CLARENCE C. GRAVLEEH. RUSSELL BERNARDWILLIAM R. LEONARD

New Answers to Old Questions: Did Boas Get It Right?

Heredity, Environment, and Cranial FormA Reanalysis of Boas's Immigrant Data

ABSTRACT Franz Boas's classic study, Changes in Bodily Form of Descendants of Immigrants, is a landmark in the history of anthro-

pology. More than any single study, it undermined racial typology in physical anthropology and helped turn the tide against early-20th-

century scientific racism. In 1928, Boas responded to critics of the immigrant study by publishing the raw data set as Materials for the

Study of Inheritance in Man, Here we present a reanalysis of that long-neglected data set. Using methods that were unavailable to

Boas, we test his main conclusion that cranial form changed in response to environmental influences within a single generation of Euro-

pean immigrants to the United States. In general, we conclude that Boas got it right. However, we demonstrate that modern analytical

methods provide stronger support for Boas's conclusion than did the tools at his disposal. We suggest future areas of research for this

historically important data set. [Keywords: Franz Boas, cranial form, immigrant study, heredity, environment]

FROM 1908 TO 1910, Franz Boas conducted an enor-mous study of changes in bodily form among descen-

dants of immigrants in New York City. Boas's team com-pleted a series of anthropometric measurements on nearlyeighteen thousand European immigrants and their chil-dren in order to determine the effect of the new U.S. envi-ronment on the physical type of immigrants. This classicstudy was the first authoritative statement on the natureof human biological plasticity, and it has had enduringimportance for our understanding of human biologicalvariation. Boas's legacy as "the man who did more thanany other to lay the ghost of racism in scientific disciplines"(Gossett 1997:450) is due, in large part, to this landmarkwork.

The immigrant study was highly controversial, and in1928 Boas answered his critics by publishing his raw dataset as Materials for the Study of Inheritance in Man, Despitethe historical significance of Boas's work, these data havebeen almost entirely overlooked. Now is a good time to re-discover this material. Nearly a century of developmentsin analytic methods facilitate the search for new answersto the old questions that motivated Boas and that remainimportant today. In this article, we use Boas's original

measurements to reevaluate his central hypotheses regard-ing the influence of environment on human bodily form.1

Given the historical significance of Boas's study, wefirst outline its development and place it in the context ofhis career as an anthropologist. This review highlights thestudy's significance for 20th-century physical anthropol-ogy and for the critique of biological determinism. Fromthis discussion, we identify three of Boas's central hy-potheses regarding the influence of environment on cra-nial form. The results of the reanalysis show that, on thewhole, Boas got it right. However, the application of ana-lytical tools not available to Boas allows us to refine hisprincipal conclusions and to understand better the extentto which changes in environment and lifestyle influencethe biology of migrant populations. The new findingshighlight the importance of reconsidering Boas's originalmaterial and should encourage others to ask new ques-tions of this historically significant data set.

BACKGROUND

Leslie Spier once remarked that Boas was perhaps "the lastman who can be said to have embraced the whole field ofanthropology" (1959:146). Some recent commentaries tendto overlook this point, emphasizing Boas's cultural over

AMERICAN ANTHROPOLOGIST 105(1):125—138. COPYRIGHT © 2003, AMERICAN ANTHROPOLOGICAL ASSOCIATION

126 American Anthropologist • Vol. 105, No. 1 • March 2003

his biological anthropology (e.g., Darnell 1998; Visweswaran1998), Yet central to Boas's legacy is his integration of lin-guistics, ethnology, archaeology, and physical anthropol-ogy in the critique of 19th-century biological determinism(Baker 1998; Barkan 1992; Smedley 1998; Williams 1996).Boas articulated this four-field attack on scientific racismin his classic The Mind of Primitive Man (1911), whichhighlights early results from the immigrant study along-side evidence from other subfields of anthropology. In-deed, the immigrant study is significant in part because itdemonstrates Boas's commitment to developing an inte-grated science of humankind.

As a physical anthropologist, Boas was concerned pri-marily with biological process and with the formation ofhuman physical types (Stocking 1968; Tanner 1959, 1981).Melville Herskovits observed that this emphasis reflectedBoas's "habit of thinking culturally" (1943:50). However,Herbert Lewis (2001) gives us reason to turn this formula-tion around. Bolstered by his rediscovery of Boas's lectureon "The relation of Darwin to anthropology" (Boas 1909),Lewis stresses that Boas's work in cultural and in biologicalanthropology was united by a concern with process andthe evolution of individuals, rather than with the classifi-cation of abstract types. He suggests that this concern "isspecifically a lesson learned from Darwin," and that Boas'swritings

foreshadow what is known today as the 'populationaT ap-proach that is basic to the modern 'Darwinian synthesis'...in contrast to an essentialist or typological one. It under-lies Boas's way of understanding race and heredity, and itis the foundation of much of his cultural anthropology.[Lewis 2001:382]

This emphasis on process and individual variation setBoas apart from most of his contemporaries and is centralto his critique of race. Anthropologists of the day gener-ally assumed that humankind consisted of a few distinct,fixed races or types—" 'permanent forms' which havelasted without variation from the beginning of our moderngeological period up to the present time" (Boas 1940:35).Following this assumption, most were preoccupied withdeveloping racial typologies based on supposedly suitablemeasurements of racial phylogeny. The immigrant studywas significant because it disputed the validity of suchmeasurements on empirical grounds and thereby helpedto undermine racial classification as "the raison d'etre ofphysical anthropology of the living" (Kaplan 1954:781).

Boas's immigrant study is best remembered for itschallenge to the "central tabernacle of the doctrine" ofrace, the cephalic index (Tanner 1981:250). This simplemeasure, the ratio of head breadth to length, was valuedmost of all for its supposed stability. Anthropometristsagreed that a useful measurement for racial classificationwould have to fulfill a number of requirements: It wouldhave to be resistant to environmental influences, it wouldhave to be unaffected by cultural practices, and it shouldbe possible to demonstrate heritability. Head form was

thought to satisfy all these criteria (Gould 1996; Marks2002; Montagu 1997).

Yet, early in his career, Boas objected to the signifi-cance his colleagues attributed to the cephalic index. In1899, he argued in the American Anthropologist (AA) thatthe cephalic index "may be a very desirable measurementin one case, while in another case it may be of no valuewhatever. Measurements should always have a biological sig-nificance. As soon as they lose their significance they losealso their descriptive value" (Boas 1940:169, emphasisadded). This sentiment set the stage for Boas's immigrantstudy, which put the biological significance of the ce-phalic index to an empirical test.

The immigrant study was conceived in March 1908when Boas submitted a proposal to the U.S. ImmigrationCommission (Boas 1910, 1912a; Stocking 1968). Althoughthe study was a continuation of Boas's prior theoretical in-terests, he was careful to couch his work in terms thatwould appeal to the interests of the commission as well.The important question, he wrote, was whether the "mar-vellous [sic] power of amalgamation that our nation hasexhibited for so long a time" would continue to have thesame effect on the new immigrants from eastern andsouthern Europe (Stocking 1974:202).

Boas's initial proposal to the Commission called for astudy much grander in scale than the one he eventuallycarried out. He posed a broad set of research questions andfigured that it would require measurements on 120,000participants to obtain reliable answers (Stocking 1974).The actual study was somewhat more modest in scope.From 1908 to 1910, Boas and a team of 13 assistants col-lected a series of anthropometric measurements on 17,821immigrants and their children living in New York City,The sample was stratified by immigrant group so thatseven groups were represented: East European Hebrews,Bohemians, Sicilians, Neapolitans, Poles, Hungarians andSlovaks, and Scotch. The largest of these groups was theEast European Hebrews, with around six thousand indi-viduals in the study. Bohemians, Sicilians, and Neapoli-tans were represented in equal number at about threethousand individuals each, and smaller numbers of the re-maining groups rounded out the sample (Tanner 1959).About fifty-five hundred of the study participants wereadults age 25 and over, and more than two-thirds were be-tween the ages of four and 25 (Boas 1912a:84). Roughlyforty percent were born in the United States, while the restwere born in Europe (1912a; 10-23).

"In planning the investigation," Boas wrote, "it seemeddesirable to select such measurements as would be mostcharacteristic in defining the stage of development andthe characteristic racial types of each group" (1910:33). Toassess the stage of development, Boas and his team aimedto collect measurements of stature, weight, and generalphysiological development for each person. They were un-able to measure people without clothing, so only the stat-ure measurements were obtained for the entire sample. Todefine the "characteristic racial types of each group," Boas

Gravlee, Bernard, and Leonard • Reanalysis of Boas's Immigrant Data 127

measured maximum head length and width, the width offace between the zygomatic arches, and color of hair, eyes,and skin. Boas excluded skin and eye color from his dis-cussion of the data because of problems in standardizingthese measurements. His 1912 report does include a briefchapter on hair color, however (1912a;93-98).

Boas published his results in several forms, each bear-ing the title Changes in Bodily Form of Descendants of Immi-grants. First, in 1910, Boas submitted his initial report tothe Commission. Two years later, he presented his ex-tended analysis to the Commission in a final report thatwas reprinted by Columbia University Press that sameyear. Boas also published the results in the AA in 1912 andin his collection of essays in 1940.2

Because the main question of interest was the effect ofthe U.S. environment on new immigrants, Boas's principalcomparison was between U.S.- and foreign-born childrenof each group. The differences he discovered revealed "muchmore than was anticipated" (Boas 1910:7). Throughout hisreport, Boas emphasized the cephalic index, "which hasalways been considered as one of the most stable and per-manent characteristics of human races" (1910:7). His com-parison of U.S.- and foreign-born children, however,showed that the cephalic index "undergoes far-reachingchanges due to the transfer of races of Europe to Americansoil" (1910:7). Figure 1, reproduced from Boas's prelimi-nary report, illustrates Boas's analytical approach to theproblem. He used this graph to show that "the two racesin Europe" (1910:9) are quite distinct, but that their chil-dren born in the United States show an intermediate typeof head form, beginning early in childhood and persisting

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Age

Foreign-born Hebrews

U.S.-born Hebrews

U.S.-born Sicilians

Foreign-born Sicilians

FIGURE 1. Boas's comparison of head form of U.S.- and foreign-born Hebrew and Sicilian males.

throughout life. Boas drew out the implications in a pas-sage that must have been astonishing at the time;

The east European Hebrew, who has a very round head,becomes more long-headed; the south Italian, who in Italyhas an exceedingly long head, becomes more short-headed;so that both approach a uniform type in this country, sofar as the roundness of the head is concerned. . . . Thisfact is one of the most suggestive ones discovered in ourinvestigation, because it shows that not even those char-acteristics of a race which have proved to be most perma-nent in their old home remain the same under our newsurroundings; and we are compelled to conclude thatwhen these features of the body change, the whole bodilyand mental make-up of the immigrants may change.[1910:7-8]

For Boas, then, the immigrant study demonstrated notonly plasticity of human cranial form but also plasticity ofhuman potential. This point was critical to the broader ar-gument against racial determinism he developed in TheMind of Primitive Man,

Table 1, taken from Boas's 1912 report, shows that themean differences between U.S.- and foreign-born childrenpersisted for each of the four largest immigrant groups inall anthropometric measures. Boas pointed out, however,that not all changes occurred in the same direction(1912a:57). Indeed, he noted that the direction of changeis uniform across all groups only for width of face. Boasnever proposed any compelling explanation of these dif-ferences, but he did point out the decline in statureamong Sicilians. Writing to a member of the ImmigrationCommission, Boas concluded: "We can now say with greatcertainty to the Sicilians that they should stay away fromNew York, because the hygienic influences are bad"(Stocking 1974:213). Boas did not pursue this matter anyfurther, however, and the explanation for differencesamong groups in response to the new environment re-mains an open question.3

Boas's conclusion about the differences between U.S.-and foreign-born children is more persuasive than is hisadvice for the Sicilians. He recognized that his finding was"so surprising and unexpected that it requires the mostthorough-going criticism before being accepted as defi-nitely established" (Boas 1910:43). He therefore supple-mented his initial results with three further analyses.

First, he thought it necessary to test whether the ob-served differences in head form became more pronouncedwith increased exposure to the new environment. To in-vestigate this question, Boas first divided the U.S.-bornchildren of each immigrant group into those born withinten years and those born more than ten years after theirmothers' arrival in the United States. He then comparedthese measurements to each other, to those for foreign-born children, and to the general average for the total se-ries. This analysis revealed the greatest changes in headform for children born more than ten years after theirmothers' arrival. Boas also observed even more markedchanges in weight and stature (1910:44). Taken together,

128 American Anthropologist • Vol. 105, No. 1 • March 2003

TABLE 1. Boas's presentation of mean differences in anthropometric measures between U.S.- and foreign-born children.

Nationalityand Sex

Bohemians:MalesFemales

Hebrews:MalesFemales

Sicilians:MalesFemales

NeapolitansMalesFemales

Length of Head(mm)

-0.7-0.6

+2.2+1.9

-2.4-3.0

-0.9-1.7

Width of Head(mm)

-2.3-1.5

-1.8-2.0

+0.7+0.8

+0.9+1.0

CephalicIndex

-1.0-0.6

-2.0-2.0

+1.3+1.8

+0.9+1.4

Width of Face(mm)

-2.1-1.7

-1.1-1.3

-1.2-2.0

-1.2-0.6

Stature(cm)

+2.0+2.2

+1.7+1.5

-0.1-0.5

+0.6-1.8

N

170180

654259

188144

248126

Note: Differences calculated within each yearly age group and weighted by number in each group (Boas 1912a:56).

these results were evidence for the "strong and increasingeffect of the American environment" (1910:17).

The second supplementary analysis was the compari-son between children and their own immigrant parents.Boas realized that the differences between children bornwithin ten years and those born more than ten years aftertheir mothers' arrival could possibly be explained by dif-ferences in the type of immigrants from one year to thenext. The only way to avoid this objection would be tocompare children with their own parents. Boas reasonedthat if the differences between immigrant parents andtheir children born in the United States were greater thandifferences between parents and their children bornabroad, there would be additional evidence for the influ-ence of environment on physical type. This comparisonshowed that the difference in cephalic index between par-ents and their own children was greatest when the chil-dren were born in the United States. The effect alsoseemed to increase with time, since even greater differ-ences between parents and their children were observedwhen the children were born more than ten years aftertheir mothers' arrival. This finding was consistent withthe comparison of U.S.- and foreign-born children, and itreinforced Boas's claim about the influence of environ-ment.

The third supplementary analysis was an attempt tohead off the objection that secular changes in Europecould account for the results. Boas recognized that thecomparison between immigrants and their descendantsnecessarily referred to groups that immigrated at differenttimes. For example, he noted that the parents of 15-year-old U.S.-born children immigrated more than 15 yearsago; the parents of 15-year-old foreign-born children im-migrated less than 15 years ago. The observed differencesbetween U.S.- and foreign-born children could thereforebe an artifact of comparing different immigrant cohorts(Boas 1940:64). To rule out this explanation, Boas com-pared children born in Europe in a given year with U.S.-born children of mothers who left Europe in the sameyear. Boas found that the differences in cephalic index

persisted throughout the total series, which seemed "toeliminate entirely this source of error" (1940:69),

Boas summarized these findings in a 1912 article forthe AA, in which he outlined the ten "principal results" ofhis study (1912b:530-533). All ten can be regarded as test-able hypotheses, but we will consider only the three mostimportant here:

HI: There are significant differences in head form be-tween U.S.-born and foreign-born descendants of immi-grants; these differences are not the same direction in allgroups; they develop early in childhood and persistthroughout life.

H2: The influence of U.S. environment on changes inhead form increases with the duration of time elapsed be-tween arrival of the mother and birth of the child; chil-dren born more than ten years after their mothers' arrivalshow greater differences in head form than those bomwithin ten years.

H3: There are significant differences in head form be-tween U.S.-born children and their own immigrant par-ents; these differences are greater than those between for-eign-born children and their parents.

These findings deserve priority in the reanalysis ofBoas's data because they provide the most compelling evi-dence for plasticity of head form. This point, more thanany other, caused an outburst of public and professionalattention, since it challenged one of the basic tenets ofphysical anthropology and the contemporary under-standing of "race" (Gould 1996:140; Herskovits 1943:47;Stocking 1968:180; Tanner 1981:250). Almost immedi-ately after Boas published his preliminary report to theCommission in 1910, European and U.S. scholars weighedin with their criticism, and the Commission itself dis-missed Boas's conclusions (Baker 1998:107). Alternativeexplanations for the findings ranged from poor measure-ment technique to a high illegitimacy rate among immi-grants; however, none of these objections was so originalthat it was beyond Boas's own imagination; even in hispreliminary report he took considerable pains to preemptthem (e.g., 1910:35-37, 52).

Gravlee, Bernard, and Leonard • Reanalysis of Boas's Immigrant Data 129

The protracted debate over the immigrant study gaveBoas the opportunity to clarify and refine his position in aseries of publications that lasted nearly until his death in1942 (Boas 1912a, 1912b, 1936, 1940). Boas's most im-pressive response to the controversy was his decision in1928 to publish 504 pages of raw, handwritten data fromthe immigrant study, supplemented by additional meas-urements on Hebrew families (Boas 1928). The idea ofpublishing such a mountain of data seems remarkableeven today when modern telecommunications wouldmake it accessible to almost anyone. The idea of doing itin 1928 is far more striking—even if Boas was known forhis tendency to append "page upon page of raw data" tohis papers "when publication outlets would permit"(Stocking 1968:171).

This habit had something to do with his stern com-mitment to scientific method, which also earned him areputation. As ]. M. Tanner notes: "Boas, with his un-bounded regard for scientific integrity and the ethics of re-search, made a practice of publishing all his raw datawhenever possible, so that others also could use them tofurther knowledge" (1981:244). This practice extended,more famously, to Boas's work as a linguist. He and hisstudents published thousands of pages of Native Americantexts, sometimes with little or no analysis. In fact, ofBoas's 5,000 pages of published work, 4,000 pages areunannotated translations of Kwakiutl language texts (Ber-man 1996:216). Leslie White (1963) complained thatthese texts were not intelligible because they were withoutcommentary, and George Peter Murdock (1949:xiv n. 5)mocked Boas's "five-foot shelf" of monographs as contrib-uting little to understanding the social structure of theKwakiutl.

Nevertheless, as Lewis argues, "these are not the worksof a mindless fact-collector" (2001:388). The publicationof Boas's immigrant data in particular shows that "forBoas there was always a point to the collection of facts; itwas usually in order to test propositions" (Lewis 2001:388). Thus, we would extend Lewis's assessment of Boas'sunannotated texts to his raw anthropometric data fromthe immigrant study: "It is true that relatively little hasbeen done with them, but Boas had hopes for their use"(2001:388).

MATERIALS AND METHODS

Data Entry

Figure 2 shows a single page from the original data setpublished in Materials, As the figure shows, the data set in-cludes information on immigrant group, age, sex, familialrelationships (mother, father, son, or daughter), year ofimmigration, and birthplace (Europe or the United States).In addition, it includes six anthropometric variables: maxi-mum head length, maximum head width, bizygomaticwidth, stature, eye color, and hair color. To make this datauseful for modern researchers, our first task was to convert

the handwritten data into machine-readable format, Thedata set we produced will be made available electronicallyas a resource to scholars.

A team of undergraduate students assisted in data en-try, and one of us (Gravlee) was responsible for monitor-ing the quality of the data set. We randomly selected 50pages of Materials to check manually for errors. Thosepages contained 12,474 observations, and we found 48 er-rors, for an error rate of 0.0038. Next, we searched the en-tire data set for extreme values on each variable and dis-covered another 347 errors. Finally, following Jantz et al.(1992:442), we plotted head length versus head breadthand face breadth versus head breadth to identify addi-tional outlying values on the cranial measurements. Thisprocedure uncovered 17 errors in data entry. Altogether,then, we identified and corrected 412 data entry errors. As-suming representativeness of the 50-page sample, wewould expect only about 483 errors over the 504 pages ofBoas's data set, making the number of undetected errorsnegligible.

Data QualityAn additional concern is the quality of Boas's original dataset, an issue that attracted much criticism from Boas's con-temporaries. The greatest potential source of error is thelack of any systematic sampling technique (Tanner 1959:102). Despite Boas's "methodological meticulousness"(Herskovits 1943:39), he was not as wary of sampling erroras we might be today, and there is very little discussion ofsampling in any of his publications on the immigrantstudy. The relevant question is whether the lack of ran-dom sampling procedures renders the data set useless formodern researchers.

Here we might follow the example of a group of re-searchers who recently rediscovered the anthropometricdata Boas collected on North Amerindians in 1892 (Jantz1995; Jantz et al. 1992; Szathmary 1995). They ask whethernonrandom sampling might have introduced some sys-tematic bias for the specific traits being studied. In thecase of the immigrant study, such bias might have oc-curred, for instance, if there were patterned differences insocioeconomic status between U.S.- and foreign-born chil-dren. The Boas data set does not include the informationnecessary to resolve this issue conclusively, but the pax-ent-offspring comparisons make this objection a mootpoint. There is no obvious consequence of Boas's samplingprocedures so damaging that it should prevent us fromtaking a second look at his material,

A second potential threat to data quality is interobser-ver measurement error, which was the favorite target ofBoas's critics. However, Boas was sensitive to interobservererror in the design of his study, so that "particular painswere taken to make their measurements comparable"(Boas 1910:35), In various reports, Boas discusses in detailprocedures to ensure interobserver reliability and respondspoint-by-point to his critics (1910:35-37, 1912a:82-92,

130 American Anthropologist • Vol. 105, No. 1 • March 2003

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Gravlee, Bernard, and Leonard • Reanalysis of Boas's Immigrant Data 131

19l2b:539, 1940). The consensus now seems to be thatBoas's data are reliable. Even G. M. Morant and Otto Sam-son (1936), who were critical of Boas's conclusions, con-ceded that the data regarding interobserver variation sug-gest that the errors "were not large enough to influenceappreciably comparisons made between different parts ofthe total material" (1936:14).

Again, the recent reanalyses of Boas's Amerindiandata are instructive. Richard Jantz (1995; Jantz et al. 1992)and Emoke Szathmary (1995) point out that Boas wasaware that interobserver variation was a problem and tooksteps to minimize it—nearly twenty years before he under-took the immigrant study. The challenge of ensuring com-parability in the Amerindian data was even greater, since50 observers from the East Coast to the West Coast wereinvolved. Still, Jantz et al. (1992) conclude that Boas's ef-forts to reduce measurement error were successful enoughto regard the data as reliable. If Boas was able to achievesufficient comparability in 1892 with 50 observers, someof whom he never met, we have reason to believe that hewas able to do so in 1909 with 13 of his graduate stu-dents.4

A final issue of data quality causes some concern. Boasreports measurements for 17,821 individuals (1912a:84),of whom 10,509 were males. Materials does not contain allof these measurements. The new data set includes only13,836 individuals, less than half of whom are males (Ta-ble 2). This discrepancy is all the more surprising, sinceBoas states that the published material includes not onlythe data from the original immigrant study but also an ad-ditional "series of Hebrew families measured in 1913"(1928:viii). Nevertheless, Materials contains some 876fewer Hebrews, 877 fewer Sicilians, 852 fewer Bohemians,and 634 fewer Central Italians than are described in Boas'sreports. There is no apparent explanation for this differ-ence, and there is no way to determine how it might affectthe reanalysis. It would be a worthwhile project for futureresearchers to explain this discrepancy and locate themissing data.

Statistical Methods

To test the main hypothesis regarding differences betweenU.S.- and foreign-born children in the mean cephalic in-dex (HI), we modeled the effect of age, sex, birthplace,and immigrant group on cephalic index, using analysis ofcovariance (ANCOVA). Following Boas, this analysis in-cluded all second-generation immigrants aged 25 and un-der for whom data were available. Of the 8,242 descen-dants of immigrants under age 25, data are missing forbirthplace in 626 cases, and another 14 cases have missingvalues for cephalic index. Thus, there were 7,602 validcases for this analysis- For all analyses, we retain Boas's di-vision of the sample into seven immigrant groups in orderto ensure comparability with his results.

The initial model included a cross-product interactionterm to test Boas's observation that the effect of birthplace

varied across immigrant groups. Because the interactionwas significant, appropriate follow-up tests examinedseven hypotheses—one for each immigrant group—of thegeneral form:

Cephalic index;/* = \x + age + sex/ + usborri/ + immigrant* +usborn*immigrant/* + error;/*

where u denotes the overall mean; age is continuous; sex(.denotes the /th level of sex {i = 1,2); usborn^ denotes the/th level of birthplace (/ = 1,2); immigrant^ denotes the kthlevel of immigrant group (k = 1, 2, 3, 4, 5, 6, 7); and us-born*immigrant/ik denotes the (;,fcth) interaction effect ofbirthplace and immigrant group. This procedure producesa series of univariate ANCOVAs that test the simple maineffect of birthplace at each level of immigrant group, ad-justed for age and sex.5

Next, we used two analytical approaches to test Boas'sconclusion that the influence of U.S. environment in-creases with the time elapsed between mother's immigra-tion and child's birth (H2). The first mimics Boas's analy-sis by dividing descendants of immigrants into threegroups: foreign-born, U.S.-born less than ten years aftermother's immigration, and U.S.-born ten years or more af-ter mother's immigration. This division excluded 1,017U.S.-born descendants who were missing data on mother'syear of immigration, leaving 6,585 cases available foranalysis. Mean age- and sex-standardized cephalic indexesof the three groups were compared using analysis of vari-ance (ANOVA), and a cross-product interaction termtested Boas's observation that the temporal effect variesacross immigrant groups. Follow-up tests included Bonfer-roni-adjusted pairwise comparisons.

The ANOVA approach to the hypothesized temporaleffect has the advantage of replicating Boas's analysis, butin dichotomizing the time elapsed between mother's im-migration and child's birth, this approach throws away alot of information. Therefore, the second means of testingH2 was to treat the time elapsed between mother's immi-gration and child's birth as a ratio-level variable in a leastsquares regression analysis. Time elapsed was estimated bysubtracting the respondent's age and mother's year of im-migration from 1910, the last year of Boas's data collec-tion. Then, to satisfy the assumption of normality, thesquare-root transformation of time elapsed was modeledas a predictor of age- and sex-standardized cephalic indexseparately for each immigrant group. This model also in-cluded maternal height to control for possible confound-ing effects. Of the 4,632 U.S.-born descendants of immi-grants in the entire data set, 1,047 were missing datanecessary to calculate time elapsed, and another sevenwere missing data for cephalic index. This analysis there-fore included the remaining 3,578 individuals.

Finally, we used parent-offspring correlations and re-gression coefficients to test Boas's conclusion that the dif-ferences in head form between U.S.-born children andtheir parents are greater than those between foreign-bornchildren and their parents (H3). In separate regression

132 American Anthropologist • Vol. 105, No. 1 • March 2003

TABLE 2. Descriptive statistics for major variables, by immigrant group.

N

Age (yr)

Stature (cm)Head Length(mm)Head Width(mm)BizygomaticWidth (mm)

N

Age (yr)

Stature (cm)

Head Length(mm)Head Width(mm)

BizygomaticWidth (mm)

Bohemian

1,324

24.8(15.3)

147.9(.409)

176.9(.171)150.0(.152)

130.0(.182)

964

23.9(16.9)

149.9(.515)

182.5(.228)154.1(.198)

132.5(.220)

CentralItalian

1,329

23.6(15.3)142.6(.415)177.1(-181)144.9(.152)127.0(.189)

1,000

22.6(17.2)

141.3(.497)181.4(.244)148.3(.187)

128.5(.233)

Hebrew

2,08721.7

(14.3)141.4(.351)175.5(.148)146.9(.120)

126.8(.152)

1,89220.0

(15.1)141.5(.391)

180.3(.168)150.1(.136)

128.8(.162)

Hungarianand Slovak

Females346

22.3(13.5)143.0(.708)

175.8(.323)148.7(.272)

129.5(.321)Males

304

21.2(15.0)

143.3(.773)179.7(.384)

152.6(.334)

131.8(.364)

Polish

272

22.0(13.8)140.2(.787)

179.0(.365)

146.8(.295)129.0(.321)

205

23.9(15,7)

146.7(1.037)

182.2(.496)151.7(.399)

133.5(.466)

Scotch

143

25.6(14.8)154.0

(1.188)

184.3(.470)

144.5(.415)

127.5(.519)

140

28.7(17.8)

158.1(1.385)

191.6(.557)150.2(.460)131.9(.623)

Sicilian

1,48924.1

(14.6)145.1(.378)181.0(.164)142.4(.127)

126.6(.163)

1,118

24.8(16.5)147.7(.471)

186.8(.216)

146.6(.159)

130.0(.211)

Note: Mean age is given with standard deviation in parentheses. Age-adjusted means with standard errors in parentheses are given for headlength, head width, bizygomatic width, and stature. Subsample sizes are the number of valid cases for all variables.

analyses for U.S.- and foreign-born children, we comparedthe child's age- and sex-standardized cephalic index withboth mother's and father's cephalic index. We repeatedthese analyses with the midparent cephalic index, or theaverage of mother's and father's cephalic index, as an in-dependent variable.

RESULTS

Table 3 compares the age- and sex-adjusted mean cephalicindexes for U.S.- and foreign-born descendants of immi-grants age 25 and under (HI). Consistent with Boas's find-ings, this table shows that the differences in head form be-tween U.S.- and foreign-born descendants are small inmagnitude and vary in direction across immigrant groups(compare Table 1 and Table 3; see also Figure 3). The initialANCOVA model confirmed the interaction between birth-place and immigrant group (F = 40.73, df= 6, p < .001),making it necessary to compare U.S.- and foreign-bornchildren within each immigrant group in subsequent in-ferential analyses.

The results of these follow-up tests are also reported inTable 3. The ANCOVA for age- and sex-adjusted cephalicindex by birthplace within each immigrant group showsthat, for the four largest groups in Boas's sample, the dif-ferences in head form between U.S.- and foreign-born chil-dren are highly significant. For Sicilians, Central Italians,Bohemians, and Hebrews, the probability of observing

such large differences if they did not exist in each popula-tion is less than 1/1000. However, the results for the threesmallest groups in Boas's sample provide less convincingevidence in support of Boas's hypothesis. The differencesin head form between U.S.- and foreign-born descendantsof the Scotch, and of the Hungarian and Slovak samplesare of borderline significance, and the Polish sample pro-vides no evidence whatsoever of a generalizable differ-ence.

Table 4 presents the initial test of Boas's conclusionthat the influence of the U.S. environment increases withthe time elapsed between mother's immigration and child'sbirth (H2). This table provides little support for Boas's con-clusion. Only for the Bohemian and Hebrew samples isthere evidence of a difference in head form between thetwo groups of U.S.-born descendants of immigrants, thoseborn less than and those born at least ten years after theirmothers' immigration. However, both cases exhibit the pat-tern Boas cited, since descendants born at least ten yearsafter their mothers' arrival show differences from their for-eign-born counterparts more extreme than those of the re-maining U.S.-born descendants. This pattern is also evi-dent in the Sicilian and Scotch samples, although thedifferences between the two groups of U.S.-born descen-dants are of dubious significance in these cases.

The formation of two groups at a cut point of tenyears is in itself an arbitrary procedure imposed by the

Gravlee, Bernard, and Leonard • Reanalysis of Boas's Immigrant Data 133

TABLE 3. Age- and sex-adjusted mean cephalic index of U.S - and foreign-bom descendants of immigrants, by immigrant group.

BohemianCentral ItalianHebrewHungarian and SlovakIT. ishScotchSicilian

N

1,159886

1,486215151115S4r,

U.S.-Born

Adjusted Mean ± SE

84.97 ± 1082.96+ ,1.182.94 ± 0984.78 ± 2384.32 ± 2778.36 ±,3180.31 ±.14

N

163497

1,15915398Mi

Foreign-Born

Adjusted Mean ± SE

85.92 ± .2682.06 ±.1584.61 ±.1085.35 ± 2784.42 ± .3479,45+ 5378.95+ .11

F

12.0223.37

152,523.180.192.91

56.32

P.001.000,000.074.661.088.000

Note: Descendants of immigrants age 25 and under. Means, F-statisties, and associated significance values (p) from ANCOVA of cephalic indexbv birthplace within each immigrant group, adjusted for age and sex, df= 1.

computational limits of Boas's day. The least squares re-gression analysis in Table 5, however, retains the continu-ous variation in the time interval between mother's arrivaland child's birth and provides more information about itsexplanatory power. The results show that, for the two largestimmigrant groups in this analysis, cephalic index changesas a linear function of the time elapsed between arrival andbirth, controlling for maternal stature (Hebrews: p1 = -.141, p= 000; Bohemians: p1 = -.099, p = 004). Although this as-sociation is highly statistically significant, the magnitudeof the relationship is notably small.

There is also limited evidence of such a linear relation-ship for the Sicilian and Central Italian subsamples. Partialcorrelations between cephalic index and time elapsed, con-trolling for maternal stature, are .098 (p - .032) and - 068(p = .056), respectively, although the regression model in-cluding maternal stature is not statistically significant.Meanwhile, there is no evidence of an association betweencephalic index and time elapsed for the Scotch, Polish, or

88

86

% 84

jS 82Q.1)u

80 1 r

-—

%X \ X

Foreign born U.S. born

FIGURE 3. Age- and sex-adjusted mean cephalic index of U.S.-versus foreign-born children, by immigrant group.

Hungarian and Slovak samples. This finding is consistentwith the initial comparison of cephalic index foT U.S.- andforeign-born immigrant descendants. Table 5 also showsthat the strength of the association between cephalic in-dex and time elapsed is remarkably weak across all groupIn no case does the time elapsed between arrival and birthexplain more than two percent of th variation in cephalicindex, as measured by the square i f the part correlations.'Indeed, for most groups it explains less than one percent.

Finally, parent offspring correlations and regressioncoefficients for cephalic index are presented separately forU.S.- and foreign-born families in Table 6 (H3). The differ-ences between the two groups of immigrant descendantsare clear. In terms of head form, foreign born descendantsare notably more similar to their parents than U S-borndescendants are to theirs. The difference in Pearson's correlation between the two groups of descendants is nearlyidentical for both mother-offspring and father-offspringcorrelations (.191 and ,198, respectively). This pattern issummarized by the midparent-offspring correlations forU.S.- and foreign-born descendants (.431 and .643, respectively). Furthermore, the temporal effect of the change inenvironment can be seen in the smaller parent-offspringcorrelations for U.S -born descendants born more than tenyears after mothers' arrival than for those born within thefirst ten years. These figures corroborate Boas's conclusionthat a change in environment leads to decreasing similarity between parents and offspring in terms of head form.

DISCUSSION

In general, the reanalysis of Materials supports the princi-pal hypotheses derived from Boas's immigrant study, butit also provides new intormation to refine his conclusionsabout the plasticity of head form. The evidence is clearthat there are statistically significant differences in ce-phalic index between U.S.- and foreign-born descendantsof the Sicilian, Central Italian, Bohemian, and Hebrew im-migrant samples (HI). As Boas concluded, the changes inhead form are moderate in size and vary in directionacross immigrant groups. The use of inferential statisticsnot available to Boas allows us to reject the null hypothe-sis of equality of means for U.S - and foreign-born descen-dants ot the four largest subsamples, but it requires us to

134 American Anthropologist • Vol. 105, No, 1 • March 2003

TABLE 4. Pairwise comparisons of mean age- and sex-standardizedcephalic index by trichotomized birthplace, by immigrant group.

Foreign-Born Foreign-Born U.S.-Born < 10V. V. V.

U.S.-Born < 10 U.S.-Born > 10 U.S.-Born > 10

Bohemian/-/SECentral ItalianHSE

HebrewHSEHungarian and SlovakHSEScotch/-/SEPolish/-/SE

Sicilian/-/SE

.138

.081

-.263*.053

.321*

.041

.144

.105

.145

.210

.033

.121

-.297*.052

.289*

.076

-.154*.064

.588*

.049

.036

.133

.289

.182

.140

.179

-.361*.086

,151*.060

.109

.063

.268*

.054

-.180.139

.143

.201

.172

.179

.064

.092

*Significant at a = .05 level after Bonferroni adjustment for multiplecomparisons.

be more conservative in our conclusions for the remaininggroups. For the smallest subsamples, there is insufficientevidence to conclude that significant differences in meancephalic index exist between the two groups of immigrantdescendants.

These mixed results point to the impact of sample sizeon the probability of detecting a difference in head formbetween U.S.- and foreign-born immigrant descendants,given the modest size of that difference. Boas himself wasconcerned about this point. In responding to criticismthat the total number of observations was inadequate,Boas pointed out that "in most cases the differences be-tween the foreign-born and U.S.-born series are consider-ably larger than their mean square errors" (1912b:545). Inhis partial report, however, Boas noted that "only a few of

the European types have been tested, and none in ade-quately large numbers" (1910:33). The results presentedhere partly substantiate Boas's concern, as the test of HIfor the Poles, Scotch, and Hungarians and Slovaks wouldhave been unlikely to discover a difference in cephalic indexeven if one existed in these populations (observed power =.091, .402, and .479, respectively). Such low power valuesreflect the small effect size of the change in environmentover a single generation on cephalic index.

The significance of this reanalysis is demonstratedwell by the test of Boas's hypothesis that the influence ofthe U.S. environment on changes in head form increaseswith the duration of time elapsed between mother's immi-gration and child's birth (H2). Limited by the data process-ing technologies of his day, Boas was forced to reduce theduration of time to an ordinal variable with only two cate-gories. As the results presented here demonstrate, this ap-proach does not provide a powerful test of Boas's hypothe-sis. The accessibility of computing technology todayfacilitates a superior approach that treats the time elapsedbetween immigration and birth as a continuous predictorin a least squares regression model, and the results clarifyBoas's conclusions in two important ways.

First, the regression model demonstrates a linear rela-tionship between time elapsed and cephalic index; Boas in-ferred but could not establish such a direct effect. Inferen-tial statistics now give us confidence that this result isunlikely to be an artifact of chance. Second, the regressioncoefficients specify that this relationship is uniformlyweak across all groups: The time elapsed between mother'simmigration and child's birth explains less than two per-cent of the variation in cephalic index, although some ofthese associations are highly statistically significant. Theseanalyses serve as a reminder that, given sufficiently largesample size, we can demonstrate impressive statistical sig-nificance even in the absence of meaningful biological sig-nificance (Benfer 1968).

The lack of evidence for a strong association is not en-tirely surprising, given that time elapsed since mother'simmigration is only a rough proxy for the effect of manyunspecified intervening variables. However, it exposes animportant limitation of Boas's analysis. George Stocking

TABLE 5, Regression of age- and sex-standardized cephalic index on time elapsed and mother's stature, by immigrant group.

NTime Elapsed

PSEP

Mother's StaturePSEP

Adjusted R2

Model p

Bohemian862

-.099.032.004

.049

.004

.147

.009

.007

CentralItalian

786

-.068.036.056

-.031.006.379.003.117

Hebrew1,065

-.141.026.000

.007

.005

.828

.018

.000

Hungarianand Slovak

169

-.025.090.752

.003

.014

.972-.011

.950

Polish128

-.132.099.138

-.130.016.143.016.132

Scotch82

-.118.083.309

.157

.013

.177

.004

.321

Sicilian479

.098

.042

.032

-.008.007.868

.006

.097Note: Square-root transformation of time elapsed; p = standardized regression coefficient.

Gravlee, Bernard, and Leonard • Reanalysis of Boas's Immigrant Data 135

TABLE 6. Parent-offspring regressions for cephalic index of U.S.-and foreign-born descendants of immigrants.

Z 10 YearsMother-Offspring

bTSEN

.365

.353

.0261,428

Father-Offspring

bTSEN

.315

.326

.032819

Midparent-Offspring

bTSEN

.420

.411

.033819

U.S.-Born<10 Years

.360

.391

.0182,145

.335

.346

.0261,218

.405

.441

.0241,218

Total

.365

.379

.0143,787

.321

.336

.0182,517

.412

.431

.0192,156

Foreign-Born

.590

.570

.0172,508

.539

.534

.0201,782

.648

.643

.0201,511

Note: Regressions use age- and sex-standardized cephalic index fordescendants of immigrants; cephalic index is standardized sepa-rately for material, paternal, and midparental values; all correla-tions are significant at a = .001 level; subgroups of U.S. born do notadd to total because cases with missing values for year of mother'simmigration are excluded; b = unstandardized regression coeffi-cient; r = Pearson's correlation coefficient.

notes that "the most crucial positive evidence for the influenceof the U.S. environment was the fact that changes inphysical type varied directly with the time elapsed be-tween the arrival of the mother and the birth of the child"(1968:178, emphasis added). OUT analysis shows that thisevidence is actually quite weak. In addition, the reanalysisraises questions about potential bias as a result of missingvalues in tests of H2. Missing values in the ANOVA and re-gression analyses require us to exclude roughly thirteenand twenty-two percent of eligible cases, respectively. Wefound no evidence of a statistically significant differencein cephalic index between dropped and remaining cases,yet the extent of missing values weakens the evidence fora temporal effect of a change in environment on cranial form.

However, our analysis also provides new, more com-pelling evidence for the plasticity of head form. We useparent-offspring correlations and regression coefficientsto test Boas's conclusion that U.S.-born descendants aremore dissimilar to their immigrant parents than foreign-born descendants are to theirs (H3). To substantiate thisconclusion, Boas pointed to mean differences in cephalicindex between parents and both U.S.- and foreign-bornoffspring. This approach was sophisticated for its time, butthe parent-offspring regression provides a better, more di-rect measure of the similarity among parents and theirU.S.- and foreign-born children. As Boas hypothesized, ourresults show that children born in the U.S. environmentare markedly less similar to their parents in terms of headform than foieign-born children are to theirs (r = .412 andr= ,648, respectively). Moreover, inferential statistics prac-tically eliminate the possibility that this observation is aresult of random sampling error (p < .001 for all regressions).

This finding thus corroborates Boas's overarching conclu-sion that the cephalic index is sensitive to environmentalinfluences and, therefore, does not serve as a valid markerof racial phylogeny.

For each of the principal hypotheses, then, the appli-cation of new analytical techniques to Boas's data set over-comes some of the limitations in Boas's original analysisand provides new insight into the plasticity of head form.It is worth emphasizing that the limitations in Boas's analy-sis were imposed by data processing technology, not byhis lack of statistical sophistication. Indeed, Boas "broughtto his problems a greater degree of statistical knowledgethan practically anyone else concerned with human biol-ogy in America or Continental Europe" (Tanner 1959:78;see also Camic and Xie 1994; Xie 1988). In the days ofpencil, paper, and Hollerith machines, there were severetechnological constraints on the type of analysis onecould carry out. As Jantz and Spencer remark in their dis-cussion of Boas's Amerindian data, "the volume of data isenormous and difficult to handle even with modern com-puters" (1997:188). Additionally, statistics was a relativelyyoung discipline, and many of the methods that are nowstandard were not developed until well after Boas com-pleted the immigrant study.

Nevertheless, Boas understood the analytical prob-lems involved in his work, and he foresaw many of thetechniques we have used to extend his analysis. In 1894,Boas published an article in the AA in which he describedcorrelations between two anthropometric measurements.Two decades later he tried to estimate the hereditary com-ponent of head measurements and stature by comparingsibling and parent-offspring correlations, an attempt helater abandoned with concern over the number of simpli-fying assumptions (Boas 1940:82-85; Tanner 1959).

Boas was a pioneer in other techniques as well. Hersko-vits proclaims that "the most important contribution ofBoas to anthropometry" (1943:49) might turn out to be asimple formula that expresses, in a rudimentary way, theidea behind analysis of variance, which R. A. Fisher didnot work out until the 1920s (Agresti and Finlay 1997). By1916, Boas had already published an article in which heworked out the mathematical proofs to split total popula-tion variation into what we would now call between-group and within-group variance. Characteristically, Boashimself was the first to point out the tentative nature ofhis calculations, but he was sure a further elaboration ofthe method would enable us to attack the problem of he-redity and environmental influence (Herskovits 1943;Tanner 1959).

Yet even the normally cautious Boas was impressed bythe "wholly unexpected" finding of changes in the cephalicindex of descendants of immigrants. At the time he con-ceived the immigrant study, the prevailing view was thathumans could be divided into a number of distinct, fixedraces or types. The champions of this view were physicalanthropologists, who placed enormous value on the fixityof traits, particularly head form, to validate their elaborate

136 American Anthropologist • Vol. 105, No, 1 • March 2003

racial typologies. In this context, Boas's immigrant studywas revolutionary. His demonstration of plasticity in headform "laid to rest, forever, the belief that body charac-teristics were . . . only under hereditary control" (Littleand Leslie 1993:67). The old notion of race has been slowto die out, but Boas's study of immigrants and their chil-dren was a crucial step toward the development of themodern anthropological concept of race.

Other biological disciplines had long recognized theplasticity of organisms, but Boas's immigrant study wasthe first authoritative statement on human biological plas-ticity. Since then, plasticity has become an important con-cept in physical anthropology. In the 40 years after Boas'sstudy, at least 25 researchers conducted studies of plastic-ity and the environment (Kaplan 1954), and the effortcontinues up to the present day (e.g., Bogin and Loucky1997). John Allen has argued that Boas himself was notentirely clear about the meaning of the term:

With regard to the idea of plasticity, Boas could not tie theloose ends of this problem together without the analysis-of-variance technique, which would have provided themathematical justification he sought, or without a hierar-chical conception of gene and morphology. [1989:82]

Today we have both of the things that Allen says im-peded Boas's understanding of human plasticity. Analysisof variance is now taught in beginning statistics classes,and we have replaced Boas's understanding of genotypeand phenotype as mutually exclusive with a hierarchicalconception of the two. Even more sophisticated advancesin both statistics and human biology invite further explo-ration of Boas's data.

Indeed, Boas himself issued the invitation. In the briefintroduction to Materials Boas explained: "It seemed nec-essary to make the data accessible because a great manyquestions relating to heredity and environmental influ-ences may be treated by means of this material"(1928:viii). Given Boas's hope that others would tacklethese questions, we suspect Tim Ingold is right that Boas"would have been among the first to put his copious ma-terials on the web" (2001:398). Fortunately, we are now ina position to do so.

The availability of Boas's data set in an accessible for-mat makes further exploration feasible, and there remainmany new uses for the data. Among the priorities for futureresearch should be the study of familiar resemblances toestimate environmental influences on growth (Bogin 1999;Mueller 1986). Here it is important to emphasize that Boas'sdata set—"the largest collection of family measurementsever published" (Tanner 1981:250)—includes not only thehead form data but also measurements of stature, one ofthe most frequently examined traits in family studies.

The accessibility of Boas's data set also facilitates fu-ture research on the nutritional and hygienic status of theimmigrants and descendants in Boas's study relative tomodern-day populations and to their contemporaries inEurope and North America. Drawing on existing researchin historical anthropometries (Cuff 1995; Fogel 1986;

Komlos 1994; Tanner 1986), Boas's data can be examinedto learn more about the status of immigrants in their newhome, the effects of migration on growth, and the selec-tion involved in the process of migration. Boas himself an-ticipated such questions, even if he was unable to pursuethem (Boas 1910:28; Stocking 1974:202).

CONCLUSION

Even though Materials has been cited in a number ofprominent places (Allen 1989; Barkan 1992:82; Jantz andSpencer 1997; Tanner 1959, 1981), it remains relativelyobscure. When it is mentioned, it is generally regarded asan interesting historical fact, not as a vital source of re-search material. The relative obscurity of Boas's data is per-haps not surprising. As Stephen Jay Gould observed in TheMismeasure of Man, "Scientists are used to analyzing thedata of their peers, but few are sufficiently interested inhistory to apply the method to their predecessors. Thus,many scholars have written about Broca's impact, but noone has recalculated his sums" (1996:58).7 Of course,Gould could just as well have made this point about FranzBoas instead of Paul Broca, the 19th-century master of cra-niometry and scientific racism. In anthropology, Boas'simmigrant study is textbook material, widely cited as aturning point in the discipline's treatment of race. Yet, for90 years, no one recalculated his sums, even though Boastook the extraordinary step of publishing his original dataset as volume six of the Columbia University Contributionsto Anthropology.

We believe that the historical significance of Boas'simmigrant study makes the reanalysis of his data set im-perative. In this article, we have replicated Boas's analysisand tested his principal conclusions regarding the plastic-ity of head form. We conclude that, on the whole, Boaswas right, despite the limited analytical tools at his dis-posal. However, the strongest evidence that environmen-tal factors influence the cephalic index is not the direct as-sociation between cephalic index and the time elapsedbetween mother's immigration and child's birth, as pre-viously had been thought. Rather, it is the difference inparent-offspring correlations and regression coefficientsbetween U.S.- and foreign-born immigrant descendantsand their parents. This result provides new insight intothe immigrant study and helps us refine Boas's main con-clusions. There remain many questions to ask of Boas'sdata, and the effort to address them would be consistentwith Boas's own commitment to scientific method.

Renewed attention to Boas's relatively neglected workin physical anthropology is also timely and appropriate,given the increasing fragmentation of our discipline alongsubdisciplinary lines. The immigrant study is significantin part because it highlights Boas's fundamental concernwith process and individual variation, which integrates hiscultural and biological anthropology and sustains his cri-tique of biological determinism. At a time when the "grow-ing divide between physical and cultural anthropologists"

Gravlee, Bernard, and Leonard • Reanalysis of Boas's Immigrant Data 137

(Mukhopadhyay and Moses 1997:523) impedes researchon race and human diversity, we would be wise to adoptBoas's commitment to anthropology as an integrated sci-ence of humankind.

CLARENCE C. GRAVLEE School of Public Health, University ofMichigan, Ann Arbor, MI 48109-2029H. RUSSELL BERNARD Department of Anthropology, Univer-sity of Florida, Gainesville, FL 32611WILLIAM R. LEONARD Department of Anthropology, North-western University, Evanston, IL 60208

NOTESAcknowledgments. This material is based on work supported undera National Science Foundation Graduate Research Fellowship(CCG). We would like to acknowledge Christopher McCarty (Bu-reau of Economic and Business Research at the University of Flor-ida) and John Dominy for assistance in entering the data.1. At the time of writing, we were aware of only two partial reana-lyses: Morant and Samson's (1936) reanalysis of the East EuropeanHebrews data and Fisher and Gray's (1937) reanalysis of the Sicil-ian series. Shortly after submitting our manuscript for publication,we learned of a recent M.A. thesis (Sparks 2001) that analyzes4,668 individuals from Boas's data set. While our manuscript wasin press, Sparks and Jantz (2002) published their reanalysis of theimmigrant data in which they conclude that Boas was wrong.2. For the sake of clarity, we will generally cite the 1910 report.Unless otherwise noted, the same material can be found in the1912 final report to the Commission, which is more than fivetimes greater in length but contains little more in the way of text.3. For more on environmental influences on cranial form, seeBeals et al. 1984, Henneberg 1988, and Henneberg and Steyn 1993.4. Even so, the reliability of Boas's data need not be taken forgranted. Jantz et al. (1992:442) originally used the plotting methoddescribed above to detect measurement errors in Boas's Amerin-dian data. Using the same technique, we identified only a singleimplausible value; this case was in fact marked as suspicious inBoas's original material and is excluded from the reanalysis.Twenty-nine other dubious cases are excluded from the test ofBoas's conclusion that the influence of environment on head formincreases with time. These cases appear suspicious because they arecoded as U.S. born but produced negative values in the computa-tion of time elapsed between mother's immigration and child'sbirth. We should note also that the most serious critique of the re-liability of Boas's measurements came from R. A. Fisher and H.Gray (1937), who reanalyzed the Sicilian data. As far as we areaware, neither Boas nor anyone else ever responded to their criti-cism; John S. Allen (1989:83) seems to endorse it. We intend to ad-dress Fisher and Gray's analysis in a future publication using theentire data set, not just the Sicilian data.

5. We used the LMATRIX subcommand in SPSS 9,0 for Windows.6. Strictly speaking, it is the square of the part, rather than partial,correlations that reflect the proportion of variance in cephalic in-dex explained by time elapsed (Blalock 1964). However, in thiscase, the part correlations are practically identical to the partialcorrelations—and to the standardized partial regression coeffi-cients. For the sake of brevity, we do not present the correlationsseparately,7. Gould is not alone in recognizing the value of reexamining clas-sical data sets. Leon Kamin, for example, noted the improbabilityof Sir Cyril Burt's published results and launched an inquiry thateventually exposed Burt's astonishing fraud. Burt's studies of theheritability of IQ in separated twins had long been regarded as thegold standard among IQ researchers, largely on account of Burt'ssupposedly rigorous methods. We now know, however, that Burt'sinfluential work was based on a complete and utter fabrication ofdata and even of colleagues (Rose et al. 1984:101-106).

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