Cerebral organization in bilinguals : I. Lateralization

There were no differences in lateral dominance indices between first and second languages in English-Hebrew bilinguals tested with a dichotic word test. Lateral dominance was the same for both languages regardless of when the second language was learned, how long it had been used, or how well it was known (according to a self-rating scale). In addition, the “traditional” sex differences were found where females had a significantly better overall recall performance but a significantly smaller difference in performance between the right and left ears.     

Matching of movements made independently by the two arms in normal humans

Comparisons were made of voluntary movements of the right and left arms in normal human subjects. A series of movements of different amplitudes, made at the subject' own speed, was performed with one limb. After a rest period, the same series was repeated with the contralateral limb. The relation between movement peak velocity and movement amplitude was linear and was the same for both arms. With repeated testing over periods up to two months, the slope of the peak velocity-amplitude relation decreased during the first week, thereafter remaining unchanged. In a second series of experiments, six normal subjects continuously wore a 1 lb (0.45 kg) weight strapped to their left (non-dominant) forearm for up to 1 week. This resulted in an increase in the slope of the peak-velocity/amplitude relation in this arm. A parallel change occurred in movements made independently by the right (non-loaded) arm. A similar matching of movement performance of the two limbs was seen following removal of the weight. The data is interpreted as proving support for the hypothesis that there is a single movement "command" which is applied to both limbs. The interaction of this command with the limbs which have similar second-order mechanical properties yields similar movements even when they are made independently.     

Perceptual organization of acoustic stimuli by budgerigars (Melopsittacus undulatus): I. Pure tones

A new combination of operant conditioning and psychophysical scaling procedures was used to study auditory perception in a small bird. In a same-different discrimination task, budgerigars learned to discriminate among pure tones that varied along one or more acoustic dimensions. Response latencies were used to generate a matrix of interstimulus similarities. Multidimensional scaling procedures were used to arrange these acoustic stimuli in a multidimensional space that supposedly reflects the bird's perceptual organization. For tones that varied in intensity, duration, and frequency simultaneously, budgerigars were much more sensitive to frequency changes. From a set of tones that varied only in intensity, it was possible to calculate the growth of loudness with intensity for the budgerigar. For tones that varied only in frequency, budgerigars showed evidence of an "acoustic fovea" for frequency change in the spectral region of 2-4 kHz. Budgerigars and humans also differed in their perceptual grouping of tone sequences that rise, fall, or remain constant in pitch. Surprisingly, budgerigars were much less responsive to pitch contour than were humans.     

The directionality and functional organization of frontoparietal connectivity during consciousness and anesthesia in humans

Frontoparietal connectivity has been suggested to be important in conscious processing and its interruption is thought to be one mechanism of general anesthesia. Data in animals demonstrate that feedforward processing of information may persist during the anesthetized state, while feedback processing is inhibited. We investigated the directionality and functional organization of frontoparietal connectivity in 10 human subjects anesthetized with propofol on two separate occasions. Multichannel electroencephalography and a computational method of assessing directed functional connectivity were employed. We demonstrate that directed feedback connectivity is diminished with loss of consciousness and returns with responsiveness to verbal command. We also applied the Dendrogram classification method to assess the global organization of directed functional connectivity during consciousness and anesthesia. We demonstrate a state-specific hierarchy and subject-specific subhierarchy in functional organization. These data support the hypothesis that specific states of human consciousness are defined by specific states of frontoparietal connectivity.     

The discrimination of dog odours by humans

The domestic dog is able to identify both individual conspecifics, i.e. other dogs, and individual interspecifics, e.g. humans, by smell. Whilst humans can recognise individual members of their own species using olfactory information, it is unknown whether they can identify members of any other species in this manner. We examined the ability of humans to identify individual dogs by smell. Twenty-six dog owners were required to smell two blankets, one impregnated with the odour of their own dog, the other impregnated with the odour of an unfamiliar dog. Participants were required to indicate which of the odours smelt the strongest, which smelt the most pleasant, and which of the odours belonged to their own dog. Most of the participants (88.5%) were able to recognise the odour of their own dog. They showed no significant bias, however, in responding which of the odours they thought smelt the strongest or most pleasant. The results indicate that dogs produce odours that are individually distinctive to their owners, and highlight the fact that humans can recognise members of another species using olfactory cues--an ability presumably acquired without conscious effort.     

The discrimination of cat odours by humans

We explored the ability of humans to identify individual cats by smell. Twenty-five cat owners were required to indicate which of two odours (one belonging to their own cat and one belonging to an unfamiliar cat) smelt the strongest, most pleasant, and which belonged to their own cat. Only thirteen (52%) of the participants were able to recognise the odour of their own cat.     

Acoustic classification of alarm calls by vervet monkeys (Cercopithecus aethiops) and humans (Homo sapiens): I. Natural calls

A 2-choice, operant-conditioning-based classification procedure was developed in which vervet monkeys (Cercopithecus aethiops) categorized species-typical snake and eagle alarm calls recorded from individually identified free-ranging animals. After preliminary training with a pair of calls from a single animal, 2 vervets were tested with novel exemplars produced by a variety of callers. Experiment 1 combined testing with continued training in routine classification of 14 new calls. In Experiment 2, the subjects were tested with 48 novel calls in rapid succession. Human (Homo sapiens) control subjects participated in the first study without extended preliminary training. Monkey and human subjects both showed immediate transfer to classification of unfamiliar alarm calls, despite variations both in voice characteristics and reproduction quality.     

Community: The Place where Theology is made

An expanded version of a paper given at a seminar on "contextual theology" held in November 1983 at the Pastoral Institute at Multan, in the Punjab, Pakistan.     

Picture memory: role of figure-ground organization.

Alterations to the figure of pictures committed to visual memory are more easily detected than alterations to the ground, both in single and paired stimulus tests. Data for 40 scenes from 54 undergraduates suggest that perceptual processes interact with information storage and/or retrieval.     

The evaluation and control of acoustical standing waves

Calibration of a standard pigeon box subsequently modified for use as an acoustical chamber in a frequency discrimination experiment revealed that the enclosure was not acoustically “flat”. Standing waves were detected at each of the six frequencies measured. To ascertain whether the maximum standing waves recorded (3.0 dB) could serve as an added or alternative cue for pigeons tested in the chamber on a frequency discrimination problem, pure-tone intensity difference thresholds were determined for two pigeons at 1.0, 2.0, and 3.0 KHz. The results of the experiment indicated that the smallest intensity difference detectable was 10.0 dB, a value that was 7.0 dB above the maximum standing wave measured in the box. These data suggest that the modified pigeon chamber is suitable to test pure-tone frequency discriminations in pigeons in the range of 1.0 to 3.0 KHz.     

Geometric orientation by humans: angles weigh in

Human participants were trained to navigate to two geometrically equivalent corners of a parallelogram-shaped virtual environment. The unique shape of the environment combined three distinct types of geometric information that could be used in combination or in isolation to orient and locate the goals: the angular amplitudes of the corners, the relative wall length relationships, and the principal axis of symmetry. In testing, participants were placed in manipulated versions of the training environment that tested which types of geometry they had encoded and how angular information weighed in against the other two geometric properties. The test environments were (a) a rectangular environment that removed the angular information, (b) a rhombic environment that removed wall length information and drastically reduced the principal axis, and (c) a reverse-parallelogram-shaped environment that placed angular information against both wall length and principal axis information. Participants chose accurately in the rectangular and rhombus environments, despite the removal of one of the cues. In the conflict test, participants preferred corners with the correct angular amplitudes over corners that were correct according to both wall length relationships and the principal axis. These results are comparable to recent findings with pigeons and suggest that angles are a salient orientation cue for humans.     

The different types of limb apraxia errors made by patients with left vs. right hemisphere damage

Limb apraxia errors were compared among normal controls and right- or left-hemisphere-damaged patients as they imitated gestures with the ipsilateral hand. Both brain-damaged groups made similar errors on nonrepresentative and representative/intransitive movements. In contrast for pretended object use movements (transitive), the left-hemisphere-damaged group made more arm position and classical body-part-as-object errors while the right hemisphere group made as many partial errors and more less-primitive, body-part-as-object errors than the left-hemisphere-damaged group. These results help explain why a certain percentage of right-hemisphere-damaged patients are labeled apraxic, but also suggest that the left hemisphere is more important for integrating intrapersonal space and the “representation” of extrapersonal space.     

The phenomenological-existential comprehension of chronic pain: going beyond the standing healthcare models

A distinguishing characteristic of the biomedical model is its compartmentalized view of man. This way of seeing human beings has its origin in Greek thought; it was stated by Descartes and to this day it still considers humans as beings composed of distinct entities combined into a certain form. Because of this observation, one began to believe that the focus of a health treatment could be exclusively on the affected area of the body, without the need to pay attention to patient’s subjectivity. By seeing pain as a merely sensory response, this model was not capable of encompassing chronic pain, since the latter is a complex process that can occur independently of tissue damage. As of the second half of the twentieth century, when it became impossible to deny the relationship between psyche and soma, the current understanding of chronic pain emerges: that of chronic pain as an individual experience, the result of a sum of physical, psychological, and social factors that, for this reason, cannot be approached separately from the individual who expresses pain. This understanding has allowed a significant improvement in perspective, emphasizing the characteristic of pain as an individual experience. However, the understanding of chronic pain as a sum of factors corresponds to the current way of seeing the process of falling ill, for its conception holds a Cartesian duality and the positivist premise of a single reality. For phenomenology, on the other hand, the individual in his/her unity is more than a simple sum of parts. Phenomenology sees a human being as an intending entity, in which body, mind, and the world are intertwined and constitute each other mutually, thus establishing the human being’s integral functioning. Therefore, a real understanding of the chronic pain process would only be possible from a phenomenological point of view at the experience lived by the individual who expresses and communicates pain.