Lloyd Alexander Jeffress (November 15, 1900 – April 2, 1986) was an acoustical scientist, a professor of experimental psychology at the

University of Texas at Austin The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...

, and a developer of mine-hunting models for the

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during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

and after, Jeffress was known to psychologists for his pioneering research on auditory masking in

psychoacoustics Psychoacoustics is the branch of psychophysics involving the scientific study of sound perception and audiology—how humans perceive various sounds. More specifically, it is the branch of science studying the psychological responses associated wit ...

, his stimulus-oriented approach to

signal-detection theory Detection theory or signal detection theory is a means to measure the ability to differentiate between information-bearing patterns (called stimulus in living organisms, signal in machines) and random patterns that distract from the information (ca ...

psychophysics Psychophysics quantitatively investigates the relationship between physical stimuli and the sensations and perceptions they produce. Psychophysics has been described as "the scientific study of the relation between stimulus and sensation" or, m ...

, and his "ingenious" electronic and mathematical models of the auditory process. Jeffress received the first-ever

silver medal A silver medal in sports and other similar areas involving competition is a medal made of, or plated with, silver awarded to the second-place finisher, or runner-up, of contests or competitions such as the Olympic Games, Commonwealth Games, etc ...

in Psychological and Physiological Acoustics from the

Acoustical Society of America The Acoustical Society of America (ASA) is an international scientific society founded in 1929 dedicated to generating, disseminating and promoting the knowledge of acoustics and its practical applications. The Society is primarily a voluntary org ...

in 1977 for "extensive contributions in

, particularly

binaural hearing Sound localization is a listener's ability to identify the location or origin of a detected sound in direction and distance. The sound localization mechanisms of the mammalian auditory system have been extensively studied. The auditory system us ...

, and for the example he has set as a teacher and scholar."

Early life and education

Lloyd A. Jeffress was born on November 11, 1900, in

San Jose, California San Jose, officially San José (; ; ), is a major city in the U.S. state of California that is the cultural, financial, and political center of Silicon Valley and largest city in Northern California by both population and area. With a 2020 popul ...

, the only child in a family that moved a short time later to

Portland, Oregon Portland (, ) is a port city in the Pacific Northwest and the largest city in the U.S. state of Oregon. Situated at the confluence of the Willamette and Columbia rivers, Portland is the county seat of Multnomah County, the most populous co ...

, where Jeffress grew up and went to high school. From grammar school on, one of Jeffress' closest friends was double

Nobel Prize The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfr ...

winner Linus Pauling, who regularly credited Jeffress with showing him his first chemistry experiment when they were both 13. In 1918, Jeffress enrolled at Oregon Agricultural College (later

Oregon State University Oregon State University (OSU) is a public land-grant, research university in Corvallis, Oregon. OSU offers more than 200 undergraduate-degree programs along with a variety of graduate and doctoral degrees. It has the 10th largest engineering co ...

) at Corvallis, where he was Pauling's roommate. The next year, he transferred to the

University of California at Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant univ ...

as a

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

major, but, while completing that degree, he became increasingly interested in the newly expanding field of experimental psychology. Jeffress was accepted as a graduate student in psychology at the only school to which he applied, UC Berkeley, in 1922, and soon associated himself with Warner Brown. Jeffress completed a dissertation with Brown in 1926 concerning the galvanic skin response, and the two men remained close friends until Brown's death. As a college senior at Berkeley, Jeffress met Sylvia Bloomberg, who was then a first-year graduate student in psychology working with

Edward C. Tolman Edward Chace Tolman (April 14, 1886 – November 19, 1959) was an American psychologist and a professor of psychology at the University of California, Berkeley. Through Tolman's theories and works, he founded what is now a branch of psychology know ...

and who lived in the same boarding house as Jeffress. The Jeffresses moved to Texas in the summer of 1926, where Lloyd began his 51-year career teaching at the

. In 1927, psychology first became a department separate from philosophy at Texas, and Jeffress was one of six members of the new psychology department in a UT faculty of 111. Jeffress was promoted to full professor in 1937 and was Chairman of the UT psychology department from 1936 to 1947.

Later years

In 1971, Jeffress retired from full-time teaching at the University of Texas and went on modified service. In this role, he taught courses in mathematical statistics to graduate students and introductory statistics to undergraduates. He retired from the university and became a

professor emeritus ''Emeritus'' (; female: ''emerita'') is an adjective used to designate a retired chair, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person who has been "permitted to retain as an honorary title ...

in 1977. After retiring at 76, Jeffress went to work at Dynastat, an Austin company specializing in testing and evaluation of voice communication systems that is owned by one of Jeffress' first doctoral students, William D. Voiers. Jeffress had the responsibility of getting the everyday operations of Dynastat computerized. This included developing programs for analyzing speech perception data. He continued to work for Dynastat until 1984. Jeffress died in Austin on April 2, 1986, at the age of 85. After his death, UT established the Lloyd A. Jeffress Memorial Fellowship, the first winner of which was Dr. Beverly Wright, who went on to win the

's R. Bruce Lindsay Award for the advancement of theoretical or applied acoustics, or both. Linus Pauling wrote after Jeffress' death: "I have many friends, but I continue to think of Lloyd Alexander Jeffress as my best friend."

Life in science

Jeffress' academic lineage descended directly from the "father of Experimental Psychology," Wilhelm Wundt, in four steps. Jeffress' Ph.D. advisor at Berkeley, Warner Brown, had studied with Robert S. Woodworth, who was a student of James McKeen Cattell, who was a student of Wundt. While he was at Berkeley in 1925, his knowledge of physics and love of gadgets led him to develop a self-recording maze that gained him a publication—his first—with one of the best-known cognitive psychologists of his time, E.C Tolman. Both psychology and physics would remain of interest to him, and he often had to struggle with his loyalties to one or the other. Jeffress's career was notable in that his scientific career gained momentum throughout his life, rather than consisting of a "great flutter of activity" followed by a slow decline. Of his more than 115 published papers, only 14 were published before he was 50 years old. It was only after he began his long association with UT's Defense Research Laboratory (DRL) in 1950 that he had assistants capable of, and interested in, doing all the menial work necessary to implement and run the experiments he said he had been thinking about all along.

The Jeffress model

Beginning about 1940, Jeffress' primary research interest was the auditory system, especially the mechanisms underlying sound localization. His most cited article, "A Place Theory of Sound Localization", was in the 1948 Journal of Comparative and Physiological Psychology. In the article, he describes a hypothetical neural network capable of cross-correlating the temporal (time) information at the two ears and thereby extracting the small differences that can exist in the time of arrival of a wavefront at the two ears, thus localizing the sound. This neurocomputational model that explains how auditory systems can register and analyze small differences in the arrival time of sounds at the two ears in order to estimate the direction of sound sources became known as the Jeffress model. The Jeffress model was used as an accepted explanatory basis for many of the facts of binaural hearing for more than 60 years, and it has repeatedly been shown to be conceptually correct, although not explicitly correct neurally. Otolaryngologist Peter Cariani of the Harvard Medical School wrote on Scholarpedia: "Subsequent neuroanatomy and neurophysiology has largely confirmed the basic premises of the basic model (see (Joris and Yin 2007; Joris 2006; Joris et al. 1998) albeit (arguably) with better correspondences in birds than in mammals. ... Whether discrepancies between the original Jeffress' model assumptions and the more recent neurophysiological data constitute a refutation of the core signal processing principles of the model (binaural temporal cross-correlation operations on temporally-coded inputs) has been a matter of ongoing discussion and debate." The Jeffress model is also part of any discussion of

coincidence detection in neurobiology Coincidence detection in the context of neurobiology is a process by which a neuron or a neural circuit can encode information by detecting the occurrence of temporally close but spatially distributed input signals. Coincidence detectors influen ...

. In teaching about sound localization, Jeffress was known to ask his students: "What are the three most important aspects of sound?" Students often answered, "Frequency, amplitude, and phase." "No!" Jeffress would exclaim. "Where it is, whether it can eat you, and whether you can eat it."

The Hixon Symposium

Jeffress left Austin for only one year following his arrival in 1926. In 1947 and 1948, he worked as the Hixon visiting professor at the

California Institute of Technology The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...

, where he brought together many premiere scientists of his day to examine the state of knowledge about human behavior and the brain. The Hixon professorship developed out of a conversation Jeffress had had with Linus Pauling, who was then at Caltech. Pauling remembers that around 1946, a gift was made to the school to support work on the functioning of the brain. Pauling was a member of the Hixon Fund Committee, which decided to use the money to hold a symposium on cerebral mechanisms. Because they understood preparation for and running such a symposium would be difficult and would require a knowledgeable person, Pauling suggested Jeffress, whom the committee accepted, and who then lived for the year in the Paulings' house in Pasadena while Pauling and his family were at Oxford. The participants in the 1948 Hixon Symposium on neural mechanisms were noted academics from a number of disciplines: Pauling (chemistry),

Heinrich Klüver Heinrich Klüver (; May 25, 1897 – February 8, 1979) was a German-American biological psychologist and philosopher born in Holstein. After having served in the Imperial German Army during World War I, he studied at both the University of Ha ...

(

cybernetics Cybernetics is a wide-ranging field concerned with circular causality, such as feedback, in regulatory and purposive systems. Cybernetics is named after an example of circular causal feedback, that of steering a ship, where the helmsperson m ...

John von Neumann John von Neumann (; hu, Neumann János Lajos, ; December 28, 1903 – February 8, 1957) was a Hungarian-American mathematician, physicist, computer scientist, engineer and polymath. He was regarded as having perhaps the widest cove ...

(

cellular automata A cellular automaton (pl. cellular automata, abbrev. CA) is a discrete model of computation studied in automata theory. Cellular automata are also called cellular spaces, tessellation automata, homogeneous structures, cellular structures, tessel ...

Karl Lashley Karl Spencer Lashley (June 7, 1890 – August 7, 1958) was a psychologist and behaviorist remembered for his contributions to the study of learning and memory. A ''Review of General Psychology'' survey, published in 2002, ranked Lashley as the 61 ...

(behavior and learning), Ogden Lindsley ( precision teaching),

Rafael Lorente de Nó Rafael Lorente de Nó (April 8, 1902 – April 2, 1990) was a Spanish neuroscientist who advanced the scientific understanding of the nervous system with his seminal research. He was a member of the National Academy of Sciences. The National Acad ...

(

neuroanatomy Neuroanatomy is the study of the structure and organization of the nervous system. In contrast to animals with radial symmetry, whose nervous system consists of a distributed network of cells, animals with bilateral symmetry have segregated, defin ...

neurophysiology Neurophysiology is a branch of physiology and neuroscience that studies nervous system function rather than nervous system architecture. This area aids in the diagnosis and monitoring of neurological diseases. Historically, it has been dominated b ...

Warren McCulloch Warren Sturgis McCulloch (November 16, 1898 – September 24, 1969) was an American neurophysiologist and cybernetician, known for his work on the foundation for certain brain theories and his contribution to the cybernetics movement.Ken Aizawa ( ...

(neural network modeling), and W.C. Halstead (

neuropsychological assessment Neuropsychological assessment was traditionally carried out to assess the extent of impairment to a particular skill and to attempt to determine the area of the brain which may have been damaged following brain injury or neurological illness. Wit ...

). Many of the papers collected in ''Cerebral Mechanisms in Behavior: The Hixon Symposium,'' with Jeffress as editor, became classics cited in thousands of scientific articles. The ''Science'' magazine review of the book said: "The Hixon Symposium has significance for anyone concerned with the theory of human behavior and contraptions man himself has built—namely, computing and cybernetic machinery." The book was first published in 1951 and was reissued in 1969.

Mine-hunting research at DRL

At the outset of World War II, Jeffress was able to draw directly upon his undergraduate training in physics. Professor Paul Boner of the UT Physics Department took leave from Texas to work at the Underwater Sound Lab at

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher le ...

, and Jeffress was asked to take over his freshman physics course. Upon his return after the war, Boner became director of the Defense Research Laboratory (DRL) at the University of Texas, and Jeffress eventually became head of the Psychoacoustics Division. DRL became Applied Research Laboratory (ARL) in 1968. Before joining DRL as a part-time staff member in 1950, Jeffress worked on campus at UT with the War Research Lab, where he helped with the development and testing of a new gun sight for the B-29 and B-36 bombers, as well as with the Military Physics Research Lab. Both of those Labs eventually became part of DRL. Jeffress' first project at DRL was to determine whether the improvement humans show when detecting binaural rather than monaural signals could be adapted to Navy sonars. Jeffress designed and built an experimental binaural sonar that he and his students tested at Austin's

Lake Travis Lake Travis is a reservoir on the Colorado River in central Texas in the United States. Serving principally as a flood-control reservoir, Lake Travis' historical minimum to maximum water height change is nearly 100 feet. In 2018 alone, it saw ...

. While this project was unsuccessful, it initiated a program at DRL on masking and binaural hearing that endured, and was highly productive, for more than 20 years. In 1953, DRL had collected extensive raw data during the evaluation of several US Navy mine-hunting sonars. These data, which were in the form of photographic and magnetic tape recordings, had to be analyzed in detail to provide quantitative measures of target detection probability, location errors, etc., as a function of a number of variables. Because Jeffress had a much better knowledge of probability and statistics than anyone else then on the DRL staff, he was invited to undertake the necessary analyses. Jeffress quickly planned the analysis operation, invented and built the complex analysis hardware, analyzed the data, and published the results, all in a matter of a few months. Almost overnight, Jeffress had established his reputation as an expert in mine hunting, a reputation that was to grow steadily over the next two decades. This initial work, together with subsequent similar evaluations, led Jeffress to the development of a mine-hunting technique known as clustering. He first used data collected at sea to develop the technique, he then proceeded to use numerical models (which involved random number theory), and finally developed a theoretical model (in closed analytical form). The Navy readily accepted his work and requested that he write the tactical doctrine on clustering. This document, together with other reports he wrote, remained the standard works on mine hunting and were still to be found on every mine-hunting craft in the US Fleet at Jeffress' death. Jeffress made many contributions to the science of mine countermeasures, especially in the areas of precise radio and acoustic navigation systems. Much of his work in this area was declassified in 1997, more than 10 years after his death. One of Jeffress' memorials recalled that Jeffress was considered remarkable at DRL because he was able to pursue his university teaching, do his fundamental research in psychoacoustics, and do his applied work in mine hunting all at the same time—and be successful at all three. The same memorial notes that Jeffress managed to get funding at DRL from the Navy in a unique way: "Jeffress' basic research in psychoacoustics at DRL was sponsored by the Navy's Bureau of Ships, an agency that normally deals with the development and procurement of hardware, while much of his applied work in mine hunting was funded by the

Office of Naval Research The Office of Naval Research (ONR) is an organization within the United States Department of the Navy responsible for the science and technology programs of the U.S. Navy and Marine Corps. Established by Congress in 1946, its mission is to plan ...

(ONR), whose charter is to sponsor fundamental research."

Notable achievements

In the early 1950s, when Jeffress was in his 50s, some research by J.C.R. Licklider and I.J. Hirsh on what later came to be called masking-level differences caught Jeffress' attention and began him on a two-decade research program in which he and his students documented various aspects of the binaural system's performance in signal-detection tasks. Upon his death, the ''American Journal of Psychology'' (AJP) called Jeffress the "acknowledged authority" on auditory masking and masking-level differences. Jeffress also had a long-standing interest in pitch perception, and published on such issues as short-term fluctuations in the tuning of the auditory periphery and the continuously changing pitch of a beating two-tone complex (see articles below). Jeffress' approach to understanding sensory and perceptual behavior was to examine the physical stimulus carefully first to attempt to isolate those aspects of it that appeared to be critical. Perhaps the best example of this was his treatment of

as applied to human observers: "reinventing" signal-detection from a physics perspective, according to the AJP. In a series of papers published in the ''Journal of the Acoustical Society of America'' in the 1960s, Jeffress developed what he called a "stimulus-oriented" view of human detection performance. The AJP called his 1964 article, "Stimulus-Oriented Approach to Detection Theory," a classic. Jeffress was known for building and testing models to simulate components of the auditory system. In particular, he simultaneously developed mathematical and electrical models of monaural signal detection and compared their performance under a number of stimulus manipulations to that of humans detecting under the same stimulus conditions. The final versions of these models were highly successful at predicting numerous psychophysical facts. Jeffress joined the

in 1939 and was elected a fellow in 1948. He served the ASA for eight years as a

Journal of the Acoustical Society of America The ''Journal of the Acoustical Society of America'' is a monthly peer-reviewed scientific journal covering all aspects of acoustics. It is published by the Acoustical Society of America and the editor-in-chief is James F. Lynch (Woods Hole Oceanog ...

associate editor of psychological acoustics beginning in 1962. This was among the longest terms of service for any associate editor, and it was the longest for an associate editor in psychological and physiological acoustics. Upon Jeffress' retirement as associate editor, the job was re-examined and found to be too much for one person, and two subsections were formed with an associate editor for each. Jeffress was also a fellow of the

American Association for the Advancement of Science The American Association for the Advancement of Science (AAAS) is an American international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific respons ...

(AAAS) and of the

American Psychological Association The American Psychological Association (APA) is the largest scientific and professional organization of psychologists in the United States, with over 133,000 members, including scientists, educators, clinicians, consultants, and students. It ha ...

(APA). Although nominated for membership in the

Society of Experimental Psychologists The Society of Experimental Psychologists (SEP), originally called the Society of Experimentalists, is an academic society for experimental psychologists An experiment is a procedure carried out to support or refute a hypothesis, or determin ...

, he was never invited to join. In 1971, Jeffress received the Beltone Award for distinguished accomplishment as an educator, and, in 1978, the UT Psychology Department honored his long and distinguished service during its golden anniversary activities. In 1979, Jeffress received the Distinguished Service Award of the American Speech-Language-Hearing Association.

Bibliography

Articles

* Tolman, E.C.; Jeffress, L.A. (1925) "A self-recording maze," ''

Journal of Comparative Psychology The ''Journal of Comparative Psychology'' is a peer-reviewed academic journal published by the American Psychological Association. It covers research from a comparative perspective on the behavior, cognition, perception, and social relationships of ...

'' 5: 455
DOI 10.1037/h0074396
*Jeffress, L.A. (1944), "Variations in pitch," ''

American Journal of Psychology The ''American Journal of Psychology'' is a journal devoted primarily to experimental psychology. It is the first such journal to be published in the English language (though '' Mind'', founded in 1876, published some experimental psychology ea ...

57: 63
DOI 10.2307/1416859
WOS:000200117900003 *Jeffress, L.A. (1948), "A place theory of sound localization," ''

Journal of Comparative and Physiological Psychology The ''Journal of Comparative and Physiological Psychology'' was a peer-reviewed academic journal published by the American Psychological Association. It was established in 1921 as the result of a merger between two journals, ''Psychobiology'' (191 ...

'' 41: 35
DOI 10.1037/h0061495
WOS:A1948UP82300005, PM 18904764 *Deatherage, B.H.; Jeffress, L.A.; Blodgett, H.C. (1954), "A note on the audibility of intense ultrasonic sound," ''

'' 26: 582
DOI 10.1121/1.1907379
WOS:A1954UD61800019 *Wilbanks, W.A.; Blodgett, H.C.; Jeffress, L.A. (1954), "The effect of large interaural time differences upon the judgment of sidedness," ''

'' 26: 945
DOI 10.1121/1.1928003
WOS:A1954UD61900129 *Jeffress, L.A.; Blodgett, H.C.; Sandel, T.T.; and Wood, C.L., III. (1956), "Masking of Tonal Signals," ''

'' 28, 416-426
DOI 10.1121/1.1908346
*Feddersen, W.E.; Sandel, T.T.; Teas, D.C.; Jeffress, L.A. (1957), "Localization of high-frequency tones," ''

'' 29: 988
DOI 10.1121/1.1909356
WOS:A1957WK52200002 *Jeffress, L.A.; Blodgett, H.C.; Wood, C.L. (1958), "Detecting a signal in noise," ''

'' 30: 802
DOI 10.1121/1.1909767
WOS:A1958WK53300018 *Jeffress, L.A. (1958), "Medial geniculate body – a disavowal," (letter) ''

'' 30: 802
DOI 10.1121/1.1909769
WOS:A1958WK53300019. *Jeffress, L.A.; Moushegian, G. (1959), "Hearing," '' Annual Review of Psychology'' 10: 395
DOI 10.1146/annurev.ps.10.020159.002143
WOS:A1959CCX0500015 *Moushegian, G.; Jeffress, L.A. (1959), "Localization of low-frequency tones," ''

'' 31: 830
DOI 10.1121/1.1930368
WOS:A1959WK54300028 *Jeffress, L.A.; Taylor, R.W. (1961), "Lateralization vs localization," ''

'' 33: 482
DOI 10.1121/1.1908697
WOS:A19612936B00007 *Jeffress, L.A. (1962), "Absolute Pitch," ''

'' 34: 987
DOI 10.1121/1.1918237
*Jeffress, L.A.; Blodgett, H.C.; Deatherage, B.H. (1962) "Effect of Interaural Correlation on the Precision of Centering a Noise," ''

'' 34: 1122
DOI 10.1121/1.1918257
*Jeffress, L.A. (1964), "Stimulus-Oriented Approach to Detection Theory," ''

'' 36: 766
DOI 10.1121/1.1919064
*Jeffress, L.A. (1968), "Mathematical and electrical models of auditory detection," ''

'' 44: 187
DIO 10.1121/1.1911053
WOS:A1968B547300025, PM 5659833 *Love, L.R.; Jeffress, L.A. (1971) "Identification of brief pauses in fluent speech of stutterers and nonstutterers," ''Journal of Speech and Hearing Research'' 14: 229, WOS:A1971J703100001, PM 5558075 *Jeffress, L.A. (1972), "Binaural Signal Detection," ''Foundations of Modern Auditory Theory, Vol. 2,'' Tobias, J.V., ed., Academic Press, New York *McFadden, D.; Jeffress, L.A.; Russell, W.E. (1973), "Individual differences in sensitivity to interaural differences in time and level," ''

Perceptual and Motor Skills ''Perceptual and Motor Skills'' is a bimonthly peer-reviewed academic journal established by Robert B. Ammons and Carol H. Ammons in 1949. The journal covers research on perception or motor skills. The editor-in-chief is J.D. Ball (Eastern Virgini ...

'' 37: 755, WOS:A1973R662300017, PM 4764506 *Green, D.M.; Nachmias, J.; Kearney, J.K.; Jeffress, L.A. (1979) "Intensity discrimination with gated and continuous sinusoids," ''

'' 66: 1051
DOI 10.1121/1.383324
WOS:A1979HQ54600014, PM 512214

Selected Defense Research Laboratory Acoustical reports

*DRL-A-89, "Statistical Methods Applied to Mine Hunting," by L. A. Jeffress, et al., 12 November 1956, Originally Confidential *DRL-A-208, "A Proposed Navigational System for MSOs," by L. A. Jeffress, 14 February 1963, Confidential

Selected books and reports

*Jeffress, L.A., ed., ''Cerebral Mechanisms in Behavior: The Hixon Symposium eld at the California Institute of Technology in September, 1948'' Wiley, New York (1951) *Jeffress, L.A., ''Masking and Binaural Phenomena,'' DRL Acoustical Report 245, University of Texas at Austin Defense Research Laboratory, Defense Technical Information Center (1965) *Jeffress, L.A., ''Study: Mine-Hunting Techniques,'' DRL Acoustical Report 246, University of Texas at Austin Defense Research Laboratory (1966) *Jeffress, L.A., ''Contributions of Psychophysics to Sonar,'' (Report ARL-JM-69-23) Applied Research Laboratories, University of Texas, Austin (1969) *Jeffress, L.A., ''Mine Hunting Procedures,'' (Report ARL-TR-69-28) Applied Research Laboratories, University of Texas, Austin (1969)(Confidential).

References

Works cited

* {{DEFAULTSORT:Jeffress, Lloyd A. University of Texas at Austin faculty California Institute of Technology faculty Scientists from California University of California, Berkeley alumni Scientists from Portland, Oregon People from San Jose, California People from Austin, Texas 1900 births 1986 deaths Fellows of the Acoustical Society of America Fellows of the American Association for the Advancement of Science Fellows of the American Psychological Association