Short-term memory in the deaf: a test for speech coding.
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Adolescent↗
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Results for “Form Perception”
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Conditioned after-images. I.
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Acoustic Stimulation↗
Detection of mild aphasia: a study using the Token Test.
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Adult↗
A new version of duplex perception: evidence for phonetic and nonphonetic fusion.
In a series of experiments, a variant of duplex perception was investigated. In its original form, duplex perception is created by presenting an isolated transition to one ear and the remainder of the syllable, the standard base, to the other ear. Listeners hear a chirp at the ear receiving the isolated transition, and a full syllable at the ear receiving the base. The new version of duplex perception was created by presenting a third-formant transition in isolation to one ear and the same transition electronically mixed with the base to the other ear; the modified base now has all the information necessary for syllabic perception. With the new procedure, listeners reported hearing a chirp centered in the middle of their head and a syllable in the ear presented the modified base that was clearer than that produced by the isolated transition and standard base. They could also reliably choose the patterns that contained the additional transition in the base when attending to either the phonetic or nonphonetic sides of the duplex percept. In addition, when the fundamental frequency, onset time, and intensity of the isolated third-formant transition were varied relative to the base, the phonetic and nonphonetic (lateralization) percepts were differentially affected, although not always reliably. In general, nonphonetic fusion was more affected by large differences in these variables than was phonetic fusion. However, when two isolated third-formant transitions were presented dichotically, fusion and the resulting central location of the chirp failed markedly with relatively small differences in each variable. The results were discussed in terms of the role of fusion in the new version of duplex perception and the nature of the information that undergoes both phonetic and nonphonetic fusion.
Adult↗
Color- and edge-sensitive channels in the human visual system: tuning for orientation.
After subjects scanned red stripes tilted clockwise off vertical and green stripes tilted equally but counterclockwise, vertical test stripes appeared tilted counterclockwise when red but clockwise when green. As the angle between scanned and test stripes was increased from 0 degrees to 75 degrees , the magnitude of the tilt aftereffect rapidly increased to a peak between 10 degrees and 15 degrees and then dropped close to zero at about 40 degrees , a result consistent with narrowly tuned edge-sensitive channels.
Adaptation, Ocular↗
Curvature as a feature of pattern vision.
Prolonged inspection of convex lines of one color and concave lines of another color can cause the appearance of oppositely colored aftereffects in curved, achromatic test lines. These effects, strongly dependent on radius of curvature, cannot be attributed to tilt or orientation. It is concluded that these results are not encompassed by models of the visual system that are based on rectilinear arrays and that curvature is a specific feature of human visual perception.
Color Perception↗
Curvature detectors in human vision?
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Adaptation, Physiological↗
Space perception in early infancy: perception within a common auditory-visual space?
Human infants aged I to 7 months were exposed to modifications of the normal spatial relationship between their mothers' face and voice. There was no evidence that such modifications were experienced by the infants as violations of a preexisting expectancy for face and voice to occupy the same spatial location.
Auditory Perception↗
Iconic storage: the role of rods.
The hypothesis that rods mediate iconic storage was tested by presenting letters of one color against a field of another. The colors were chosen to be discriminable only by the cones, only by the rods, or both. Under dark adaptation, the rods had little if any effect on partial-report advantage; however, they were important in determining the phenomenal persistence of the stimulus. Under light adaptation, the rods played no apparent role in either type of persistence.
Afterimage↗
Prosopagnosia: a clinical, psychological, and anatomical study of three patients.
Three patients with prosopagnosia are described of whom two had right occipital lesions. An analysis of visual and perceptual functions demonstrated a defect in perceptual classification which appeared to be stimulus-specific. A special mechanism for facial recognition is postulated, and the importance of the right sided posterior lesion is stressed.
Aged↗
Visual object recognition.
Visual object recognition is of fundamental importance to most animals. The diversity of tasks that any biological recognition system must solve suggests that object recognition is not a single, general purpose process. In this review, we consider evidence from the fields of psychology, neuropsychology, and neurophysiology, all of which supports the idea that there are multiple systems for recognition. Data from normal adults, infants, animals, and brain damaged patients reveal a major distinction between the classification of objects at a basic category level and the identification of individual objects from a homogeneous object class. An additional distinction between object representations used for visual perception and those used for visually guided movements provides further support for a multiplicity of visual recognition systems. Recent evidence from psychophysical and neurophysiological studies indicates that one system may represent objects by combinations of multiple views, or aspects, and another may represent objects by structural primitives and their spatial interrelationships.
Adult↗
Some aspects of visual physiology of the honeybee.
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Action Potentials↗
Recognition of apertures in overhead transparent barriers by leopard frogs.
Anurans have independent systems for detecting moving stimuli and stationary opaque objects. We have discovered that leopard frogs will also orient to, and spontaneously and accurately jump through, circular apertures in overhead transparent covers. When given a choice between one large aperture of 3.8 cm diameter, and three apertures of smaller but equal diameter (2.5 cm diameter, 1.9 cm diameter, or 1.3 cm diameter) they choose the larger diameter aperture at a frequency (64, 87 and 97%, respectively) that is statistically greater than chance. In only 1 of 255 attempts was there a jump to the overhead cover that was not directed at an aperture. Atectal frogs are still able to detect and jump accurately through transparent apertures. Frogs cannot distinguish between two apertures of equal diameter if one aperture is covered with clear plastic with high light transmissibility (92% of transmissibility of air). However, if the plastic covering of the aperture has a residue which reduces light through the cover from 92 to 87% of the transmissibility of air, frogs will jump to the uncovered aperture at a frequency that is statistically greater than chance. Our results show that leopard frogs have an extremely well developed ability to detect overhead apertures just as they can vertical obstacles. They are able to jump towards such openings with a small margin of error independent of the tectal visual system.
Animals↗
Cube drawing performances in normal ageing and Alzheimer's disease: data from the PAQUID elderly population-based cohort.
To assess the influence of age and other sociodemographical variables, depressive symptomatology and the occurrence of Alzheimer's disease (AD) on cube drawing, we examined the performance of 858 normal subjects and 17 incident AD patients in the PAQUID population-based study. Cube drawing was first performed on verbal command and, in case of failure, a model of a cube was given to the subjects to copy. Normal subjects had some difficulties in drawing a cube on verbal command, evidenced by 40% failure in the drawing-to-command condition, while only 17% still failed in the drawing-to-copy condition. Multivariate logistic regressions showed that age, gender, and educational level were associated with cube drawing failure in both conditions, but depressive symptomatology was only associated with persistent failure in the drawing-to-copy condition. Seventy-six point five percent of incident AD subjects failed in the drawing-to-command condition and 64.7% did not benefit from the presentation of the model. Analysis showed that persistent failure in the copy condition was the best level of differentiation between normal and AD subjects.
Age Factors↗