Configurational effects in visual information processing

These experiments show that the perceptual organization of a multielement display affects both the speed and accuracy with which a target letter in it is detected. The first two experiments show that a target is detected more poorly if it is arranged in good form (a perceptual Gestalt) with noise elements than if it is not. This effect is not confounded with target-noise proximity or display size, and it holds for stimuli terminated by the subject’s response as well as for stimuli of very brief duration. Increasing the number of noise elements can actually improve performance if the added noise elements increase the degree to which the noise elements form perceptual groups separately from the target. A third experiment tries out a new method for scaling the perceptual structure of an array, and it shows that the main features of the first two experiments can be predicted from the scaled perceptual structure of the arrays they used.     

Memory effects in visual spatial information processing

Eight, ten and twelve year old children were tested on a novel procedure involving the successive presentation of the standard and comparison stimuli. Two hypotheses were evaluated, one dealing with memory effects, and the other with children's pre-testing of choice responses in spatial information processing. It was found, in general, for both spatial perception and coordination of perspectives tasks, that there was no short memory decay for spatial information, but that opportunities to pre-test choice responses improved performance. It was inferred from these data that the performance superiority under simultaneous than successive conditions is attributable to opportunities to pre-test responses and not to memory effects, as opposed to successive conditions is attributable to opportunities to pre-test responses and not to memory effects.     

Depth of visual information processing

The depth of visual information processing is identified with the longest randomly-generated binary-encoded spatial pattern whose partial repetitions can be detected. In contrast with the auditory detection of sequentially-presented constraints, the depth of perceptible visual encoding of spatially-presented constraints is sharply limited. Depths of about 35 were achieved for one-dimensional constraints; depths of perhaps 3 or 4 were achieved for two-dimensional constraints imposed in only one direction and depths of perhaps 2 for two-dimensional constraints imposed in two directions. With one-dimensional constraints, it is shown that the inferred depth of processing is partially determined by the number of pattern representations and by the spatial distance between successive representation for visual displays of fixed size.     

Hierarchical stages in the processing of visual information

Attention, Perception, & Psychophysics - Previous research had indicated that when subjects are instructed to report one of a number of visually displayed items, both the number and spacing of...     

Age and the selectivity of visual information processing

Two experiments were conducted to assess age differences in the selectivity of visual information processing. Selectivity was measured by the amount of interference caused by nontarget letters when subjects detected a target letter in a visual display. In both experiments, young and elderly groups participated in search and nonsearch conditions; in the search condition targets appeared anywhere in the display, whereas in the nonsearch condition targets were confined to the center position of the display. In the first experiment, subjects were assigned to either condition for two sessions of testing, and in the second experiment each subject participated in both conditions. In both experiments nontargets produced larger interference effects for old compared to young adults in the search condition but not in the nonsearch condition. The obtained pattern of age effects could not be explained by age-related reductions in parafoveal acuity. The findings indicate that the magnitude of divided-attention deficit increases with age, whereas focused-attention deficits are unaffected by aging.     

Lateral masking in visual information processing

When unrelated letter strings are presented tachistoscopically, the end letters are reported more often than their neighbors; and when spaces are inserted into strings, performance on certain adjacent letters is superior to performance on those letters when no spaces were present. An experiment was conducted to determine the nature of those spacing effects. Letter strings were presented at a variety of retinal locations, and spaces were inserted into different positions in the instructed left-right processing order. The space effect was unrelated to processing order, but it was dependent on retinal location. To account for the various asymmetries, it was necessary to postulate that letters tend to interact with adjacent lettersand that the interaction was not spatially symmetric. Furthermore, it was found that spaces had greater effects on “right-hand” letters than on symmetric letters. It was therefore concluded that letters interact at the feature level.     

Multifactorial context effects on visual recognition memory

While effects of contextual change or constancy on memory are widely found when tested by free and cued recall, there is greater inconsistency in context effects on recognition. This study employed a paradigm maximizing target-context interactivity and specificity to reveal three levels of context effects on successful retrieval, as well as context effects on the generation of false alarms, thereby revealing separable contributions of target-context binding, additive familiarity, and configural constancy. The separability of these factors enables the use of memory context effects as tools for investigating associative memory.     

Multifactorial context effects on visual recognition memory

While effects of contextual change or constancy on memory are widely found when tested by free and cued recall, there is greater inconsistency in context effects on recognition. This study employed a paradigm maximizing target–context interactivity and specificity to reveal three levels of context effects on successful retrieval, as well as context effects on the generation of false alarms, thereby revealing separable contributions of target–context binding, additive familiarity, and configural constancy. The separability of these factors enables the use of memory context effects as tools for investigating associative memory.     

The role of visual information in the processing of

Visual information provided by a talker’s mouth movements can influence the perception of certain speech features. Thus, the “McGurk effect” shows that when the syllable /bi/ is presented audibly, in synchrony with the syllable /gi/, as it is presented visually, a person perceives the talker as saying /di/. Moreover, studies have shown that interactions occur between place and voicing features in phonetic perception, when information is presented audibly. In our first experiment, we asked whether feature interactions occur when place information is specified by a combination of auditory and visual information. Members of an auditory continuum ranging from /ibi/ to /ipi/ were paired with a video display of a talker saying /igi/. The auditory tokens were heard as ranging from /ibi/ to /ipi/, but the auditory-visual tokens were perceived as ranging from /idi/ to /iti/. The results demonstrated that the voicing boundary for the auditory-visual tokens was located at a significantly longer VOT value than the voicing boundary for the auditory continuum presented without the visual information. These results demonstrate that place-voice interactions are not limited to situations in which place information is specified audibly. In three follow-up experiments, we show that (1) the voicing boundary is not shifted in the absence of a change in the global percept, even when discrepant auditory-visual information is presented; (2) the number of response alternatives provided for the subjects does not affect the categorization or the VOT boundary of the auditory-visual stimuli; and (3) the original effect of a VOT boundary shift is not replicated when subjects are forced by instruction to \ldrelabel\rd the /b-p/auditory stimuli as/d/or/t/. The subjects successfully relabeled the stimuli, but no shift in the VOT boundary was observed.     

Auditory accessory effects on visual processing

A series of experiments on intersensory facilitation demonstrates that non-informative sound of low to moderate intensity (30/80 dB) facilitates the reaction to a visual stimulus. By manipulating the preprocessing and perceptual stages of the visual signals, it appears that auditory intensity reduces choice reaction time independently from the positive influence of the intensity and duration of the visual imperative signal, but interacts with the effect of stimulus degradation. Degraded stimuli take more profit of the sound than intact stimuli. Besides a short-term activation effect, originated by accessories of the auditory modality, on the motor adjustment stage (cf. Sanders 1983), the results suggest that the accessory influences the stage of feature extraction.     

Two forms of persistence in visual information processing

Iconic memory, which was initially regarded as a unitary phenomenon, has since been subdivided into several components. In the present work we examined the joint effects of two such components (visible persistence and the visual analog representation) on performance in a partial report task. The display consisted of 15 alphabetic characters arranged around the perimeter of an imaginary circle on the face of an oscilloscope. The observer named the character singled out by a bar-probe. Two factors were varied: exposure duration of the array (10, 50, 100, 150, 200, 300, 400 or 500 ms) and duration of blank period (interstimulus interval, ISI) between the termination of the array and the onset of the probe (0, 50, 100, 150, or 200 ms). Performance was progressively impaired as both exposure duration and ISI were increased. The results were explained in terms of a probabilistic combinatorial model in which the timecourses of visible persistence and of the visual analog representation are regarded as time-locked to the onset and to the end of stimulation, respectively. The impairing effect of exposure duration was attributed to the relatively high spatial demands of the task that could be met optimally by information in visible persistence (which declines as a function of exposure duration), but less adequately by information in the visual analog representation. A second experiment, employing a task with lesser spatial demands, confirmed this interpretation.     

Age-related changes in rate of visual information processing

Each of four groups of 12 subjects performed four psychophysical tasks. The age ranges of the four groups were 19-31, 45-57, 58-70, and 71-83 years, respectively. All four tasks required some form of visual information processing: Two were backward-masking tasks; two were temporal-integration tasks. In all four tasks increasing temporal functions over age were obtained, suggesting slower processing rates as age increased. The results support an active processing model of visual perception that interprets duration of visible persistence and duration of interval in which backward masking is effective as indices of the time course of early stages in the processing of stimulus features. The evidences also suggests that backward masking and visible persistence may be mediated by distinct mechanisms that are affected differently by aging processes. A model that conceptualizes the visual system as a multichannel processor is proposed as an explanation for some of the findings.     

The role of visual perspective in information processing

Social events can be described from the perspective of either a person in the situation in which the event occurs (e.g., “John came into…”) or that of an outside observer (“John went into…”). We find that when individuals are disposed to form visual images, they have difficulty comprehending both verbal statements and pictures when the perspective from which the event is described differs from the perspective from which they have encountered similar events in daily life. Furthermore, the disposition to form visual images increases the intensity of emotional reactions to an event when the event is described from the perspective of someone in the situation in which it occurs. These effects are not evident, however, among individuals who typically process information semantically without forming visual images.     

The effects of context and content on immediate processing in reading

Four experiments were conducted to examine the processes by which fluent readers comprehend prose. In each study the material was presented a few words at a time on an on-line visual display and the subject pressed a button to move on from one display to the next. The inter-reponse time was used as an index of local processing difficulty. The results of Experiment I indicated that readers pause considerably at the ends of clauses and sentences, and that they show no tendency to speed up across sentences. This pattern of results questions the role of prediction in reading. In Experiments II and III immediate processing was found to be unaffected by two types of syntactically-predictive clue and the effect of a third (semantic) clue was equivocal. Experiment IV replicated the results of Experiment I and showed, in addition, that pausing at the ends of clauses and sentences is a function of the difficulty of the content of the text. More detailed analyses showed that reading rate is modulated by the frequency of the words and by the number of characters in the display. Taken together the results suggest that reading rate is largely determined by the speed with which a reader can access the meanings of words and construct a representation of the text rather than by the speed with which they can formulate and test successive predictions about it.     

The effect of sleep-loss on processing information in the functional visual field

Two experiments are reported on the effects of sleepstate on performance in a same/different matching task, where two visual signals are presented under visual angles of either 10°, 45°, or 100°. The first study showed a stronger effect of sleep-loss at a more wide display. The effect consists of two parts: one is interpreted as due to the initiation and execution of the shift of gaze from the one to the other signal, and the other to the requirement of integrating successively perceived signals. These interpretations were tested in the second study. It was found that a more pronounced effect of sleep loss occurred when two signals are successively presented, but not when the signals are simultaneously viewed, while preceded by a shift of gaze. The implications of the data are discussed.     

Object identification in context: the visual processing of natural scenes.

When we view a natural visual scene, we seem able to determine effortlessly the scene's semantic category, constituent objects, and spatial relations. How do we accomplish this visual-cognitive feat? The commonly held explanation is known as the schema hypothesis, according to which a visual scene is rapidly identified as a member of a semantic category, and predictions generated from the scene category are then used to aid subsequent object identification. In this paper I will first outline and offer a critique of the evidence that has been taken to support the schema hypothesis. I will then offer an alternative framework for understanding scene processing, which I will call the local-processing hypothesis. This hypothesis assumes a modular, informationally-encapsulated architecture, and explicitly includes the role of covert visual attention in scene processing.     

Categorical processing of visual stimuli in relation to geometrical,graphemic, or lexical context

Summary Categorical perception was first demonstrated in studies of speech sounds (Liberman, Harris, Hoffman, & Griffith, 1957). The present work employed visual stimuli to explore categorical responding in relation to the context in which the stimuli were embedded. The target stimulus was a vertical line whose length was varied from 20 to 31 min (approximately) in steps of 1.2 min. Experiment 1 examined the effect of a geometrical context on the subjects' ability to discriminate between pairs of lines. The context improved performance, but produced no evidence of categorical responding. In Experiment 2 a graphemic context depressed performance, but failed to show clear evidence of categorization. By contrast, strong evidence of categorical responding was obtained in Experiment 3, in which the graphemes used in Experiment 2 were embedded in meaningful words. From this pattern of results it is argued that categorical responding is reflective not of relatively peripheral perceptual activity, but of higher-order decision processes.