David M. Green

Lutfi:

I’m going to start. My name is Bob Lutfi. Today’s date is September 16, 2020. The time is 9:44 a.m., and I am about interview Dr. Green for the Acoustical Society of America Technical Committee on Psychological and Physiological Acoustics. Dr. Green is at his home in Daytona Beach, Florida. Because of the current COVID-19 pandemic, I am interviewing him remotely from my home in Tampa, Florida. I have volunteered to conduct this interview as a friend, colleague, and longtime beneficiary of Dr. Green’s work. Dr. Green, thank you for agreeing to do this interview for the archives of the Acoustical Society of America. What year did you join ASA?

Green:

Let me begin with a few words. In a Congressional committee meeting, they usually let the plaintiff say a few words to begin with. I just want to say, I’m 88 years old, so when I say it was a long time ago, it may be as long as a half-century ago. And that’s part of my answer to this first question. I was really stunned by it because I knew I was a graduate student, but that was back in 1950 to ’60. But, I finally figured out how I could answer it. I was the President of the Society from 1981 to ’82, and during that time, we used to have a dinner meeting—a banquet—at the Society meetings, and, among other things, we would give awards to the various technical committee meetings and so on.

But we’d also give a certificate to anybody who’d been in the Society for 25 years. This was a nice piece of paper that looked like a college degree or something. And it was signed by the president. I was asked to sign, I think, 10 or 20 of these certificates when I was president in ‘81. And Betty Goodfriend was the Society secretary at that time, and as I was trying to sign my name—I’m left-handed, so I reached around and had the pencil pointing at me—she put a piece of cardboard on the paper and said, “I just want to put that there so you won’t mess up the rest of the certificate. Just sign your name there.” I went through and signed 10 or 12 certificates. And what we did was that the president would call out the names of the 25-year certificate people, and they would come up and stand in front of the Society, and then we’d give them a big hand. So, I started reading them, and I finally came to the last one, and it turned out to be me. I was there 25 years ago when I joined the Society, so that would put it at about 1956. I don’t remember what happened when I came to the end. She put my certificate at the end. I either read my name because I wanted the applause, or I probably just skipped it. That’s my story. I was a second-year graduate student, 1956, at the University of Michigan when I joined the Society. Next question.

Lutfi:

What area of acoustics were you interested in?

Green:

Psychoacoustics.

Lutfi:

What were your reasons for joining the Acoustical Society?

Green:

I thought it was a good organization, and it was obviously in my field of interest.

Lutfi:

Was there anyone who encouraged you to join the acoustical society?

Green:

Yes, J. C. R. Licklider. He was a professor at MIT at the time. I think he was chairman of PNP at the time of this first meeting I went to in 1956. He encouraged me to join the Society, and he also announced that there was going to be a PNP meeting that evening, and I was invited to that. I was a little perplexed because I was just a student and didn’t belong to the PNP committee at that time.

Lutfi:

Dr. Green asked me to answer this question: what Acoustical Society Committees were you a member of? And really, there are too many to list, so we’re going to move on. He may also want me to answer this question: what positions in Acoustical Society did you hold or do you presently hold?

Green:

You’ve got a list of them in front of you, and I think it’s accurate. I don’t hold any positions now. I’m retired from the Acoustical Society.

Lutfi:

Is there any particular Acoustical Society meeting or meetings that stand out as being something special, humorous, or different?

Green:

I think the first one would qualify. Lick, as I said, invited me to it, and I was a student. I’m not even sure I was a member of the Society at that time. And I explained all that, and he said, “Oh, come to the meeting anyway. It’s an open meeting. We’re going to have a bar. We just sit around, tell stories, and drink.” So, I attended, and I was introduced to many of the prestigious members of the Society at that time. And I enjoyed it very much. And I think Lick started the custom of having an open PNP meeting, where everybody could express their opinion. It certainly was en vogue when I was chairman of PNP and later when I was president, I attended the PNP meetings. It was an open meeting. It was just lots of fun, and everybody was in good spirits, and it really, I think, was a grand way to handle the PNP committee meetings. But, I know the other committee meetings that I’ve attended are more serious, and I don’t know whether they’re more useful or not.

Lutfi:

Are there any Society members that you’ve met who had especially influenced your future?

Green:

Probably Lick. Licklider. J. C. R. Licklider

Lutfi:

Is there anything you care to say about the Society, past, present, or future?

Green:

I recently attended it when one of my students got the silver medal, and it is much larger than what I remember. It seems to me a little more formal. But that, you would expect with the change in size. Other than it has grown very large, I can’t say anything.

Lutfi:

Besides the Acoustical Society, what other professional organizations do you belong to? And again, there are so many, maybe you just want to identify a few that are special for you.

Green:

Not really. And in any case, I’ve retired from I think every single one of them. The Acoustical Society, the National Academy, ASA, AAAA. I have been out of societies for probably 10 to 15 years at least.

Lutfi:

And you haven’t provided an oral history or interview for any other organization?

Green:

Oh, yes, I have. 10 to 15 years ago, I interviewed Ira Hirsch for a similar interview, and I turned his papers in. And at that time, we were taking recordings of the interview, and I turned that in. And about a year later, he interviewed me. So, I really am surprised that I’ve been asked to have another interview. Apparently, the first interview was lost. At least, I’ve never heard about it since. That’s the end of my answer.

Lutfi:

But you haven’t done any interviews for different organizations, only Acoustical?

Green:

That’s true.

Lutfi:

We’re going to go onto some early years, pre-college. Before college, what were your hobbies, special interests, heroes, etc.?

Green:

I don’t really think I had any. I had a pretty ordinary high school experience, I think. I can’t really remember much about it.

Lutfi:

Were there any subjects, events, or activities that you enjoyed in high school?

Green:

I liked math a lot, but it was a small high school. It was about 60 people in my graduating class. The principal of the high school was a math major in college, and he taught a special course. There were about five or six of us that took that special course in mathematics. But unfortunately, he’d only gone up to advanced algebra and didn’t know anything about calculus, so we never got to calculus. And in the sciences, there was unfortunately only one faculty member, and he was a chemist who had graduated during the Depression and got a job in a paint factory, so he knew how to mix paints, but he practically didn’t know anything about physics. And I was very interested in radios. There was a radio illustration in the textbook, and I was particularly interested in this heterodyning that they talked about, where they would move frequency bands around. And I asked him about it, and he said he didn’t know anything about heterodyning. In fact, he confessed he didn’t know much about any physics except chemistry. He was a good teacher, but he just didn’t have a background. It was a limited education in high school because of the smallness of the school, and the faculty were not widely trained in all the disciplines.

Lutfi:

This next question, you may have just answered it. Looking back, were there any persons during that time who had a strong influence on you?

Green:

Well, the math principal certainly did, but it was limited. And the lady who taught Latin was a good Latin teacher. I learned a little first-year Latin, but that was about the extent of it.

Lutfi:

We’ll go onto your college years, undergraduate. Where did you first go to college, and what was your major?

Green:

I first went to the University of Chicago, and I was an undergraduate. The president had recently been changed. It was Dr. Hutchins, and he introduced a program of a four-year college degree that everyone could take. In fact, he would accept sophomore high school students as candidates. Essentially, it was a four-year program in liberal arts, and there were 16 courses you had to take, four each year. And before you started, they gave you tests. And if you passed the test in any of the topics, you didn’t have to take that. Typically, for a high school graduate who was fairly advanced, it was a two-year college education. And I took the exam, passed out of the other courses, so I took it for two years and graduated from the University of Chicago.

But it was entirely liberal arts. Plato, Aristotle, Thucydides, that sort of thing. Unfortunately, I also passed out of all the mathematics, so I didn’t take any math for two years right out of high school. Later, when I got to the University of Michigan, I really regretted that. But it was a good program, and the teachers were very good. But it was somewhat limited in its coverage, especially for me, in the science and math department.

Lutfi:

What was the major?

Green:

There wasn’t any major. You couldn’t major. You had to take these 16 courses and pass them. And you either passed them when you first got to Chicago and passed the test on that course, or you took the course and passed it at Chicago. A lot of kids got out in one year and would come in as freshman, so they would graduate when they were the equivalent of a high school junior. One of the guys across the hall from me was in third-year medical school, and I think he was 21. And so he graduated and became a doctor at 22.

Lutfi:

As an undergraduate, did you belong to any special clubs or participate in any special school activities?

Green:

At Michigan, no. I was on the debate team in Chicago. I went to Michigan, and I was, at that time, more interested in philosophy than anything else. But I also was interested in psychology, so I went to the desk at the University of Michigan where they were signing up candidates, and the guy talked me into taking three psychology courses. He said I could take the philosophy course later, and I got interested in psychology from then. At the University of Michigan, I was a psychology major.

Lutfi:

Tell us about your undergraduate college days. Was there any particular person, teacher, professor, or someone special who had a strong influence on you or your future?

Green:

Well, not as an undergraduate because there wasn’t anybody in psychoacoustics. There was a vision man, and I was an observer in his lab. But he was a very unusual guy and sort of hard to get along with. I was one of the people who didn’t get along with him.

Lutfi:

During that period of your life, who was your inspirational model?

Green:

Well, I better tell you what happened at the University of Michigan. After my first year, I got a job with Spike Tanner in the Electronic Defense Group. He was doing work on radar, so I started working for him. I’d run subjects for him. At that time, John Swets was there as well, getting his PhD in vision, actually. And Spike and John had created the signal detection theory, and I got interested in that. Spike gave me a paper, which I read, and the next day, I came in, and he said, “Did you read the paper?” And I said, “Yes.” And he said, “Do you understand it?” And I said, “I think I do.” And he said, “No, you can’t understand it. You’re too little.” And I said, “Well, why don’t you ask me some questions?”

So, he did, and I passed all his questions, so he got more interested in me. I finally took a job at the Electronic Defense Group as some sort of technician and worked with Spike and John for my senior year. During my senior year, I developed a theory about why duration of the stimulus would affect its detectability. I was, at that time, part of the honors course in psychology for my senior year, and that was going to be my thesis for the senior year. Unfortunately, I was going to do that experiment always in vision. But unfortunately, we couldn’t get a glow tube. It was right after the War, and they were scarce. We just couldn’t get a glow tube to run the experiment. I got nervous. I had to turn in a thesis, and I couldn’t do any work.

So, I pointed out to Spike Tanner that we had all the electronic equipment set up, why couldn’t we just do it with an auditory signal? We would simply turn the tone on for different durations and measure its detectability as a function of signal duration. And so, that’s what we did. And I submitted the thesis, and it was approved. It actually was the topic of one of my first papers in psychoacoustics. That went on, and because of my interest in psychoacoustics and my relationship with Spike and John Swets, I decided to stay at Michigan for my graduate work. And so, that’s what I did. I worked all through graduate school, half time at the Electronic Defense Group.

Lutfi:

Is it fair to say that if you were able to do the vision experiment, you might be in vision all these years?

Green:

Yeah, probably because I didn’t know anything about psychoacoustics before I decided to make the equipment into an auditory experiment from a visual experiment.

Lutfi:

Did you ever participate in a rally, protest, or cause?

Green:

Not that I can remember.

Lutfi:

Looking back, would you go to the same college and take the same major if you could start all over again?

Green:

I can’t imagine doing anything different than what I did.

Lutfi:

Let’s move on to graduate level now, master’s degree. You, of course, went on to graduate training at University of Michigan.

Green:

Right, I spent first and second year as a graduate student at the University of Michigan. I became acquainted with Lick, and he became acquainted with my work. So, he invited me to apply for an NSF pre-doctoral fellowship, and I would spend my third year at MIT instead of Michigan. And since there was nobody at Michigan who had any interest in psychoacoustics, except me, they had no reason to reject this plan. And I got the fellowship, and I went to the third-year graduate school at MIT with Licklider as my advisor.

And I actually completed a small experiment there, and then that summer of the third year, I went down to Bell Labs and did another experiment, and those two experiments were the basis for my PhD thesis. The fourth year, I went back to Michigan, wrote up the thesis, and was examined by Clyde Coombs, a professor of Michigan who was in the mathematical end, so he could understand it. Dave Birch was my formal thesis advisor. He was a learning man, ran rats. But he had some mathematical [background]. He could understand what an integral meant. He was my thesis advisor—very kindly took over the job, although he didn’t make any claim to know anything about acoustics. Lick became a member of the committee. Gordon Peterson, the speech man, had left Bell Labs and joined the faculty, so he agreed to sit on the committee.

And Merle Lawrence, who worked with a colleague of Weaver’s at Princeton, and he was in the medical school, and he agreed to be the fifth member of the committee. It turned out the day my orals was called, there was another technical meeting in town of [inaudible] on psychoacoustics. And Jim Egan was there. I can’t remember whether Lloyd Jeffress was there or not, but I had learned about Lloyd and corresponded with him in the meantime. By the time I took my thesis, I was pretty well-acquainted with a lot of people in psychoacoustics.

Lutfi:

I think you answered this next question, what led you to that choice of school and curriculum. Anything else you want to say about that?

Green:

Not really. Oh, I should explain that Michigan was close by. After I graduated from the University of Chicago, I wanted to be a Naval pilot. I applied during that summer, and one of the first steps was to take a medical exam. They looked in my ears and said, “Oh my goodness.” I had had otitis media as a boy, and both eardrums had either been broken or punctured—lanced by a doctor—so I had a lot of scars on my tympanic membrane. And the people in the Navy said, “Well, you can’t be a pilot, so don’t even think about it. We’d like you to join the Navy, but you’re not going to be a pilot.” So, at that point, I decided, “Well, maybe I better go back to school for another year or so.”

And at that point, I met Clara Lofstrom, who became my wife. She had an RN degree and was interested in getting another degree in psychiatric nursing. And when I went up to Chicago to move her from one place to another, her former hospital, the University of Illinois, had closed the program. So, she and I went back to Michigan and spent Michigan with my folks, and we got married at that same time. So, I was married, working half-time at the Electronic Defense group. I can’t imagine any other college path because I was sort of already doing what I wanted to do and making a modest amount of success in it.

Lutfi:

How were you supported during that time?

Green:

Well, I was working half-time at the Electronic Defense Group, and Spike had hired me as a senior in the undergraduate college for $1 an hour. Spike was not strong on administrative details, so I just stayed at $1 an hour. Finally, the end of the first year at Electronic Defense Group… it was a radar lab, and there were a lot of secret projects going on, so you had to sign in as you came into the lab. One Saturday morning, I was there signing in, and the guy behind me happened to be the director of the lab. And he looked at my signature and said, “Oh, you’re Dave Green.” I said, “Yeah.” And he said, “Could you come and see me on Monday morning in my office?” And I said, “Sure.”

I went to his office, and he said, “You’ve been working here a full year now, and you’ve now published three papers.”—or technical reports at the lab—and I said, “Yeah.” And he said, “Well, you act like an engineering student.” And I said, “Well, that’s what I do.” And he said, “Well, engineering students get $3 an hour, and you’re only getting $1.” So, he said, “I’m going to raise your salary.” He did on that day. And I don’t think many people can brag about a 300% change in salary. But maybe there are a few out there.

Lutfi:

Let’s move on to graduate school. You continued your doctorate at the University of Michigan. What led you to that choice of school?

Green:

I went there, as I said, because I was rejected as the Navy pilot, and I decided I’d go someplace that was close. I’d really planned on going in the Navy, so I hadn’t really made any plans at all. University of Michigan was about 35 miles from where I lived, so I went over to the University of Michigan, applied, and was accepted. And, as I say—you’ve heard my history—I was going to go into vision, then I went into audition, so I stayed at Michigan. Michigan really didn’t have anybody. It got Merle Lawrence and Gordon Peterson there while I was a student, but they still didn’t have anybody in the psychology department. Spike Tanner did not have a PhD through all the time I worked with him. He was a candidate, but one of the requirements as a PhD at Michigan was you had to have two languages, and one of them… Spike had selected German, and he tried the exam the first time, and he had apparently a real serious disagreement with the man who proctored the exam in German, the German professor. And so, he would never take the exam again. He actually got his degree, I would say five years after I graduated because the German instructor died. He went in and took the exam from another man who he wasn’t having trouble with, passed it immediately, and got his degree. And later, he was hired at the University of Michigan, so he was a genuine psychoacoustics person at the University of Michigan, and he was their first one.

Lutfi:

Can you tell us a little bit about your doctorate thesis there?

Green:

No, as I just explained, my doctorate was done at MIT partly and Bell Labs for the second part. And at Bell Labs, I used a heterodyne signal, which amused me because I was trying to understand what it was as a high school student, but now I was using it as part of my doctoral thesis. That’s what I did. And then, I wrote the thesis up my fourth year at Michigan. The reason I was anxious to spend a third year somewhere else was that another gentleman, Billy Denver was his name, graduate student, had finished in three years, and the department refused to write him a letter of recommendation to any place he applied to as a faculty member because he was too quick at Michigan.

They kept him an extra year as a teaching assistant or something, and then finally would write letters for him in the fourth year. I knew there was no sense in hurrying Michigan because they demanded that you spend four years in graduate school. So, I went to MIT for a year, and then came back, and was a fourth-year graduate student, so they would write letters for me. I don’t remember if they ever wrote any letters because by that time, I was acquainted with other people in the field who knew what my work was like.

Lutfi:

Okay, we can move on to your professional career now. After college, what was your first place of employment, your first title, and what did you do there?

Green:

I went to MIT as an assistant professor. Well, it was in the economics department because MIT didn’t have a psychology department. But they had a small group in social relations, I don’t know what they called it, and we taught undergraduate courses in psychology.

Lutfi:

We’re going to go through here, one-by-one, each of the positions you held in order. At MIT, were there any special accomplishments, developments, or projects that you contributed to while you were there?

Green:

I was writing papers all the time there. I don’t know how many I published, I’ve never counted it that way. But in any case, MIT had finally decided to start a psychology department, and they got in a man I didn’t get along with very well, so I immediately wanted to leave. I’d been there five years. And so, I left for the University of Pennsylvania as an associate professor and stayed there three years. Our youngest son, George, had ear troubles similar to what I had experienced, and once the winter came in Philadelphia, he would be in breaking his ears just the way I had, so we tried to find someplace that would be less stressful for him. I went to the University of Pennsylvania as an associate professor, and after three years, I left there to go to the University of California at San Diego as a full professor in 1966. And I stayed there for seven years.

Lutfi:

And then, there was Harvard University.

Green:

Yeah, then I left UCSD. They had just opened, and Bill McGill, George Mandler, and Norman Anderson were the first people there the first year. And then there were four or five of us who came in the second year, and I was one of them. Unfortunately, we had trouble. We got up to about nine or ten faculty members, and then we had a great deal of trouble hiring anybody else. They’d keep turning down anybody we’d propose. I thought probably, if I left for Harvard, that would be a good thing for UCSD, and I think it turned out to be a very good thing for them. In any case, I went to Harvard University. I took Smitty Stevens’s place. S. S. Stevens had been a longtime member of the Harvard experimental faculty, and during the war, he’d run this psychoacoustics lab, which had hired many luminaries in psychoacoustics—Licklider, George Miller, Kyle Kreider. Dr. Stevens was retiring, and I took his job, so I became the second professor of psychoacoustics at Harvard. I stayed there for almost ten years, and then I went to the University of Florida as a research graduate professor, which meant I had no teaching obligations, I could simply do research. But, all the time I was at Florida, I taught regularly, both undergraduate and graduate classes. And finally, I retired in 1996. And that’s only 25 years ago. And I’ve been retired ever since.

Lutfi:

During that whole time, were there any special accomplishments, developments, or projects that you contributed to that you want to talk about? I know there have been many.

Green:

No, I can’t think of anything. During that time, as an extracurricular activity, I was an expert witness at the Bose Electronics Company. They make speakers. They sued Consumer Reports over a review they wrote of his speaker, and I was an expert witness on that first trial, which was held in Massachusetts in Boston. It went through an appeal court, and finally, the Supreme Court. The Consumer Report people won, and that was sort of an interesting byline at the time. And the other extracurricular activity was, during all the time at Harvard, I worked for Bolt, Beranek, and Newman as an acoustics consultant, and we worked on various projects there. One noteworthy project was with Ken Stevens, the speech man from MIT. He and I worked on a project on high-frequency hearing.

Also, during that time, BB&N was asked to look at some tapes that had been found connected to the JFK assassination, and I and a couple of other people—Fred Wightman and Dennis McFadden—actually went to Dallas and were present when a reenactment of the assassination occurred. And I had to write a report on that for the Assassination Committee in Washington. But other than that, I published two books. One was from Pennsylvania with John Swets—Green and Swets—on the theory of signal detection. And then I had a sabbatical at Oxford—no, at Cambridge, sorry; the first one was at Cambridge—and I wrote another book called Introduction to Hearing. And I published papers during that time. I started my book Profile Analysis when I was on sabbatical at All Souls College at Oxford University.

Lutfi:

What is your present marital status?

Green:

I’m married. My first wife died after 25 years of pancreatic cancer. And we had four children: Allan, Phillip, Kathy, and George. One of my graduate students when I got the Silver Medal in Psychoacoustics said that he knew I had children because I had numbered them. And I said later that I knew a graduate student, I think he was number three, who made this remark. In any case, about a year after her death, I met Marian Heinzmann, who is my present wife, and we have now been married 40 years. And she was a secretary in the Fine Arts Department at Harvard, and some mutual friends introduced us. We don’t have any children, but she’s a good mother to the previous kids.

Lutfi:

When and where did you meet your spouse?

Green:

Clara and I met when I was a student at the University of Chicago. She was a nurse at one of the local hospitals. Marian and I met when… I went into work at Harvard a day after Christmas, and I was chairman at the time. And the associate chairman came in about 11 o’clock and said, “Are you going to lunch?” And I said, “Yeah.” And he said, “Well, let’s go up to the cafeteria.” It was on the first and second floor. And I said, “Sure.” So, we went for lunch, and his wife brought this lady who she’d worked with at Harvard as an administrator, which was when they introduced me to Marian. And I think we said hello to each other, and at that point, Eddie Newman came up. Eddie Newman was a professor at Harvard and was very loquacious.

And he literally stood at the table while we were eating, and I forget what his topic was, but he could go on on practically anything. He just talked, and talked, and talked. I don’t think Marian and I ever said a word to each other the whole meal. But in any case, the meal ended, and two days later, I asked her if she’d like to go to lunch, and she agreed. Unfortunately, I had played squash with the assistant chairman at 11 o’clock that day, and in the course of our squash game, he smashed me with his squash racquet right straight in the face. And I could barely move my jaw. But, I picked her up for lunch, and she wasn’t feeling very well.

And so, we went to have lunch, and we went to a small French restaurant around the corner from wherever we were and had onion soup and a small beer. And that was our lunch. And we both enjoyed it very much because we couldn’t eat anything else. And that started our courtship. We got married, I think, in 1980. It’s one of the few dates I can remember. So, we’ve been married 40 years, and she’s still with me and has been helping me. Recently, I’ve been diagnosed with lung cancer—the slow kind, not the smoker’s kind. And we’re still in the middle of that. And she’s been a great help.

Lutfi:

This is the final question. You’ve had many graduate students, post-docs, and colleagues work with you. Is there anything you’d like to say about those individuals?

Green:

Yes, there is. I won’t name all the post-docs and graduate students, there have been many, but many of them have won prizes already. Bob Shannon won the ARO prize. Neal Viemeister and Roy Patterson both won the Silver Medal in Psychological and Physiological Acoustics. Bill Yost has been president of the Acoustical Society and a Gold Medal winner. And Virginia Richards won the Troland Award, a prize of the National Academy of Science.

Finally, I’d like to say something about close friends in the Society under the rubric of “who influenced you?” Of course, they are Spike Tanner and John Swets, who became collaborators, and John and I wrote the book on signal detection theory. But in addition, Dennis McFadden, Erv Hafter, Duncan Lewis, Bill McGill, J. C. R. Licklider, James P. Egan, Lloyd Jeffress, S. S. Stevens, Jack Nachmias, yourself Bob Lutfi, and there are probably more who I’ve left out, but I thank them all. They have been a great area of support and encouragement to me.

Lutfi:

And that brings us to the end, and I want to thank you.

[End]