Showing papers in "Perception in 1977"
TL;DR: Although some aspects of the results support the scanpath hypothesis of Noton, it is suggested that an alternative interpretation is possible.
Abstract: Recordings were made of the eye fixations of three subjects in two tasks involving black-and-white photographs of faces. In the first task, subjects matched a test face with a previously viewed target face; in the second task, subjects compared two simultaneously presented faces. The eye movements were recorded with a corneal reflection technique. Each subject showed an individual fixation strategy for the tasks; in particular each subject had one or more preferred facial feautres which were viewed foveally in both tasks. The subjects also showed some tendency to use a regular sequential pattern of eye movements. However, the sequences used differed from one task to the other. Although some aspects of the results support the scanpath hypothesis of Noton, it is suggested that an alternative interpretation is possible.
377 citations
368 citations
TL;DR: The problem about visual discrimination between seeing objects in motion and perception of motion of the perceiver (locomotion) was taken up and most subjects perceived themselves as sitting in an elevator continuously moving upward or downward.
Abstract: The problem about visual discrimination between seeing objects in motion and perception of motion of the perceiver (locomotion) was taken up. A flow of vertical motion was presented to limited areas of the far periphery (45 degrees-90 degrees) of the retina simultaneously with optical information about a stationary room over the rest of the retina. The result was that most subjects perceived themselves as sitting in an elevator continuously moving upward or downward. Thus, peripheral motion stimulation over a few percent of the retinal area determines locomotion perception in apparent competition with information about a static state over the rest of the retina. The same type of stimulus presented to the central part of the retina always brought about perception of object motion and a static perceiver. Effects of size and localization of the area stimulated with the motion flow was studied. Theoretical consequences and problems for further experimental analyses are discussed.
207 citations
TL;DR: The results suggest that visual proprioception functions to maintain postural stability before infants have learned to stand, as well as conflicting visual, and mechanical proprioceptive information on postures.
Abstract: The effect of conflicting visual, and mechanical proprioceptive information on postural stability was compared in two groups of infants. The older group could sit or stand unsupported, while the younger group could sit but could not yet stand. The results suggest that visual proprioception functions to maintain postural stability before infants have learned to stand.
185 citations
TL;DR: It is suggested that colour- and brightness-contour registration in the visual channel is a problem which may be solved neurally by master brightness signals locking slave colour signals.
Abstract: An optical technique is described for projecting two-colour pictures with controlled brightness contrast, which may be set to zero—at isoluminance. Colour registration is maintained without adjustment or special setting up. It is suggested that colour- and brightness-contour registration in the visual channel is a problem which may be solved neurally by master brightness signals locking slave colour signals. The projection apparatus allows the supposed master brightness signals to be removed—at isoluminance—when contour disturbances should occur. Observations of this kind are reported.
183 citations
TL;DR: The ability of hearing adolescents to use speech-read information in order to report lists of CVC words presented in white noise was investigated and it was indicated that vision provided a complementary source of information for the perception of speech.
Abstract: The ability of hearing adolescents to use speech-read information in order to report lists of CVC words presented in white noise was investigated. The conditions of stimulus presentation included were auditory and visual information in synchrony, out of synchrony, auditory input alone, visual input alone, and a condition where the information presented in the auditory input conflicted with the visual input. The results indicated that the amount and type of type of information reported varied according to the condition of presentation, and that vision provided a complementary source of information for the perception of speech.
156 citations
TL;DR: The present study attempted to assess the relative salience of different parts of the human face through the manipulation of the features contained in the Photofit Kit, and found Nose changes were least likely to be noticed, followed by mouth and eyes, with foreheads producing the lowest rate of error.
Abstract: The present study attempted to assess the relative salience of different parts of the human face through the manipulation of the features contained in the Photofit Kit. Subjects observed a face constructed from the kit before attempting to identify the same face in an array of alternatives. The alternatives differed from the target in only one feature and this was systematically varied within the array. Nose changes were least likely to be noticed, followed by mouth and eyes, with foreheads producing the lowest rate of error. This order of features held irrespective of the similarity of the distractors or whether judgements were made in the presence or in the absence of the target. The chin region produced different results depending upon the similarity of the distractors. The results are discussed in relation to earlier experiments in which Photofit and previous studies of cue saliency were used.
146 citations
TL;DR: A model of how people use this information to infer the metre of unaccompanied melodies is described here, in the form of a computer program, and involves a definition of melodic repetition which encompasses repetitions that include certain kinds of variation.
Abstract: The occurrence of relatively long notes, and the repetition of melodic phrases are important cues to the metre, or regular beat, of a piece of music. A model of how people use this information to infer the metre of unaccompanied melodies is described here. The model is in the form of a computer program, and involves a definition of melodic repetition which encompasses repetitions that include certain kinds of variation. The program has been applied to the task of analysing the metric structure of the forty-eight fugue subjects of the Well-Tempered Clavier by J S Bach. The program is discussed in relation to other models both of musical understanding and of sequential concept learning.
121 citations
TL;DR: The verbal and manual responses (distance indices) differed greatly, but were found to be related by a constant transform, and the range of target distances had no effect on either index.
Abstract: Subjects made verbal reports of the perceived distance of near visual targets and indicated their distances by pointing at them with an unseen hand. The targets were presented under three stimulus conditions: monocular, binocular, and multicue. Two ranges of target distance were studied in separate experiments: 11–39 cm and 21–33 cm. When reciprocals of both response distance and target distance were plotted, all functions were approximately linear. The verbal and manual responses (distance indices) differed greatly, but were found to be related by a constant transform. The range of target distances had no effect on either index. The standard deviation of the manual response was about half that of the verbal response. Stimulus condition had a large effect, with the multicue condition producing the greatest change in indicated distance, and the monocular condition the least. The results are discussed with reference to the definition of perceived distance, and hypotheses concerning the integration of distan...
109 citations
TL;DR: A behavioural method is described for the measurement of various visual spatial acuities in kittens as young as thirty days of age and applications are given of applications of the technique to measurement of the visual acuity for gratings in normal kittens.
Abstract: A behavioural method is described for the measurement of various visual spatial acuities in kittens as young as thirty days of age. Expamples are given of applications of the technique to measurement of the visual acuity for gratings in normal kittens as well as to studies of the time course of behavioural recovery from the effects of early monocular visual deprivation.
101 citations
TL;DR: A simple model has been developed to determine whether the perception of visual movement is due to the geometric projection of the vestibular evaluation on the visual vector, or the inverse.
Abstract: In the present work, we have shown the effect of a vestibular stimulation on the velocity perception of a moving scene. The intensity of this effect is related to the amplitude of the cart acceleration, image velocity, spatial frequency of the visual stimulus, and the angle between the directions of cart and image movement. A simple model has been developed to determine whether the perception of visual movement is due to the geometric projection of the vestibular evaluation on the visual vector, or the inverse.
TL;DR: The effects of orientation and spatial frequency of grating stimuli upon suppression were examined with a binocular rivalry paradigm in a group of ten strabismic patients and in a control normal group.
Abstract: The effects of orientation and spatial frequency of grating stimuli upon suppression were examined with a binocular rivalry paradigm in a group of ten strabismic patients and in a control normal group. Duration, frequency, and period of rivalry were examined as functions of differences in orientation and spatial frequency of dichoptic achromatic sinusoidal gratings. Records were made of responses by the sighting and by the nonsighting eye as well as responses during periods of combined binocular vision. Strabismic subjects reported normal binocular rivalry when presented with gratings of dissimilar orientation. Suppression of the deviating eye in strabismic subjects occurred with stimuli of similar orientation and was unaffected by spatial-frequency differences between dichoptic stimuli. Suppression was most intense under conditions that normally stimulate stereopsis and sensory fusion.
TL;DR: Two studies on the amplitude, latency, and waveform of human visual evoked responses to the onset of sine-wave grating patterns indicated that the peak latencies of both early and late waves were a function of the spatial frequency of the stimulus.
Abstract: Two studies on the amplitude, latency, and waveform of human visual evoked responses to the onset of sine-wave grating patterns were made. Results indicated that the peak latencies of both early and late waves were a function of the spatial frequency of the stimulus. The amplitude of the early wave (N1−P1) was consistently greatest at low spatial frequencies while the late wave (N2−P2) showed consistent attenuation at low spatial frequencies. In addition the location of the peak amplitude response of the late, but not the early, wave depended on the location (macular versus extramacular) and area (small versus large stimulus field) of retina stimulated. These findings are discussed in the light of evidence for separate transient and sustained systems within the human visual system.
TL;DR: Two kinds of models for taking into account the sensory processes at work in the detection of visual motion: the feature model and the frequency-filter model are proposed and it is proposed that they are consistent.
Abstract: Two kinds of models have been proposed for taking into account the sensory processes at work in the detection of visual motion: the feature model and the frequency-filter model.The problem of the complementarity of these models is raised. On the basis of empirical data, it is proposed that they are consistent.
TL;DR: Five probability distributions for the description of temporal fluctuations in the perception of ambiguous figures were fitted to previously obtained experimental results and classified according to their efficiency in describing the data, finding the gamma, Wiener, and Capocelli-Ricciardi distributions showed the highest efficiency.
Abstract: Five probability distributions for the description of temporal fluctuations in the perception of ambiguous figures were fitted to previously obtained experimental results and classified according to their efficiency in describing the data. The gamma, Wiener, and Capocelli-Riciardi distributions showed the highest efficiency, while the chi2 and Taylor-Aldridge distributions showed a very low effiency. Therefore the underlying process may be described either by a simple Poisson model or by a random-walk model. For the gamma distribution there was a strong correlation between the parameters, while for the Wiener distribution this correlation was lower.
TL;DR: The results indicate that the so-called ‘oblique effect’ is confined to mechanisms with poor temporal resolving power, probably the sustained channels which have been studied psychophysically and neurophysiologically by others.
Abstract: Contrast thresholds were measured for vertical and oblique grating patterns. As shown previously, at higher spatial frequencies sensitivity for vertical is much greater than that for oblique. Present results show that this difference in sensitivity is found only with low rates of temporal modulation; with higher temporal frequencies this orientation difference disappears. Moreover, when contrast thresholds are based on the perception of flicker, vertical and oblique sensitivities are essentially identical even at low flicker rates. These results indicate that the so-called ‘oblique effect’ is confined to mechanisms with poor temporal resolving power, probably the sustained channels which have been studied psychophysically and neurophysiologically by others.
TL;DR: The results show that the target having the higher contrast with its background is perceived as the nearer, contradicting the well-known concept according to which the brighter target should in any case be perceivedAs the nearer (‘relative brightness’ cue).
Abstract: A black and a white target are displayed, in five different conditions, on five grey backgrounds having different degrees of brightness (from very bright to very dark). The results show that the target having the higher contrast with its background is perceived as the nearer. With the off-white background, e.g., the black target appears as the nearer to the observer. This contradicts the well-known concept according to which the brighter target should in any case be perceived as the nearer (‘relative brightness’ cue). The conclusion is that the frame of reference must be taken into consideration: study of the indicators to distance in an empty space and per se is not sufficient.
TL;DR: It is suggested that it might be fruitful if the tilt illusion and the rod-and-frame illusion were conceived of as illusions resulting from inducing figures composed of all or part of n gratings of spatial frequency intersecting at angles of 180°/n.
Abstract: Orientation illusions occur when the inducing figure is a line or grating (the tilt illusion) or a square outline frame (the rod-and-frame illusion). In the range of inducing figure tilts between vertical and horizontal, the tilt illusion describes one cycle of positive (direct) and negative (indirect) effects but the rod-and-frame illusion describes two such cycles. In two experiments, angular functions of illusions were measured with the six possible inducing figures which result when two of the four sides of a square inducing frame are deleted. As expected, the parallel-sided frame amputations induced angular functions similar to the tilt illusion and these functions differed from those induced by the orthogonal-sided amputations. In agreement with previous findings on the nonadditivity of tilt illusions, the sum of angular functions induced by frame amputations, which together form a complete frame, were not always equivalent to the angular function induced by a complete frame, and there were asymmetr...
TL;DR: The authors studied reaching behavior in 18- to thirty-two-week-old infants as a function of binocular convergence and found that the reaches obtained were nearly always directed at the virtual object defined by convergence and corrections of the reaches, if any, were made rather late and often not before the hand arrived at the place of the virtual objects.
Abstract: Reaching behavior in eighteen- to thirty-two-week-old infants was studied as a function of binocular convergence. The infant looked at the object to be reached for through prism arrangements which changed convergence only. The reaches obtained were nearly always directed at the virtual object defined by convergence. Corrections of the reaches, if any, were made rather late and often not before the hand arrived at the place of the virtual object.
TL;DR: The hypothesis that visual motion aftereffect is a manifestation of the adaptation recovery function of velocity sensitive mechanisms is shown to support.
Abstract: Visual motion aftereffect characteristics comparable to those associated with rotary and translatory movement of a test field are demonstrated for simulated rectilinear motion of the observer. The intensity and time duration of the phenomenon are shown to be positively correlated. The implications of this for individual observers are considered. The results of this experiment are correlated with those for adaptation and for recovery from adaptation that were obtained from the same group of observers. The findings are shown to support the hypothesis that visual motion aftereffect is a manifestation of the adaptation recovery function of velocity sensitive mechanisms.
TL;DR: In this paper, the effect of each component angle was generally independent of other angles and independent of any overall perspective appearance of the figure, and the shortening effect produced by an acute angle was limited to the contiguous quarter, whue the lengthening effect of an obtuse angle extended undiminished from the contiguous quarters to the next quarter.
Abstract: Perspective theories for the Muller-Lyer illusions have considered them to reflect constancies normally permitting the viewer to compensate for distance in estimating the true size of three-dimensional objects. Our experiments suggest a rather different perspective theory involving object recognition.A novel experimental procedure was used. Each of the separate groups of thirty subjects viewed only one of nineteen experimental drawings based on the Muller-Lyer figures. They judged the overall length of the shaft and divided it into subjectively equal quarters. The major findings were that the effect of each component angle was generally independent of other angles and independent of any overall perspective appearance of the figure. The shortening effect produced by an acute angle was limited to the contiguous quarter, whue the lengthening effect of an obtuse angle extended undiminished from the contiguous quarter to the next quarter.Perspective photographs are shown, demonstrating that these angle-induced...
TL;DR: The time decay of the motion aftereffect has been measured psychophysically, and it is found to depend on the spontaneous recovery from the adapted state, and the contrast of the test grating.
Abstract: Short-term adaptation to moving sinusoidal gratings results in a motion aftereffect which decays in time. The time decay of the motion aftereffect has been measured psychophysically, and it is found to depend on (i) the spontaneous recovery from the adapted state, and (ii) the contrast of the test grating. We have measured the decays for various test conditions. An extrapolation of the measurements allows us to obtain a decay which represents the time course of the spontaneous recovery of the direction-sensitive mechanisms.
TL;DR: The effect of auditory flutter upon perceived visual frequency is possibly due to modification of a subjective criterion rather than, as previously suggested, to the entrainment or time-locking of physiological signals in the visual pathway.
Abstract: Changes in the physical rate of a clicking or fluttering sound caused changes in the rate at which a simultaneously viewed light appears to flicker, even though the physical flicker rate remains constant. Perceived flicker rate increases in response to a rate of change of flicker frequency, and this auditory 'driving' does not depend on whether the auditory and visual sources have the same location. Visual evoked potentials do not correlate with 'driving'. Thus, the effect of auditory flutter upon perceived visual frequency is not due to the properties of Morrell-type bimodal neurons, nor does it reflect the activities of neurons responsible for maintaining correspondence between perceived auditory space and perceived visual space. The effect is possibly due to modification of a subjective criterion rather than, as previously suggested, to the entrainment or time-locking of physiological signals in the visual pathway.
TL;DR: Different bodily locations such as the palm were tried and the orientation was found to depend in most instances upon the direction in which the surface faced, and several possible theories were tested against the data.
Abstract: When a bilaterally asymmetrical figure is drawn on the skin at various bodily positions, the observer often reports that the figure he "sees" is reversed. On the head and neck, for example, figures drawn to the front of an imaginary line through the centre of the head, approximately in line with the ear canal are seen as reversed, and those to the rear of this line as correctly orientated. Different bodily locations such as the palm were tried and the orientation was found to depend in most instances upon the direction in which the surface faced. Several possible theories were tested against the data.
TL;DR: It was found that the tilt illusion can be induced with subjective as well as with real contours, suggesting that it is inappropriate to attribute the perception of real and subjective contours to fundamentally different processes.
Abstract: Exposure to one edge renders another edge less visible as a function of relative orientation. Experiment 1 showed that orientation-selective masking occurs between phenomenal edges located at sites where the visual display is homogeneous (subjective contours) as well as between edges defined in terms of luminance discontinuity (real edges). In addition, real contours can be masked by subjective contours, and vice versa. In experiment 2 it was found that the tilt illusion (apparent expansion of the angle formed by intersecting lines) can be induced with subjective as well as with real contours. These results suggest that it is inappropriate to attribute the perception of real and subjective contours to fundamentally different processes.
TL;DR: The results of the experiment showed that a texture surface which under binocular viewing appears to be oriented vertically and perpendicular to the line of sight in fact is tilted such that the portions of the texture surface above and below fixation incline toward and away from the observer, respectively.
Abstract: The existence of a tilted binocular disparity space was experimentally established. The results of the experiment showed that a texture surface which under binocular viewing appears to be oriented vertically and perpendicular to the line of sight in fact is tilted such that the portions of the texture surface above and below fixation incline toward and away from the observer, respectively. Under monocular viewing such a discrepancy between apparent and objective vertical tilt is not observed. This suggests that under binocular viewing the cortical representations of the upper and lower visual hemifields are biased toward uncrossed and crossed disparities, respectively. The tilted binocular disparity space is explained in terms of an experientially induced disparity gradient effected during development of the binocular system.
TL;DR: It is suggested that the scintillations are produced by small involuntary eye movements over the contours and that the associated disappearances might be due to binocular rivalry.
Abstract: Prolonged observation of a stationary grating has a number of perceptual consequences. Initially the lines appear well-resolved and straight. The lines then take on a wavy and oscillating appearance, which is followed by scintillation of the pattern. The scintillations are often accompanied by cloudy disappearances of the grating. A streaming or scintillating aftereffect is visible subsequently, upon viewing a homogeneous surface. The literature concerning these effects is reviewed and several experiments are reported which examined the apparent waviness and scintillating disappearances. The basis for the apparent waviness remains unresolved. It is suggested that the scintillations are produced by small involuntary eye movements over the contours and that the associated disappearances might be due to binocular rivalry.
TL;DR: A classification system which partitions cornered torus figures into meaningful subsets which can be used to identify both formal and psychological properties of known as well as unknown possible and impossible figures in much the same manner as with the periodic table of chemical elements.
Abstract: The empirical study of impossible figures requires that independent variables be well-specified. This paper provides an aid for such a task by developing a classification system which partitions cornered torus figures into meaningful subsets. These can be used to identify both formal and psychological properties of known as well as unknown possible and impossible figures in much the same manner as with the periodic table of chemical elements. The classification is polytopic (for demensional) and is formally, not empirically, derived. Coherent three-dimensional and two-dimensional forms of the system are possible without loss of information.
TL;DR: Seven adult male squirrel monkeys adapted successfully to prisms displacing in equal and opposite directions after protracted training under certain conditions, and conserved adaptation to both prisms without benefit of readaptation trials.
Abstract: Seven adult male squirrel monkeys adapted successfully to prisms displacing in equal and opposite directions. After protracted training under certain conditions, they succeeded in conserving adaptation to both prisms without benefit of readaptation trials. Results obtained with thirty-six undergraduates under similar conditions of test (although for a much shorter period) are also reported.
TL;DR: With few exceptions the model was found to hold well up to 40 min of prism viewing regardless of type of exposure background and target specificity.
Abstract: Prism adaptation as measured by negative aftereffects (NA), proprioceptive shifts (PS), and visual shifts (VS) was assessed as a function of amount of exposure time and target specificity, whether an exposure and a test target background were the same or different, to determine the validity of Wilkinson's linear model (NA = PS+ VS). With few exceptions the model was found to hold well up to 40 min of prism viewing regardless of type of exposure background. In addition target specificity affected magnitude of the NA component of adaptation but not the PS and the VS components.