Showing papers in "Journal of Experimental Psychology: Human Perception and Performance in 1983"

Spatial Extent of Attention to Letters and Words.

Abstract: The spatial extent of attention to visually presented letters and words was investigated using a probe technique. The primary task required subjects to categorize (a) five-letter words, or to categorize the middle letter of (b) five-letter words or (c) five-letter nonwords. The probe task required the subjects to respond when the digit 7 appeared in one of the five letter positions. Probe trials were inserted at the onset of letter and word processing in Experiment 1 and 500 msec after letter and word processing in Experiment 2. In both experiments, probe trials produced a V-shaped function of reaction times across probe positions for the letter-categorization task for word and nonword stimulus conditions. In contrast, a relatively flat reaction time function was found for the word-categorization tasks. An analysis of the data based on a quantitative model of attentional spotlight distributions suggests that the spotlight width in the letter tasks is one letter space, and the spotlight width in the word task is typically five spaces.

Tests of the automaticity of reading: dilution of Stroop effects by color-irrelevant stimuli.

Abstract: A color word shown next to a color bar can facilitate color naming if it is congruent with the correct response; otherwise it will interfere with color naming. The congruence and conflict effects are both diminished (diluted) by the presentation of a color-neutral word elsewhere in the field. A row of X's also produces some dilution. The dilution effect represents attentional interference rather than sensory interaction or response conflict. Because Stroop effects are susceptible to interference, the involuntary reading of color words does not satisfy one of the standard criteria of automaticity.

Is continuous visual monitoring necessary in visually guided locomotion

Abstract: Subjects were asked to walk to targets that were up to 21 m away, either with vision excluded during walking or under normal visual control. Over the entire range, subjects were accurate whether or not vision was available as long as no more than approximately 8 sec elapsed between closing the eyes and reaching the target. If more than 8 sec elapsed, (a) this had no influence on distances up to 5 m, but (b) distances between 6-21 m were severely impaired. The results are interpreted to mean that two mechanisms are involved in guidance. Up to 5 m, motor programs of relatively long duration can be formulated and used to control activity. Over greater distances, subjects internalized information about the environment in a more general form, independently of any particular set of motor instructions, and used this to control activity and formulate new motor programs. Experiments in support of this interpretation are presented.

Movements of attention across the visual field

Abstract: Vocal reaction times were measured for targets presented at three distances from fixation The targets were preceded by a cue, and the time interval between the cue and the target (stimulus-onset asynchrony; SOA) was varied For each peripheral distance, the reaction time function initially declined as SOA was increased and then reached asymptote The further the target from fixation, the longer the SOA at which the function reached asymptote The asymptotic SOA values were taken as a measure of the time it takes attention to reach a given target Comparisons of these values for the three peripheral distances permitted estimating the velocity of attention movements These measurements suggest that when summoned by a peripheral cue, attention travels through space at a constant velocity of about 1 degree per 8 msec Language: en

The cost of visual filtering.

Abstract: Speeded choice responses (reading or naming) to a relevant stimulus under conditions of spatial uncertainty are delayed by the simultaneous occurrence of other events. This "filtering cost" occurs despite high discriminability of target and distractors, which allows parallel detection of the target in search through the same displays. Reading is also delayed when the removal of irrelevant objects from the field coincides with the onset of the target. Filtering costs are caused by the processing of events rather than by the mere presence of irrelevant items. They are eliminated by advance information about the location of the target or by advance presentation of maintained distractors.

Hierarchical control of rapid movement sequences.

Abstract: Are movement sequences executed in a hierarchically controlled fashion? We first state explicitly what such control would entail, and we observe that if a movement sequence is planned hierarchically, that does not imply that its execution is hierarchical. To find evidence for hierarchically controlled execution, we require subjects to perform memorized sequences of finger responses like those used in playing the piano. The error data we obtain are consistent with a hierarchical planning as well as execution model, but the interresponse-time data provide strong support for a hierarchical execution model. We consider three alternatives to the hierarchical execution model and reject them. We also consider the implications of our results for the role of timing in motor programs, the characteristics of motor buffers, and the relations between memory for symbolic and motor information. Language: en

Selective attention to multidimensional auditory stimuli.

Abstract: Event-related brain potentials (ERPs) elicited by multidimensional auditory stimuli were recorded from the scalp in a selective-attention task. Subjects listened to tone pips varying orthogonally between two levels each of pitch, location, and duration and responded to longer duration target stimuli having specific values of pitch and location. The discriminability of the pitch and location attributes was varied between groups. By examining the ERPs to tones that shared pitch and/or locational cues with the designated target, we inferred interrelationships among the processing of these attributes. In all groups, stimuli that failed to match the target tone in an easily discriminable cue elicited only transitory ERP signs of selective processing. Tones sharing the "easy" but not the "hard" cue with the target elicited ERPs that indicated more extensive processing, but not as extensive as stimuli sharing both cues. In addition, reaction times and ERP latencies to the designated targets were not influenced by variations in the discriminability of pitch and location. This pattern of results is consistent with parallel, self-terminating models and holistic models of processing and contradicts models specifying either serial or exhaustive parallel processing of these dimensions. Both the parallel, self-terminating models and the holistic models provide a generalized mechanism for hierarchical stimulus selections that achieve an economy of processing, an underlying goal of classic, multiple-stage theories of selective attention. Language: en

Are variations among right-handed individuals in perceptual asymmetries caused by characteristic arousal differences between hemispheres?

Abstract: We propose that much of the variance among right-handed subjects in perceptual asymmetries on standard behavioral measures of laterality arises from individual differences in characteristic patterns of asymmetric hemispheric arousal. Dextrals with large right-visual-field (RVF) advantages on a tachistoscopic syllable-identification task (assumed to reflect characteristically higher left-hemisphere than right-hemisphere arousal) outperformed those having weak or no visual-field asymmetries (assumed to reflect characteristically higher right-hemisphere than left-hemisphere arousal). The two groups were equal, however, in asymmetries of error patterns that are thought to indicate linguistic or nonlinguistic encoding strategies. For both groups, relations between visual fields in the ability to discriminate the accuracy of performance followed the pattern of syllable identification itself, suggesting that linguistic and metalinguistic processes are based on the same laterally specialized functions. Subjects with strong RVF advantages had a pessimistic bias for rating performance, and those with weak or no asymmetries had an optimistic bias, particularly for the left visual field (LVF). This is concordant with evidence that the arousal level of the right hemisphere is closely related to affective mood. Finally, consistent with the arousal model, leftward asymmetries on a free-vision face-processing task became larger as RVF advantages on the syllable task diminished and as optimistic biases for the LVF, relative to the RVF, increased. Language: en

Catching Skills in Infancy

Abstract: Infants were induced to reach for fast moving objects whose velocity and starting position varied. Altogether, 144 reaches were analyzed by a technique that took into consideration the three-dimensional properties of reaches. It was found that reaches in all conditions were aimed close to the meeting point with the object. The precision in timing of a reach was about a twentieth of a second, and the systematic timing errors were close to zero. The results suggest that the infant reaches in reference to a coordinate system fixed to the moving object instead of to the static background, that is, the infant's hand is moved with the object at the same time as it is moved toward the object. It is concluded that the capacity to time and coordinate one's movements in the catching of a moving object is a very basic and early developed skill. Language: en

Perception of surface curvature and direction of illumination from patterns of shading.

Abstract: Three experiments examine the perceptual salience of shading information for the visual specification of three-dimensional form. The observers in these experiments were required to estimate the surface curvature and direction of illumination depicted in computer-synthesized images of cylindrical surfaces, both with and without texture. The results indicate that the shininess of a surface enhances the perception of curvature, but has no effect on perceived direction of illumination; and that shading is generally less effective than texture for depicting surfaces in three dimensions. These and other findings are used to evaluate the psychological validity of several mathematical analyses of shading information that have recently been proposed in the literature.

Does global precedence really depend on visual angle

Abstract: Global advantage has been found in some studies to hold only in stimuli subtending no more than 7 degrees - 10 degrees of visual angle. We argue that those studies confounded globality and eccentricity. To avoid this confound we used stimuli with all their elements located along their perimeter (e.g., Cs and circles). These were presented in two visual angle conditions, small (2 degrees) and large (17.25 degrees). In Experiment 1 subjects had to indicate either the direction of an opening of a C made up of circles or of Cs that were the elements of a circle. Contrary to previous findings, global advantage was found for both large and small visual angle conditions. Results from a control condition seem to indicate that the major determinant of that global advantage was relative size. In Experiment 2 subjects responded to the global or local levels of right- or left-facing Cs made up of right- or left-facing Cs. For the small visual angle condition, the global level interfered with processing of the local level, but not vice versa. For the large visual angle, however, interference effects were smaller and symmetrical, even though a sizeable difference in mean reaction time was observed between the responses to the local and global levels. It is suggested that the time it takes to respond to a level when relevant and the level's effectiveness as a distractor when irrelevant are determined at two different stages of processing.

Evaluation and integration of visual and auditory information in speech perception.

Abstract: Three experiments were carried out to investigate the evaluation and integration of visual and auditory information in speech perception. In the first two experiments, subjects identified /ba/ or /da/ speech events consisting of high-quality synthetic syllables ranging from /ba/ to /da/ combined with a videotaped /ba/ or /da/ or neutral articulation. Although subjects were specifically instructed to report what they heard, visual articulation made a large contribution to identification. The tests of quantitative models provide evidence for the integration of continuous and independent, as opposed to discrete or nonindependent, sources of information. The reaction times for identification were primarily correlated with the perceived ambiguity of the speech event. In a third experiment, the speech events were identified with an unconstrained set of response alternatives. In addition to /ba/ and /da/ responses, the /bda/ and /tha/ responses were well described by a combination of continuous and independent features. This body of results provides strong evidence for a fuzzy logical model of perceptual recognition.

Latency of sequential eye movements: Implications for reading.

Abstract: The best available estimates indicate that the average minimum latency of saccadic eye movements (175-200 msec) approaches the mean duration of fixations in reading (200-250 msec). This fact presents a problem for models of reading which assume that an eye movement is initiated only after substantial information is processed on a fixation. Three experiments are reported that support earlier estimates of saccadic latency; the experiments were conducted under conditions in which the length of measured latencies could not reflect a motoric refractory period, spatial uncertainty, or temporal uncertainty.

Dyslexic and normal readers' eye movements.

Abstract: Dyslexic and normal readers' eye movements were compared while tracking a moving fixation point and in reading. Contrary to previous reports, the dyslexic and normal readers did not differ in their number of saccades, percentage of regressions, or stability of fixations in the tracking task. Thus, defective oculomotor control was not associated with or a causal factor in dyslexia, and the dyslexics' abnormal eye movements in reading must be related to differences in higher cognitive processes. However, individual differences in oculmotor efficiency, independent of reading ability, were found within both the dyslexic and normal groups, and these differences were correlated in reading and tracking tasks.

Letter migration in word perception.

Abstract: : These experiments demonstrate that the perception of two distinct words in a briefly presented display can interact, causing perceptual migrations of letters from one word to the other. For example, when LINE and LACE are presented, subjects might report seeing LICE or LANE instead of LINE. Several properties of the letter migrations were revealed: Migrations are more frequent when the words are separated by smaller physical distances; a majority of the migrations are a result of letters being copied from one word to the other, not from the interchange of letters of the two words; migrations to a word are less frequent when subjects focus attention on that word; and migrations are far more frequent when the words share letters in common. This last result suggests that migrations are not caused by a loss of spatial information at the letter level, that is, by free-floating letters being wrongly combined. Rather, migrations occur because of structural limitations at a high level of the word-recognition process, perhaps during lexical activation. Implications for models of multiple-word perception are discussed. (Author)

Imagery paradigms: how vulnerable are they to experimenters' expectations?

Abstract: The effects of experimenters' expectations on subjects' responses in imagery paradigms were investigated by leading some experimenters to believe that performance based on the use of imagery would be superior to performance based on perception. Other experimenters were led to expect perceptual superiority. Three paradigms are tested. Experiment 1 considered imaginal and perceptual acuity as functions of the size and relative brightness of the stimulus patterns; Experiment 2 compared imaginal and perceptual scanning of maps; and Experiments 3 and 4 studied the identification of rotated hands after imaginal or perceptual priming. In all the experiments, subjects' performances varied with the experimenters' beliefs, suggesting that these paradigms are sensitive to subtle influences from experimenters' tacit, unintentional cues. Experiment 4 probed the ability of observers to identify both tacit cues and the experimenters' expectations. The observers accurately assigned the experimenters' beliefs but were unable to systematically detect distinguishing and differential characteristics of the experimenters' presentations of the instructions. Analysis of taped transcriptions yielded some differences in temporal phrasing. Implications of these results are discussed.

Initial stages of visual information processing in dyslexia.

Abstract: Four experimental tasks were employed to explore the initial stages of visual information processing in a group of dyslexic boys and in a group of normal control subjects ranging in age from 8 to 14 years. Two tasks involved visual backward masking; the other two were temporal integration tasks. The backward-masking tasks yielded evidence of slower rates of visual information processing in dyslexic children; the temporal-integration tasks yielded evidence of longer duration of visible persistence in dyslexic children. This effect was most evident in situations in which sequential stimuli impinged on the same retinal location. Some age trends in the development of these effects are noted. It is suggested that the dyslexic visual system may take an unusually long period of time to recover from the aftereffects of neural activity evoked by an inducing stimulus. Language: en

Investigating the boundaries of reading units: Letter detection in misspelled words.

Abstract: In two experiments, subjects searching for the letter t in passages that contained some misspellings made many more errors on the word the than on other correctly spelled words. Accuracy increased dramatically when the word the and the other words containing t were misspelled, even when the misspelled word was the same shape as the original. These findings define a word-inferiority effect, which stands in contrast to the superior perception of letters in words over nonwords commonly found in tachistoscopic studies. In a third experiment, subjects searched for the letter n in passages typed normally or typed with all interword spaces replaced by the symbol +. Detection errors on the word and were greatly reduced when the interword spaces were replaced by +s, but errors on other words, including those ending in the suffix morpheme -ing, were not affected by this manipulation. These results suggest that frequent function words are processed in terms of reading units that are larger than the letter and include the interword spaces.

Invariances in the acoustic expression of emotion during speech.

Abstract: An experiment was designed to test whether different individuals produce similar voice patterns when they read the same emotional passage. Quantitative scoring criteria were developed that reflect the extent to which different individuals consistently produce similar constellations of acoustic attributes in response to the same emotional context. The scoring procedure was applied to the voice tracks of standard utterances produced by 11 subjects reading 10 different emotionally evocative scripts. The results supported the hypothesis that different individuals produce standard acoustic configurations to express emotions. Because acoustic properties reflecting contrastive stress consistently varied with emotional context over syntactically and semantically identical utterances, some factor related to emotional context other than syntax or semantics must account for the variations. An evolutionary argument that emotion communication can be seen as intention communication is presented to account for these variations. Implications for theories of emotions and of intentional generative semantics are discussed.

Response tempo and separable--integral responding: evidence for an integral-to-separable processing sequence in visual perception.

Abstract: Three experiments were conducted to examine the relation between response tempo and separable-integral responding. A restricted classification paradigm, in which similarity-based (integral) and dimensionally based (separable) classifications were pitted against one another, was used with the dimensions of length and density (all experiments) and size and brightness (Experiment 3). The subjects were college students (Experiments 1 and 2) and kindergarten, second-, and fifth-grade children (Experiment 3). In all three experiments, rapid responding was associated with fewer dimensional and more similarity responses than was slow responding. This result held when response tempo was simply measured (Experiments 1 and 3) and when it was manipulated by the experimenter (Experiment 2). The results were interpreted to be consistent with models of dimensional processing in which holistic, integral processing precedes analytic dimensional processing. Language: en

Binocular rivalry and semantic processing: out of sight, out of mind.

Abstract: Previous studies of binocular rivalry have shown that some aspects of a phenomenally suppressed stimulus remain available for visual analysis. The question remains, however, whether this analysis extends to the case of semantic information. This experiment examines that question using a semantic-priming paradigm in which prime words were briefly flashed to an eye during either dominance or suppression phases of binocular rivalry. Reaction times on a lexical-decision task were significantly shortened (the semantic-priming effect) only when prime words were presented to an eye during dominance; suppression acted to impair word recognition and to eliminate semantic priming. These results are inconsistent with certain cognitive models of binocular rivalry.

Similarities in the Control of the Speech Articulators and the Limbs: Kinematics of Tongue Dorsum Movement in Speech

Abstract: The kinematics of tongue dorsum movements in speech were studied with pulsed ultrasound to assess similarities in the voluntary control of the speech articulators and the limbs. The stimuli were consonant--vowel syllables in which speech rate and stress were varied. The kinematic patterns for tongue dorsum movements were comparable to those observed in the rapid movement of the arms and hands. The maximum velocity of tongue dorsum raising and lowering was correlated with the extent of the gesture. The slope of the relationship differed for stressed and unstressed vowels but was unaffected by differences in speech rate. At each stress level the correlation between displacement and peak velocity was accompanied by a relatively constant interval from the initiation of the movement to the point of maximum velocity. The data are discussed with reference to systems that can be described with second-order differential equations. The increase in the slope of the displacement/peak-velocity relationship for unstressed versus stressed vowels is suggestive of a tonic increase in articulator stiffness. Variations in displacement are attributed to the level of phasic activity in the muscles producing the gesture.

A Memory Model of Sequential Effects in Scaling Tasks

Abstract: Subjects judge successive stimuli to be overly similar in psychophysica l scaling tasks. This is called assimilation. They also tend to judge each stimulus as overly different from more previous events. This is called contrast. To examine a twostage linear model of these sequence effects, we asked subjects to judge the relative intensity of successive tones. In support of the model, responses again depended lawfully on prior events. These memory effects occur in a variety of scaling tasks and are consistent with two assumptions: (a) Successive events assimilate in memory, and (b) subjects compare each stimulus to a collection of memories of prior events to generate a response. The trial-by-trial analysis used to test the model also showed that even in magnitude-estimation studies, equal stimulus ratios do not result in equal response ratios, except on average. This article suggests that examinations of trial-by-trial performance might be useful in studying memory and judgment processes.

Word recognition in Serbo-Croatian is phonologically analytic.

Abstract: A lexical-decision task was conducted with bialphabetic readers of Serbo-Croatian. It was shown that letter strings that can be assigned both a Roman and a Cyrillic alphabet reading incur longer latencies than does the unique alphabet transcription of the same word. This within-word phonological-ambiguity effect was obtained for both words and pseudowords, but the effect was more exaggerated with words. In addition, the magnitude of the difference depended on the number and distribution of ambiguous characters in the ambiguous letter string. It was concluded that lexical decision in Serbo-Croatian necessarily involves a phonologically analytic strategy.

Parafoveal visual information and semantic contextual constraints.

Abstract: Two experiments are reported that examine the influence of semantic contextual constraints on an individual's ability to use parafoveal visual information. Subjects were presented either a word (reptile) or a row of Xs in foveal vision along with a parafoveal nonword (snckks) centered 2.3 degrees or 5 degrees to the left or right of fixation. The subjects were asked to pronounce the parafoveal stimulus aloud. During their eye movement to that stimulus, the nonword was replaced by a word that was either (a) semantically related to the foveal item and visually related to the parafoveal preview nonword (snakes), (b) semantically unrelated to the foveal item and visually related to the preview (sneaks), (c) semantically related to the foveal item and visually unrelated to the preview (lizard), or (d) semantically unrelated to the foveal item and visually unrelated to the preview (limits). In Experiment 1, subjects were only given 250 msec to use the semantic context, whereas in Experiment 2, subjects were given 1,250 msec. The results of both experiments yielded highly significant effects of contextual constraints and parafoveal visual information. However, the first experiment yielded additive effects of the two variables, whereas the second experiment yielded interactive effects. The results are discussed in light of recent arguments regarding the importance of contextual constraints for the use of parafoveal visual information. Language: en

Distribution of visual attention over space.

Abstract: Subjects viewed 3 X 3 grids in which different subsets of the nine squares were designated as "figure," either by physical shading of those squares or by a verbal instruction to imagine those squares as shaded. The time taken by participants to respond "on" or "off" the figure was measured for single or multiple probe dots, which all appeared on or off the figural subset together, and which had already been shown to be equally detectable against shaded or unshaded squares and in all nine locations within the grid. In contrast to the set-size effect generally found in experiments on memory scanning, reaction time did not necessarily increase with the number of squares in the figural subset. Instead, the critical variable, which in previous research may often have adventitiously covaried with set size, was the spatial compactness of the subsets (as indexed by square-root-area over perimeter): Probes of less compact figures required more time to classify correctly. Subjects were evidently more successful in confining their attention to sets of mutually proximal items. Reasons are given for believing that this principle may also apply in the more abstract representational or semantic spaces that determine reaction times and errors in various other cognitive tasks. Language: en

Response selection and initiation in speeded reactions: a pupillometric analysis.

Abstract: Three studies are described in which the task-evoked pupillary response is recorded during simple and disjunctive reactions in order to examine its contribution as a measure of the motoric and cognitive aspects of performance in these tasks. In simple reactions a pupillary dilation began about 1.5 sec before the imperative stimulus and peaked about 1 sec after the stimulus. The rate of dilation was inversely related to the interstimulus interval. In disjunctive reactions, both "Go" and "No-Go" responses elicited significant dilations but the No-Go dilation was smaller than the Go dilation. When the response was delayed 2.5 sec after the discrimination stimulus, the dilation to both Go and No-Go responses was much reduced. The pupillary response related to response selection was estimated at 55% of that associated with motor preparation and execution. The probability of responding was found to affect the amplitude of the dilation to No-Go responses but not that to Go responses. The data point to a significant contribution of preparatory motor processing in No-Go reactions and to an overlap between decisional and motoric processing in disjunctive reactions. Language: en

Can response preparation begin before stimulus recognition finishes

Abstract: The present experiments were designed to determine whether information obtained early in the process of recognizing a stimulus can be used to begin preparing keypress responses before recognition of the stimulus has completely finished. This question is relevant to the recent debate between discrete (e.g., Sternberg, 1969a) and continuous (e.g., McClelland, 1979) models of human information processing. Stimulus sets were chosen so that recognition processes could extract incomplete preliminary information about a stimulus much faster than they could extract secondary information needed for unique stimulus identification. Discriminability of the secondary information was manipulated to vary the opportunity for response preparation based on preliminary information, with difficult secondary discriminations providing more time for response preparation than easy ones. Precues were given on some trials to allow response preparation to occur before the stimulus was presented, thereby reducing any difference in response preparation as a function of discriminability. Continuous models predict that precues should facilitate response preparation less when the secondary discrimination is difficult than when it is easy, and discrete models predict equal facilitation regardless of secondary discrimination difficulty. Evidence of response preparation was obtained with some but not all stimulus sets. The results were interpreted as support for the asynchronous discrete coding model (Miller, 1982a), in which response preparation can begin only after recognition processes have completely activated a code used in categorizing the stimulus. Language: en