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The Twins Modern Lifestyle Essay

On the current American Jewish scene, one group stands out for its seemingly successful integration of traditional religious behavior and belief with full participation in modern society.

Consider the landscape. On the liberal side of the religious spectrum, Conservative Judaism, until recently the largest of the denominations, identifies itself as traditional, but only a minority of its adherents strive to observe the dictates of Jewish law (halakhah). As for more liberal movements, most of their members make no claim to be exemplars of traditional Judaism but rather regard themselves as advocates of—to invoke the names of the best-known movements—reform, reconstruction, or renewal. Meanwhile, at the opposite end of the continuum, one finds Orthodox groups that, while punctiliously observant, self-consciously insulate themselves to one degree or another from Western culture or explicitly reject the assumptions of modernity.

This leaves the sector known as Modern Orthodoxy. Relatively small in number, making up just 3 percent of American Jewry as a whole—and by no means comprising all who identify themselves as Orthodox—it alone seems to have found the sweet spot: a synthesis of the modern with traditional Jewish observance. Recent surveys, including Pew’s Portrait of Jewish Americans, make clear just how well the Modern Orthodox have combined both parts of their name.


1. Who Are the Modern Orthodox?

Organizing their family lives far more traditionally than do their liberal counterparts, the Modern Orthodox tend to marry earlier and to maintain a fertility rate well above replacement level; only small percentages intermarry. In order to insure the transmission of their religious commitments, they enroll nearly all of their children in the most immersive forms of Jewish education. Their synagogues, unlike most of those in the Conservative or Reform orbit, are teeming with regular worshipers every day of the week. Many sizable ones offer multiple prayer services every morning, afternoon, and evening, accommodating the busy schedules of individual worshippers. They also report rising numbers of men and women participating in study classes, and even of teenagers seeking out opportunities to learn on Sabbath afternoons. In a reinforcing loop, as one rabbi notes, “more intensive learning has created greater levels of observance.”

Synagogue life is further reinforced by the life of school and summer camp. Day-school attendance from early childhood through high school has become de rigueur for Modern Orthodox families. According to Pew data, 90 percent of those between the ages of eighteen and twenty-nine have attended a day school for at least four years—a much higher figure, incidentally, than the one for their parents or grandparents. The figures for summer camps are comparably impressive.

None of this would be feasible without financial resources. Nationally, according to Pew, 37 percent of Modern Orthodox households have incomes of over $150,000, a figure not matched by any other Jewish denomination. In the metropolitan New York area, home to the largest concentration of Orthodox Jews of all stripes, the Modern Orthodox contingent shows the largest proportion earning $100,000 or more and $150,000 or more.

This relative affluence makes it possible for some in the community to support key institutions with generous donations, including scholarship assistance for day-school families. It also means that a large majority are able to shoulder the costs of Jewish living. Only those with resources—and commitment—can afford to live within walking distance of synagogues, purchase kosher food products, pay membership dues and building-fund assessments to synagogues, and, most expensive of all, cover K-12 tuition costs in day schools and send their children to Orthodox summer camps. Despite this heavy financial burden, there is no evidence that significant numbers have opted for public schools—or decided to limit the size of their families.

Finally, none of this comes at the expense of active participation in American society. Just like their counterparts elsewhere in the Jewish community, the Modern Orthodox attend college and earn advanced degrees at far higher rates than most other Americans. Both men and women go on to work, as we have seen, in the more lucrative sectors of the American economy. Some rise to positions of great distinction in their fields of endeavor, including in American public life (e.g., Jack Lew, the current Secretary of the Treasury; Michael Mukasey, former U.S. Attorney General; and Joseph Lieberman, former Democratic nominee for the Vice Presidency).


In short, Modern Orthodoxy in America appears healthy and vibrant, with functioning communities not only in large metropolitan areas but in nearly every mid-size Jewish community and even some smaller cities like Indianapolis, New Orleans, Bangor, ME, and Worcester, MA. Given the movement’s successes—and the cachet of dynamism that attaches to it—one might expect its leaders to be in a mood to congratulate themselves.

And yet that is not the case. A close reading of what Modern Orthodox leaders are saying publicly, and even more bluntly in private, reveals a great deal of anxiety about current trends within their communities. (In what follows, I will be relying in part on interviews conducted on the understanding that quotations would not be attributed.)

The anxieties being voiced have partly to do with numbers. Although the majority of those raised Modern Orthodox remain in that camp, the community does suffer defections, leading to worries about the possibility of demographic decline. But it is not only the potential erosion of its population that agitates the movement. A battle now rages for its soul—a tug of war over both practices and ideas that is pitting rabbis against each other even as some lay people work to push their synagogues onto new paths. At bottom, this internal struggle is over nothing less than the foundational assumption of the movement: that it is indeed possible to combine fidelity to traditional Judaism with modern values and understandings.


2. Pressure from the Right

To grasp the dynamics of the current struggle, it is critical to understand that it is playing out against challenges from both the “traditional” and the “modern” side of the equation. (Specialists on Orthodoxy have sub-divided it into many more groupings than two, but these are the major ones.) I’ll begin with the traditionalist challenge, which derives from the increase and growing self-confidence of another sector within the larger Orthodox world itself. That sector comprises the haredim, often known in English as the “ultra-Orthodox.”

The haredi camp encompasses both a number of hasidic sects and the spiritual descendants of their no less pious historical antagonists: the mitnagdim, or opponents of Hasidism, since that movement’s emergence in the 18th century. In the metropolitan New York area, haredim tend to cluster in enclaves like Williamsburg, Boro Park, and Crown Heights in Brooklyn and certain neighborhoods of Queens, as well as Lakewood, New Jersey and a couple of upstate New York counties. Haredi communities also exist in such cities as Baltimore, Los Angeles, and Chicago. Wherever they are, the haredim have distinguished themselves not only by their aloofness from much of Western culture and learning, or by the wary distance they maintain in social interactions with Gentiles, but also by their self-segregation from their fellow Jews, emphatically including the Modern Orthodox—and precisely because of the latter’s accommodation of American mores, openness to the wisdom of the Gentiles, and willingness to interact with non-Orthodox Jews and their leaders.

Historical antecedents to the current stand-off between the modern and haredi sectors of Orthodoxy are not far to seek. During the mass migration of East European Jews at the turn of the 20th century, some rabbis strove to recreate the all-embracing religious culture of Eastern Europe in the New World setting. Jeffrey Gurock, the foremost historian of American Orthodoxy, labels these rabbis “resisters”—the main object of their resistance being the intrusion of American ways into their lives. Against them stood more moderate immigrant and native-born rabbis whom Gurock labels “accommodators.” Each group established its own rabbinic organization (or, in the case of the resisters, three separate organizations).

As the immigrant population adapted to America, the accommodating or Modern Orthodox position triumphed. Symptomatically, Modern Orthodox rabbis played an outsized role as chaplains during World War II; in the postwar era, the dominant face of American Orthodoxy was that of Yeshiva University-trained rabbis (and their counterparts at the Hebrew Theological College in Skokie, IL) who were joined together in the Rabbinical Council of America (RCA). The Modern Orthodox ideal was conveyed by the motto of YU, Torah u’madda, usually translated as Torah and secular knowledge or, more broadly, Western culture and learning. For second- and third-generation American Jews attracted to this synthetic ideal, the figure they looked to was Rabbi Joseph B. Soloveitchik, who embodied the ideal through his mastery of rabbinic texts and his broad knowledge of and continuing engagement with Western philosophy.

But even as Modern Orthodoxy reached the peak of its influence, an influx of Holocaust-era refugees from both Nazism and Communism gave a powerful boost to the resisters’ cause. The newcomers came with an ideology of separatism that had developed in Europe and found institutional expression in the Agudath Israel movement established in the early part of the century. As the haredi Rabbi Yaakov Weinberg of Baltimore’s Ner Israel yeshiva put it: “there is an ‘otherness’ to us, a gulf of strangeness that cannot be bridged, separating us from our compatriots.”

During the second half of the 20th century, the key lines of division hardened. The resisters were intent on rejecting much of “enlightened” Western culture—whose bankruptcy, in their view, had been exposed in the depravity of the Holocaust—and no less bent on insulating themselves from what they saw as the corrupting morals of secular modernity. The accommodators, for their part, while recognizing that not everything condoned by modern fashion was in sync with traditional Judaism, were open to absorbing “the best that has been thought and said,” regardless of its source. They flocked to universities and entered the professions, working side by side with non-Jews. They also maintained connections with Jews who were not traditionally observant but with whom they were prepared to work toward common ends. The most noteworthy common end was Zionism, which they embraced despite its largely secular leadership—a step shunned by the resisters, many of whom remain staunchly non-Zionist to the present day.


In the face of withering criticism hurled at them by their critics among the resisters, Modern Orthodox Jews insisted on the legitimacy of their way of life—stressing, in addition to the embrace of Zionism, the value of what Jews can learn from Gentiles; full participation in the larger society (bounded only by strict adherence to Jewish ritual observance); and the provision to girls and women of the same kind of Jewish education received by boys and men (though not necessarily in mixed-sex settings). As we have seen, this insistence paid off handsomely.

Now, however, several developments have combined to give rise to a well-founded anxiety. One source of concern, alluded to above, is demography. Just a few decades ago, the modern sector constituted the large majority of Orthodox Jews; in our time, it has become vastly outnumbered by the Orthodox resisters and is on track to decline even further. As compared with the 3 percent of American Jews who (according to Pew) identify themselves as Modern Orthodox, 6 percent identify themselves as haredi. In absolute numbers this translates into an estimated 310,000 adult haredim compared with 168,000 adult Modern Orthodox.

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The disparity only widens when we look at younger age cohorts. Whereas those raised Modern Orthodox constitute 18 percent of American Jews over sixty-five, they represent only 2.9 percent of those between eighteen and twenty-nine. Something closer to the reverse holds among those raised haredi, who constitute only 1.6 percent of Jews aged sixty-five and older but rise to 8 percent of the eighteen-to-twenty-nine-year-olds.

And then there are the children. A 2011 population study of Jews in the New York City area estimated the number of haredi children at 166,000, roughly four times the number of Modern Orthodox children. Marvin Schick, who used different categories in a 2009 national census of day schools, counted 125,000 children in haredi schools versus 47,000 in Modern Orthodox and so-called Centrist Orthodox schools. (The latter subgroup eschews coeducation in its middle schools and high schools.) Since then, by all accounts, the numbers of haredi children have only increased.

To be sure, this is not the only circumstance depleting the numbers of Modern Orthodox Jews in the United States. Another one, ironically, stems from the movement’s great success in imbuing its young with Zionist values. Precise numbers are lacking, but by some estimates as many as 20 percent of Modern Orthodox youngsters who spend a year or more in Israel during the “gap” between high school and college end up making their homes there for at least some period of time. Needless to say, settling in Israel is socially and religiously approved behavior within the Modern Orthodox world; but that does not diminish its demographic impact on the community as a whole.

Still another worrying sign is the not insignificant rate of defection to more liberal movements. Thus, among those between the ages of thirty and forty-nine who have been raised Modern Orthodox, fully 44 percent have moved religiously leftward; among those between eighteen and twenty-nine, 29 percent no longer identify as Orthodox. (The commentator Alan Brill may have been the first to coin the term “post-Orthodox” for this population.) True, as noted above, Modern Orthodoxy is much more successful than liberal denominations at retaining its members, and it continues to attract from them as many as it loses; but the losses hurt.


If the relatively static size of their community, and the sheer demographic heft of the haredim, afford grounds for worry about the long-term viability of the Modern Orthodox way of life, beyond this concern lies another, related one: what some Modern Orthodox rabbis describe as a crisis of confidence among their laity. A salient symptom of that crisis, visible even among some otherwise highly acculturated Modern Orthodox families, is the decision to gravitate rightward toward haredi or semi-haredi schools and synagogues. Such families are driven, contends one of their rabbis, by “religious insecurity and feelings of guilt about that insecurity.” This rabbi therefore sees his role as twofold: insisting on the validity of modern Orthodoxy even as he encourages his congregants to intensify their commitment and practice. As he admits, it is a difficult balance to negotiate, and for some it does not suffice. Another rabbi, voicing exasperation over the rightward drift in his community, musters sarcasm to describe his congregants’ perceptions: “If you are not [religiously] serious, you go to my shul; if you are more serious, you go to more right-wing shuls because there are communal advantages to being there.”

As it happens, the Pew data suggest that the movement rightward may be balanced by a movement of haredi Jews traveling in the opposite direction. Moreover, those joining “right-wing shuls” do not generally move into haredi communities. It would thus be more accurate to see the so-called “slide to the right” as a matter less of massive defections to the haredi camp than of a shift within Modern Orthodoxy, led in this instance by those inclined to adopt aspects of haredi life while remaining nominally Modern Orthodox.

In some cases, the “slide” takes merely symbolic or token form, as when men wear black hats during prayer and women adopt haredi-style head coverings while otherwise continuing to maintain their very modern style of life. More significant, and much more distressing to stalwarts of Modern Orthodox values, has been the assimilation—some would say infiltration—of a “neo-haredi” worldview into some of the movement’s key institutions.

Since the passing of Rabbi Soloveitchik from the scene some 30 years ago, the Yeshiva University world has lacked an authoritative figure who personifies for the broader public the synthesis proclaimed in YU’s motto of Torah u’madda. Meanwhile, a neo-haredi group of roshei yeshiva—the term, often translated as deans of talmudic academies, more accurately connotes advanced teachers of rabbinic texts—has planted its flag at YU’s Rabbi Isaac Elchanan Rabbinical Seminary (RIETS), which educates, ordains, and shapes the religious and halakhic worldview of Modern Orthodox rabbis. In addition, Modern Orthodox day schools often employ haredi teachers who likewise communicate their ideology to impressionable students and may encourage them after graduation to attend an Israeli yeshiva or girls’ seminary where neo-haredi perspectives predominate. Of late, some long-time Modern Orthodox synagogues have also taken to hiring haredi or neo-haredi rabbis to fill their pulpits. And the community as a whole has become dependent on haredim who fill certain ritually critical roles, including as scribes who write Torah scrolls and other religious documents, kosher slaughterers, and supervisors of kosher food production.

Most subversive of all has been the internalization of the idea that haredi Judaism represents the touchstone and arbiter of Orthodox authenticity, period. This has placed Modern Orthodoxy on the defensive, handcuffing it to a way of thinking at odds with its founding assumptions. Willy-nilly, by absorbing the resistant mindset, important sectors of the movement have thereby undermined Modern Orthodoxy’s accommodative ideology and, worse, have made it more difficult to help their members navigate as observant Jews who embrace modern culture.


3. Pressure from the Left

If the challenge represented by the haredim exerts pressure on modern Orthodoxy from one direction, another and equally great challenge makes itself felt from the opposite direction. To Rabbi Yitz Greenberg, speaking at a recent forum on the Pew study, Modern Orthodox Jews live “on the same [cultural] continuum” as their non-Orthodox counterparts, being no less “exposed to the attractions of modernity and the acids of skepticism/historical criticism/social mores,” and no less likely to succumb to those twin forces, both the “attractions” and the “acids,” than are Conservative, Reform, or for that matter non-affiliated and secular Jews. Rabbi Greenberg even attributes the “demographic decline” of the movement primarily to this factor.

Actually, as we have seen, the problem is not (or not yet) one of serious decline but rather of demographic stasis. But there can be no doubt that Modern Orthodox Jews have become at least as alert to the most controversial issues roiling their movement from the Left as from the Right. To adapt Jeffrey Gurock’s nomenclature of resisters versus accommodators, which he applied to the struggle within the larger Orthodox world between the haredim and the Modern Orthodox, we may say that Modern Orthodoxy itself is now beset by a no less bitter or momentous struggle: between its own internal resisters attracted by haredi Judaism and accommodators more willing to adapt Jewish law to 21st-century ethical sensibilities.

Undoubtedly, the most hotly debated set of issues concerns the status of Orthodox women. Sexual equality is now taken for granted in most Modern Orthodox homes, and holding males and females to different standards is increasingly unthinkable. Under the circumstances, why should it not occur to some girls that they too might don t’filin (phylacteries), traditionally the accoutrements of male worship? How much Torah and Talmud ought girls and women be encouraged to study? May women serve as synagogue presidents? May they conduct their own prayer services, lead parts of mixed services, or wear t’filin during public worship? And, drawing the greatest heat: what are rabbis prepared to do to release “chained” women (agunot), whose husbands have refused to grant them a proper writ of divorce?

Other debates center on the proper treatment of homosexuality and homosexuals in the Orthodox community; how the community should relate to non-Orthodox Jews; the authority exercised by the Israeli chief rabbinate in matters pertaining to American Orthodox Jews; the authority of congregational rabbis vis-à-vis that of roshei yeshiva; the latitude, if any, for interpreting the theological category of “Torah from Heaven”—i.e., the belief that the Torah was dictated verbatim by God to Moses; and more.

In short, the same culture wars that have engulfed non-Orthodox Jews, Catholics, and Protestants now rage in the modern-Orthodox world.

This is not the place to discuss the complex legal and theological arguments on these issues advanced by different rabbinic authorities. Suffice it to say there are deep differences over who is credentialed to issue legal rulings and how flexible is Jewish law. On one side, Modern Orthodox resisters argue they are constrained by halakhic precedent even when it comes to mitigating the suffering of agunot. On the other side, accommodators tend to interpret Jewish law as in some degree subject to historical circumstances; Blu Greenberg, the preeminent leader of Orthodox feminism, has encapsulated this view tersely, declaring that “where there’s a rabbinic will, there’s a halakhic way.” Many advocates of new thinking see the principal driver of change as the larger Orthodox community, with rabbis lagging behind.


While such disagreements on matters of Jewish law occupy the foreground, a series of cultural forces in the background are seen by all as shaping current debates.

Rabbinic authority is waning. Rabbis across the spectrum of Modern Orthodoxy, resisters and accommodators alike, point to a community that has absorbed American understandings of the sovereign self. “What rabbis say does not matter,” is a refrain I have heard repeatedly. “Authority is in retreat,” declares one rabbi; says another, “People like traditional davening (prayer) and singing; but when it comes to halakhah impinging on them, then they resist.” In one haredi school, the head of Jewish studies states without any prompting, “In today’s age, the model of rabbinic authority does not exist. We don’t live in ghettoes anymore, so you have to reach students where they are. Saying ‘because it is so’ no longer works.”

In private conversation, the same lament recurs regardless of ideological position, although some go on to lay the blame for the loss of rabbinic authority on their opponents. On the accommodative side, the prevailing sentiment is that hidebound rabbis have brought this situation on themselves because, when it comes to the demands of modernity, they are “oblivious and clueless.” From the resisters, one hears that the accommodative wing has undermined the authority of recognized legal decisors by running to peripheral figures who are only too willing to approve innovations. Many sense their loss of authority so keenly that they shy away from asserting their views on the major cultural issues of the day even when they personally feel strongly about them.

Accelerating these trends is the new reality of the Internet. Thanks to it, states one rabbi, “everybody has a right to have a position; everyone has a de’ah [opinion] about everything.” Educated Jews can look up answers to their own questions and choose from the answers available online. Many feel empowered in this role simply by dint of their day-school education and by the time they have spent studying in Israel, even as they are also encouraged by modern culture’s stress on individual autonomy to act according to the dictates of their conscience.


In this connection, day schools themselves are faulted by some for inadequately preparing their students to cope with the intellectual and moral challenges they encounter once they enter college. Rabbis on both sides agree that the failure lies in the deliberate neglect of questions of belief, theology, and the “why” of observance. From my own visits to Orthodox day schools, I question this critique. To me the problem seems more fundamental: there is no way fully to prepare Orthodox young people for the transition from their insular and homogeneous environment to the environment of the university, where the reigning values are so at odds with traditional Judaism. Be that as it may, however, efforts to remediate the situation are being made by rabbis in both the resistant and accommodative wings who are undertaking to teach their congregants about what is relevant and meaningful in Judaism rather than focusing solely on the study of texts. “I used to give heavy-duty classes on rishonim and aharonim,” one rabbi on the side of the resisters informed me, referring to classical rabbinic commentators. “Now I teach about derekh eretz [proper behavior], women and ritual observance, and tz’dakah [Jewish giving].”

One thing is certain: an estimated 70 percent of Modern Orthodox college students are enrolled in secular institutions of higher learning, and the impact of their experience there cannot be ignored. True, many of the parents and grandparents of current students also attended secular colleges, but it can be postulated that academic values and assumptions have changed since then, or that they are instilled far more explicitly than they were in the past, or both. On every campus today, incoming students are required to attend an intensive orientation program during which they are exposed to strongly formulated judgments about diversity, tolerance, and correct thinking. In this hothouse atmosphere, how is it possible for Orthodox students to argue in defense of the unequal treatment of women in the domain of religious observance? Can one conceivably emerge from a college experience today without having encountered attitudes toward sexual behavior at odds with traditional Orthodox beliefs?

Making it still harder to shelter today’s Modern Orthodox Jews is that they have strayed beyond the commuter colleges favored by an earlier generation. Once on campus, moreover, they are also less likely to shy away from courses on sexual roles, psychology, comparative religion—or modern biblical criticism—that will challenge views they absorbed during their day-school years and from their elders.


As with the challenge from the haredim, so with the challenge from “modernity,” one can trace the effects on the institutional level as well as the personal. Acknowledging the seriousness of both challenges, some among Modern Orthodoxy’s accommodative leaders and activists, male and female alike, have been pushing to reinvigorate and reinforce the movement’s founding ethos from within. To generalize, one might say that these efforts are aimed simultaneously at fending off the inroads of “haredization” and at incorporating, to some unspecified degree, the “open” ethos of modern liberal culture.

In 1996, an organization, Edah, was founded with that just that dual purpose in mind. Its leader, Rabbi Saul Berman, issued a pamphlet spelling out “a variety of Orthodox attitudes to selected ideological issues”—with the emphasis on “variety.” The issues ranged from the treatment of women in Jewish law to the meaning of Torah u’madda, from pluralism and tolerance within Orthodoxy to outreach aimed at non-Orthodox Jews. A year later, Edah was joined by the Jewish Orthodox Feminist Alliance (JOFA), whose declared mission is to advance “social change around gender issues in the Orthodox Jewish community.”

Although Edah folded after a decade, JOFA continues with its work. And in the meantime, a number of other institutions and initiatives have arisen, each dedicated to fostering change in the Modern Orthodox world. They include Yeshivat Chovevei Torah (YCT), an accommodative rabbinical seminary competing with YU’s RIETS, and Yeshivat Maharat, which styles itself as the “first institution to ordain Orthodox women as clergy”; both of these institutions are associated with a camp that has come to be called Open Orthodoxy. Allied with them is the International Rabbinical Fellowship, whose announced aim is to stand up for “the right, responsibility, and autonomy of individual rabbis to decide matters of halakhah for their communities.”

In the same orbit, if not necessarily of the same mind, are women-only prayer groups as well as “partnership minyanim” where men and women share the responsibility of leading different parts of the prayer services in a manner deemed acceptable to select rabbinic authorities. To disseminate new thinking, Modern Orthodox bloggers have been busy putting forth more “progressive” perspectives. One of them, the website TheTorah.com, grapples with the findings and conclusions of modern biblical scholarship, long regarded as inherently inimical to the teachings of traditional Judaism.

It is not unusual for some Modern Orthodox Jews and their rabbis to pick and choose among these activities. Members of women’s prayer groups, for example, may confine themselves to that initiative alone. Some students at YCT may support partnership minyanim while others do not. Some students at YCT and Yeshivat Maharat decline to identify themselves personally with Open Orthodoxy. Interestingly, it has been estimated that as many as 40 rabbinical students at RIETS itself would participate in a partnership minyan even though several of the leading talmudists at that institution have unequivocally proscribed such prayer services.

In sum, it is problematic to assume that individuals, even if they share a willingness to stretch the boundaries of Orthodoxy, form part of a common accommodative camp. Nor is it possible to quantify the number of Modern Orthodox Jews sympathetic to any of these efforts, though most observers assume it is relatively small and limited to a few centers of liberal thinking in New York, Washington, Boston, and Los Angeles. Still, just as it means something that Modern Orthodox congregations in, for example, St. Louis and Kansas City have sought out women to serve in a quasi-rabbinic role, it seems safe to assume that the 85 or so rabbis ordained so far at YCT and now occupying positions on campuses, in day schools, in chaplaincies, and in pulpits all around the country have had an impact of their own. The same can be said for the ideas making their way into every corner of the Modern Orthodox community through the reach of the Internet.


4. Toward a New Synthesis?

The most basic consequence of these cumulative changes is an increased awareness that the ground is shifting. As one observer has put it, “everyone knows the lines are moving.” The same individual notes how, “in shuls, people talk about how far to the Right modern Orthodoxy has gone.” Meanwhile, for those opposed to Open Orthodoxy, the ground is similarly perceived to be shifting, albeit in a distinctly different if not heretical direction.

The discomfort has led some rabbis to speak of a widening chasm within the movement and the inevitability—if not the desirability—of a schism. On the resisters’ side, those insisting that lines must be drawn have mostly limited themselves to fighting against new practices rather than ostracizing people, although, in a few synagogues, men who participate in partnership minyanim have been banned from leading services in their home congregations, and there are concerted efforts to bar YCT graduates from being hired by major Modern Orthodox synagogues. Some resisters have also taken to dismissing their opponents as closet Conservative Jews; to one prominent rabbi, the Open Orthodox should be known as “the observant non-Orthodox.”

For their part, advocates of Open Orthodoxy have shown little hesitancy about castigating their traditionalist opponents as reactionaries. Resentment toward Yeshiva University boils over in statements that the institution has fallen under the sway of rabbis with no understanding of today’s world and has become intellectually bankrupt. By contrast, Open Orthodox rabbis pride themselves on their hospitality to those who are not Orthodox. “We create an open space and do not say ‘no,’” one leader declares. Another draws the distinctions differently: “YU is modernist; [its people] think they are right. They draw lines in the sand. YCT people are post-modern. We see no conflict between intellectual openness and using critical tools, even as we remain committed to halakhah.”

And then there are those in the middle who feel sympathy for both sides and want a peaceful resolution that will keep everyone in the same camp. At a celebration of recent RIETS ordainees, a keynote speaker emphasized a single theme: we at YU are open; we have always stood for openness. Was this a peace offering to the progressive side of the spectrum, another salvo in the battle over legitimacy, or perhaps both? Others watch in embarrassment as “the hotheads” denounce each other. In most quarters, there is a sense that the current situation is unsustainable.


Of course, it is possible to view the factionalism within Modern Orthodoxy as a sign of vitality. Thus, one might say that differences have arisen because those on each side, equally committed to the Jewish future, are alarmed by the unhelpful ideas or policies being promoted by their counterparts on the other side. One might even remark that, in the fastidiously “non-judgmental” climate prevalent today in the rest of the American Jewish community, it is refreshing to encounter Jews prepared to stake a claim to what they see as true, necessary, and obligatory.

Worth noting, in any event, is that the programs and institutions spawned by rival factions are stimulating a welcome spirit of creativity. As Yehuda Sarna, the rabbi of New York University’s Bronfman Center, has observed, “There are multiple Torah and college options, multiple rabbinical schools, multiple forms of Orthodox Zionism, multiple ways of engaging with modernity, multiple entry and exit points to the community.” One merely has to cite the range of Orthodox websites issuing commentaries on the weekly Torah portion, and compare those offerings with the paucity of non-Orthodox counterparts, to appreciate the dynamism. The same can be said about bloggers in all sectors of the Modern Orthodox community who address everything from matters of theology to preparing brides for their wedding night.

Moreover, despite conflicts over practices, Modern Orthodox Jews of all stripes observe the same religious common core—daily prayer, kosher food restrictions, laws of family purity, Sabbath and festival celebrations. In fact, one of the contentions of the accommodators is that they are in no danger of going the way of Conservative Judaism precisely because, whereas the Open Orthodox live and work in religiously observant communities, Conservative rabbis historically made legal decisions for communities that did not observe Jewish law. Open Orthodoxy can experiment with new ideas and interpretations, they contend, because the commitment to Jewish law will keep them and their followers in check.

In “The Rise of Social Orthodoxy,” a recent essay in Commentary, Jay Lefkowitz put this perspective succinctly: “I imagine [that] for many others like me, the key to Jewish living is not our religious beliefs but our commitment to a set of practices and values that foster community and continuity.” Assumed in this formulation is that practices and values will remain unaffected by changing beliefs. But is that right? In fact, as we have seen, a whole set of core Modern Orthodox assumptions is under assault both from forces outside Modern Orthodoxy and from the partisans of those forces within, and there is considerable evidence that some practices, and even some values, are changing as a result.

Thus far, the Modern Orthodox world has managed to flourish and persist by creating a community of practice and by focusing most of its intellectual energy on intensified Talmud study. This is not to be minimized. The movement’s vibrant communal life, high levels of observance, and serious engagement with traditional texts are monumental achievements. But, caught as Modern Orthodoxy is between the absolutism and insularity of haredi Judaism and the realities of an open and radically untraditional American society, are those achievements sufficient to retain a population well integrated into American life and profoundly influenced by its mores, assumptions, and values?

The urgent question for Modern Orthodoxy is which values can be accommodated without undermining religious commitment and distorting traditional Judaism beyond recognition—and, conversely, what losses will be sustained if Modern Orthodoxy should undertake more actively to resist the modern world in which its adherents spend most of their waking hours. The same urgent question, mutatis mutandis, has confronted other Jewish religious movements in the past, and has continued to haunt their rabbis and adherents long after they made their choice of a path forward. That is one reason why today’s unfolding culture wars within Modern Orthodoxy carry far-reaching implications not only for that movement but for the future of American Judaism as a whole.


NOTE: My thanks to the following rabbis who agreed to off-the-record interviews for this essay: Saul Berman, Avi Bossewitch, Yonatan Cohen,  Zev Farber, Jeffrey Fox,  Barry Freundel, Kenneth Hain, Yosef Kanefsky, Bob Kaplan, Dov Linzer, Yechiel Poupko, Steven Pruzansky,  J.J. Schacter, Uri Topolosky, Kalman Topp and Daniel Yolkut. I also interviewed Maharat Ruth Balinsky and Elana Stein Hain. And I benefited from conversations with Rabbi Yitz Greenberg, Professor Benjamin Gampel, Dr. Larry Grossman, Jay Lefkowitz, and Ruthie Simon. I’m very grateful to fellow participants in the Oxford Summer Institute in Modern and Contemporary Judaism, where an earlier draft of this essay was discussed. Special thanks to Steven M. Cohen, who ran copious data for me and helped me parse them.


  1. The Unresolved Dilemmas of Modern Orthodoxy by Jack Wertheimer
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  4. Why Modern Orthodoxy Is in Crisis by Adam Ferziger
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Stress pervades our lives. We become anxious when we hear of violence, chaos or discord. And, in our relatively secure world, the pace of life and its demands often lead us to feel that there is too much to do in too little time. This disrupts our natural biological rhythms and encourages unhealthy behaviours, such as eating too much of the wrong things, neglecting exercise and missing out on sleep.

Racial and ethnic discrimination, along with lack of educational opportunities and economic advancement take their toll on a large segment of the population in the United States. Incarceration is the rule rather than the exception for some of the most vulnerable. Adverse experiences in infancy and childhood, including poverty, leave a lifelong imprint on the brain and body, and undermine long-term health, increasing the incidence of cardiovascular disease, diabetes, depression, substance abuse, anti-social behaviour and dementia. How does all of this stress ‘get under our skin’? What does it do to our brains and our bodies? What can we do about it? And is stress so multifaceted and pervasive that we could have trouble controlling it at all?

The psychologist Jerome Kagan at Harvard University recently complained that the word ‘stress’ has been used in so many ways as to be almost meaningless; he suggests it’s warranted only for the most extreme circumstances or damaging events. But my decades of experience suggest another approach. The insidious power of stress to ‘get under the skin’ was the focus of a MacArthur Foundation Research Network that I joined more than two decades ago, uniting me with social scientists, physicians and epidemiologists around a common problem: how to measure and evaluate stress from our social and physical environments. Our collaboration, continued under the auspices of the National Scientific Council on the Developing Child, has shown that stress acts on the body and brain, profoundly influencing health and disease.

Our findings are nuanced, starting with the fact that not all stress is the same. ‘Good stress’ involves taking a chance on something one wants, like interviewing for a job or school, or giving a talk before strangers, and feeling rewarded when successful. ‘Tolerable stress’ means that something bad happens, like losing a job or a loved one, but we have the personal resources and support systems to weather the storm. ‘Toxic stress’ is what Kagan refers to – something so bad that we don’t have the personal resources or support systems to navigate it, something that could plunge us into mental or physical ill health and throw us for a loop.

Now let us put these three forms of stress into a biological and behavioural context by invoking ‘homeostasis’ – the physiological state maintained by the body to keep us alive. It is through homeostasis that we maintain body temperature and pH (alkalinity and acidity) within a narrow range, keep our tissues perfused with oxygen and our cells fed. To maintain this steady state, our body secretes hormones such as adrenalin. Indeed, when we encounter an acute perceived threat – a large, menacing dog, for example – the hypothalamus, at the base of our brain, sets off an alarm system in our body, sending chemical signals to the pituitary gland. The pituitary, in turn, releases ACTH (Adrenocorticotropic hormone) that activates our adrenal glands, next to our kidneys, to release adrenalin and the primary stress hormone, cortisol. Adrenalin increases heart rate, blood pressure and energy supplies; cortisol increases glucose in the blood stream and has many beneficial effects on the immune system and brain, among other organs. In a fight-or-flight situation cortisol moderates immune-system responses, and suppresses the digestive system, the reproductive system and growth processes, as well as signalling brain regions that control cognitive function, mood, motivation and fear.

Biochemical mediators such as cortisol and adrenalin help us to adapt – as long as they are turned on in a balanced way when we need them, and then turned off again when the challenge is over. When that does not happen, these ‘hormones of stress’ can cause unhealthy changes in brain and body – for example, high or low blood pressure, or an accumulation of belly fat. When wear and tear on the body results from imbalance of the ‘mediators’, we use the term ‘allostatic load’. When wear and tear is strongest, we call it allostatic overload, and this is what occurs in toxic stress. An example is when bad health behaviours such as smoking, drinking and loneliness result in hypertension and belly fat, causing coronary artery blockade. In short, the mediators that help us to adapt and maintain our homeostasis to survive can also contribute to the well-known diseases of modern life.

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The word stress is often explained as a ‘fight-or-flight response’. But what really affects our health and wellbeing are the more subtle, gradual and long-term influences from our social and physical environment – our family and neighbourhood, the demands of a job, shift work and jet lag, sleeping badly, living in an ugly, noisy and polluted environment, being lonely, not getting enough physical activity, eating too much of the wrong foods, smoking, drinking too much alcohol. All these contribute to allostatic load and overload through the same biological mediators that help us to adapt and stay alive.

Even though we now know all this, we often hear that measuring our cortisol levels will tell us if we are stressed. This reflects a misunderstanding at two levels. First, a single measure of cortisol will tell us nothing since cortisol levels go up and down within minutes – and halting this fluctuation impairs ongoing adaptive plasticity within the brain. Moreover, cortisol fluctuates throughout the day, going up in the morning to awaken us and then declining, except for a rise at lunch time, until it falls to low levels in the evening before we go to bed. Flattening this diurnal rhythm is a consequence of sleep deprivation and certain forms of major depression; a flat rhythm not only attenuates a robust, adaptive cortisol stress response but it also promotes obesity and high cholesterol, risk factors for diabetes and cardiovascular disease. It does so in part by causing the liver to make the ingredients to deposit body fat.

Cortisol is not the ‘bad guy’: it has a normal physiological role, coordinating the metabolism with activity and sleep

There are several ways to measure cortisol to determine whether the normal daily rhythm has been derailed. We can collect urine overnight or over the day. We can measure cortisol in hair from the forehead, which gives an index of our cortisol production over days. Or we can measure cortisol in our saliva at multiple times during the day, or before, during and after a stressful challenge, such as talking about something personal before a group of strangers. The stressful challenge gives us a picture of the efficiency of our allostasis – marked by turning up our cortisol response when challenged and needed for adaptation to maintain homeostasis, and then turning it off when the stressor is over so as not to produce adverse effects of allostatic load and overload.

Failure to turn on cortisol when needed is bad, leaving the door open for the body’s inflammatory response to compensate in an imperfect way. Too much inflammation can kill us as in septic shock. Failure to turn off cortisol after the stress is over produces negative effects too. Among the consequences are an increase of fat production, leading to obesity, diabetes, depression and eventual heart disease – all contributors to allostatic load.

Given our need for a robust cortisol response in the face of stress, the second misunderstanding about cortisol is the notion that it’s the ‘bad guy’. Rather, cortisol has a normal physiological role; it helps us adapt to stressors and coordinates our metabolism with daily activity and sleep patterns. We would not live very long or well without our cortisol! As my former student Firdaus Dhabhar, now a neuroimmunologist at the University of Miami, found, the early morning rise of cortisol, along with the stress response, activates immune function so that we can fight an infection or repair a wound. Likewise, the normal ‘morning awakening’ rise of cortisol that helps rouse us and makes us hungry for breakfast enhances the body’s response to immunisation if administered in the morning. The body’s response is like an orchestra involving many players working in harmony.

If the body functions like an orchestra, the conductor is the brain. It stores memories from bad as well as good experiences, and works with the body to keep us alive by minimising those subtle and long-term influences that cause allostatic load and overload. What we call the ‘wisdom of the body’ refers back to allostasis, the active process of biological adaptation and its role in maintaining homeostasis. Indeed, the brain is a plastic and vulnerable organ, continually sculpted by experience. It changes its architecture and function as part of allostasis. One recent study shows how the brain architecture of a mother is sculpted during pregnancy as part of the formation of attachment to the child. Other studies show how musicians’ brains develop, with greater skill leading to an increased neuron size and enhanced connections between sensory and motor-control regions of the cerebral cortex.

As opposed to motherhood and musicianship, toxic stress can increase anxiety by causing neurons in the amygdala, a brain region controlling anxiety and aggression, to become larger. Mindfulness practices such as meditation can reverse the process and reduce the size of those neurons, along with the stress. And regular physical activity, such as walking every day, causes genesis of new neurons in the hippocampus, a brain region that is essential for daily memory and spatial orientation; and it also improves memory and mood.

We also need to consider where our genes fit in, and understand that they do not rigidly determine our destiny, but rather provide the foundation on which our experiences shape our brains and bodies over the life course via ‘epigenetic’ mechanisms, which operate ‘above the genome’ – controlling the expression of genes without changing the genetic code. Epigenetics drives the seamless integration of experiences, both good and bad, acting on our genetic code over our life course. We now understand that epigenetics is the means by which stress acts on the body, the genome, and the brain.

My life’s work has helped me to tell the story of stress, starting with the mentors for my dissertation, completed in 1964. These two Rockefeller University scientists, Vincent Allfrey and Alfred Mirsky, taught me the fundamentals of epigenetics in the 1960s, before there was much interest in it, and when epigenetics meant something quite different, namely, the emergence of characteristics as a fertilised egg developed into a living organism. Development from embryo to independence is programmed into each species, but the individual characteristics that emerge are influenced by experience, and that is where the modern use of ‘epigenetics’ comes from. An example of this is a pair of identical twins with genes that predispose them to schizophrenia or bipolar illness. Even with the same DNA, the probability that one twin will develop the disease when the other twin gets it is only in the range of 30-60 per cent, which leaves plenty of room for experiences and other environmental factors to either prevent or precipitate the disorder.

Allfrey and Mirsky studied proteins called histones, which package and order DNA. Histones can be chemically modified to unwind the double helix, allowing genes to be expressed. Around 1960 , researchers showed that hormones such as cortisol and oestradiol used this mechanism to turn on genes in the uterus and liver, and this became a focus of my work in 1966.

In conditions of toxic stress, the same organs of the body are targeted for damage 

Before long, I had changed my focus from the liver to the brain. As with cortisol in the liver, hormones of the adrenals and gonads could alter gene expression in the brain, working synergistically with other biochemical mediators to alter brain structure and function. Because experience itself affected these hormones, experience moulded what was now called the ‘epigenetic effects’.

This led to the finding that the adrenal stress hormone cortisol acts epigenetically on a brain structure called the hippocampus, which we now know mediates memory of daily events in space and time and also regulates mood. In other words, the hippocampus is a ‘GPS’ of the brain, a discovery that in 2014 saw the Nobel Prize awarded jointly to the UK-based neuroscientist John O’Keefe and the Norwegian scientists May-Britt Moser and Edvard Moser.

The hippocampus has since become a gateway into learning how sex hormones, metabolic hormones and stress hormones enter the brain, bind to receptors and act epigenetically to positively regulate structure and affect our behaviour. It has also helped us study conditions of toxic stress, when the same hormones and mediators contribute to allostatic overload; when that happens, the organs of the body, including the heart and the brain, are targeted for damage in a toxic storm.

Over the course of decades, my laboratory participated in, and in some cases initiated, these discoveries with the help of some remarkable students, postdoctoral fellows and colleagues. Among them was Ron de Kloet, now a professor at the University of Leiden, who studied the impact of synthetic glucocorticoids, which serve as potent inhibitors of inflammation and immune function, and stimulators of liver glucose metabolism (hence the name ‘glucocorticoid’). Cortisol is a natural glucocorticoid, and de Kloet found that synthetic glucocorticoids such as the medication dexamethasone (DEX) are actively excluded from the brain while cortisol gets in. But when a medication is given to quell inflammation, it can shut off the body’s ability to make cortisol. Then, when DEX treatment is terminated, the body and brain become deficient in cortisol, causing terrible mood swings and metabolic and immune disruption. After that, de Kloet went on to show, in his own laboratory with his student Hans Reul (now professor at the University of Bristol) that cortisol in the hippocampus binds to two receptor types, called MR and GR, to produce its myriad of important actions in the brain.

Another important advance was made by a student in my laboratory, Robert Sapolsky, now a professor at Stanford and a well-known author of a number of books, who found that, over the lifespan of a rat, the cortisol equivalent in the rat – corticosterone – gradually causes ‘wear and tear’ on the hippocampus, impairing not only memory and mood but also the ability to shut off the production of its glucocorticoids. This effect is more evident in animals and people who have experienced toxic stress. The ‘glucocorticoid-cascade hypothesis of stress and ageing’, as it is called, was the basis for the concept of allostatic load and overload. Sapolsky also did seminal work on dominant and subordinate baboons in Africa, and laid the groundwork for how income, education and human social hierarchies impact physical and mental health.

Until we grasped the impact of epigenetics, the brain was regarded as structurally stable in adult life, and the main focus for understanding normal and abnormal brain function was neurochemistry and neuropharmacology. During the 1980s, practitioners relied largely on antidepressants such as Prozac along with an array of antipsychotic medications to help patients heal.

Then in 1988, Elizabeth Gould, now a neuroscientist and professor at Princeton, came to my laboratory as a postdoctoral fellow. She introduced us to an old method hailing from the late 1800s and to Camillo Golgi, an Italian neuroanatomist who won a Nobel Prize for it. The Golgi technique, when done right, allows the investigator to visualise and measure the dendrites (like tree branches) emerging from neurons, and even the spines (sites of synapses, or connection, with other neurons) on those dendrites. Using the Golgi technique, Gould together with the Japanese biological psychiatrist Yoshifumi Watanabe showed that dendrites shrink and spine synapses are lost on hippocampal neurons after chronic stress lasting several weeks. The effect was due, in part, to the actions of glucocorticoids such as cortisol. In contrast, Catherine Woolley (now a professor at Northwestern University) showed that spine synapses come and go during the rat’s oestrous cycle (comparable to the human menstrual cycle) because of the fluctuations of the ovarian hormone oestradiol and progesterone.

Remarkably, in both cases, the hormones did not work alone and required, among other mediators, the main neurotransmitter in the brain, glutamate. Thus, circulating hormones not only enter the brain and bind to receptors but also participate with the brain’s own neurotransmitters in what we now call ‘adaptive plasticity’ – structural changes in the brain to enhance our success and survival. Adaptive plasticity underlies behavioural and neurological adaptation to the world. For example, shrinkage of dendrites in the hippocampus protects those neurons from damage by over-stimulation during toxic stress. Cyclic fluctuations of spine synapses during the oestrous (and human menstrual) cycle underlie differences in behaviour, including mood swings. The actions of oestradiol on cognitive function and their absence after the menopause have become the focus of hormone therapy to slow cognitive ageing and prevent Alzheimer’s disease, and the work on this topic by my colleague John Morrison, now director of the Primate Research Center at University of California, Davis (some in collaboration with us) has been very influential. Likewise, the contributions by our former postdoctoral fellow Roberta Brinton, now professor at the University of Arizona, have opened new avenues for use of the hormone progesterone as a protective agent for the ageing and damaged brain.

Gould and her students Woolley and Heather Cameron (now principal investigator at the US National Institute of Mental Health) also established that neurons of the dentate gyrus, part of the hippocampus, die and are replaced via the process of neurogenesis, which continues over the entire life course. They found that toxic stress suppresses that neurogenesis, and shrinks the hippocampus, while other laboratories went on to show that physical activity increases neurogenesis not only in young but also in older animals.

Regular physical activity is the most important behaviour that one can do to maintain brain and body health

These revelations about adult brain neurogenesis have huge implications not only because of the recognition that stem, or progenitor, cells might be used to treat brain damage, but also because of their meaning for lifestyle. Regular physical activity increases this neurogenesis in old as well as young people, and improves memory and mood and even enlarges the hippocampus, which tends to shrink in depression and diabetes among other conditions. Within six months to a year, regular aerobic activity such as walking an hour a day five out of seven days a week not only makes the hippocampus larger and improves memory but also improves decision-making by improving blood flow and metabolic function in the prefrontal cortex, a brain region essential for self-regulation of emotions and impulses as well as working memory. Indeed, regular physical activity is the most important behaviour that one can do to maintain brain and body health. And, as a further illustration of brain-body communication, the ability of exercise to stimulate neurogenesis requires that at least two hormones be taken up from the body into the brain. One of them, IGF-1, comes from the liver, and the other, cathepsin B, comes from muscle.

Plasticity of the brain extends to the diurnal cycle of waking and sleeping, and reaches beyond the hippocampus to other brain regions. A former student, Conor Liston, now an assistant professor of psychiatry at Weill Cornell Medical School, found that some, but not all, synapses in many parts of the cerebral cortex turn over during the day-night cycle due to the fluctuation of cortisol. Interfering with that cycle at the wrong time of day interferes with motor learning, eg learning to play golf. Considering how many ways we modern humans interfere with our natural day-night rhythm – for example, by turning on a light in the middle of the night – this is a lesson to all of us to give the ‘wisdom of the body’ a better chance to help us.

Another way that we interfere with the natural cycle is through shift work and jet lag. Our former post-doctoral fellow Ilia Karatsoreos, now an associate professor at Washington State University, found that creating an animal model of shift work caused dendrites in the prefrontal cortex (the brain region that governs our ability to regulate emotions and impulses, as well as working memory) to shrink and the animal to become cognitively rigid when challenged with a memory task that required changing the rules. Moreover, the shift-work animals became fatter and insulin-resistant, signs of pre-diabetes and depressive-like behaviour. Shift work in our own species is associated with greater obesity, diabetes, cardiovascular disease and mental-health problems.

The prefrontal cortex also responds to what we can call ‘tolerable stress’. During his MD-PhD thesis research, Liston assessed a group of medical students for perceived stress (how much or little they felt in control of their lives). He found that those with the highest perceived stress were slower in doing a cognitive-flexibility test, and also had slower functional connectivity in a brain circuit involving the prefrontal cortex when tested in a fMRI machine. The reason we can call this ‘tolerable stress’ is that, after a vacation, these impairments disappeared, showing the resilience of the young adult brain. Parallel studies of perceived stress on an animal model allowed Liston to see shrinkage of neuronal dendrites and reduction of synapses in the prefrontal cortex that explained the deficits in cognitive flexibility.

To complete the story of brain plasticity we need to describe how the same stressors cause dendrites to shrink and synapses to be lost in the prefrontal cortex and hippocampus. The answer comes from Sumantra Chattarji, a professor at India’s National Centre for Biological Sciences in Bangalore, and his team: dendrites in the basolateral amygdala, the seat of fear and anxiety and strong emotions, grow and become more branched, increasing a sensation of anxiety.

Liston found that dendrites in the orbitofrontal part of the prefrontal cortex also expand, increasing vigilance. In the short term, these changes might be adaptive, because anxiety and vigilance can aid us during dangerous or uncertain times. But if the threat passes and the behavioural state ‘gets stuck’ and persists along with changes in neural circuitry, such maladaptation requires intervention to open ‘windows of plasticity’ with a combination of pharmacological and behavioural therapies.

Again, regular physical activity can strengthen both prefrontal cortex and hippocampus control of the amygdala. This means that we are better able to control moods and emotions as well as impulses, and are more efficient in making decisions. Another approach to chronic anxiety is mindfulness-based stress reduction (MBSR), which has been shown to decrease the amygdala in some. Both MBSR and meditation are gaining in popularity as a way of reducing anxiety and thus reducing perceived stress.

Some of this research also has implications for post-traumatic stress disorder (PTSD). Chattarji has found that a single, traumatic stressor can lead to formation of new synapses in the basolateral amygdala after a week or two. The appearance of those new synapses is accompanied by a gradual increase in anxiety. This type of delay is a feature of PTSD. What we have shown with Chattarji is that a timed elevation of cortisol at, or shortly after, a traumatic stressor actually prevents the delayed increase in amygdala synapses. Now there is evidence that low cortisol at the time of trauma – during open-heart surgery or after a traffic accident – is a risk factor, and that rising cortisol during or right after trauma can reduce later PTSD symptoms.

Also, our (and other) research shows that the impact of toxic stress varies across sex. Women are more prone to depression after toxic stress, while men are more likely to respond with antisocial behaviours and acts. We and others find that there are receptors for both oestrogens, androgens and progestins in both the male and female brain that regulate memory, pain, coordinated movement and other critical functions. But thanks to genetically programmed sex differences in our brains, men and women respond differently to stress. These sex differences occur throughout the brain and not just in regions such as the hypothalamus that are involved in reproduction. In fact, new research indicates that, at the molecular and genetic level, male and female responses to stress in the hippocampus can be strikingly different. Sure, studies of men and women’s brain activity show that both sexes do many of the same things equally well, but use somewhat different brain circuits to do so – lending some credence to the ‘men are from Mars, women are from Venus’ hypothesis!

Stress hits us differently depending on our experience early in life. Our former postdoctoral fellow Michael Meaney, now professor at McGill University, has led the way in demonstrating the important role of postnatal maternal care in emotional and cognitive development. Infant rats raised with a nurturing mother develop less emotionality and greater ability to explore novel places and things. Pups raised with an anxious mother who provides inconsistent care show the opposite outcome.

Epigenetics also plays a role. This is clear from studies looking at cross-fostering of infants between good and bad mothers. Switching mothers and pups alters the outcome, pointing to what is now referred to as epigenetic behavioural transmission.

Complementing this, we now know that, even before conception and during life in the womb, paternal and maternal obesity can affect the child. This might involve ‘epigenetic’ changes of the DNA of the sperm and egg that do not alter the genetic code per se, but, rather, how it is read; parental obesity increases the risk that the child will also become obese. Women who lose weight through gastric bypass surgery prior to conception do not transmit obesity to children, while those who remain obese through gestation put children at higher risk.

We can never reverse the effects of experiences, positive or negative, but we can move on to recovery and redirection

Adverse early life experience involving poverty, abuse and neglect affects how genes are expressed, and determines how well brain regions such as the hippocampus, amygdala and prefrontal cortex develop and function during childhood into young adulthood. Indeed, the brain is continually changing with experience, which creates memories and alters brain architecture via mechanisms that are facilitated in part by circulating sex, stress and metabolic hormones and chemicals produced by the immune system.

These insights have led to a new view of epigenetic changes over the life course. Epigenetic changes determine trajectories of health and disease and the plasticity of the brain. But they also offer opportunities for changing the trajectory as life goes on.

We can never roll back the clock and reverse the effects of experiences, positive or negative, or the epigenetic change they produce. But we can move through those experiences to recovery and redirection; also, we can develop resilience through epigenetic change. New trajectories can engender compensatory changes in the brain and body over the life course.

This perspective has led to a new field of study, called ‘life course health development’ (LCHD), spearheaded by Neal Halfon, a researcher and paediatrician at the University of California, Los Angeles. LCHD emphasises the importance of events prior to conception and in the womb because of their ability to generate epigenetic change; for the same reason, LCHD looks to the influence of income, education and abuse.

In synch with this, our increasing knowledge of brain plasticity is giving rise to therapies based on self-regulation. These cognitive techniques, tapping mindfulness, breathing and more, can reduce toxic stress to at least more tolerable stress. Metabolic and cardiovascular health, not to mention memory and mood, can all be enhanced by a healthy diet, positive social interactions, adequate sleep, and regular physical activity. Government policies and business cultures that promote these values are key – whether dealing with housing, transportation, healthcare, education, flexible working hours or vacations, decisions at the top can dramatically impact healthspan of the population throughout life. Healthy behaviours and humanistic policies can ‘open a window’ of plasticity and allow the wisdom of the body to exert itself. With the windows open, targeted behavioural interventions – for instance, intensive physical therapy for stroke – can shape brain circuits in a more positive direction. Even if one has gotten off to a bad start in life, the trajectory can be changed by understanding how to lower the allostatic load and banish toxic stress.

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Bruce McEwen

is Alfred E Mirsky professor of neurosciences and behaviour and head of the Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology at Rockefeller University in New York City. His award-winning research on stress and the brain has been published in Proceedings to the National Academy of Sciences, Journal of Neuroscience, and Molecular Psychiatry. He lives in New York.


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