The Enhancement Imperative: The Evolutionary Neurophysiology of Durkheimian Solidarity

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The Enhancement Imperative: The Evolutionary Neurophysiology of

Durkheimian Solidarity*

MICHAEL HAMMOND

Department of Sociology, University of Toronto

Durkheimian solidarity, especially in regard to religion, is reanalyzed in terms of

recent developments in the neurosciences and evolution. Neurophysiological studies

indicate that religious arousers can piggyback on reward circuitry established by

natural selection for interpersonal attachments. This piggybacking is rooted in uneven

evolutionary changes in cognitive capacities, emotional arousal capabilities, and pre-

conscious screening rules for rewarding arousal release. Uneven development means

that only a special class of enhanced arousers embedded in macro social structures can

tap some of the reservoirs of expanded arousal release protected by these screening

rules. It becomes imperative that part of collective social life offers these special

arouser packages. Beginning with religion and inequality, the social construction of

enhanced arousers leaves a trail across human history. However, this trail is not quite

what Durkheim had in mind.

INTRODUCTION

The technological advances and theoretical changes in the neurosciences and evolutioncast new light on many aspects of the sociological tradition. This article looks atDurkheimian solidarity. Durkheim believed that humans must link strong interpersonalattachments with another set of emotionally strong bonds to larger social structures. Tobe emotionally attractive, these structures must be marked by a high degree of differ-entiation, such as the contrast between the sacred and the profane. Without a secondset of attachments to such high-contrast structures, humans are incomplete and are farmore likely to experience psychological anxiety and anomie. For Durkheim, the studyof this second set of ties lay at the heart of the new field of sociology. Durkheim alsoclaimed that these high-differentiation structures marked out a path through humanhistory. Religion was the first and most historically common example of this extendedsolidarity. Later, other forms of emotionally loaded differentiation, such as the socialdivision of labor, would appear to provide solidarity under different historical condi-tions (Durkheim [1893] 1964; Hammond 1983; Lukes 1973:24–25, 138–40).

Unfortunately, Durkheim never attempted to specify just why humans were wiredto be so attracted to highly differentiated social creations. In his obsession with theidea that society has its own unique objective reality, he was content to state his law ofgravitation in the social world ([1893] 1964:339) without investigating the nature of hisgravity. Similarly, he rejected the idea of an innate religious sentiment regularlyfueling the emergence of religion ([1895] 1964:107), but he did not try to specify thereward circuitry that might lie at the basis of contrasts such as the sacred and the

*I am most grateful to the editor and anonymous reviewers of Sociological Theory for their many helpfulsuggestions on this article. I would also like to thank David Franks, Barry Johnston, Warren TenHouten,and especially Alexandra Maryanski for their stimulating discussion or written commentary on variousthemes in the article. Address correspondence to: Michael Hammond, Department of Sociology, Universityof Toronto, 725 Spadina Avenue, Toronto, Canada M5S 2J4; E-mail: [email protected].

Sociological Theory 21:4 December 2003# American Sociological Association. 1307 NewYork Avenue NW,Washington, DC 20005-4701

profane. He also made no effort to probe into the deeper dynamics of collective ritualsthat were a part of his concept of ‘‘effervescence,’’ in which religious beliefs andsentiments were transformed into social solidarity. With his commitment to socialphenomena having a sui generis reality, he was not to look into the black box of thehuman mind that generated such creations.

Today, however, we can begin to pry open this box a little. Parts of Durkheim’smodel can now be tentatively grounded in both evolutionary theory and neurosciencedata. Other parts are not supported, but point in the direction of new possibilities forsociological theory. For example, in much the same manner as Durkheim saw ties toindividuals and social structures as woven together, the new revolutionary technol-ogies to study the brain demonstrate that strong personal attachments and religiousexperiences use many of the same neurophysiological components for rewardingemotional release. In order for them not to get in each other’s way, there must be ameans to regulate the use of these common components. The manner in which thisregulation occurs gives the neurophysiological groundwork for some of Durkheim’sclaims about solidarity. From this perspective, humans have an imperative to seek outmacro social constructions offering additional attractive arousal release. Only high-contrast structures can tap these reservoirs. Religion is, in part, a product of thatimperative. To understand these dynamics, it is necessary to review recent research onreligion in the neurosciences and to examine the role of uneven neurophysiologicalchanges in the evolutionary origin of humanity.

THE NEUROPHYSIOLOGY OF PIGGYBACKING

Although incomplete at present, neuroscience research indicates that religious experi-ences do not have their own specific subsystems of arousal rewards. Instead, religionseems to piggyback upon processes established before the origin of our species andexpanded in our evolutionary formation. The subcortical areas of specialized sub-systems and neurotransmitters for various kinds of attachments are not all known ingreat detail (Fisher, Aron, and Brown 2002; Le Doux 2002:233). Like other subsys-tems of reward circuitry, however, they are beginning to be unveiled (Bartels and Zeki2000; Farrow et al. 2001; Knutson 2002; Smith and Stevens 1999, 2002). Hormonesfrom the hypothalamus, such as vasopressin and oxytocin, have been demonstrated tobe crucial to some aspects of partner loyalty and parenting behavior in attachment(Carter 1998; Fisher, Aron, and Brown 2002; Konner 2002:325–26). Studies of somereligious experiences have also shown increases in hormones such as vasopressin(MacLean, Walton, and Wenneberg 1994). Similarly, heightened activity in areas ofthe temporal lobe such as the hypothalamus and the amygdala, as well as in otherareas such as the anterior cingulate, has been shown to be stimulated by arousersinvolving strong personal bonds and by arousers involving religious activities (Joseph1996; Newberg, d’Aquili, and Rause 2001:4, 42–45; Saver and Rabin 1997).

The piggybacking hypothesis also provides a framework in which to interpret otherrecent discoveries in the neuroscience of religious experiences while awaiting a parallelstudy in regard to attachment experiences. For instance, Andrew Newberg and hiscolleagues have used single-photon-emission computed tomography (SPECT) scan-ning to demonstrate that some religious stimuli have a dampening impact on theposterior superior parietal area, associated with maintaining a physical sense of theself as a separate object in the world (Newberg, d’Aquili, and Rause 2001). Dampeningactivity in this orientation area is associated with feeling close to spiritual beings or

360 SOCIOLOGICAL THEORY

feeling connected to another level of reality. At first glance, it might appear likely thatthis dampening of the sense of self in the world would have a disorienting impact onindividuals. If this dampening had been useful elsewhere in our evolutionary history inregard to other arousers, however, then the ability to piggyback on these other experi-ences could be felt positively. What other interest might find such a dampening to beattractive? The most likely candidate is an attachment interest in which the temporarydampening of the self as a separate object in the world could be used to stimulate andreinforce a strong personal tie between individuals. If religious arousers could tap intothis same pattern, then this dampening would be interpreted positively in terms of veryappealing contact with other beings or other worlds of experience. Once again, inproducing this second set of attachments, religious stimuli seem to be able to piggybackon arousal reward pathways already established for other ties.

Without its own reward circuitry, religious arousers could make use of the variety ofsubsystems for personal ties. As Melvin Konner (2002:323–33) indicates, parent-child,sibling and other kin, male-female, and nonsexual friendship bonds appear to havesome elements specific to a tie and other elements shared in common. With piggyback-ing, each could provide a pathway to arousal rewards. Similarly, there is growingevidence that romantic attraction has some of its own subsystems in regard to hor-mones, neurotransmitters, and other subcortical elements (Bartels and Zeki 2000;Fisher, Aron, and Brown 2002), and it could be that religious arousers are able todouble up here also. Indeed, with such stacking, religion might be able to use a numberof reward pathways linked to a number of different interests. For instance, RhawnJoseph (1996:287) notes that sexual arousal has its own reward circuitry and that somereligious experiences have demonstrated characteristics indicating a sexual component.

From the point of view of the economy of natural selection, if there are selectiveadvantages to individuals engaging in a collective construction such as religion, thenthere is a real benefit to a piggybacking relationship. The alternative of evolving afully separate subsystem for religion entails a great many more changes. Given thedifficulties of integrating any new developments into an already complicated struc-ture, evolution normally takes the path of lesser change for any selective advantage.As Alexandra Maryanski and Jonathan Turner stress, evolution prefers extensions,elaborations, and alterations of a biological heritage rather than dramatic mutations(Maryanski and Turner 1992:57). This is part of the ‘‘principle of conservation oforganization’’ (Stebbins 1969:103–04, 125). Metaphorically speaking, evolution’s con-cern is with getting the most benefits for the least number of changes. In the case beingconsidered here, by letting two sets of ties use the same neurophysiological com-ponents, individuals would have a selective advantage that accomplishes this taskin a most elegant and parsimonious manner.

However, piggybacking does create a potential problem. Unless it is regulated insome manner, it is entirely possible that interpersonal attachments and religion couldquite literally get in the way of one another. Given the finite capacity of any rewardsystem, an increase in the use of the common components for personal bonds couldentail a decrease in possible use for religious ties, and vice versa. Empirically, this doesnot appear to be the case. Individuals with strong religious beliefs do not have, on theaverage, fewer or less intense personal ties than individuals without such beliefs, andnonbelievers do not have, on the average, a greater number of or more intensepersonal ties than believers (see, e.g., Fischer 1982:208–14). Thus, if there is a selectiveadvantage to piggybacking, there must be some means evolved to regulate this dual use.

What is the evolutionary logic in this piggybacking arrangement? There are twoissues to be considered. First, there is the question of ultimate causation. What are the

THE ENHANCEMENT IMPERATIVE 361

selective advantages in using this doubling-up system? What would individuals gainwith group creations such as religion piggybacking arousal rewards? Second, there isthe question of proximate causation. What are the means used to create such anarrangement and to limit the possible difficulties in such a dual-use system? Let uslook at one of the advantages in terms of increased social-network size amongindividuals and some of the mechanisms that might be used to extend network size.

Maryanski and Turner (1992) argue persuasively that for a number of reasons, thescale of reliable social ties had to be increased for humans in comparison to thepattern of our closest evolutionary relatives and to the presumed pattern of our lastcommon ancestor. Increased solidarity was facilitated both by the major expansion ofour cognitive capabilities in areas such as language and communication and by thelesser but still significant expansion of our affective capacities. Turner (2000:92) hasdemonstrated this in summarizing the comparative evidence for the relative size ofbrain components in great apes (i.e., the gorilla, the chimpanzee, and the orangutan),humans, and a primitive mammal. The neocortex had the greatest increase in relativesize. However, there were also substantial enlargements of subcortical areas such asthe diencephalon, the amygdala, the septum, and the hippocampus. These enlargedareas are all possible sources of additional affective capacities.

With more capacities, humans could have more strong affiliations. These ties couldhave a great deal of reliability, based, in part, on the rewarding arousal release in suchlinkages. Many other valuable social resources could flow along the lines rooted inthese affective dynamics, and the two lines of exchange could reinforce one another.In order to maintain a high degree of flexibility—a characteristic demonstrated inmuch of human evolution—the selective advantage was not in favor of a hard-wiredfixing of the direction or number of these ties. Affective loading was ideal for this role.It increased reliability, with a minimum sacrifice in flexibility.

There are two paths that could have had a selective advantage in the pursuit ofmore emotionally rewarding ties. The first was to make parallel and balanced changesin the expansion of affective capacities and in the preconscious rules for convertingadditional stimuli into rewarding arousal. Even changes would mean more of thesame—in this case, more direct personal ties on a one-to-one basis. The greater theresources available, the greater would be the number of personal ties. This extensionof personal ties occurred to some extent, but equally important was a second strategyto expand social-network size. The second path was to make uneven changes inrelation to arousal-release capacities and arouser-screening rules. Uneven develop-ment would create an indirect means to produce a much larger number of reliable tiesthan was possible with direct personal bonds. As we shall see below, in our evolu-tionary context of origin, religion was one such indirect vehicle. Before examining thelogic in favor of uneven changes, however, it is necessary to outline the basic pre-conscious rules for the conversion of arouser additions into rewarding arousal release.

AROUSER SCREENING

The human brain has a wide range of stimulus-appraisal mechanisms, with an equallywide range of conscious and unconscious triggers shaping responses (Le Doux 1996).One set of these mechanisms is made up of arouser-screening rules preconsciouslyshaping responses to stimuli based upon more or less recent responses to otherarousers (Hammond 1999, 2001). The basic conversion question in these screeningrules is, how much arousal release in exchange for how much stimuli strength?


Habituation is probably the most familiar rule. Faced with the repetition of a novelattractive arouser, arousal release begins to decrease. The same arouser produces lessrewarding arousal. Habituation thereby creates an arousal reservoir ready for use ifanother novel attractive arouser appears. Although there are a number of factors thatcan affect the rate of habituation, there is ultimately a significant preconsciouselement in such a discounting of arouser impact. Even though we are members of aspecies with awesome cognitive capacities, we do not have the means to be directlyaware of these arouser screens, and we cannot consciously prevent this arousal-dampening.

The preconscious screening rules that are the most important sociologically arethose that control the release of additional rewarding arousal in the face of a varietyof additional arousers. For instance, at some point it takes stronger and strongerarouser contrast values to trigger the same arousal release produced before with lessercontrasts. At some further point, even the strongest of arouser additions only pro-duces a diminished arousal release. At some endpoint, no arouser additions willproduce anything much in the way of rewarding arousal, and such additions mayproduce negative arousal. These conversion codes are at the root of diminishingmarginal utility measured in terms of arousal rewards. If natural selection favorsonly a limited variety of stimuli, then the preconscious discounting of the arousalimpact of additional stimuli is severe and irreversible. If there is a selective advantageto more extended variety, then the discounting is eased in the face of certain types ofarouser packages (Hammond 1999).

Changes in arouser screening can be a part of wider evolutionary changes. Take theexample of a species in which, under one set of circumstances, natural selection hasfavored a strategy for males involving the pursuit of the largest number of differentfemale partners possible. Novelty of additional arousers is given precedence in arouserscreening, and familiarity leads to a rapid decline of sexual interest. One of theconsequences of this strategy is to limit the amount of male-male long-term cooperationand the amount of male-female cooperation. Such stable ties are very difficult with thismale sexual strategy. What if circumstances change and there is selective pressurefavoring more male-male or male-female cooperation? Sexual interest must remainstrong, but the screening for additional sexual arousers will have to be altered todiscourage the pursuit of too much novel variety. Increase the rate of dampening fornovel additions, and sexual interest can remain high while focusing on a smaller numberof potential partners. At the opposite extreme from the novelty-maximization strategy,the screening codes can be set to favor only one mate at a time, with a rapid discountingof any additional sexual interest. Or the schedule can be set somewhere in between thesetwo extremes, with some sexual interest in additional females, but also a diminishingreturn curve as the number of additions increases. Different circumstances can producedifferent outcomes. By changing the preconscious screening protocols, natural selectioncan change the pattern of activity in the pursuit of any interest.

In terms of natural selection, one advantage of arouser screening is the controlledflexibility made possible by adjusting the different points at which screening rules kickin. They can be set to not have a significant impact on the first arousers appealing to aninterest or some combination of interests. Individuals will then pay almost any cost foreven the most basic stimuli. Calculations of effort, time, and risk are often minimal ifthe alternative is no such arousers available at all. However, beyond that point, screen-ing comes more and more into play. Its role is to ensure that interest is extended onlyunder better and better conditions in terms of arouser strength and access costs. Asmore and more arousers become available, there occurs a point sooner or later when


only more and more stimuli differentiation without a parallel increase in costs willtrigger sufficient arousal release to fuel expanded interest. In other words, onlyDurkheimian-like high-contrast differentiation can tap additional arousal reservoirs,and this only occurs if the price is right. If those costs are high, and the screening codesare limiting rewarding arousal release, then the ratio of attractive arousal to unattrac-tive costs will not be inviting. This decreases the appeal of any further extension ofinterest and increases the appeal of other activities pursuing other interests.

The special arouser packages with additional attractive contrasts not paralleled byequal cost increases are called ‘‘enhancements’’ (Hammond 2001, 2002). The dispro-portionality in their ratio of arouser contrasts to access costs can counter the effects ofarousal dampening in the screening rules. In a wide variety of circumstances, ifenhanced arousers are available, interest is extended. If they are not, arousal releaseis eroded, and before too long, individuals turn to other activities. Different settings ofthe arouser-screening codes determine when only enhancements will extend interest.These special packages can be required early on with arouser additions, or they cancome into play later on.

The disproportionality requirement in the ratio of arouser contrasts to access costscan have both an absolute and a relative quality. There can be an initial absolutebaseline for the extension of interest. Without some disproportionality, interest willsimply not go much beyond such a point. Most important sociologically are circum-stances offering more and more disproportionate additions. These additions canextend interest again and again. The impact of such additions is relative to thestrength of the previous disproportionate packages. The rule here is that the greaterthe number of enhancements piled on one another, the greater must be the ratio ofincreases in appealing arouser contrasts to changes in access costs. Otherwise, reward-ing arousal release will simply not be there.

Hammond (1999) discusses some of the general aspects of neuromodulation thatare part of arouser screening. Universal patterns in electrochemical transmission ofneural messages create one basis for such variable arousal release. For instance, byaltering the active zones at the terminal ends of the cell, neurotransmitter commu-nication between cells can be altered. This makes it possible for experiences tomodify the properties of synapses (Carlson 1995). These changes can be stored asa kind of memory that, in turn, alters the response to future stimuli (see also Bearand Linden 2001). Natural selection can operate on these mechanisms of electro-chemical transmission to direct interest toward and away from different sets ofarousers. Similarly, hormone and neurotransmitter release can be tied to the degreeof differentiation in stimuli available.

Neuroscientists have looked at arouser screening in other primates by wiring upspecific neurons associated with interests such as feeding. One of the classic studies ofthese rules in action was done with rhesus monkeys by E. T. Rolls and his colleagues(1986). In this experiment, the monkeys were presented with four attractive andfamiliar foods, one after another. Arousal impact was measured in terms of neuralfiring rates. The first three were similar in their appealing contrasts and in their initialarousal impact. The fourth had greater contrast values, but was available with noextra effort. It was an enhanced arouser because it offered more appealing contrastswith no parallel increase in access costs. After consuming a great deal of the firstarouser, interest fell off completely in more of that substance, but not in eating itself.Screening rules simply required that further interest be fueled by different stimuli. Thepresentation of the second and third arouser had a lessened impact, but still enough toextend interest somewhat. The fourth had had a much greater initial impact, and after


a great deal of consumption, only the presentation of the fourth produced an arousalspike back up to the original level of the first three. That is, only the enhanced arousercontrasts of the fourth produced enough interest to continue eating after the pre-sentation of the first three stimuli. Altogether, the interest in eating was extended byarouser variety, but not proportionately to the variety of stimuli presented. Havingfour attractive arousers did not quadruple interest, but the package did extend interestgreatly.

We do not permit the wiring-up of specific neurons in the human brain as we do inother primates, but it is clear that the same pattern exists in humans. As B. J. Rollsand colleagues (1981) have demonstrated in humans, increase the variety of attractivefoods available and interest will be extended—but not proportionately to the increasein food variety. There is no plausible reason to assume that other interests involving avariety of possible arousers in rhesus monkeys or in humans are wired any way otherthan is the case for the interest-in-food variety. Arouser screening for greater contrastvalues is the common pattern. Details may vary in the screening schedule, such as interms of the starting points for arouser depreciation or the later points at which onlyenhanced arousers will continue interest. These variations do not alter the basicpattern, however.

How important are enhancements to be? How many members of a population arethey meant to touch? The answer depends on the selective pressures in the evolu-tionary origin of a species. In many nonhuman species, enhanced arouser packagesmay only appear occasionally, such as in the case of exceptional food-provisioningopportunities. Their role is comparatively minor. It is good to take advantage of themwhen they occur, but it is also possible to live without them. They are only options. Inthe human case, enhancements are an imperative on a regular basis for the entirepopulation. So much potentially attractive arousal is protected by arouser screeningthat humans will always seek out at least one—or preferably more than one—of thesespecial packages. To understand this imperative, it is necessary to look at the evolu-tionary logic in preferring uneven rather than balanced changes in arousal capacitiesand screening rules.

EVEN OR UNEVEN DEVELOPMENT?

As noted above, there were two basic alternatives with selective advantages in regardto using expanded affective capacities to frame extended tie networks. The first was tohave balanced changes between expanding arousal capacities and delaying increasedcontrast requirements in arouser screening for the release of that arousal. This wouldreduce the arousal-dampening impact for ties to additional human beings, who canhave only a limited contrast value in terms of differences from other, already emo-tionally moving humans. With a less demanding screening schedule, there would besufficient contrasts among other available individuals to provide more rewardingarousal and extend network size.

Even development did extend networks to some extent, but it was supplementedwith a second strategy based on uneven changes and enhanced arousers. Direct tiesbetween individuals can have high flexibility and reliability, but they require sig-nificant investments of time and emotional energy on a case-by-case basis. At somepoint, there was a selective advantage to using an indirect approach that couldproduce an even greater number of reliable ties without as much in the way offurther increases in affective arousal capacities and further changes in screening


rules. Indirect ties between individuals through a common, emotionally laden thirdpoint, such as a social structure, can produce a greater number of reliable ties with alesser increase in affective capacities and a smaller change in the conversionschedule. The triangulation to a common attachment is an ideal bridge betweenindividuals. It can link a greater number of individuals with fewer total costs than adirect tie-by-tie construction. This is only possible, however, if the bridge is anenhanced structure offering the special package of increased arouser contrast valueswithout a parallel increase in access costs. That is, the larger structure must offer anarouser package that further additions to direct personal bonds cannot equal.Otherwise, individuals will stick with personal ties.

From the point of view of natural selection, how to best produce this extension ofinterest? Take an attachment interest, and lag evolutionary changes in arouser screen-ing for increased contrast values behind the expansion of affective capacities. For theaddition of more strong personal bonds, this uneven development will produce earlydampening in relation to the significant reservoirs of attractive arousal release remain-ing available for attachments. That is, such early screening will dampen interest inadditional direct personal ties even though the affective resources remain for moresuch bonds. The attachment interest will have to turn to enhanced structures able toaccess these arousal reservoirs through very special arousers available at much thesame costs as regular direct ties.

Once again, there are two basic paths that might have selective advantages inregard to this uneven development and its emphasis on enhanced arousers. First,there could be precise, hard-wired detailing of the enhanced structures providing thecommon point of reference for a large network of individuals. Second, there could belittle or no detailing. In the first case, evolution could create preconscious triggers andreward pathways specific to these enhanced structures, thereby guaranteeing theirappearance. However, there were problems with such detailing in the human case. Itwould go against the general trend to increase flexibility in the behavioral repertoireof humans. It would also require more neurophysiological changes than the alter-native of not specifying the enhancements for network extension. Evolving major newreward pathways and appraisal mechanisms specifically for the extended interestwould clearly be more problematical than simply piggybacking on existent compon-ents. The easiest solution would be the second alternative: mix uneven changes inarousal capacities and arouser-screening rules along with little or no precise detailingfor the enhancement imperative created by this combination.

All of this was made possible by the last aspect of uneven development, the massiveexpansion of human cognitive capabilities. There were many other selective factorsfavoring this expansion, but one factor was its role in creating enhanced arousers. Anyenhancement requires disproportionality in arouser contrasts and access costs. Hard-wired detailing can provide both. If such scaffolding was not to be used in the humancase, however, there must be other developments that could make a contribution tomeeting this disproportionality demand. Our cognitive skills can offer such a possi-bility. They can handle vastly increased amounts of information to create and main-tain very special enhanced arouser packages. Hard-wired detailing represents a type ofknowledge based upon the past experience of individuals expressed in terms ofreproductive success. Without such specifications, it is crucial that there exist sophis-ticated tools to substitute another form of knowledge framing action for any interest.The greater the cognitive capacities, the less additional detailing is required. The lessthe detailing, the greater is the behavioral flexibility, for enhanced arousers or for anyother human pursuit.


RELIGION AND THE ENHANCEMENT IMPERATIVE

As noted earlier, Durkheim made no attempt to look into the black box of the humanbrain to trace the beginnings of an interest in gods and spirits as part of the sacred. Inhis definitive intellectual biography of Durkheim, Steven Lukes argues that Durkheimwas an early and long-time admirer of French intellectuals, such as Fustel deCoulanges, who asserted that gods are nothing else than the beliefs of individuals(Lukes 1973:62). However, Durkheim also argued that these beliefs were not totallyillusory ([1912] 1976:262, 417). They were only partly illusory. What was real was thesociety itself from which these beliefs emerged. For Durkheim, the world of gods andspirits was ‘‘only society transfigured and conceived symbolically’’ ([1924] 1953:52).This transfiguration meant that humans were able to attach themselves to a specialmacro structure with many attractive characteristics that direct personal ties to otherindividuals could not offer. It was no wonder, therefore, that for Durkheim, humanswere irresistibly attracted to such social attachments. This position was part ofDurkheim’s fixation on the idea that society has a sui generis objective reality of itsown, a stance that few support today.

How might Durkheim’s position be reanalyzed in terms of the enhancement impera-tive? This alternative model suggests that the symbolic conceptions of gods and spiritsdo offer a set of attachments with qualities that purely personal ties to other humanbeings cannot offer. Humans have the expanded cognitive capacities for these symbolicrenderings at a reasonable cost. We have the arousal reservoirs to fuel these additionalattachments. There are also real selective advantages to such additions. One of thoseadvantages is that a religious species can have reliable social networks far larger thanthose our evolutionary cousins have. Such religiously framed networks would be partlyillusory in Durkheim’s terms, but they would also be very real.

For natural selection, there are two steps to predisposing humans to increase theirnetwork size through a construction such as religion. The first step is to have earlyarouser screening for an attachment interest. This quickly launches individuals on aquest for enhanced arousers that can tap the deep arousal reservoirs remaining. In ourevolutionary context of origin, with dispersed and often nomadic populations havingonly limited technologies, what kind of special beings could offer increased arousercontrast values without a similar increase in access costs? These beings must be enoughlike regular human beings to be able to tap into already-established reward pathways,but they must also have enough appealing extraordinary characteristics to counter theeffects of screening rules for arouser additions using those pathways. Is this not a gooddescription of the sacred beings that emerge in all these cultures? These creations haveenough anthropomorphic qualities to open the gates of arouser screening, and enoughextrahuman characteristics to push through that barrier. Let them have control ofdifferent parts of the natural world. Let them shape the path of illness and death, orrecovery and rebirth. In any specific set of historical circumstances, let them do thingsthat ordinary humans can only dream of in that situation. The result is that high-contrast additions become available for much the same costs as more direct personalties. In the face of such Durkheimian high-contrast differentiation, the arousal releasewill feel totally real. Ties to these enhanced beings will be experienced as just as real asbonds to other human beings. The evidence of this parallel experience is in theneurophysiological studies of piggybacking referred to above.

This piggybacking highlights the importance of anthropomorphism in providing abridge to additional arousal release. Having spirit beings with some human characteris-tics is more than a useful cognitive tool in aiding individuals to grasp the nature of the


sacred. It is also a vehicle for easing access to reward systems that predate our emergenceas a species. The animism and ancestor worship so common to hunter-gatherer religionsare the first examples of this pattern. As Durkheim noted, in terms of representing thephysical world, these religions are ‘‘scarcely more than a fabric of errors,’’ but theirappeal lies elsewhere ([1912] 1976:225). The degree of anthropomorphism can vary, bothon an individual and collective level, but it will always be an element of any religiousbelief within a population as a whole.

The second step in predisposing humans to creations such as religion is to set theearly arouser screening for very high-contrast values that only a larger social group canprovide on a regular basis. If the requirement is for elevated differentiation, it is goingto be very difficult for individuals, families, or close kin to create and maintain suchvery special arouser packages by themselves on a regular basis over the long term. Thecosts in terms of time and effort would simply be too great in the face of arouserscreening that demands increased contrast values without a parallel increase in thosecosts. For example, the larger group can afford to support specialists devoting extratime and effort to these creations, thereby taking some of the load off many otherindividuals. Similarly, the larger group can have collective rituals with a comparativeimpact that more micro units cannot regularly match except at a greater individual cost.

Evolve the right set of arouser-screening rules, and by the standards of our closestevolutionary cousins, only a large number of individuals can regularly create thosespecial arousers without having any individual or small group of people pay too greata cost. The result is a species that must seek out a wide breadth of ties and that can usean enhancement package such as religion to frame those ties. Durkheim’s emphasis onthe role of totemic systems in early religion is a good example of the social-bridgealternative to tie-by-tie networks. A shared totem links many different individualswithin a group. Totem differentiation between groups organizes even larger numbers.The social-breadth requirement also increases the penalties for cheating on resourceexchange among individuals who share a package of these sacred beings. The cheaterthen risks the potential punishment from the sacred world, and also risks having thenumber of ties to other humans drop below the expanded size necessary to maintainthe sacred world without too great a burden on the individual.

With a body ready to trigger attractive arousal release from reservoirs protected byearly arouser screening, the rewards for such symbolic transfigurations are immediateand powerful, especially in a ritual social context involving other individuals experi-encing the same dynamics. In such circumstances, our bodies will leap at theseopportunities, especially if they are the only enhancements regularly available. Thus,the Durkheimian ‘‘effervescence’’ of religious ritual can be rooted in uneven neuro-physiological changes and the enhancement imperative these developments create.The result is that in many circumstances, the most moving response to this imperativefor many individuals has been the social construction of religion.

The enhancement model also supports Durkheim’s claim that in worshippinga religion, individuals are in fact worshipping their own social world, but are unawareof this ([1912] 1976:209, 225). Once again, from his perspective on the existence of a suigeneris social reality, Durkheim has no inclination to ask what deeper elements mightbe at the roots of such a dynamic. The preconscious arousal release from enhancedarousers creates this dynamic. It might feel as if the sacred is the origin of these arousalrewards, but in fact, those rewards are a product of preconscious screening rules ofwhich we have no means to be directly aware. Thus, even though social constructionssuch as religion are a product of individuals, they will feel as if they have another origin,and believers will be predisposed to act as if the sacred does in fact originate elsewhere.


Using an enhancement strategy, the selective advantage would nudge individualstoward these types of constructions without using hard-wired details specificallydesigned for religion. There is no need for anything like what popularly might becalled a ‘‘religion gene.’’ Just lag the arouser-screening schedule such that humanscannot find special enhanced arousers through efforts among their closest personalties. Individuals must then find a way to make a linkage to a greater number ofindividuals, who of course are caught up in the same quest for extended attachments.In a vast range of social conditions, one product of this common quest is the socialstructure we label ‘‘religion.’’

It should be noted that an enhanced structure such as religion helps humanity copewith some of the problems created by the massive increase in our cognitive capacities.A very smart species is going to have concerns that others will not. As Robert Hinde(1999) has demonstrated, problems such as understanding otherwise inexplicableevents, sensing a degree of control over one’s life, and giving life meaning emergewith all our new capacities. Simultaneously, religion emerges as one response to suchdilemmas. Such an enhancement can both extend social cooperation and reducepsychological anxiety. This article has tried to suggest one proximate mechanism ofattachment piggybacking for this emergence. There are bound to be other mechanismsrooted in other interests that religion might serve, but these, too, should soon becoming into the light as neuroscientists sharpen their skills and technologies.

Finally, the enhancement-imperative model provides one factor to help to accountfor what might appear to many social theorists to be the astounding perseverance ofthe belief in spiritual beings of one kind or another in contemporary high-technologycultures in which the forces of secularization should be at their apex. Given ourevolutionary origins and neurophysiological developments, the arousal-releaserewards for a belief in spiritual forces are not simply going to disappear. It is muchmore likely that such enhancements will continue to be very appealing to a wide rangeof individuals. In the face of a wide variety of alternative enhanced secular arouserpackages in modern high-technology cultures, the comparative emphasis on religiousenhancements might erode somewhat, but the appeal of these spirits is not going toevaporate completely.

BACK TO DURKHEIMIAN SOLIDARITY

Let us review Durkheimian solidarity in light of this enhancement model. Durkheimmade three basic claims. First, humans have a need not just for strong directpersonal attachments, but also for bonds to emotionally moving, macro socialstructures. Without these additional ties, humans suffer from anomie or psycho-logical anxiety. Therefore, for Durkheim, it is crucial to find social structures offer-ing this solidarity. The enhancement model suggests a mechanism that creates animperative to find enhanced ties and that facilitates the piggybacking of ties.The natural-selection logic behind enhancement supports Durkheim’s first claim.Second, Durkheim argued that only high-contrast differentiation could frame theseadditional ties. Anything less does not seem to have the emotional impact necessary.The enhancement model makes it clear why such high contrasts are necessaryfor individuals carrying early arouser-screening rules guarding deep arousal reservoirs.Once again, Durkheim’s claim is supported. Third, Durkheim asserted that in pre-industrial societies, religion, with its sacred-profane differentiation, was the mosthistorically common social construction for these dynamics. The enhancement model


highlights the natural-selection logic that made the emergence of the sacred so universalin our first historical context.

Altogether, the enhancement-imperative model suggests that in certain respects,Durkheim was right. We are wired to seek more than close personal ties. We must alsoseek at least one set of enhanced arousers. To overcome the dampening effect of thearouser addition conversion schedule, these enhancements must be marked by high-contrast differentiation. These enhancements are regularly available only in moremacro social constructions. A web of close personal ties, however moving it mightbe, will not be able to tap additional rewarding arousal release protected by earlyscreening for enhanced arousers. The most likely enhancement to appear in our earlyhistory was religion. No other social structure could regularly offer so many high-contrast arousers to so many individuals at such reasonable costs.

However, the enhancement model also highlights the limitations of Durkheim’sperspective on solidarity. Humans might always seek out linkages to social structuresmuch larger than the network of personal ties they can sustain, but this extendedsolidarity does not necessarily translate into the functional unity Durkheim so desper-ately sought. It is clear that Durkheim was conflating solidarity and unity by makingthe assumption that network-extending attachments only work effectively if they aretied into a fully integrated social system. All members of a group might be required tosustain a structure such as religion in our evolutionary context of origin, but this isnot necessarily the case after our exodus from that small-scale world. The difficultiesin Durkheim’s position are evident in his strained attempt, using the concept oforganic solidarity, to argue that the social division of labor in larger-scale societiescan play the same solidarity- and unity-inducing role that religion can play at asmaller scale. The division of labor does provide heightened differentiation, but at amassive cost, with some benefiting much more than others. It is no wonder thatDurkheim could never specify just how such inflated inequality was going to reintro-duce both solidarity and functional integration to modern social life.

Similarly, other enhanced arouser packages such as racism, ethnicity, and nation-alism that hyperinflate differences among individuals might be good vehicles forsolidarity extension, but with very different consequences than Durkheim wouldhave wished. Like religion, such packages provide high-contrast arousers with anthro-pomorphic qualities, making it easier to tap into our basic attachment interests. Likereligion, the additional arousal release triggered by such enhancements can be veryappealing. But the other consequences of these enhancements hardly fit into thefunctionalist model. The same is true for social inequality in general.

ENHANCEMENTS AND INEQUALITY

Like the differentiation between the sacred and the profane, the pursuit of statusdifferentiation can also be shaped by arouser-screening rules that piggyback differentbehavioral responses on top of one another. Attachments come in two packages, oneenhanced and one not. Social inequality also comes in proportionate and dispropor-tionate packages (Hammond 1999). Proportionate inequality provides status contraststhat parallel the costs expended to acquire such differentiation. Disproportionateinequality provides status contrasts that do not require parallel cost expenditures. Inour earliest history, there were some circumstances favoring the inequality of propor-tionate packages, and other circumstances favoring disproportionality. Once again, justas in the case of attachment and religion, with uneven changes in cognitive capacities,


affective release reservoirs, and arouser-screening rules, humans could readily produceboth basic patterns, as well as different mixes of those patterns. They could also movecomparatively easily between these alternatives. This gave our species unparalleledflexibility while pushing individuals toward lesser or greater degrees of inequalitydepending upon specific circumstances.

As with extended attachments, scientists are just beginning to peek into the blackbox of the neurophysiology of inequality to try to trace the mechanisms that makesuch packages possible. Research has already focused on the neurotransmitter sero-tonin (see, e.g., Sanderson 2001:292–93). Higher serotonin levels seem to have apositive impact on a wide variety of behavior, and that is one reason why serotonin-elevating drugs such as Prozac can be used to counter depression. Studies have linkedserotonin rates to social status in both males and females (Westergaard et al. 1999).There is some evidence that serotonin also serves as a conduit to other activationsystems by regulating the frequency and intensity of arousal release elsewhere (Higleyet al. 1996). In any case, natural selection can operate at the level of such substanceswith regard to shaping an interest such as status differentiation.

It is possible to set a hypothetical arousal-release schedule for neurotransmittersand hormones (Hammond 2002) such that in certain situations there is a dampenedinterest in expanded inequality, as well as active resistance to such inequality. In othersituations, the same preconscious arouser-screening rules can heighten interest ininflated inequality and dampen resistance to such an extension. The fine-tuning ofthe screening rules has to be somewhat different than in the attachment case, but theextension of interest is very similar. In many conditions, only disproportionatearouser packages will be able to trigger additional arousal release on a regularbasis. Once again, two or even more behavior patterns can be produced from thesame reward system without too much interference and without hard-wired detailingof outcomes. In our evolutionary context of origin, this piggybacking had manyselective advantages for individuals. With our exodus from that early history,however, the outcomes tilted more and more to favor the expansion of inequality toextremes that had little to do with the origins of this piggybacking.

Take the example of ascriptive male and female gender-solidarity groups in huntingand gathering societies (Hammond forthcoming). Like religion, such macro socialconstructions have significant indirect advantages in extending gender networks forcooperation and resource exchange far beyond that of our evolutionary relatives. Likereligion, these creations add social ties at a lesser cost per tie than that incurred usingmore direct personal attachments. These gender groupings are particularly importantin partially reducing the male-male competition seen in our closest evolutionaryrelatives, as well as in expanding the scope of female-female cooperation. Both werenecessary steps to a hunting-and-gathering division of labor, allowing humans tooccupy successfully a whole new range of ecological niches.

From the point of view of natural selection, what is the most efficient means to pushindividuals toward these gender-solidarity groups? Just as in the case of religion, this isa two-step process. First, use early arouser screening, but in this case, focus on a status-differentiation interest. The result is that individuals will soon be looking to add someenhanced arousers offering further attractive status contrasts without a parallel increasein access costs. For a number of reasons, the only enhancements widely available insuch contexts are ascriptive gender-status markers. Ascription is appealing in the faceof early arouser screening because it imputes performance differences, but does notnecessarily demand that all individuals actually demonstrate their superiority on anyspecific valued quality. Simultaneously, ascription discourages or prevents others from


trying to show that they, too, have certain qualities meriting that status. Limiting meritcompetition can provide a tremendous cost savings for those protected by ascriptivewalls. Thus, with ascription, the variety of status arousers available to an individual canincrease, without a necessary parallel increase in the costs of claiming those status markers.

As with religion and attachment, the second step is to set arouser screening for astatus-differentiation interest such that at least some of the disproportionalitydemanded to trigger additional rewarding arousal release is too great for individuals,families, or close kin to maintain over the long term. In the face of this arouserscreening, only the larger collective group, such as all males or all females, can providesome of the cost-efficient enhanced-status arousers. Individuals will then quickly bepushed to seek out extended ties within such macro groups in order to access thesespecial arouser packages, and many other resources can flow along the lines estab-lished by these ties. Once again, there is no need for what might popularly be called an‘‘ascription gene’’ to account for this emergent behavior. What we label ‘‘ascription’’ issimply the least costly enhancement in many circumstances. If individuals are pursu-ing enhancements, most will go for ascription first. The potential inflation of ascrip-tive differentiation and the disproportionate escalation of merit inequality werecapped by the small scale of our evolutionary context of origin. With our exodus,these enhancements rapidly expanded in size and shape, often with many tragicconsequences (Hammond 1999). It is important to note, however, that the samemodel of early arouser screening and enhancements can help to explain the regularemergence of another striking behavior pattern in humans.

In his Division of Labor in Society ([1893] 1964), Durkheim did try to turneconomic differentiation and inequality into a new form of solidarity in presenting asocial evolutionary sequence to organic solidarity in modern industrial cultures. But itis clear that Durkheim was stretching things here. As plausible as his analysis of thefunctional origin of religion might be, his perspective on the parallel macro integra-tion effects of the social division of labor is implausible. The extended social ties thatmight be created by economic differentiation are real enough, but it does not followthat these translate into macro social unification. Indeed, an enhanced status interestrooted in such extended networks can lead to the fevered pursuit of goals having justthe opposite impact on many members of a population. It could be that Durkheimwas right in arguing that differentiation structures such as the sacred and the profaneor social stratification are tied together—but not because of their common function inpromoting solidarity. Instead, they are tied together in terms of their reliance on acommon pattern of uneven neurophysiological development fueling a quest forenhanced arouser packages.

Despite these problems with Durkheim’s perspective on solidarity in more complexsocieties, his basic insight that these dynamics leave a trail across our history waspartially correct. Durkheim clearly saw that high-contrast differentiation was animperative for human beings. Its arousal release was somehow crucial to the sociallife of the new species. Solidarity-inducing enhancements such as religion were oneproduct of this imperative. Collective ascriptive inequality was another product fuel-ing expanded social networks. After the historical exodus from our evolutionarycontext of origin, both enhancements flourished. But—especially in the caseof inflated inequality—they also produced many developments that compromisedthe Durkheimian dream of macro solidarity in larger societies. Eventually, a thirdenhancement package appeared with high-technology production and consumptionon a mass scale (Hammond 1999:356). These technological enhancements make high-contrast and low-cost arouser packages available for virtually all interests, even as


classic enhancements such as religion and inflated inequality continue to be attractive.The competition among these three enhancement packages gives our modern culturestheir special imprint.

CONCLUSION

At the very beginning of modern sociology, Durkheim suggested that there was a keylinkage between high-contrast differentiation and solidarity that produced a socialevolutionary sequence in human history. When one follows the trail of enhancedcontrasts rooted in uneven neurophysiological changes, a sequence does appear, eventhough the focus is not always on solidarity. This is not quite the path Durkheim hadin mind, but it shows how sociological tradition and modern neurosciences can befused into a new synthesis.

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The Enhancement Imperative: The Evolutionary Neurophysiology of Durkheimian Solidarity