which perceivers use processing heuristics to direct processing to aspects of the input that are potentially important for determining the structure of the final figure, working primarily from the outside in.     

Depth,Perception, and Action: Past,Present, and Future

This paper examines how images of depth are employed in the psychoanalytic literature and how they illuminate or obfuscate. It examines as well the price of using familiar terminologies to introduce new ideas, a practice more common in psychoanalysis than in many other disciplines. By obscuring the differences between old ideas and new through using the same terminology for both, the sense of adherence and belonging to the psychoanalytic community is enhanced but the ability to see fully the new possibilities for theory and practice to which these new ideas point is constrained. In elaborating on this point, the paper also considers the differences between a past-centered, archaeological model and a model in which older patterns are perpetuated through their repeated consequences, both intended and unintended. In such a model both action and perception are taken into account, as the aim of analysis becomes not just the patient’s internal world but her lived life.     

Valence specific laterality effects in prosody: expectancy account and the effects of morphed prosody and stimulus lead

The majority of studies have demonstrated a right hemisphere (RH) advantage for the perception of emotions. Other studies have found that the involvement of each hemisphere is valence specific, with the RH better at perceiving negative emotions and the LH better at perceiving positive emotions [Reuter-Lorenz, P., & Davidson, R.J. (1981) Differential contributions of the 2 cerebral hemispheres to the perception of happy and sad faces. Neuropsychologia, 19, 609-613]. To account for valence laterality effects in emotion perception we propose an 'expectancy' hypothesis which suggests that valence effects are obtained when the top-down expectancy to perceive an emotion outweighs the strength of bottom-up perceptual information enabling the discrimination of an emotion. A dichotic listening task was used to examine alternative explanations of valence effects in emotion perception. Emotional sentences (spoken in a happy or sad tone of voice), and morphed-happy and morphed-sad sentences (which blended a neutral version of the sentence with the pitch of the emotion sentence) were paired with neutral versions of each sentence and presented dichotically. A control condition was also used, consisting of two identical neutral sentences presented dichotically, with one channel arriving before the other by 7 ms. In support of the RH hypothesis there was a left ear advantage for the perception of sad and happy emotional sentences. However, morphed sentences showed no ear advantage, suggesting that the RH is specialised for the perception of genuine emotions and that a laterality effect may be a useful tool for the detection of fake emotion. Finally, for the control condition we obtained an interaction between the expected emotion and the effect of ear lead. Participants tended to select the ear that received the sentence first, when they expected a 'sad' sentence, but not when they expected a 'happy' sentence. The results are discussed in relation to the different theoretical explanations of valence laterality effects in emotion perception.