Target Structure and Echo Spectral Discrimination by Echolocating Bats

Simmons, James A.; Lavender, W. A.; Lavender, B. A.; Doroshow, C. A.; Kiefer, Steven; Livingston, Richard A.; Scallet, Andrew C.; Crowley, David E.

doi:10.1126/science.186.4169.1130

Cited by 123 publications

(83 citation statements)

References 9 publications

(11 reference statements)

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“…Carollia produces broadband and high-frequency FM signals which are well suited for this task. Hence, Carollia could potentially use dierences in surface texture as a cue to distinguish ripe from unripe fruits and fruits from other objects by analyzing dierences in the spectral or temporal signature of the returning echo (Bradbury 1970;Habersetzer and Vogler 1983;Mogdans and Schnitzler 1990;Ostwald et al 1988;Schmidt 1988;Simmons and Vernon 1971;Simmons et al 1974Simmons et al , 1995. However, our study with untrained bats in the¯ight cage showed that both species approached, and even bit into foam rubber models of Piper which clearly diered in surface structure from real fruits.…”

Section: Role Of Surface Structurementioning

confidence: 41%

The roles of echolocation and olfaction in two Neotropical fruit-eating bats, Carollia perspicillata and C. castanea , feeding on Piper

Thies

Kalko

Schnitzler

1998

Behavioral Ecology and Sociobiology

207

226

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We studied the echolocation and foraging behavior of two Neotropical frugivorous leaf-nosed bats (Carollia perspicillata, C. castanea: Phyllostomidae) in ā ight cage. To test which cues Carollia uses to detect, identify, and localize ripe Piper fruit, their preferred natural food, we conducted experiments under seminatural conditions with ripe, unripe, and arti®cal fruits. We ®rst oered the bats ripe fruits and documented their foraging behavior using multi¯ash stereophotography combined with simultaneous sound recordings. Both species showed a similar, stereotyped foraging pattern. In search¯ight, the bats circled through the¯ight cage in search of a branch with ripe fruit. After ®nding such a branch, the bats switched to approach behavior, consisting of multiple exploration¯ights and the ®nal approach when the bats picked up the fruit at its tip and tore it o in¯ight. Our behavioral experiments revealed that odor plays an important role in enabling Carollia to ®nd ripe fruit. While foraging, Carollia always echolocated and produced multiharmonic, frequency-modulated (FM) signals of broad bandwidth, high frequency, short duration, and low intensity. We discriminated an orientation phase (mostly a single pulse per wingbeat) and an approach phase (groups of two to six pulses per wing beat). We conclude from the bats' behavioral reaction to real and arti®cial fruit as well as from characteristic patterns in their echolocation behavior that during exploration¯ights, Carollia changes from primarily odor-oriented detection and initial localization of ripe fruit to a primarily echo-oriented ®nal localization of the position of the fruit.

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Section: Role Of Surface Structurementioning

confidence: 41%

The roles of echolocation and olfaction in two Neotropical fruit-eating bats, Carollia perspicillata and C. castanea , feeding on Piper

Thies

Kalko

Schnitzler

1998

Behavioral Ecology and Sociobiology

207

226

View full text Add to dashboard Cite

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“…The limited temporal resolution led to the conclusion that bats generally evaluate echoes in the frequency domain when time differences of less than 100·s in overlapping echoes are offered (Beuter, 1980;Simmons et al, 1974). Nevertheless, behavioural experiments showed that Eptesicus fuscus perceives electronically generated echoes of two front targets in terms of two distinct reflections, and this with a resolution of up to 2·s (Simmons, 1989;Simmons et al, 1998).…”

Section: Temporal Pattern and Spectral Domainmentioning

confidence: 99%

“…Ostwald et al, 1988;Schmidt, 1988;Schmidt, 1992;Schnitzler and Henson, 1980;Simmons et al, 1974). Hitherto the objects used for object recognition tasks were such that their echo heavily changed with the angle of sound incidence (Bradbury, 1970;Simmons et al, 1974;Simmons and Vernon, 1971), which renders it difficult to determine the decisive echo feature. We used the simplest possible concave form, the hollow hemisphere, because of its extraordinary acoustic properties.…”

Section: Introductionmentioning

confidence: 99%

Size discrimination of hollow hemispheres by echolocation in a nectar feeding bat

Simon

Holderied

Helversen

2006

Journal of Experimental Biology

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the echo's temporal and spectral pattern as well as in amplitude.Bats were simultaneously confronted with seven different sizes of hollow hemispheres presented from their concave sides. Visits to one particular size were rewarded with sugar water, while we recorded the frequency of visits to the unrewarded hemispheres. We found that: (1) bats learned to discriminate between hemispheres of different size with ease; (2) the minimum size difference for discrimination was a constant percentage of the hemisphere's size (Weber fraction: approximately 16% of the radius); (3) the comparison of behavioural data and impulse response measurements of the objects' echoes yielded discrimination thresholds for mean intensity differences (1.3·dB), the temporal pattern (3-22· s) and the change of spectral notch frequency (approximately 16%). We discuss the advantages of discrimination in the frequency and/or time domain.

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“…The behavior ofbats in nature and in laboratory experiments shows that the shape oftargets is encoded in sonar sounds (see, e.g., Busnel & Fish, 1980;Griffin, Friend, & Webster, 1965;Simmons et al, 1974). However, sonar sounds have many different dimensions (amplitude changes, frequency composition, cross-correlation between the emitted sound and the returning echo, and so on).…”

Section: Examining the Availability Of Information And Its Representamentioning

confidence: 99%

Computational analyses in cognitive neuroscience: In defense of biological implausibility

Dror

Gallogly

1999

Psychonomic Bulletin & Review

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Because cognitive neuroscience researchers attempt to understand the human mind by bridging behavior and brain, they expect computational analyses to be biologically plausible. In this paper, biologically implausible computational analyses are shown to have critical and essential roles in the various stages and domains of cognitive neuroscience research. Specifically,biologically implausible computational analyses can contribute to (1) understanding and characterizing the problem that is being studied, (2) examining the availability of information and its representation, and (3) evaluating and understanding the neuronal solution. In the context of the distinct types of contributions made by certain computational analyses, the biological plausibility of those analyses is altogether irrelevant. These biologically implausible models are nevertheless relevant and important for biologically driven research.The goal of cognitive neuroscience researchers is to uncover the cognitive processes that underlie human intelligence and the human mind, and not to understand any computational entity, per se. Because humans are biological, neuroscience research and its integration into cognitive theory have been the focus of the transition from cognitive science to cognitive neuroscience (see, e.g., . As a relatively new approach, cognitive neuroscience is still in the process ofexploring and establishing the various ways knowledge from differentdomains can becombinedinto a more complete and accurate description of cognition. The foundation and strength of cognitive neuroscience are in bridging knowledge from different and distinct disciplines. As the field progresses in its empirical discoveriesand its theoretical foundations, cognitive neuroscientists are beginning to realize how the integration of different domains can contribute to the overall understanding of the human mind, as This paper was supported by grants awarded by AFRL (Air Force Research Laboratory) to I.E.D. We owe thanks to many people who have read various versions of this paper or who have discussed related issues with us. These discussions about biologically implausible computational analyses in cognitive neuroscience, and perhaps the strong opposition we found to their acceptance, prompted us to write this paper. In particular, we would like to thank Steve Kosslyn, Bill Estes, Randy O'Reilly, Christof Koch, Mike Mozer, Stevan Hamad, and Allan Pantle. We also want to thank Randi Martin, David Adams, William Bechtel, Art Glenberg, and an anonymous reviewer for very helpful comments. We need to point out, however, that these people do not necessarily support our arguments (some of them even bluntly oppose them). The ideas expressed in the paper reflect our own viewpoint, and only we carry the responsibility for the arguments and views in this paper. Correspondence should be addressed to I. E. Dror, Department of Psychology, Southampton University, Highfield, Southampton SO 17 I BJ, England (e-mail: dror@coglab.psy.soton.ac.uk; www: http://www.cogsci.soton. ac.uk...

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Target Structure and Echo Spectral Discrimination by Echolocating Bats

Cited by 123 publications

References 9 publications

The roles of echolocation and olfaction in two Neotropical fruit-eating bats, Carollia perspicillata and C. castanea , feeding on Piper

The roles of echolocation and olfaction in two Neotropical fruit-eating bats, Carollia perspicillata and C. castanea , feeding on Piper

Size discrimination of hollow hemispheres by echolocation in a nectar feeding bat

Computational analyses in cognitive neuroscience: In defense of biological implausibility

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