Context Of Perception Research Articles

Visual interpretation of known objects in constrained scenes

Recent work on the visual interpretation of traffic scenes is described which relies heavily on a priori knowledge of the scene and position of the cam era, and expectations about the shapes of vehicles and their likely movements in the scene. Knowledge is represented in the computer as explicit three-dimensional geometrical models, dynamic filters, and descriptions of behaviour. Model-based vision, based on reasoning with analogue models, avoids many of the classical problems in visual perception: recognition is robust against changes in the image of shape, size, colour and illumination. The three-dimensional understanding of the scene which results also deals naturally with occlusion, and allows the behaviour of vehicles to be interpreted. The experiments with machine vision raise questions about the part played by perceptual context for object recognition in natural vision, and the neural mechanisms which might serve such a role.

Study approaches of nursing students: effects of an extended clinical context

In the first part of this study a comparison is made between the approaches to studying adopted by failing and achieving nursing college students. It is concluded that failing students manifest approaches to studying that are, in some respects, conceptually difficult to interpret. This conclusion is presented against a background of similar findings that have emanated from other recent studies on student learning. The second part of this study investigates the influence of contextual perceptions on the manifestation of the approaches to studying adopted by achieving students. In thus exploring the manifestation of different forms of contextualized approaches to studying (which are referred to as study orchestrations) a distinction is made between the influences attributable to 'conventional' and 'clinical' sets of contextual variables. In an extension of previously reported studies, it is concluded that the combined set of these contextual variables explains significantly more of the variation in study approaches than the set of 'conventional' variables. It is further concluded that, under the influence of an extended set of contextual variables, conceptually related, but differing forms, of study orchestration may be manifested; a general form which is readily interpretable in terms associated with 'conventional' academic contextual variables and a clinical form which, in the present study, is associated specifically with a nursing academic environment. The implications of these conclusions for nursing education are discussed and areas for future research are indicated.

Olfactory perception in honeybees: Concatenated and mixed odorant stimuli, concentration, and exposure effects

Here we present results obtained from 7 different series of experiments, all employing odor conditioning of proboscis extension in worker honeybees and each designed to address a particular question involving olfactory perception. The questions relate to: temporal complexity of odor cues; effects of concentration, suppression, and/or potentiation in mixture perception; acquisition and extinction rates, as well as levels of generalization associated with aliphatic compounds that have the same functional groups or same alkyl radical length; and the effects of continuous exposure to odorants in the first several days of adult life on various learning and discrimination tasks involving olfactory perception. From the data obtained in these experiments we were able to conclude the following: First, worker honeybees have a limited ability to perceive complex temporal odor-quality patterns in olfactory stimuli — they learn to associate the quality of only the last part of the stimulus with a sucrose reward. Second, we confirm that citral is qualitatively different in several perceptual contexts involving odor learning and conditioning and our results help elucidate the nature of these differences as they relate to learning, discrimination, mixture perception, and continuous exposure to particular odorants. Third, we appear to have uncovered some important perceptual differences between functional groups attached to the first as opposed to the second carbon atom of alkyl radicals. Finally, we failed to uncover any significant effects relating to continuous exposure to odorants during the first several days of a worker's adult life, despite evidence that considerable sensory development takes place during this period. Thus ontogenetic changes to the peripheral system due to environmental effects appear to leave basic perceptual systems unaltered.

Calculation of a constant Q spectral transform

The frequencies that have been chosen to make up the scale of Western music are geometrically spaced. Thus the discrete Fourier transform (DFT), although extremely efficient in the fast Fourier transform implementation, yields components which do not map efficiently to musical frequencies. This is because the frequency components calculated with the DFT are separated by a constant frequency difference and with a constant resolution. A calculation similar to a discrete Fourier transform but with a constant ratio of center frequency to resolution has been made; this is a constant Q transform and is equivalent to a 1/24-oct filter bank. Thus there are two frequency components for each musical note so that two adjacent notes in the musical scale played simultaneously can be resolved anywhere in the musical frequency range. This transform against log (frequency) to obtain a constant pattern in the frequency domain for sounds with harmonic frequency components has been plotted. This is compared to the conventional DFT that yields a constant spacing between frequency components. In addition to advantages for resolution, representation with a constant pattern has the advantage that note identification (‘‘note identification’’ rather than the term ‘‘pitch tracking,’’ which is widely used in the signal processing community, is being used since the editor has correctly pointed out that ‘‘pitch’’ should be reserved for a perceptual context), instrument recognition, and signal separation can be done elegantly by a straightforward pattern recognition algorithm.

Tactual learning and cross-modal transfer of an oddity problem in young children

The ability to solve tactual oddity problems, and transfer of oddity learning across the visual and the tactual modalities, was studied in 3- to 8-year-old children ( N = 294). Oddity tasks consisting of one odd and two equal objects were made from stimuli that were easily discriminated visually and tactually. The results showed that tactual oddity learning increased gradually with age. The growth in tactual performance begins later than visual, suggesting that children are more adept at encoding visual stimulus invariances or relational properties than tactual ones. Bidirectional cross-modal transfer of oddity learning was found, supporting the suggestion that such transfer occurs when training and transfer oddity tasks share a common vehicle dimension. The cross-modal effect also shows that oddity learning is independent of a specific modality-labeled perceptual context. Our results are consistent with the view that development of oddity learning depends on a single rather than a dual process, and that the oddity relation may be treated as an amodal stimulus feature.

Critical influence of particular experiences in the perception of letters, words, and phrases.

Letters are generally easier to identify in regular words or pseudowords than alone or in irregular items. This advantage seems to imply that word perception depends on knowledge of general structure. We found, however, that the perceptual advantage of letters in pseudowords over single letters could be increased by preexposing the pseudowords, or reversed by preexposing the single letters. Similarly, preexposure of words alone or in phrases resulted in a perceptual advantage for whichever display had been experienced. The success of identification also depended on the type of task previously performed on test items, and on the reinstatement of prior processing and perceptual context, rather than on only the test items and task themselves. We concluded that memory preserves information about the details of particular perceptual experiences, and that identification depends critically on the similarity of current demands and processing context to the demands and contexts of particular previous experiences.

A Study of the Mental Model of a Complex Dynamic System: The Effect of Display Aiding and Contextual System Training

The acquisition of mental models and the effect of instructions and a display aid on the performance on a complex dynamic processing system were examined in this experiment. Thirty subjects monitored a dynamic bar graph display of six system variables and were tested under three different conditions: 1) subjects were given contextual instructions and a picture display-aid which provided a perceptual context in which to interpret the changing variables (group P/B). 2) Subjects were only provided non-context instructions and tested by a bar graph display (group B). 3) A transfer group was trained under the same condition as same as group P/B and tested with the bar graph display (group P/B - B). The data showed that the combination of the context instructions and the meaningful display aid improved subjects' performance significantly. The accuracy of diagnosis of the group P/B was the highest among the three groups. It was also seen that training with the context instructions themselves could improve the accuracy of diagnosis although the difference between the transfer group and group B was not significant statistically.

Tonal hierarchies and perceptual context: An experimental study of music behavior.

Tonal hierarchies and perceptual context: An experimental study of music behavior.

Perceptual context effects on line discriminations by monkeys as measured by choice response accuracy and eye movements

Stumptailed monkeys (Macaca arctoides) were given two two-choice line-discrimination problems in which the lines were presented either alone or embedded in a patterned context that was the same in all cases. When the stimuli were a left- and a right-tilting line, the addition of the context significantly improved performance, as measured by frequency of correct choice responses. It also decreased choice response latency, duration of visual fixations, and frequency of scanning back and forth between the two stimuli. When the stimuli were a horizontal and a vertical line, the addition of the context had the opposite effect on all the performance measures. These results are very similar to those found with adult and infant humans when given the same stimuli. They suggest that the pattern perception of monkeys, like that of humans, involves top-down or holistic processing of incoming visual information.

Creativity in Middle and Late School Years

The purpose of the study was to follow the development of creativity defined as the inclination to transgress the confines of an established perceptual context in youngsters aged 12-16 years, after having studied 4-11-year-olds previously. There were altogether 142 subjects, 24-33 in each age group, who were tested with a special percept-genetic creativity test (PG). A creativity-fantasy scale was also applied together with a percept-genetic personality test (MCT). After a creative peak among 10-11-year-olds, 12-year-olds showed a significant decrease of strong creativity signs, a simultaneous increase of compulsive and kindred defense strategies and decrease of signs of anxiety. The recovery of creativity was slow during high puberty (14-15 years) but more marked after (16 years). Using the duality of inwardness and the outside world as a point of departure the paper discusses the fluctuations between high and low creative periods and, among other things, tries to explain why they are more pronounced among subjects with an academic home background.

Toward an Explanation of Defensive Projection in Normals: The Role of Social Cognition

“Defensive projection' was described by Sigmund Freud in 1911 as an unconscious cognitive defense contributing to paranoia. Since that time, projection has remained relatively unexplained as a complex cognitive act. How projectors are able to deceive themselves to the point of successfully denying threatening traits and attributing them to others remains one of the unresolved questions The present studies considered two cognitive skills that, if lacking, could create a perceptual context promoting faulty attribution, self-deception, and effective projection. Social insight” represents the person's perceptiveness and accuracy in analyzing social situations, and “facial decoding” reflects the ability to infer emotions from facial cues. Deficiencies in either could contribute to misattribution and could interfere with self-correction of faulty perceptions. The first study corroborated the expected relation between poorer social cognition (low social insight and low facial decoding) and the greater use of def...

Children's perception of sibilants: The relation between articulation and perceptual development

When synthetic fricative noises from an [∫]−[s] continuum are followed by [a] and [u], adult listeners perceive fewer instances of [∫] in the context of the rounded vowel [u] (Mann & Repp, 1980). This perceptual context effect presumably reflects adjustment for certain coarticulatory effects and implies tacit knowledge of coarticulation and its consequences. To clarify the role of articulatory experience in the ontogeny of such knowledge and the consequent perceptual adjustment, the present study examined the effect of rounded and unrounded vowels on the perception of [s] and [∫] by adults, 5-, and 7-year-old children who produce [∫] and [s] and 7-year-old children who misarticulate these phonemes. All three groups of children showed a context effect equivalent to that of adults and independent of age and articulation ability. Therefore, productive mastery of [s] and [∫] is not critically responsible for perception of the [s]−[∫] distinction, nor for perceptual sensitivity to the consequences of sibilant-vowel coarticulation.

Creativity in Early and Middle School Years

The purpose of the study was to follow the development of creativity defined as the inclination to transgress the confines of an established perceptual context in children aged 7 to 11 years, after having studied 4-6-year-olds previously. One group of 55 7-8-year-olds, divided in a younger and/or more cognitively immature subgroup (I) and an older and/or more mature one (II), and one group of 31 10-1 1-year-olds (III), were tested with a special percept-genetic creativity test (PG) which significantly correlated with a creativity-fantasy scale. While creativity decreased in group I as compared with younger children, it increased drastically in group III, as did anxiety signs in a percept-genetic personality test (MCT) applied in all groups. While thus creativity seemed to benefit from a certain amount of anxiety, it was obviously blocked by excessive amounts or by low anxiety tolerance. The low creativity tide in 7-year-olds could perhaps be associated with the beginning of regular school in Sweden, but the high tide at the age of 10-11 years would perhaps point to an autonomous developmental rhythm.

Relative Ideas Revisited: A Reply to Thomas

158. RELATIVE IDEAS REVISITED: A REPLY TO THOMAS In "Hume's Relative Ideas" I argued that what Hume called a "relative idea" is the cognitive analogue of a definite description, that relative ideas are nonimagistic, and that recognizing the distinction between positive ideas (images) and relative ideas sheds light on various issues that remain opaque apart from that distinction. Thomas has recently taken exception to my position, contending that I have "produced a 2 theory without application in Hume's framework." In reply I shall present the three cornerstones of my view and then turn to Thomas's criticisms. I. On Relative Ideas 1.What relative ideas are: In claiming that a relative idea is the cognitive analogue of a definite description, I mean only that a relative idea functions in the cognitive realm (realm of ideas) in the same way that a definite description functions in the linguistic realm. Just as the statement expressing the contextual definition of a definite description specifies the truth conditions for a statement containing that description, the statement expressing the contextual definition of a definite description corresponding to a relative idea indicates the (factual) conditions that must obtain if that relative idea succeeds in singling out an entity, i.e. , it specifies the "truth conditions" for a relative idea (see T 448, T 458, and T 84 for Hume's use of 'truth') . 2.The intellectual milieu: The expressions 'relative idea' and 'relative notion' seem to have at least two uses in eighteenth century philosophy. Some philosophers used such expressions to refer to an idea 4 or a conception of a relation. Nonetheless, since no 159. substance theorist held that a substance is a relation, this can hardly be the sense in which Locke used the expression when he claimed that one has an "obscure and relative idea of substance in general." Further, Locke's discussion of the relationship between positive ideas (images) and the relative idea of substance clearly indicates that relative ideas provide an indirect means of allowing one to know what something is on the basis of its relation to something known directly, i.e. , on the basis of its relation to a C positive idea. Locke also claimed that one's idea of 7 infinity is a relative idea, he seems to have held that the idea of power is a relative idea, and given his account of perception, it is at least reasonable to suggest that relative ideas are found in perceptual contexts. Similarly, Berkeley maintained that one has a relative notion of immaterial substance, but no relative notion of material substance, since in the former case, but not in the latter, one has a notion 9 of the relation between: a substance and its attributes. Outside the "way of ideas" one finds the distinction between direct and relative "conception" clearly spelled out in Reid' s Essays on the Active Powers of the Human Mind. Reid wrote: Of some things, we know what they are in themselves; our conception of such things I call direct. Of other things, we do not know what they are in themselves , but only that they have certain properties or attributes, or certain relations to other things; of these our conception is only relative. 10 Reid contended that our conceptions of mind, of body, of powers, and of secondary qualities are relative conceptions , that at least some of our conceptions of large numbers of things and of polygons are relative conceptions , and that relative conceptions are operative in memory. Now given that there seems to have been a fairly 160. widely recognized doctrine of relative conception in the eighteenth century, given that the contexts in which Hume used the term 'relative idea' are contexts in which proponents of relative conception employed that term, and given that Hume stated philosophical issues in terms of the conceptual system of his time, I consider it reasonable to suggest that Hume recognized and held a doctrine of relative conception even though he did not devote so much as a paragraph to stating that doctrine. 3. The relation of images to relative ideas: A relative idea is inherently complex: it includes a positive idea (or ideas) and a relation...

Development of perceptual adjustment for the coarticulatory effects of rounded vowels on preceding fricatives

When synthetic fricative noises from an [∫] − [s] continuum are followed by [a] and [u], listeners perceive more instances of [s] in the context of [u] [V. A. Mann and B. H. Repp, Perc. Psychophys. 28, 213–228 (1980)]. This perceptual context effect presumably reflects adjustment for the coarticulatory effects of rounded vowels on preceding fricatives. We have begun to examine the development of this effect, asking children to label stimuli from “save”‐“shave” and “sue”‐“shoe” continua, constructed by following noises from an [∫] and [s] continuum with periodic portions excerpted from natural tokens of “shave” and “shoe.” The subjects include normal adults, 5‐, 7‐, and 9‐year‐old children who correctly produce both [∫] and [s], and 7‐year‐olds who misarticulate these fricatives. Thus far we have found that the magnitude of the vocalic context effect is typically greater for adults, yet children at all ages show a significant effect whose magnitude is not a function of age. These findings, to be supplement...

Influence of preceding fricative on stop consonant perception.

The effect of a preceding fricative on the perceived place of stop consonant articulation was investigated in a series of experiments. In experiment 1, we preceded synthetic syllables from two [tV]--[kV] continua with fricative noises appropriate to [integral of] or [s] and showed that more velar stops are perceived in the context of [s]. Experiment 1 also demonstrated a decrease in the magnitude of this perceptual context effect with increased temporal separation of fricative noise and CV portion, and with introduction of a vowel before the noise, which permitted a subjective syllable boundary after the fricative. Experiment 2 showed that although the effect of the fricative on stop perception declines initially with temporal separation, it may persist in reduced form over intervals as long as 375 ms. Experiment 3 replicated the basic fricative context effect using improved stimuli, but failed to replicate the reduction with an intervening syllable boundary obtained in experiment 1, which presumably was due to the vowel preceding the fricative. Experiments 4 and 5 revealed that the fricative context effect depends both on the phonetic category assigned to the fricative and on the specific spectral properties of the fricative noise. Experiment 5 also revealed a reciprocal effect of the stop consonant on fricative identification. We hypothesize that these perceptual effects serve to compensate for coarticulatory dependencies between stop consonants and preceding fricatives.

Influence of preceding liquid on stop-consonant perception.

Certain attributes of a syllable-final liquid can influence the perceived place of articulation of a following stop consonant. To demonstrate this perceptual context effect, the CV portions of natural tokens of [al-da], [al-ga], [ar-da], [ar-ga] were excised and replaced with closely matched synthetic stimuli drawn from a [da]-[ga] continuum. The resulting hybrid disyllables were then presented to listeners who labeled both liquids and stops. The natural CV portions had two different effects on perception of the synthetic CVs. First, there was an effect of liquid category: Listeners perceived “g” more often in the context of [al] than in that of [ar]. Second, there was an effect due to tokens of [al] and [ar] having been produced before [da] or [ga]: More “g” percepts occurred when stops followed liquids that had been produced before [g]. A hypothesis that each of these perceptual effects finds a parallel in speech production is supported by spectrograms of the original utterances. Here, it seems, is another instance in which findings in speech perception reflect compensation for coarticulation during speech production.

Influence of vocalic context on perception of the [zh]-[s] distinction.

When synthetic fricative noises from a [∫]-[s] continuum are followed by [a] or [u] (with appropriate formant transitions), listeners perceive more instances of [s] in the context of [u] than in the context of [a]. Presumably, this reflects a perceptual adjustment for the coarticulatory effect of rounded vowels on preceding fricatives. In Experiment 1, we found that varying the duration of the fricative noise leaves the perceptual context effect unchanged, whereas insertion of a silent interval following the noise reduces the effect substantially. Experiment 2 suggested that it is temporal separation rather than the perception of an intervening stop consonant that is responsible for this reduction, in agreement with recent, analogous observations on anticipatory coarticulation. In Experiment 3, we showed that the vowel context effect disappears when the periodic stimulus portion is synthesized so as to contain no formant transitions. To dissociate the contribution of formant transitions from contextual effects due to vowel quality per se, Experiment 4 employed synthetic fricative noises followed by periodic portions excerpted from naturally produced [∫a], [sa], [∫u], and [su]. The results showed strong and largely independent effects of formant transitions and vowel quality on fricative perception. In addition, we found a strong speaker (male vs. female) normalization effect. All three influences on fricative perception were reduced by temporal separation of noise and periodic stimulus portions. Although no single hypothesis can explain all of our results, they are generally supportive of the view that some knowledge of the dynamics of speech production has a role in speech perception.

Influence of preceding liquids on stop-consonant perception

When a syllable-final liquid precedes a syllable-initial stop, it may influence the perceived place of stop-consonant production. To demonstrate this phenomenon, the CV portions of natural tokens of /al da/, /al ga/, /at da/, and /at ga/ were excised and replaced with closely matched synthetic stimuli forming a /da/-/ga/ continuum. The resulting hybrid disyllables were then presented to listeners who labeled both liquids and stops. More “g” responses were given to stops which replaced /ga/ than to those which replaced /da/, indicating that the preceding VC portion (/al/ or /ar/) contained cues to the following stop consonant. In addition, many more “g” responses were given to stops which followed /al/ than to those which followed /ar/. Spectrograms of the original utterances suggest, in accordance with this perceptual finding, that stops following /l/ are produced with a relatively more forward place of articulation than those following /r/. More detailed acoustic measurements are now in progress. Here, it seems, is another instance where coarticulation accounts for a perceptual context effect. [Work supported by NICHD and BRS.]

Referential description by children in negative form

Previous experiments indicate that young children have difficulty in describing referents in negative terms. It is suggested that use of negation is unnatural (and therefore difficult) in many descriptive tasks because children tend to focus their attention on referent and to ignore immediate perceptual context. Additionally, negative descriptions are more natural where a referent lacks some feature of a contrasting item in context, than where it differs from it along some attribute dimension.In a small experiment normal and educationally subnormal children with mental ages from 5 to 7 years were found to have no difficulty in making negative referential descriptions in natural contexts, when their attention was drawn to context by experimenter. degree to which children's descriptions reflected awareness of context was related to their mental maturity, and there was a developmental trend in form of descriptions.