Picture perception: An analysis of visual compensation

Although geometric information is altered when a picture’s viewing point is changed, such changes often do not affect perception. Two experiments assessed pictorial perception relative to the distortions introduced by viewing point dislocation. Results provide a psychophysical demonstration of pictorial compensation and suggest that it is based on the discrepancy between the actual and an assumed-correct viewing position. An explanation of pictorial compensation is offered that could be applied to direct picture perception and to picture-in-a-picture perception.     

Flow thresholds of nonodorous air through the human naris as a function of temperature and humidity

The process of olfactory sensation is probably a Gestalt consisting of motor, physical, and chemical components formed during the transport of the odor-bearing airstream past the olfactory epithelium. In studying a sensory process, it is often necessary to examine the components independently. Apart from its contribution to the olfactory Gestalt, in dynamic olfactometry airflow may distract from, compete with, or mask chemical sensation. Four nonsmoking male subjects were employed to obtain flow thresholds of nonodorous air at eight temperature/ humidity combinations. The stimulus-generating apparatus was housed in a temperature-regulated oven. All materials in contact with the airstream were thoroughly cleaned and were constructed of nonreactive materials to avoid olfactory cues. An evaluation of the quality of the output demonstrated purity. A Béésy technique was used to deliver stimuli via a nasal catheter to the subject. Thresholds were found to be nearly identical for the lowest humidity levels regardless of the temperature. In general, the closer the temperature/humidity was to physiological normal, the higher the threshold. Since the thresholds were so strongly functions of temperature and humidity, it is likely that transduction was by trigeminal thermoreceptive afferents. The utilization of subthreshold flows in olfactory research may reduce the trigeminal component in olfaction, thus permitting better assessment of the contribution of the olfactory nerve to olfactory sensation.     

Free classification: Element-level and subgroup-level similarity

Subjects classified sets of multidimensional stimuli into two groups in any way they wished. The sets were composed of 6 or 12 stimuli: 2 or 4 instances of 3 different stimuli (e.g., 2 blue circles, 2 green circles, 2 red circles). There were striking individual differences in the preferred classification. Some subjects maximized the similarity between subgroups by matching the composition of the subgroups--one instance of each stimulus was placed in each group. The other subjects maximized the similarity among stimuli within each subgroup by placing similar stimuli in each group (the blues and greens in one group, the reds in the other). The nature of the stimuli as well as the relationships among the three stimuli had little effect on classification. In this case, cognitive styles specific to individuals but general across diverse dimensions and stimulus sets determined classification.     

Contextual effects in vowel perception II: Evidence for two processing mechanisms

Recent experiments have indicated that contrast effects can be obtained with vowels by anchoring a test series with one of the endpoint vowels. These contextual effects cannot be attributed to feature detector fatigue or to the induction of an overt response bias. In the present studies, anchored ABX discrimination functions and signal detection analyses of identification data (before and after anchoring) for an [i]-[I] vowel series were used to demonstrate that [i] and [I] anchoring produce contrast effects by affecting different perceptual mechanisms. The effects of [i] anchoring were to increase within-[i] category sensitivity, while [I] anchoring shifted criterion placements. When vowels were placed in CVC syllables to reduce available auditory memory, there was a significant decrease in the size of the [I]-anchor contrast effects. The magnitude of the [i]-anchor effect was unaffected by the reduction in vowel information available in auditory memory. These results suggest that [i] and [I] anchors affect mechanisms at different levels of processing. The [i] anchoring results may reflect normalization processes in speech perception that operate at an early level of perceptual processing, while the [I] anchoring results represent changes in response criterion mediated by auditory memory for vowel information.     

Trees as memory representations for simple visual patterns

The form of the memory representation for visual patterns consisting of a few line segments was investigated with three tasks. One task was the reproduction of remembered patterns using pencil and paper. The order in which the subparts of those patterns were reproduced was used to make suggestions about possible memory representations for the patterns. The second task involved rating the “goodness” of subparts of the patterns. These ratings were also interpreted as reflecting the underlying representations of the patterns. In the third task, the time required to recognize that a small pattern was part of a larger remembered pattern was used as further evidence about the memory representations of the patterns. The results from all three tasks are consistent with the theory that the memory representations are tree structures. Methods for deriving and comparing tree structures are discussed.     

Right hemisphere comprehension of verbs in patients with complete forebrain commissurotomy: Use of the dichotic method and manual performance

The paradigm of dichotic listening was used to investigate verbal comprehension in the right, so-called “nonverbal,” hemisphere. Verbal commands were presented to the right and left ears in the simultaneous (dichotic) paradigm. There were striking instances, especially when the left hemisphere was occupied with some extraneous task, in which the right hemisphere understood the verbal command and executed the appropriate motor responses. In those instances the left hemisphere gave no overt response. Although the left hemisphere was usually dominant, it can be nevertheless concluded that not only can the right hemisphere understand verbal commands but can also express itself manually by executing actions more complex than object retrieval or pointing. As has been known for some time, the blockage of the ipsilateral pathway seems so complete during dichotic listening in the commissurotomy patient that there is no report of the words in the left ear—only of those presented to the right. At the same time there is normal report when words are presented to the left ear alone. It was found in the present study, however, that this model is too simple and only applies to the verbal response paradigm of dichotic listening. Under circumstances of dichotic presentation where the stimulus in the left ear (ipsilateral pathway) is necessary or important to the left hemisphere for completing a task, words from both pathways are reported. One may conclude that there exists a gating mechanism in each hemisphere that controls the monitoring of each auditory pathway and the degree of ipsilateral suppression.     

Predictors of turnover of female factory workers

This study examines predictors of turnover of female factory workers in a multivariate framework. Findings indicate that organizational, job, and personal characteristics are equally important in explaining turnover. Variables significantly related to turnover were tenure, cycle time, peer leadership, communication flow, training time, family income, and satisfaction with pay. The AID technique was demonstrated as a means of identifying interaction effects.