James A. Simmons
Encyclopedia
James A. Simmons is a pioneer in the field of biosonar
. His research includes behavioral and neurophysiological studies of sound processing in the echolocating bat. From the time he began graduate research in the late 1960s to the present, he has been in the forefront of bat echolocation research. Simmons was honored as a fellow of the Acoustical Society of America (ASA) in 1996 and of the American Association for the Advancement of Science in 2000. He was awarded the ASA's second Silver Medal in Animal Bioacoustics in 2005. His current position is Professor in the Department of Neuroscience, Brown University
.
in 1965 with a double major in Psychology
and Chemistry
. He then earned a master’s degree in 1968 and a Ph.D. in Psychology in 1969 from Princeton University
. Simmons’s graduate research involved studies of echolocation in bats, under the mentorship of E. Glen Wever, one of the giants in physiological acoustics. At that time, acceptance of the processes underlying spatial perception
by echolocation was not universal, and one of the exciting moments of his graduate training came when a skeptical Nobel Laureate, Georg von Békésy
, on one of his periodic visits to Wever’s lab, came to see the behaving bats in "Building B.’’ The demonstration that Simmons conducted not only convinced Békésy that bats echolocated but that they also use echo delay to estimate target distance. It was not until some years later that Simmons found out that this was a set-up engineered by Wever and Donald Griffin, who was then at the Rockefeller University
, to convince Békésy about the bat’s extraordinary use of echolocation to determine target range. Simmons’s dissertation was entitled "Perception of target distance by echolocating bats.’’ After receiving his Ph.D., Simmons remained at Princeton University as a National Institutes of Health postdoctoral trainee for two years.
, Missouri in 1971, as an assistant professor in the Neural Science
Program that was housed in the Psychology Department. Between 1980 and 1984, he taught and conducted research as a professor in the Department of Biology and Institute of Neuroscience, University of Oregon
in Eugene, Oregon
. In 1984, Simmons moved to Brown University
in Providence, Rhode Island
, where his wife Andrea had been hired as an assistant professor in the Psychology Department. Both are now professors in the Psychology and Neuroscience Departments at Brown University, respectively.
Simmons developed methods for conducting psychophysical
studies of sonar processing by bats, and researchers around the world have adopted these methods to address a wide range of research questions. Simmons was the first to use electronically delayed playbacks of the bat’s echolocation signals to simulate target echoes for the study of perception in bats. He used such "phantom’’ target echoes to measure, for the first time, target range difference discrimination thresholds of echolocating bats. Simmons studied sonar ranging
performance in bats by determining the minimum difference in echo delay that an echolocating animal can discriminate. With this paradigm, Simmons estimated that bats can discriminate a range difference of approximately 1 centimeter, corresponding to an echo delay difference of approximately 60 microseconds.
Simmons continued to study sonar ranging performance in echolocating bats, and in the late 1970’s, he introduced a new behavioral task, requiring the bat to discriminate a sonar target returning echoes at a fixed delay from one returning echoes that alternated between two delays. In this experiment, Simmons found that the echolocating bat can discriminate a jitter in echo delay in the submicrosecond range, corresponding to a change in target distance of less than 0.1 mm. This result, originally published in 1979 in Science, "Perception of echo phase information in bat sonar,’’ demonstrated astonishing ranging accuracy by the echolocating bat. Many researchers in the field challenged the report, because they asserted it was not biologically possible for the bat’s sonar system to discriminate such small time differences at ultrasonic
frequencies. Simmons continues to work on this problem to explore biological processes that could support sensitivity to small changes in echo delay.
Through behavioral experiments, Simmons demonstrated time-varying gain
in the sonar receiver of echolocating bats. The hearing sensitivity of the big brown bat
decreases before each sonar pulse is emitted and then recovers in a logarithm
ic fashion to compensate for the two-way transmission loss of sonar returns, thereby maintaining a constant echo sensation level over a distance of about 1.5 meters. This is functionally important to the bat, as it stabilizes the bat’s estimate of echo arrival time, its cue for target distance.
In addition to Simmons’s contributions to our understanding of perception by sonar, he has conducted neurophysiological experiments in echolocating bats. One of his manuscripts published with co-authors Albert Feng and Shelley Kick in Science had a profound impact on the study of the neurophysiology of echolocating bats. This paper describes the response properties of auditory neurons in the bat central nervous system
that show facilitated responses to pairs of sounds separated by a limited range of biologically relevant delays. These neurons exhibit the response characteristic known as "echo delay-tuning’’ or "range-tuning,’’ which could provide the neural substrate for target distance coding. The published report on this population of delay-tuned neurons by Simmons and colleagues preceded the first papers by Nobuo Suga
and his group, who have since published widely on this topic.
In the past five years, Simmons has used new methods for making thermal infrared
video recordings of bats flying in natural situations. He developed a stereo video viewing system that lets him observe bats in 3D and listen to their sounds while they behave. These studies have led to new discoveries that challenge our understanding of echolocation behavior in bats.
prestigious journals including 8 in Science
, 2
in Nature
, and 20 in the Journal of the Acoustical Society of America
(JASA).
Animal echolocation
Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...
. His research includes behavioral and neurophysiological studies of sound processing in the echolocating bat. From the time he began graduate research in the late 1960s to the present, he has been in the forefront of bat echolocation research. Simmons was honored as a fellow of the Acoustical Society of America (ASA) in 1996 and of the American Association for the Advancement of Science in 2000. He was awarded the ASA's second Silver Medal in Animal Bioacoustics in 2005. His current position is Professor in the Department of Neuroscience, Brown University
Brown University
Brown University is a private, Ivy League university located in Providence, Rhode Island, United States. Founded in 1764 prior to American independence from the British Empire as the College in the English Colony of Rhode Island and Providence Plantations early in the reign of King George III ,...
.
Education
Simmons obtained his bachelor’s degree from Lafayette CollegeLafayette College
Lafayette College is a private coeducational liberal arts and engineering college located in Easton, Pennsylvania, USA. The school, founded in 1826 by James Madison Porter,son of General Andrew Porter of Norristown and citizens of Easton, first began holding classes in 1832...
in 1965 with a double major in Psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
and Chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
. He then earned a master’s degree in 1968 and a Ph.D. in Psychology in 1969 from Princeton University
Princeton University
Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....
. Simmons’s graduate research involved studies of echolocation in bats, under the mentorship of E. Glen Wever, one of the giants in physiological acoustics. At that time, acceptance of the processes underlying spatial perception
Depth perception
Depth perception is the visual ability to perceive the world in three dimensions and the distance of an object. Depth sensation is the ability to move accurately, or to respond consistently, based on the distances of objects in an environment....
by echolocation was not universal, and one of the exciting moments of his graduate training came when a skeptical Nobel Laureate, Georg von Békésy
Georg von Békésy
Georg von Békésy was a Hungarian biophysicist born in Budapest, Hungary.In 1961, he was awarded the Nobel Prize in Physiology or Medicine for his research on the function of the cochlea in the mammalian hearing organ.-Research:Békésy developed a method for dissecting the inner ear of human...
, on one of his periodic visits to Wever’s lab, came to see the behaving bats in "Building B.’’ The demonstration that Simmons conducted not only convinced Békésy that bats echolocated but that they also use echo delay to estimate target distance. It was not until some years later that Simmons found out that this was a set-up engineered by Wever and Donald Griffin, who was then at the Rockefeller University
Rockefeller University
The Rockefeller University is a private university offering postgraduate and postdoctoral education. It has a strong concentration in the biological sciences. It is also known for producing numerous Nobel laureates...
, to convince Békésy about the bat’s extraordinary use of echolocation to determine target range. Simmons’s dissertation was entitled "Perception of target distance by echolocating bats.’’ After receiving his Ph.D., Simmons remained at Princeton University as a National Institutes of Health postdoctoral trainee for two years.
Research
Simmons continued his research on bat echolocation after he moved to Washington University in St. LouisWashington University in St. Louis
Washington University in St. Louis is a private research university located in suburban St. Louis, Missouri. Founded in 1853, and named for George Washington, the university has students and faculty from all fifty U.S. states and more than 110 nations...
, Missouri in 1971, as an assistant professor in the Neural Science
Neuroscience
Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...
Program that was housed in the Psychology Department. Between 1980 and 1984, he taught and conducted research as a professor in the Department of Biology and Institute of Neuroscience, University of Oregon
University of Oregon
-Colleges and schools:The University of Oregon is organized into eight schools and colleges—six professional schools and colleges, an Arts and Sciences College and an Honors College.- School of Architecture and Allied Arts :...
in Eugene, Oregon
Eugene, Oregon
Eugene is the second largest city in the U.S. state of Oregon and the seat of Lane County. It is located at the south end of the Willamette Valley, at the confluence of the McKenzie and Willamette rivers, about east of the Oregon Coast.As of the 2010 U.S...
. In 1984, Simmons moved to Brown University
Brown University
Brown University is a private, Ivy League university located in Providence, Rhode Island, United States. Founded in 1764 prior to American independence from the British Empire as the College in the English Colony of Rhode Island and Providence Plantations early in the reign of King George III ,...
in Providence, Rhode Island
Providence, Rhode Island
Providence is the capital and most populous city of Rhode Island and was one of the first cities established in the United States. Located in Providence County, it is the third largest city in the New England region...
, where his wife Andrea had been hired as an assistant professor in the Psychology Department. Both are now professors in the Psychology and Neuroscience Departments at Brown University, respectively.
Simmons developed methods for conducting psychophysical
Psychophysics
Psychophysics quantitatively investigates the relationship between physical stimuli and the sensations and perceptions they effect. Psychophysics has been described as "the scientific study of the relation between stimulus and sensation" or, more completely, as "the analysis of perceptual...
studies of sonar processing by bats, and researchers around the world have adopted these methods to address a wide range of research questions. Simmons was the first to use electronically delayed playbacks of the bat’s echolocation signals to simulate target echoes for the study of perception in bats. He used such "phantom’’ target echoes to measure, for the first time, target range difference discrimination thresholds of echolocating bats. Simmons studied sonar ranging
Ranging
Ranging is a process or method to determine the distance from one location or position to another location or position. Another term for this method is lateration, see unilateration...
performance in bats by determining the minimum difference in echo delay that an echolocating animal can discriminate. With this paradigm, Simmons estimated that bats can discriminate a range difference of approximately 1 centimeter, corresponding to an echo delay difference of approximately 60 microseconds.
Simmons continued to study sonar ranging performance in echolocating bats, and in the late 1970’s, he introduced a new behavioral task, requiring the bat to discriminate a sonar target returning echoes at a fixed delay from one returning echoes that alternated between two delays. In this experiment, Simmons found that the echolocating bat can discriminate a jitter in echo delay in the submicrosecond range, corresponding to a change in target distance of less than 0.1 mm. This result, originally published in 1979 in Science, "Perception of echo phase information in bat sonar,’’ demonstrated astonishing ranging accuracy by the echolocating bat. Many researchers in the field challenged the report, because they asserted it was not biologically possible for the bat’s sonar system to discriminate such small time differences at ultrasonic
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
frequencies. Simmons continues to work on this problem to explore biological processes that could support sensitivity to small changes in echo delay.
Through behavioral experiments, Simmons demonstrated time-varying gain
Gain
In electronics, gain is a measure of the ability of a circuit to increase the power or amplitude of a signal from the input to the output. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. It may also be defined on a logarithmic scale,...
in the sonar receiver of echolocating bats. The hearing sensitivity of the big brown bat
Big brown bat
The Big Brown Bat is larger in size than comparative species of bats, from about 4 to 5 inches in body length, with a 11-13 inch wingspan and weighing 1/2 to 5/8 ounce. The fur is moderately long, and shiny brown...
decreases before each sonar pulse is emitted and then recovers in a logarithm
Logarithm
The logarithm of a number is the exponent by which another fixed value, the base, has to be raised to produce that number. For example, the logarithm of 1000 to base 10 is 3, because 1000 is 10 to the power 3: More generally, if x = by, then y is the logarithm of x to base b, and is written...
ic fashion to compensate for the two-way transmission loss of sonar returns, thereby maintaining a constant echo sensation level over a distance of about 1.5 meters. This is functionally important to the bat, as it stabilizes the bat’s estimate of echo arrival time, its cue for target distance.
In addition to Simmons’s contributions to our understanding of perception by sonar, he has conducted neurophysiological experiments in echolocating bats. One of his manuscripts published with co-authors Albert Feng and Shelley Kick in Science had a profound impact on the study of the neurophysiology of echolocating bats. This paper describes the response properties of auditory neurons in the bat central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
that show facilitated responses to pairs of sounds separated by a limited range of biologically relevant delays. These neurons exhibit the response characteristic known as "echo delay-tuning’’ or "range-tuning,’’ which could provide the neural substrate for target distance coding. The published report on this population of delay-tuned neurons by Simmons and colleagues preceded the first papers by Nobuo Suga
Nobuo Suga
Nobuo Suga is a Japanese biologist, famous for his research on the neurophysiology of hearing, and echolocation in bats.-Life:After achieving a bachelors degree in biology at Tokyo Metropolitan University in 1958, Nobuo studied for his doctoral thesis on the neurophysiology of hearing with Yatsuji...
and his group, who have since published widely on this topic.
In the past five years, Simmons has used new methods for making thermal infrared
Thermography
Infrared thermography, thermal imaging, and thermal video are examples of infrared imaging science. Thermal imaging cameras detect radiation in the infrared range of the electromagnetic spectrum and produce images of that radiation, called thermograms...
video recordings of bats flying in natural situations. He developed a stereo video viewing system that lets him observe bats in 3D and listen to their sounds while they behave. These studies have led to new discoveries that challenge our understanding of echolocation behavior in bats.
Awards and honors
- 1965: James McKeen CattellJames McKeen CattellJames McKeen Cattell , American psychologist, was the first professor of psychology in the United States at the University of Pennsylvania and long-time editor and publisher of scientific journals and publications, most notably the journal Science...
Prize, Lafayette College Psychology Department. - 1969: National Institutes of HealthNational Institutes of HealthThe National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
Research Scientist Development Award - 1996: Elected a fellow of the Acoustical Society of AmericaAcoustical Society of AmericaThe Acoustical Society of America is an international scientific society dedicated to increasing and diffusing the knowledge of acoustics and its practical applications.-History:...
- 2000: Elected a fellow of the American Association for the Advancement of ScienceAmerican Association for the Advancement of ScienceThe American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...
- 2005: Silver Medal in Animal BioacousticsASA Silver MedalThe ASA Silver Medal is an award presented by the Acoustical Society of America to individuals, without age limitation, for contributions to the advancement of science, engineering, or human welfare through the application of acoustic principles or through research accomplishments in acoustics...
, Acoustical Society of America, "for contributions to understanding bat echolocation."
Scientific Publications
Simmons has published extensively, with over 95 journal articles inprestigious journals including 8 in Science
Science (journal)
Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....
, 2
in Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...
, and 20 in the Journal of the Acoustical Society of America
Journal of the Acoustical Society of America
Journal of the Acoustical Society of America is a scientific journal in the field of acoustics, published by the Acoustical Society of America. It contains technical articles on sound, vibration, speech and other topics.Access to articles is by subscription or purchase, though most universities...
(JASA).
External links
- Simmons' home page at Brown UniversityBrown UniversityBrown University is a private, Ivy League university located in Providence, Rhode Island, United States. Founded in 1764 prior to American independence from the British Empire as the College in the English Colony of Rhode Island and Providence Plantations early in the reign of King George III ,...