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Biomedical subjects

L M Herman

Publications and source records attributed to L M Herman.

34 records · Page 2Linked to original sources
PubMed1985

Reporting presence or absence of named objects by a language-trained dolphin.

Referential "reporting" was defined as the transmission of information about the presence or absence of symbolically-referenced real-world objects. In Experiment 1 two bottlenosed dolphins (Tursiops truncatus), trained in earlier studies to carry out instructions conveyed by imperative sentences expressed in artificial gestural or acoustic languages, each gave spontaneous indications that an object referenced in an imperative was absent from their tank. In Experiment 2 the dolphin tutored in the gestural language was taught to make explicit reports of object absence by pressing a "No" paddle in response to imperatives referencing an absent object. Absence was reported correctly on 84% of 97 missing-object probes inserted at random intervals among 598 sentences referring to objects that were present. Reports were typically made after active search of the tank for an average of 15.0 sec. False reports, that objects present were absent, were few (7.5%). In Experiment 3, the dolphin was taught an interrogative sentence form that enabled us to ask direct questions about the presence or absence of specific objects. Responses by the dolphin on the No paddle indicated absence, while responses on a "Yes" paddle indicated presence. From one to three objects were shown the dolphin and then placed in the tank in a discrete-trial procedure. In response to the interrogative, reports or object presence or absence were better than 91% correct with a single object in the tank and either that object or some other object referenced; accuracy declined to 72-78% correct with three objects present, but was still well above chance. Several lines of evidence suggested that the dolphin was attempting to remember which objects it had been shown, rather than conducting an active environmental search as in Experiment 2. The memory strategy became less efficient as the number of objects to be remembered increased. Overall, the results evidenced the language-trained dolphin's understanding of references to present or absent objects, its ability to inventory its environment to seek information about those objects, and its ability to report its obtained knowledge to others.

Animal Communication↗
PubMed1984

Vocal mimicry of computer-generated sounds and vocal labeling of objects by a bottlenosed dolphin, Tursiops truncatus.

A bottlenosed dolphin (Tursiops truncatus) was trained to mimic computer-generated "model" sounds, using a whistle mode of vocalization. Prior to training, the whistle sounds of this dolphin were limited to a few stereotyped forms, none of which resembled the model sounds. After training, high-fidelity imitations were obtained of model sounds having (a) moderately or widely swept, slow-rate frequency modulation (1-2 Hz), (b) narrowly or moderately swept frequency modulation at moderate to rapid rates (3-11 Hz), (c) square-wave frequency transitions, and (d) unmodulated (pure-tone) waveforms. New models, not heard previously, could be mimicked immediately, often with good fidelity, including mimicry of amplitude variation that had not been explicitly reinforced during training. Subsets of familiar models were mimicked with high reliability in repeated tests. In additional training, control of the mimic response was transferred from the acoustic model to objects shown the dolphin (e.g., a ball or a hoop) so that, in effect, the dolphin gave unique vocal labels to those objects. In a test of accuracy and reliability of labeling, correct vocal labels were given on 91% of 167 trials comprised of five different objects presented in random order. The dolphin's ability for vocal mimicry compared favorably with that of the more versatile mimic birds, and it contrasted sharply with the apparent lack of vocal mimicry ability in terrestrial mammals other than humans. The ability to label objects vocally was similar to abilities shown for some birds and similar, in principle, to abilities of great apes trained in visual languages to label objects through gestures or other visual symbols.

Animals↗
PubMed1977

Memory for lists of sounds by the bottle-nosed dolphin: convergence of memory processes with humans?

After listening to a list of as many as six discriminably different 2-second sounds, a bottle-nosed dolphin classified a subsequent probe sound as either "old" (from the list) or "new." The probability of recognizing an old probe was close to 1.0 if it matched the most recent sound in the list and decreased sigmoidally for successively earlier list sounds. Memory span was estimated to be at least four sounds. Overall probabilities of correctly classifying old and new probes corresponded closely, as if recognition decisions were made according to an optimum maximum likelihood criterion. The data bore many similarities to data obtained from humans tested on probe recognition tasks.

Animals↗
PubMed1975

Bottle-nosed dolphin: double-slit pupil yields equivalent aerial and underwater diurnal acuity.

In bright daylight, and at best viewing distances, the bottlenosed dolphin resolves visual gratings approximately equally well in air and in water. Aerial resolution improves with increased viewing distance, while underwater resolution improves with decreased viewing distance. The double-slit pipil overcomes the gross myopia in air measured by ophthalmoscope and produces the indicated effects of viewing distance.

Air↗
PubMed1974

Auditory delayed matching in the bottlenose dolphin.

A bottlenose dolphin, already highly proficient in two-choice auditory discriminations, was trained over a nine-day period on auditory delayed matching-to-sample and then tested on 346 unique matching problems, as a function of the delay between the sample and test sounds. Each problem used new sounds and was from five to 10 trials long, with the same sound used as the sample for all trials of a problem. At each trial, the sample was projected underwater for 2.5 sec, followed by a delay and then by a sequence of two 2.5-sec duration test sounds. One of the test sounds matched the sample and was randomly first or second in the sequence, and randomly appeared at either a left or right speaker. Responses to the locus of the matching test sound were reinforced. Over nine, varying-sized blocks of problems, the longest delay of a set of delays in a block was progressively increased from 15 sec initially to a final value of 120 sec. There was a progressive increase across the early blocks in the percentage of correct Trial 1 responses. A ceiling-level of 100% correct responses was then attained over the final six blocks, during which there were 169 successive Trial 1 responses bracketed by two Trial 1 errors (at 24- and 120-sec delays). Performance on trials beyond the first followed a similar trend. Finally, when the sample duration was decreased to 0.2 sec or less, matching performance on Trial 1 of new problems dropped to chance levels.

Acoustic Stimulation↗
PubMed1973

Stimulus control and auditory discrimination learning sets in the bottlenose dolphin.

The learning efficiency of an Atlantic bottlenose dolphin was evaluated using auditory discrimination learning-set tasks. Efficiency, as measured by the probability of a correct response on Trial 2 of a new discrete-trial, two-choice auditory discrimination problem, reached levels comparable to those attained by advanced species of nonhuman primates. Runs of errorless problems in some cases rivaled those reported for individual rhesus monkeys in visual discrimination learning-set tasks. This level of stimulus control of responses to new auditory discriminanda was attained through (a) the development of a sequential within-trial method for presentation of a pair of auditory discriminanda; (b) the extensive use of fading methods to train initial discriminations, followed by the fadeout of the use of fading; (c) the development of listening behavior through control of the animal's responses during projection of the auditory discriminanda; and (d) the use of highly discriminable auditory stimuli, by applying results of a parametric evaluation of discriminability of selected acoustic variables. Learning efficiency was tested using a cueing method on Trial 1 of each new discrimination, to allow the animal to identify the positive stimulus before its response. Efficiency was also tested with the more common blind baiting method, in which the Trial 1 response was reinforced on only a random half of the problems. Efficiency was high for both methods. The overall results were generally in keeping with exceptations of learning capacity based on the large size and high degree of cortical complexity of the brain of the bottlenose dolphin.

Journal Article↗
PubMedDate not supplied

Managing ankle injuries in the emergency department.

We review the anatomy and physiology of the ankle joint with attention to the structures most likely to be injured. We discuss the epidemiology of ankle injuries and their physical and radiographic evaluation, including the Ottawa Ankle Rules. Treatment, consultation, and pitfalls are followed by more specific discussions of tendonitis, Achilles tendon injury, tendonous subluxations, tarsal tunnel syndrome, sonovial impingement, and injury to the os trigonum. The references provide a guide for further reading.

Ankle Injuries↗
PubMedDate not supplied

Utility of gastric brushing in the diagnosis of malignant lymphoma.

The gastric brushings (GBRs) and endoscopic biopsies obtained concurrently from 27 patients in whom malignant lymphoma was diagnosed or suggested by either modality were assessed to evaluate the utility of cytologic examination in the diagnosis of gastric lymphoma. GBRs provided a definitive diagnosis of lymphoma in 2 (28%) of 7 patients with a prior history of lymphoma and 10 (56%) of 18 patients with primary gastric lymphoma, yielding an overall sensitivity of 48%. All the lymphomas diagnosed cytologically were large cell type. GBRs were suspicious for a malignant neoplasm in four lymphoma patients whose concurrent biopsies were negative. GBRs obtained from two patients who had gastritis were reported as suspicious for lymphoma. There were no false-positive diagnoses.

Adult↗