Friday, September 27, 2019

Age Effects on SEP Citation, Plus the Baby Boom Philosophy Bust and The Winnowing of Greats

I have a theory about the baby boom and academic philosophy in the major Anglophone countries. To explain and defend it, we'll need to work through some more numbers from my analysis of citations in the Stanford Encyclopedia of Philosophy.

Recency Bias

First, left's examine recency bias in the encyclopedia. I've done this by taking David Schwitzgebel's August 2019 scrape of the bibliographic sections of all the main-page SEP entries and searching for the first occurrence of "19", "20", or "forthcoming" on each line, then retrieving the first four characters from that location. Non-numbers (except "fort") and numbers <1900 or >2019 were excluded. Everything else was interpreted as a date. (I did not include dates from before 1900, since those works citation formats are less systematic, and often a translation date is cited rather than an original publication date.)

The result is a pretty little curve peaking at 2003-2007:

[click to enlarge]

In 2014, I'd conducted a similar analysis. In those data, the peak was 1999-2003:

[click to enlarge]

And in 2010, I'd also done a similar analysis! The peak year was 2000:

[click to enlarge]

Thus, in the Stanford Encyclopedia, the most recent works appear to be somewhat disadvantaged compared to works about ten years old. Back in time from the peak years, there's a steep linear decline to about 1950, before which there are few citations and the citation rate becomes approximately flat. (Probably, serious curve fitting wouldn't show it to be three linear phases; but close enough.) Over the past nine years, the peak appears to have advanced by about five years. Since SEP entries are updated about every five years on average, we might expect some delays for that reason; and if people are a little lazy about updating references when they update their entries, that could explain why the peak isn't advancing as fast as the clock.

I assume that all these effects are recency effects. Another alternative, of course, is that early 21st century philosophy is vastly better and more citable than earlier philosophy, so that a good a 23rd century encyclopedia would show a similar curve, also massively disproportionately citing early 21st century philosophers compared to 20th century philosophers. (If you find that plausible, I have a beautiful little Proof that P to sell you!)

Based on these results, one might expect that the most-cited philosophers in the 2019 Stanford Encyclopedia would be those whose most influential works appeared around 2003-2007. However, that is not the case.

I have a twofold explanation why: The Winnowing of Greats and The Baby Boom Philosophy Bust. But it's going to take a bit of data analyses to get there.

Most Cited Philosophers, Oldest Generation

For analysis, I have divided my list of the 295 most-cited philosophers into four generations based on age: 1900-1919 (oldest), 1920-1945 (pre-boom), 1946-1964 (boomers), and 1965-present (Generation X). Age was estimated based on birthyear as recorded in Wikipedia (for most authors) or estimated based on date of undergraduate degree (assuming age 22) or in a few cases date of PhD (assuming age 29). A CSV with the data is here. I welcome corrections.

Looking at the oldest generation (1900-1919), we see some stalwarts near the top of the most-cited list: Quine at #2 and Davidson at #5. Chisholm, Strawson, Popper, Geach, Goodman, Mackie, and Anscombe all appear in the top 50. Interestingly, although 19 philosophers from this generation rank among the top 100, only 13 appear in the remainder of the list of 295.

I'm inclined to attribute this to a phenomenon I call The Winnowing of Greats. This is the tendency for the difference between the top performers and the nearly-top performers in any group to come to seem larger with historical (and other types of) distance. We're still citing Quine and Davidson, and to some extent Richard Brandt (#129) and Norman Malcolm (#236), but less famous philosophers from that generation are quickly dropping off the radar.

The intuitive idea of Winnowing of Greats is this: If you're close to a field and you want to list, say, ten leaders in that field in rank order, you might list A, B, C, D, E, F, G, H, I, and J. Another person, also close, might partly agree, maybe listing A, C, B, E, G, D, I, K, L, and M. With more distance, someone might only list or think of five -- likely A, B, C (consensus top) and two of D, E, F, or G, starting to forget about H and higher. Still later, people might only mention A, B, and C. Over time, these will come to seem the consensus "best" and thus the ones who need to be discussed on grounds of historical importance in addition to whatever other reasons there are to discuss them; and others will be relatively less mentioned and mostly forgotten except by specialists, and the gap in apparent importance between the top and the remainder will grow -- eventually becoming the "consensus of history".

We could interpret such winnowing as a type of recency bias against all but the most famous, flowing from ignorance due to distance; or we could see it as a more legitimate winnowing process.

Starting somewhere around rank #50, the philosophers from the oldest generation who are still ranked might strike those of us who know the history of 20th century philosophy to be ranked rather low relative to their historical importance. I interpret this as recency bias. Quantitative evidence of recency bias is this: Looking at only those philosophers on both the 2014 and 2019 lists, the average loss in rank between the two measures was 11 spots. (Going logarithmic, the average natural log of the rank is 4.11 in 2014 and 4.29 in 2019.)

(For the curious, Chisholm was a notable decliner, rank 12 to 19, which is proportionally large in just 5 years, while Anscombe bucked the trend, climbing significantly, from 66 to 48.)

Most Cited Philosophers, Pre-Boom Generation

The dominant generation is the pre-boom generation (1920-1945). Although this generation includes the largest number of birth years, their dominance of the top of the list is too great to be explainable by that fact alone. This generation gives us six of the top ten (Lewis, Putnam, Rawls, Kripke, Williams, and Nozick) and 33 of the top 50. Most of these authors did their most influential work in the 1960s-1980s. Despite the citation curve peaking for works written in 2003-2007, foundational work by this generation is still being heavily cited. For example, the two most-cited works in the Stanford Encyclopedia are Rawls's A Theory of Justice (1971, cited in 115 entries) and Kripke's Naming and Necessity (1980, cited in 88 entries). (More data on this soon.)

Time is starting to affect the rankings of this generation, too, with an average decline in rank of 8 (average difference in ln of .05). Notably, however, in the top 50, there is an average increase in rank of 3. (It's 1.4 if we exclude Pettit, whose rank increased markedly due to a methodological change: I now include second authors.) This difference in trajectory between the top and bottom is consistent with the Winnowing of Greats.

According to a demographic theory that I call The Baby Boom Philosophy Bust, the Baby Boom generation had a substantial demographic advantage in academic philosophy in the United States. (This probably generalizes outside of the U.S. and outside of philosophy, but let me stick with what I know.) Undergraduate enrollments in the U.S. jumped from 2,444,900 in 1949-1950 to 3,639,847 in 1959-1960 to 8,004,660 to 1969-1970 to 11,569,899 in 1979-1980. After that, enrollments continued to grow, but at a much slower pace. The latter part of this period was of course when the baby boomers hit college, but the earlier part of the period was important too, in the wake of the G.I. Bill and the fast growth of the national prestige of higher education. This national prestige was, I conjecture, partly due to the prestige of the space race and the power of the atom bomb, and it extended into the humanities and arts partly due to the popularity of the idea of IQ and the emerging notion of "creativity". (I have a colleague here at UCR, Ann Goldberg, who is doing fascinating work on the history of the concept of creativity and its role in educational institutions.)

Who was hired to teach all of these new undergraduates? It was of course, the pre-boom generation. A flood of pre-boom Assistant Professors hit the universities during this period. Doing their foundational early-career work in the 1960s-1970s, they set the agenda for the philosophy of the period. Then when the boomers got their PhDs and hit the job market in the 1980s, they discovered that pre-boomers were already astride the academy -- mid-career now, at the height of their influence, not yet ready to step aside for their younger generation. The job market was terrible, and those who made it into tenure-track positions found themselves in an academic world already dominated by Rawls, Lewis, Kripke, Fodor, etc., without a lot of new space at the top. My hypothesis is that this fact about academia in the 1980s and early 1990s means that the baby boomers grew philosophically in the shade of the pre-boom generation -- and not to the heights of prestige and influence that they would have grown to, had they not been so overshadowed in their early careers.

With this hypothesis in mind....

Most Cited Philosophers, Baby-Boom Generation

The boomers (born 1946-1964) contribute two philosophers to the top ten: Nussbaum (#9) and Williamson (#10). Another five are among the top fifty: Fine, Sober, Kitcher, Hawthorne, Smith. (Hawthorne, born 1964, is right at the cutoff between Boom and Gen X, if I have his date right.) They are thus vastly underrepresented in the top 50 compared to the pre-boomers (7 vs 33). However, they are more proportionately represented in the list as a whole (113, compared to 129 for the pre-boomers).

Could the boomers rise in relative prestige, so that if we did a similar analysis in ten or twenty years, we'd find them dominating the top 50 in the way the pre-boomers do now? I see three reasons not to think so.

First, the boomers have already started declining in citation rate, comparing 2014 and 2019, with an average rank decline of 8 (ln = +.009). Mitigating this, however, if we look at the top 100, there's an overall average rank gain of 11 (ln = -.16) -- consistent with the winnowing hypothesis.

Second, in other research, I've found that philosophers tend to reach peak influence around ages 55-70. Thus, boomers should be at their peak influence now and we shouldn't expect a lot more climbing overall.

Third, as noted above, there is a strong recency bias in the Stanford Encyclopedia citations. This should tend to favor philosophers younger than the boomers, and increasingly so over time -- especially since philosophers on average tend to do their most influential work in their late 30s and 40s.

Most Cited Philosophers, Generation X

Gen Xers (born 1965-1980) are still too young to be very well represented among the top-cited philosophers in the Stanford Encyclopedia: Only 21 qualify for the list of 295, three in the top 100 (Chalmers, Schaffer, and Sider). In the past five years, the average rank gain in this group is 16 positions (ln = -.15), so, as one would expect, they are still on an upward trajectory. Also as one would expect, many of them are new to the list as of 2019 (11 of the 21), and so not included in these trajectory averages, though headed upward in another sense.

It is, I think, too early to know if Generation X will ultimately prove also to have grown too much in the shade of the pre-boom generation. I sense that this might be so: Mainstream analytic philosophers still to a large extent live in a philosophical world whose agenda was set by Lewis, Kripke, Rawls, Williams, and Putnam.

Side note on demographic diversity of most-cited Gen X philosophers: If my gender and race/ethnicity classifications are correct, then (perhaps surprisingly?) the most-cited Gen X philosophers are slightly farther from gender parity and racial diversity than the Boomers, with 3/21 women and no Latinx or non-White philosophers (compared to the Boomers' 17% women, 2% Latinx or non-White). However, since the numbers are small, this might be chance variation.

Explanation of the Misalignment of Peak Citation Year and the Age of the Most-Cited Philosophers

To cross my t's and dot my i's: Although the peak citation years are 2003-2007, the pre-boom generation is the most cited because, due to their demographic advantage in academia, they dominated philosophy from the 1970s at least into the 1990s (and maybe they still do, despite death and retirement), shading the boomers and maybe also the Gen-Xers. Although recent work is the most cited in the aggregate, the Winnowing process hasn't yet given us the distance required for consensus on the Greats, so those recent citations remain scattered among many authors.

This post is already plenty long, so I won't bother crossing my x's and dotting my j's.

Wednesday, September 18, 2019

Applying to PhD Programs in Philosophy, Part II: Grades, Classes, and Institution of Origin

It's awfully hard to be admitted to top-ranked PhD programs in philosophy in the U.S., as I mentioned in Part I of this series.

Today: What do admissions committees look for in transcripts? In future posts, I'll talk about other aspects of the application.

First: How Admissions Committees Work

Normally, philosophy PhD admissions are decided by committees constituted of a few faculty members from the philosophy department, with higher administration formally reviewing and approving the choices. Although some faculty members work on admissions year after year, most faculty rotate on and off the committee.

At U.C. Riverside, where I teach, we receive one to two hundred applications every year, arriving in January. (Elite programs must receive hundreds more.) We have a committee of four, and two members read the files of every applicant. In February, we winnow to about 40 applicants, who are then reviewed and discussed by the whole committee. Offers go out February to March or sometimes April. We usually aim to admit about 15-20 students for a final entering class of 6-8.

In my experience, committee members employ different approaches. Some take GRE scores seriously; others don't consider them at all. Some look carefully at the letters; others think letters typically say more about the letter writer than about the applicant. Some read every writing sample, looking for gems; others don't bother with the samples unless the student looks plausible on other grounds. Some care a lot about whether the student's interests fit with strengths of the department; others happily admit students with any range of interests. These differences, along with yearly changes in committee composition, explain some of the unpredictability of the process. There is no formula.

GPA, Overall and in Philosophy

You must have excellent grades to have a reasonable prospect of admission to a top-50 ranked philosophy PhD program, unless there is something very unusual about your application. At UCR, currently ranked #32 in the U.S. in the Philosophical Gourmet Report, admitted students typically have GPAs of 3.8 or more and basically straight A's in philosophy during the last year or two of their transcript. For example, in a two-year sample of 13 entering students at UCR (excluding non-U.S. students), median GPA at the most recent previous institution was 3.89, and there were several perfect 4.0's. (Admitted students who declined our offer presumably had GPAs at least as good on average.) The lowest GPA in the two-year sample was about 3.6, but that student had straight As in the final three terms of their record.

Transcripts are evaluated holistically. Not all 3.8 GPAs are equal. What matters most are grades in upper-division philosophy courses. A "C" in chemistry your first year won't sink your application. Conversely, a 3.9 that includes a lot of A-minuses in senior-year philosophy courses doesn't look so good. We want the very strongest students, not (usually) the A-minus students.

Of course, transcript isn't everything. Eyeballing last year's applicant pool, the median GPA of rejected applicants was probably at least 3.75, and we rejected at least 16 applicants with GPAs in the 3.95-4.00 range. A great transcript earns you a closer look, but the whole application has to be impressive, standing out in a field containing dozens, or even hundreds, of other terrific students.

Yes, it's that competitive.

Institution of Origin

By institution of origin I mean where you received or expect to receive your undergraduate degree, or if you are in a Master's program, your Master's degree. Institution of origin strongly influences prospects for admission. Admissions committees tend to look more favorably on applicants from Yale and Oxford than on applicants from less prestigious schools. This appears to be especially true of the most elite PhD programs (PGR top ten ranked), perhaps less true of lower-ranked PhD programs (PGR ranked 30-50), though even among lower-ranked PhD programs I suspect that pedigree has a big influence. (Follow the links for some quantitative analysis.)

This pedigree advantage has several possible explanations. It can be difficult for faculty to evaluate transcripts from schools with which they are unfamiliar (how meaningful is that "A"?). Also, students from elite schools might be better taught how to create writing samples and personal statements that will please admissions committees. Members of admissions committees are more likely to know of, and respect the judgment of, letter writers at elite schools. They might also generally respect the ability of elite schools to select and train excellent students. And, of course, there may also be simple prestige bias.

Non-U.S. students, except from a few elite universities, are probably also disadvantaged in the admissions process, for related reasons: transcripts that can be difficult for U.S. committees to evaluate, differences in philosophical culture and training, fewer personal and professional connections. Furthermore, some programs cap their foreign admissions. At UCR, for example, the Philosophy Department normally can’t enroll more than one new foreign student per year, due to (foolish!) U.C. regulations concerning international students.

Since it can be difficult for admissions committees to evaluate transcripts from small liberal arts schools, foreign schools, and the less famous M.A. programs, it helps if students can have at least one of their letter writers address the issue with concrete comparisons. "Jill's GPA of 3.91 is the best GPA for a graduating senior in Philosophy in the past five years, among 80 graduates." Now the admissions committee knows better what that 3.91 means, in your context.

If you have attended multiple institutions (e.g., community college before undergrad), you are normally required to submit transcripts from all institutions. This can be worrying if, for example, your grades from an older institution are weak. Although ideally its best to have strong grades throughout your college career, in my experience, the most recent two years are more seriously considered than older work, so poor grades early in your education aren't necessarily an application killer. People's educational aspirations and priorities can change over time, especially if their educational path has been crooked. Admissions committees know this.

Master's Degrees

Although probably the majority of admittees to PhD programs gain admission straight from undergraduate study, a substantial minority (about a third?) have some graduate work first. Typically, this is in the form of a terminal Master's program in philosophy. If you aren't admitted into a PhD program that you like, you might want to consider applying to M.A. programs. However, there are also downsides. See the discussion of this issue in Part I.

Transcripts from M.A. programs are evaluated somewhat differently from undergraduate transcripts and often read alongside undergraduate transcripts. From the most demanding M.A. programs, a mix of A's and A-minuses is more favorably viewed than a similar mix would be at the undergraduate level, though in my experience successful applicants from M.A. programs typically do have all or mostly A's, with few A-minuses.

Do You Need to Be a Philosophy Major?

Somewhat to my surprise, when I crunched the numbers, I found that 96% of graduate students in a sample of elite PhD programs and 90% in lower-ranked programs had majored in philosophy or a cognate discipline like History and Philosophy of Science, either at the undergraduate or graduate level. This might give you the impression that unless you are a Philosophy major, your odds of admission are low.

My experience on admissions at UCR suggests that these numbers might be misleading. As long as a student has performed excellently in a substantial number of upper-division courses in philosophy (maybe six to eight), I'm not sure we care so much about the major. There's something attractive about admitting, say, a Biology major who has also done well in a bunch of philosophy courses. That student will bring an unusual perspective and set of skills to the department. The main thing is to have a track record of excellent performance in upper-division or graduate level philosophy.

If I’m right about that, maybe the very high proportion of philosophy majors among admitted students reflects a similarly high proportion in the applicant pool (or the pool of plausible applicants), rather than the preference of admissions committees.

Graduate-Level Courses

If you have the opportunity to take graduate courses in philosophy, by all means do so, especially if you're at a school with a PhD program. If you can earn an A or two in graduate-level courses in philosophy, that can really solidify the case that you're ready for graduate school -- especially if one of your letter writers compares you favorably with their current graduate students! Also, a graduate course can provide a good opportunity to write an essay that will make a good writing sample.

Unfortunately, applications generally have to be sent in early winter, so make sure you do that graduate work by fall term of the year you apply.

Honors Thesis

For some reason, we don't get many applicants who have written undergraduate honors theses, nor do many philosophy students at UCR write them. (I have supervised only two in my 22 years.) However, if your school offers this option, I would recommend considering it, especially if you are able to complete the thesis by the time of application. It establishes that you can do long-term, self-directed work, and also it gives you a taste of such work so that you can think about whether it's really for you; it's likely to be your best piece of work and so a natural candidate for a writing sample; and on top of all that, it's an intrinsically worthwhile experience!

Timing Graduation

Oddly, students completing their studies in May or June, as is traditional, are at a disadvantage compared to students who finish in December. If you start on the standard U.S. undergraduate schedule, take four years to graduate and apply at the beginning of your 4th year, 1/2 or 2/3 or your senior year won't show in your transcripts, you'll have fewer essays to draw on as writing samples, and you'll have had less exposure to potential letter writers than if you take an extra term to graduate and apply at the beginning of your fifth year.

I myself took an extra quarter at Stanford and applied in fall of my fifth year -- and I know my application was much better than it would have been had I applied in fall quarter of my fourth year. I then had fun for nine months, hanging out with friends in northern California, holding a temporary job I didn't care much about. I had plenty of time to travel to the schools that admitted me -- a wonderful experience that I'll describe in Part VII of this series.

Another possibility is to graduate your fourth year, then apply the year after. This potentially doesn't look quite as good to admissions committees, who might wonder why you didn't proceed straight to graduate school. However, let me emphasize that if you are still within one year of graduation this consideration is a relatively minor factor.

If you are more than a year past graduation, the situation is more difficult. You will need to work carefully on your Personal Statement (which I will discuss in Part V) to explain why you are now interested in pursuing graduate school in philosophy. You will probably also want to show recent engagement in academic philosophy, for example, by taking further coursework.

Part III: Letters of Recommendation


Applying to PhD Programs in Philosophy, Part I: Should you Apply, and Where?

Old series from 2007, Parts I-VII.

Wednesday, September 11, 2019

In Praise of UC Riverside Undergraduates

This year, U.C. Riverside is ranked #1 among national universities on the US News & World Report college ranking metric of "social mobility". This metric is based on six-year graduation rates among Pell Grant recipients (most of whose family incomes are below $50,000) and the relative graduation rates of Pell students vs non-Pell students.

UCR has long been notable for its success with first-generation college students, economically disadvantaged students, and students from historically underrepresented groups. Money Magazine ranks it #1 among "most transformative" public colleges (and #4 overall), based on having higher-than-expected graduation rates, earnings, and student loan repayment given the economic and academic background of its students. In 2014, when President Obama proposed a plan to rank universities based on graduation rates, percent of Pell recipients, and affordability, UC Riverside also came out as #1. Fifty-six percent of UCR students are Pell recipients, and the plurality (40%) are Latinx.

I often hear faculty from other universities complain about their undergraduates acting entitled to high grades and special treatment. I have not found this to be the case at UC Riverside. Last year, only one student complained to me about their grade, and the few who asked for accommodations or exceptions seemed genuinely to need them. Many UCR students work incredibly hard, juggling work, school, and sometimes difficult family lives. Students admitted to the U.C. system who want to party choose one of the coastal schools instead.

In theory, a school could achieve high graduation rates by making the coursework easy. Although grade inflation is widespread in academia, I don't think it is especially the case at UCR. My lower-division class "Evil", for example, requires substantial amounts of difficult reading, two essays, and three exams in a ten week term, including a comprehensive in-class final exam which students must pass in order to pass the course. Despite the difficulty of the course, it is among the most popular courses at UCR, always filling with as many spots as we can open up, usually 300-500.

Although students cannot pass Evil without passing the final exam, and about 10% normally fail the final exam, there is almost no cheating on the exam as far as I can tell. Potentially, students could cheat by going to the restroom and looking things up on their phones, but only a small percentage go to the restroom at all, and almost all of those students are quickly in and out. Only about 1% of students even spend long enough in the bathroom to call up a meaningful amount of information on their phone if they wanted to. Students in my Evil class would rather fail the final exam than cheat in that way. Those who do fail tend to blame themselves and retake the course, doing better the next time through.

You won't find me complaining about "kids these days". Not at UCR.

ETA (8:15 a.m.): Some speculations on how this comes about. Mostly, I think, it's explained by the population of students who choose UCR: solid enough academically to gain U.C. admissions, but not the ones who choose schools on grounds of attractive location or party reputation, and often commuting students from the greater L.A. area, with family ties that keep them local. Partly, it's a critical mass of diverse students, so that students from traditionally disadvantaged backgrounds don't feel unusual or isolated, and professors are accustomed to students from such backgrounds. And partly, it's the generally supportive and collaborative academic culture at UCR, in which staff, faculty, and peers all generally want to see each other succeed.

Friday, September 06, 2019

Aiming for Moral Mediocrity

New essay, just out!

  • published version: Res Philosophica, 96, 347-368
  • manuscript version

  • Introduction

    I have an empirical thesis and a normative thesis. The empirical thesis is: Most people aim to be morally-mediocre. They aim to be about as morally good as their peers -- not especially better, not especially worse. This mediocrity has two aspects. It is peer relative rather than absolute, and it is middling rather than extreme. We do not aim to be good, or non—bad, or to act permissibly rather than impermissibly, by fixed moral standards. Rather, we notice the typical behavior of people we regard as out peers, and we aim to behave broadly within that range. We aim to be neither among the best nor among the worst. We -- most of us -- look around, notice how others are acting, then calibrate toward so—so. The normative thesis is that this a somewhat bad way to be, but it's not a terribly bad way to be. Also, it is a somewhat good Way to be, but it's not a Wonderfully good way to be. It's morally mediocre to aim for moral mediocrity. This might sound like a tautology, but it's not. Someone with stringent normative views might regard it as inexcusably rotten to aim merely for mediocrity in our rotten world. Someone with much less stringent views might think that it's perfectly fine to aim for mediocrity, as long as you avoid being among the Worst. I will argue that aiming for mediocrity is neither perfectly fine nor inexcusably rotten. We're morally blameworthy not to aspire for better, but we also deserve tepid praise for avoiding the swampy bottom.

    Part One defends the view that most of us aim for about the moral middle. Part Two argues that, at least in out culture, having such an aim is not perfectly morally fine, and thus that the somewhat pejorative term mediocre is warranted, capturing in a single word both the empirical peer-relative middlingness and the moderate moral badness.

    Part One: The Empirical Thesis

    2. Following the Moral Crowd

    Robert B. Cialdini and collaborators went to Arizona's Petrified Forest National Park (2006). The park had been losing about a ton of petrified wood per month, mostly stolen in small amounts by casual visitors. Cialdini and collaborators posted four different signs intended to discourage theft, rotating their placement at the heads of different paths. Two signs were explicit injunctions: (A) "Please don't remove petrified wood from the park" (with a picture of a visitor stealing wood, crossed by a red circle and bar) and (B) "Please leave petrified wood in the park" (with a picture of a visitor admiring and photographing a piece of wood). Two signs were descriptive: (C) "Many past visitors have removed petrified wood from the park, changing the state of the Petrified Forest" with pictures of three visitors taking wood) and (D) "The vast majority of past visitors have left the petrified wood in the park, preserving the natural state of the Petrified Forest" (with pictures of three visitors admiring and photographing the petrified wood). Cialdini and collaborators then noted how much wood the visitors tookc from the paths headed by the different signs. Rates of theft were lowest (1.7%) when visitors were explicitly enjoined not to take wood (Condition A). Rates of theft were highest (8.0%) when visitors were told that many past visitors have removed wood (Condition C). Being told that many visitors have removed wood might even have increased the rates of theft, which were estimated normally to be 1% to 4% of visitors (Roggenbuck et al. 1997).

    Cialdini and collaborators also found that hotel guests were substantially more likely to reuse towels when a message to "help save the environment" was supplemented with the information that "75% of the guests who stayed in this room (#xxx) participated in our new resource savings program by using their towels more than once" than when the message to help save the environment was supplemented with other types of information or a longer injunction (Goldstein et al. 2008). Similarly, evidence suggests that people are more likely to heed injunctions to reduce household energy usage when shown statistics indicating that they using more energy than their neighbors -- and they may even increase usage when shown statistics that they are using less (Schultz et al. 2007; Allcott 2011; Ayres et al. 2013; Karim et al. 2015). Littering, lying, tax compliance, and suicide appear to be contagious (Cialdini et al. 1990; Gould 2001; Keizer et al. 2011; Haw et al. 2013; Innes and Mitra 2013; Abrutyn and Mueller Z014; Hays and Carver 2014; Kroher and Wolbring, 2015; Maple et al. 2017; Hallsworth et al. 2017; Reyes-Portjllo et al. 2018). In "dictator games" (i.e., in laboratory situations in which randomly chosen participants are given money and told they can either keep it all for themselves or share some with less lucky participants), participants tend to be less generous when they learn that previous participants kept most of the money (Bicchieri and Xiao 2009; Dimant 2015; Mcauliffe et al. 2017).


    To read more about the empirical evidence that people mostly aim for peer-relative moral mediocrity and for my reflections on the ethics of doing so, access the full paper here.