Search PubMed⌕ Search

Biomedical subjects

J P Wolz

Publications and source records attributed to J P Wolz.

4 recordsLinked to original sources
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↗
PubMed1979

Stimulus and procedural determinants of the forgetting of conditioned fear.

Two studies investigated factors believed to influence the retention of acquired fear in rats. The results show clearly that the lack of forgetting over 24-hr interval reported by previous investigators is due to a depression of performance on the immediate test (3-min retention interval) resulting from the procedure of not handling the rats during conditioning but then handling them on every trial during the retention test. In accord with the McAllister's interpretation of related results, the depression of performance after short retention intervals may be due to a lack of generalization from training to the testing situation. As the retention interval is lengthened, the amount of generalization increases and escape performance improves on a relative basis. The nature of the retention function may be severely distorted by selection of an inappropriate paradigm for its evaluation.

Animals↗