Linear Enamel Hypoplasia: What Canit Say About the Condition ofChildhood?

IntroductionChildren are not well understood nor

well represented in the archaeological record. In1989, Grete Lillehammer called for moreattention to be paid to children in thearchaeological record; however, fewarchaeologists answered her call (Kamp 2001).In fact, when a symposium on childhood wasorganized for the Society of AmericanAnthropology five years later, there were so fewpotential contributors that it took the organizerstwo attempts before the symposium could eventake place (Kamp 2001:8). The lack of study hascreated a deficiency in the knowledge of thewhole community, as understanding children iscrucial to understanding how the populationfunctions. This lack of representation of childrenin the archaeological record stems not only frompreservation issues, but also from a lack of desireto ask questions about the nature of children andchildhood. For example, children have smallerbones and as such, it takes less time for theirbones to be broken down or lost. However,preservation is a problem that can easily beovercome when it comes to understandingchildren and childhood. While it is true that ourchildhood tends to be left simply to memoriesonce we have completed it, some physicalremains of childhood stay with a person forever:teeth.

Teeth have long been used asfundamental tools to reconstruct the disease, dietand nutritional status of human groups (Cuccinaet al. 1999:405). Linear enamel hypoplasia(LEH), a dental defect produced during theformation of teeth, has been studied since theearly 1700s, however, it has almost exclusivelybeen applied at the population level(Palubeckaite et al. 2002, Cuccina 2002,Humphrey 2000, Lillie & Richards 2000,Cuccina et al. 1999, Mays 1998, Larsen 1997,Danthforth 1997, Li et al. 1995, Skinner 1996,White 1994, Moggi-Cecchi et al. 1994, Hall &Browman 1992, Whittington 1992, Goodman &Rose 1990, Olsen Kelley & Angel 1987, Rose etal. 1985, Goodman et al. 1980, Infante &Gillespie 1974).

Linear enamel hypoplasia can offermuch needed information of what it is to be achild in a society where LEH is prevalent.Information that can be gleaned from examiningLEH includes: differential treatment of the sexes,differences between the health status of elitechildren versus non-elite children, and thepatterns and implications of early weaning.

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Archaeological ProblemFeminist theory posits that women in

the archaeological record have traditionally beenportrayed as passive rather than active (Fedigan1986). While this portrayal has changed inrecent times, children have replaced females asthe passive members of society. Curiously,children were left behind in the feministmovement in archaeology, despite the fact that awoman's role as a mother is one of the strongestroles of both past and present females. Feministtheory seems to have divorced itself from thisrole of 'woman the mother' in its theories andstudies (Sofaer Derevenski 1997: 192). Instead,archaeologists have continued to see children asthe object of others' control, assuming that onlyadults are productive members of society (Kamp2001:24).

Similar to perceptions of gender studies, thestudy of children and childhood is seen by manyas intangible because the roles of children areculturally defmed. However, the recent emphasison gender studies in the archaeological recordshould force archaeologists to reconsider thepossibility of discovering children and childhood(Kamp 2001:2).

While it may be difficult to fmdchildren in the archaeological record because ofacidic soils or burial practices that omit them,there are several ways to locate them. Directevidence can be uncovered through skeletalremains and material remains; indirect evidencecan be uncovered by investigating daily lifewithin the settlement, including the time, spaceand place in which activities were carried out(Danforth 1997).

However, there are barriers that rundeeper than acidic soils or burial practices. Theassumption that juvenile skeletons do notpreserve as well as adult skeletons preventsarchaeologists from looking for juvenileskeletons (Danforth 1997). Further, becausechildren are not seen to be as important as theadults in society, they are not actively searchedout (Danforth 1997). This excavation biasprevents further data from being gathered onjuveniles. Moreover, this bias at work inprevious excavations has led to a wealth of lostdata that most likely will never be regained(Danforth 1997:130).

There are problems related to dealingwith children in the archaeological record, evenwhen children are found. Archaeologists try to

recognize patterns in data, yet this task dependson their prior expectations, knowledge andmodels, all of which can lead to bias(Chamberlain 1997:248). Part of the problem isthe concept of childhood is an adult creation(Sofaer Derevenski 1997:193). When dealingwith the notion of childhood, a Westernarchaeologist cannot allow the contemporaryWestern view of children/childhood to cloudhis/her view of children in another time or place.An archaeologist must remember that there havebeen many ways of viewing children within thecommunity of study. For instance, during theMiddle Ages in Europe children were viewed asmini-adults. Another view includes that of thePuritans, who believed that children were bornsinful and needed guidance to triumph over evil.Historically in Western culture, children havebeen seen as capable of work from a very youngage (Kamp 2001:4).

Despite the difficulties involved,children do need to be studied not only to learnabout them, but also because, "an understandingof children's economic role, attitudes towardschildren, the health of infants and children, andother aspects of childhood will improve not onlyour basic descriptions of a culture, but also ouranalysis of broader issues" (Kamp 2001:2).

BackgroundTeeth are often extremely well

preserved in the fossil record, as enamel is thehardest tissue of the human body.Mature human dental enamel is made up of 96%inorganic material (crystalline hyproxypaite),which is not subject to decay, 2% water and 2%protein (amelogenins and enamelins) (Goodmanand Rose 1990, Hillier and Craig 1992: 381).

Enamel is formed in layers byameloblast cells. The ameloblast cells moveaway from the cusp of the tooth leaving a proteinmatrix, which is later calcified behind them.Any systematic disturbance that disrupts theameloblast alters the direction of movement andas such, alters the enamel prism being formed.

If the ameloblast cells do not recoverfrom a disturbance, these ameloblasts will formno further enamel; this results in enamelhypoplasia (Rose 1985). There are four types ofenamel hypoplasia (EH): pits, vertical grooves,missing enamel and horizontal grooves (Guatelli-Steinberg & Lukacs 1999:77). Horizontalhypoplasia, more commonly referred to as linearenamel hypoplasia, can be a single sharp line onthe crown, or a single groove/furrow/ridge on thecrown surface (Guatelli-Steinberg & Lukacs

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1999:77). Once the hypoplasia is formed, itserves as a permanent marker of the prematuredeath of ameloblast cells because teeth, unlikebone, do not remodel after their formation.

Human dental development begins withthe formation of deciduous incisors around fourweeks in utero; as such, LEH can be used tomonitor an individual from four weeks in utero(Alvesalo 1997). Permanent teeth, incisors,canines and frrst molars grow in the first yearafter birth and complete their growth between theages of three and seven.Premolars and second molars develop during thethird and forth years and are completed fromages four to eight. Third molars develop betweenthe ages of seven and twelve and are completedbetween ten to eighteen years of age (Hillson2000).

To measure the age at which aparticular episode of LEH occurs, the distancefrom the cemento-enamel junction (eEl) to theLEH is measured; the distance can then begraphically converted to an age of development(Goodman & Rose 1990). This type ofcalculation is possible because research hasestablished that the emergence of deciduous andpermanent dentition does not differ greatlybetween or within groups, unlike other stressmarkers such as body size and skeletal maturity(Humphrey 2000).

Morbidity in general tends not to leavedirect evidence on the bone. In children, theleading causes of death are respiratory anddiarrhoeal diseases, which affect soft tissue andcreate even less chance to see morbidity ofchildhood within skeletal remains (Saunders &Barrens 1999). However, stress on the body canbe seen in the structure of teeth as the lack ofremodelling after formation allows a tooth tobecome a time capsule for the time period inwhich it was formed (Saunders & Barrens 1999).As a result, we can learn about childhood bystudying the dental remains of adults, who areoften better represented in the archaeologicalrecord (Rose et al. 1985 :282, Saunders &Barrans 1999).

LEH is a non-specifrc stress indicator foundon both deciduous and permanent teeth;stress includes both internal and externalforces. Internal forces include: biologicaldeterminants, for instance, geneticpredispositions and sex differences. Externalforces include: nutritional defrciencies,

disease, childbirth (low birth weight and pre-maturity), accidents, fever, and violence(Alvesalo 1997, Skinner 1996).

A large number of studies on the causesof LEH have focused on vitamin defrciencies.Two of the most prominent are defrciencies invitamin A and vitamin D. Vitamin A can beeasily lost during a fever by voiding retinal-binding protein in urine; in fact, up to half of theadult daily requirement can be lost during tofever (Skinner 1996:836,849). The consequenceof vitamin A defrciency is only a 2% decrease ingrowth, yet a 50% reduction in antibodysynthesis (Skinner 1996:849). This reduction inantibodies opens the individual up to a host ofother disease and viruses, which can placefurther strain on the body.

Vitamin D may also cause LEH byproxy; that is, a calcium-reduced diet creates avitamin D defrciency, which can lead todiarrhoea and intestinal problems often resultingin further metabolic defrciencies (Olsen Kelley &Angel 1987:200). In general, other bodilysystems tend to worsen if there is a decrease inmineral storage and a decrease in vitamin D(Seow 1992:327). To confrrm the connectionbetween vitamin defrciencies and enamelhypoplasia, studies have been completed onvarious mammals. Studies on dogs, for instance,have shown that defrciencies in vitamins A andD can cause enamel hypoplasia (Olsen Kelly &Angel 1987).

Due to the multi-causality of LEH, someresearchers have questioned its use as anutritional stress marker. However, researchhas shown LEH to be more often associatedwith populations suffering from nutritionaldeficiencies and/or infectious disease thanother populations. Furthermore, studies haveshown LEH to be more sensitive tonutritional status than tooth size, toothemergence and bone mineralization (May etat. 1993: 49). Studies have also shown thatLEH parallels other stress indicators such asheight, weight and socio-economic status(Guatelli-Steinberg & Lukacs 1999:80).Whether LEH monitors nutritional stressspecifrcally, or stress levels in general, LEHis strongly associated with stress. Thisassociation allows LEH to be used as anindicator of stress in a population or apopulation segment (Guatelli-Steinberg &Lukacs 1999:79).

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The "Osteological Paradox" has severalramifications on the study of LEH (Wood et al.1992). First, the children found to have LEHwere the survivors of a stress episode. However,those children who died without any evidence ofLEH do not necessarily represent healthychildren; instead, they represent those who diedbefore LEH could develop, This is possiblebecause while LEH is a good indicator of stress,it does not represent all stressors. Sudden deathwill not be seen through LEH; as such, it shouldnot be assumed that the children in thearchaeological record without LEH were stress-free individuals (Skinner 1996:847). To attemptto uncover which of these two options arereflected in the skeletal remains, other evidenceon the particular community and particularindividual need to be considered.

All children in the archaeologicalrecord were frail in life, as they diedprematurely. To study the possible effects ofindividual frailty and the effects of morbidityupon mortality, one individual can be followedthough childhood, comparing the defects of thedeciduous and permanent dentition as well as theage of death (Storey 1997: 119).

Materials and MethodsTo identify LEH, a bright light, lOx

hand lens and dental probe are the onlyinstruments needed. If a defect is so small that itcan only be seen under a microscope, then it isprobably not a true hypoplasia, as suchresearchers look for macroscopic as opposed tomicroscopic evidence (Goodman & Rose1990:92). To measure an episode of LEH,needlepoint Helios dial callipers are used and thedata is rounded to the nearest tenth of amillimetre (Lukacs 1992:7). To ensure bestresults, teeth should be cleaned in a nonabrasivemanner to remove excess dirt and any obscuringitems (Goodman & Rose 1990: 92).

The measured distance from the CEl'sto LEH can be graphically converted to an age ofdevelopment. The formula for this procedure isas follows: the age at formation is equal to thenegative rate of enamel development (mm peryear), multiplied by the distance of the defectfrom the CEl (in mm), plus the age at crowncompletion (Goodman & Rose 1990:97). Thismethodology was used in all of the studies usingindividuals of unknown age reviewed within thispaper. For comparative purposes, information onthe formation of the tooth matrix of differentgroups (i.e. males vs. females) is available and

used in several of the studies reviewed here(Goodman & Rose 1990:99).

There are some problems in themethodology of enamel hypoplasia; for instance,not all teeth show the same amount ofhypoplasia. Research has shown earlierdeveloping tooth crowns tend to have morehypoplasia than later developing tooth crowns(Goodman & Armelagos 1985:487). Thisprovides evidence of morphologicaldevelopmental factors influencing the expressionof EH (Goodman & Armelagos 1985:488).However, not all of the differences can beexplained via time in tooth development; thus, itis possible that there is increased genetic controlover the development of certain teeth. Teethbelieved to be heavily constrained by geneticsare referred to as polar or key teeth. The uppercentral incisors, lower lateral incisors, canines,first premolars and first molars are consideredthe polar teeth. Hypoplasia is believed to affectthese genetically controlled teeth. This isbelieved to be the case because EH may be theonly way polar teeth can react to stress, giventhat genes tightly control the speed ofdevelopment and size. Non-polar teeth, or thosewith less genetic control, can react to stress in avariety of ways such as slowing downdevelopment and decreasing in overall size.Studies providing evidence of the existence ofpolar teeth show that in response to nutritionalstress, third molars decrease in size at a greaterrate than first molars, with second molars beingintermediate in this reaction (Goodman &Armelagos 1985 :491).

There is also a problem in examiningteeth for LEH due to attrition. Attrition fromchewing or cultural modifications of teeth caninterfere with the ability to locate LEH and countthe number of stress episodes. In this paper,deciduous teeth were examined and teeth withheavy wear or unusual wear patterns wereexcluded to reduce any confounding factors.

The following three sections of thispaper each reflect their own methodology as theyare from a variety of studies. A brief outline ofthe methodology will be discussed for eachstudy.

Differential Treatment afthe SexesLEH is an indicator of stress; as such,

studies can use LEH in comparing differentgroups to one another in order to determine ifone group experiences more stress than the other.

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In some contemporary societies preferentialtreatment of one sex over the other exists. If thestudy of LEH in these cultures reveals acorrelation between the high frequency of LEHepisodes and the poorly treated sex, it may beused as evidence for differential sex treatment inpast societies where cultural practices areunknown. However, when making comparisonsbetween the sexes, female buffering must betaken into consideration (Guatelli-Steinberg &Lukacs 1999:73). I The theory of femalebuffering suggests that females are betterbuffered against parasites and infectious diseaseas a result of the demanding role thatreproduction places on the female body. In fact,research on nutritional stressors has shown thatlong-term effects of protein deprivation are morepronounced in males than females. For example,Rhesus macaque females gain weight better andare more efficient when placed on a low proteindiet compared to males (Guatelli-Steinberg &Lukacs 1999:80). In humans, females may bemore resilient at birth, as males tend to be largerwith more muscle mass and less subcutaneousfat. This leads to a higher caloric requirementand less caloric reserves for males (Guatelli-Steinberg & Lukacs 1999:82). As a result ofevidence for female buffering, many studiespropose that males in a stressful environmentwill exhibit higher levels of LEH. In other words,LEH would only be found in females if theenvironmental stressors were high throughout theentire population. As such, a higher level of LEHin females than males might be used as a markerof preferential male treatment (GuateIIi-Steinberg & Lukacs 1999:118).

1) Zhou & Corruccini (1998)In 1998 Zhou & Corruccini conducted a

study comparing EH of males and femalesduring the Chinese famine (1959-1969). 3014individuals were sampled and Goodman'smodifications of Federation DentaireInternational (FDI) were used for theclassification of LEH. Age at LEH occurrencealso followed Goodman's 1987 methodology.

Zhou and Corruccini's study found that thechances of possessing LEH during famine wasgreater than while not in a famine, securing LEHas representative of stress from the famine. Interms of the male to female ratio of LEH, therewas no significant difference between rates ofindividuals possessing LEH (Zhou & Corruccini1998).

There were several reasons for this lack ofdifference between the sexes despite the well-

documented presence of male preferentialtreatment in China during this time period. First,the authors suggest that where there is high stressamong the population as a whole, as seenthrough high stress markers and high mortalityfor the time period, preferential treatment maydisappear as there is not enough resources totreat anyone preferentially. Second, females inChina were so selected against that they diedquickly without development of LEH, and wereremoved from the population studied. It is possible that many females were removedfrom the population due to premature death,since the death rate increased by 135% duringthe famine. However, females should posses lessLEH than males in stressful circumstancesbecause of female buffering; therefore, fmdingno significant differences between the sexescould be interpreted as weak evidence of malepreferential treatment.

The Zhou and Corruccini studyprovides some evidence of differential treatmentbetween the sexes despite the extreme andunusual circumstances of the Chinese famine.However, not all evidence of preferentialtreatment as seen through LEH comes fromunusual circumstances like a political famine,nor is all of the evidence weak.

2) Goodman et af. (1987)In 1987 Goodman et af. completed a

study on the prevalence and development ofLEH in Solis Valley, Mexico.This study is useful because it includes adiversity of socioeconomic and nutritional status.Furthermore, information concerning socialsystems and social practices was known

for every individual used in the study.The study consisted of 300 Latino children fromfive communities; all of the participants involvedwere part of the Collaborative Research SupportProgram. This longitudinal study provideddetails on each family and each individual,including information on anthropometry, foodhistory, psychosocial and behaviouraldevelopment, as well as socio-economic andenvironmental conditions. Goodman modifiedthe FDI's techniques for classification of LEHand other earlier dental techniques creating themethods used in Zhou and Corruccini'saforementioned study.

The female rate for EH in Goodman'sstudy was over twice as high on the mandibularlateral incisor (polar tooth). Furthermore, whilethe male rate for EH dropped after the third yearof life, the female rate of EH remained high

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(Goodman et at. 1987). From the rate of EH ineach developmental zone, it is unlikely that theincreased frequency in females over males wasrelated to differential attrition or eruption. Basedon these data the authors suggest that malesmight have had greater access to food, shelterand health care than females (Goodman et at.1987:18 May et al. 1993).

These two studies suggest that in somecommunities males received preferentialtreatment over females, resulting in less stress.This connection seen between LEH anddifferential sex treatment allows archaeologiststo hypothesize on preferential treatment of onesex over another. If males are being treatedpreferentially in a community, by way of betteraccess to medical attention or other resources,archaeologists can also begin to makedetenninations on what it would be like to be afemale living in that community. For example,preferential treatment can lead to changes infeelings of self worth (Barlow & Durand 2002).As such, females living in a community withmale preferential treatment may see themselvesas less worthy; which, may also contribute toother cultural beliefs or behavior within thecommunity. Furthennore, if archaeologists canidentify male preferential treatment, they canalso ask questions about fonns of resistance tothis belief system possibly reflected within art,architecture or other cultural remains.

Status DifferencesAs reviewed in the study of LEH in

detennining differential treatment of the sexes,the comparison of groups though the frequencyand number of LEH episodes can provide usefuldata for understanding the life of a child. Thissame process can be used to compare high statusto low status children. If the rates of LEH are thesame between the two groups (high status/lowstatus), it can be concluded that a high level ofstress across the population inhibits the ability toprotect children and, as such, they have similarstress levels and occurrences. Alternatively, thisfinding could suggest that children are treated asa unifonn group within the community and, assuch, their familial resources do not protect highstatus children. To detennine which is the morelikely scenario, an investigation into burialpractices may indicate the place of childrenwithin the culture.

If frequency/severity of LEH betweenhigh status and low status groups are different,with the low status group having lower

rates/severity of LEH, than one couldhypothesize that the poor children are dyingbefore LEH can develop; further, that the rate ofhigh LEH represents the survivors of high statuschildren, most likely to due differential access toresources. One way to detennine whether this isthe case would be to see if there is a spike in thedeath records, similar to the Chinese faminesituation. If there is a spike in the deaths ofchildren, then such a pattern could suggest LEHis a sign of survivorship rather than frailty.However, if the frequency/severity of LEH isdifferent, with the high status groups havinglower rates/severity of LEH, one couldhypothesize that high status children areprotected from stresses via familial access toresources. As a result, the high status childrenlead very different lives from the poor children.3) Lanphear (1990)

To examine this possibility I comparedKim Lanphear's 1990 study of the MunroePoorhouse population to the 1992 Little et at.study of the high status Weir family. Both ofthese studies involved the examination of clean,maxillary central incisors and the mandibularcanines. Hypoplasias were aged usingGoodman's revisions of MassIer's chronology(Lanphear 1990, Barbara Little, e-mail to authorOctober 212004).

In regard to samples, both studies dealtwith white populations in the Southern UnitedStates between the time period of 1826 to 1907.Lanphear's 1990 study consisted of 153individuals. Her research found that 84% of theindividuals under investigation had LEH. Little's1992 study found of the 13 individuals studied,53.8% had LEH. To accommodate for thedifference in sample size, a chi-squared analysisof the data was calculated. The calculationssuggest that the difference between these twopopulations was statistically significant (p >0.05).

Statistically, the Weir family sufferedsignificantly less linear enamel hypoplasia thanthose buried in the Munroe County PoorhouseCemetery. As such, the lives of the Weir familychildren were significantly different than thelives of the children from the Munroe Poorhousein tenns of stress levels. This difference in stresslevels is most likely a result of nutritionaldifferences since the groups are contemporarywith each other and geographically similar,although access to monetary and food resourceswould have differed.

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Research has suggested that moderate,but chronic nutritional deprivation in earlychildhood can temporarily retard acquisition ofmotor skills and may permanently stunt mentaldevelopment (Steckel 1986:738). There haveeven been studies that suggest that malnutritionchanges behavioural practices, with moderatelymalnourished children becoming apathetic,emotionally withdrawn, less aggressive, whilebeing more dependent (Steckel 1986:739). Thisfact suggests that the lives of the MunroePoorhouse children were perhaps less productiveand more emotionally withdrawn than those ofthe Weir family children.

WeaningResearch has consistently linked LEH

with times of high stress; as such, a spike of LEHseen across a community at a particular age mayreflect developmental stress. One of the moststressful times in growth and development is theweaning process. Due to this correlation of stressand weaning, an extensive amount of researchhas been conducted on the link betweennutritional pathological conditions and weaning.

During weaning there is a gradual lossof the nutrients and immunity previouslysupplied through breast milk. For instance, breastmilk is the most adequate source of vitamin Dfor infants. The reduced immunity, as a result ofthe loss of breast milk, is compounded by theincrease of contact from pathogens in theenvironment (Moggi-Cecchi et at. 1994: 303, Liet at. 1995, Cuccina 2002).The decrease in breastfeeding is also associated

with independence and a reduction in childcare(Terranova & Laviola 1995). Newfoundindependence results in more play and socialinteraction (Terranova & Laviola 1995). Thus, ifone could determine when breastfeeding ceasedone could then determine when a child becamemore independent and began to act as a socialbeing within the community (Howes &Matheson: 1992).

The weaning hypothesis states that dueto the high metabolic stress associated with thecessation of breastfeeding, LEH can be predictedto be greatest during this time period (Blakey etat. 1994). In fact, research has specifically linkedWeanling diarrhoea as an indirect cause of LEH,lending support to this hypothesis (White1994:288). However, the majority of studies fmdthat LEH increases slightly after the historicallydocumented weaning time. Such timing,however, does not necessarily discount the LEHweaning hypothesis (Blakey 1994).

4) Moggi-Cecchi et at. (1994)In 1994 Moggi-Cecchi et at. completed a studyon nineteenth century individuals who lived inFlorence, Italy. The project examined the age atwhich LEH first occurred. The study involved 83crania and was conducted using Goodman'smethodology for determining the age at whichLEH occurred. Historical data for the communitysuggested a weaning age of twelve to eighteenmonths. However, in Moggi-Cecchi et at.·sfmdings the age at which most individualsexperienced their first instance of LEH was oneand a half to two years of age, about six monthsafter the historically documented weaning time.Those data, however, do not discard the weaninghypothesis because weaning is a gradualreplacement of breast milk with food; so, a six-month lag in expressing the effects of reducednutrition and antibodies is possible.

Overall, most studies of LEH peaks alsoshow that peaks of hypoplasia tend to occur sixto nine months after the historically documentedweaning age. This has been attributed to "post-weaning stress" (Blakey et at. 1994:379). Post-weaning stress is associated with increased motorand language capabilities, which expose youngchildren to frequent contact with an increasednumber of individuals and more substances, thusincreasing the chance of developing disease(Blakey et at. 1994:379). Another reason whythe peak time tends not to match weaning time isthat hypoplasia has a bias towards more defectsduring the developmental phase (two to fouryears of age), which usually intersects the timeof weaning (Blakey et at. 1994:380). However,in Codone & Rose's 1992 study of microscopicenamel defects, no evidence of a bias was foundfor this developmental time period (cited inBlakey et aI.1994:380).

Determining the time of weaning stress,not just the begirming of the weaning process, isimportant because it helps identify when anindividual begins to have greater contact withenvironmental pathogens. The increased contactwith pathogens suggests more contact with otherindividuals in the community, includingplaymates.

In cats, mice and rats the cessation ofweaning, even at an early age, encourages ahigher level of play than in control specimenswho are still being weaned (Terranova & Laviola1995: 1268). This reveals information about achild's life since children who participate inearlier social play have been found to be more

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pro-social, sociable, as well as less aggressiveand withdrawn later in childhood (Howes &Matheson 1992: 969). It was also found that thechildren who show emergence of reciprocal playearly, exhibit an earlier development in co-operative play. (Howes & Matheson 1992:969)

Play is a crucial part of childhood as itcontributes to mathematical thinking (Jarell1998: 56), literacy development (Christie 1998:80), risk-taking decision-making (Jambor 1998),humour development (Berger 1998) and masteryof social skills in general (Freitag 1998). Suchresearch, which shows that the early weaning ofa child is associated with higher levels of playand early play, could help speed up the processof social maturity allowing a child to have moreresponsibility at an earlier age. Steckel's 1986study of North American slaves in the nineteenthcentury cites children's "transitions into the adultlabour force" by the age of six to seven. Steckelalso cites the weaning age as beginning as earlyas three months, based on the given mother'scotton-picking rates. The research suggests acorrelation, in this particular case, between earlyweaning and earlier life responsibility. However,at this point the hypothesis suggesting acorrelation between earlier breastfeeding andincreased responsibility is merely conjecture.Further studies cross-culturally would need to becompleted in order to correlate early weaningwith an increased early responsibility in children.

Future of Children in Archeaological StudiesThe study of LEH can begin to explore

what it would be like to be a child by providinginformation on such topics as preferentialtreatment, differences in rearing environmentsand the beginnings of individualization. Basedon the research discussed in this paper, it is clearthat LEH alone cannot offer enough data toconfIrm a particular claim with suffIcientauthority; good archaeological research requiresmultiple lines of evidence to substantiate a givenclaim. In the case of LEH, many differentmethods can be used to shed light on some of thequestions concerning the legitimacy of theclaims, or simply to back up a particular study'sfmdings.

To confmn the time of weaning in anindividual, nitrogen stable isotope analysis couldbe used; this would allow the social andbehavioural ramifIcations to be examined morereliably (Katzenberg 2000: 318). Further,isotopic studies can offer information on thetypes of diets children were consuming, in

addition to information on the migration patternsof individuals during their childhood years.These types of studies would create moreevidence that would allow for in-depthhypothesis testing on children in a particularculture. However, such isotopic studies havetheir drawbacks; fIrstly, isotopic studies areexpensive to conduct; secondly isotope analysisis a destructive technique that may not bepermitted on particular samples. However, withproper consent, isotopic studies in conjunctionwith LEH analysis could provide a clearerunderstanding of what it would be like to be achild in a particular society.

Another scientifIc technique that couldbe useful in these types of studies is DNAanalysis, it can identifY disease pathogens inskeletal remains. The technique would allow fora discovery of the pathogens contained within aparticular individual. This would assist thearchaeologists in pinpointing the cause of stressin an individual or population (Saunders &Barrens 1999).

Archaeological methods can also bolsterthe evidence provided by LEH studies. Todetermine whether children were seen as personswithin a society, archaeologists could studyburial patterns. For example, if children wereconsidered "outsiders" one could look to see ifnormal (i.e. adult) mortuary practices for thecommunity (i.e. location, grave goods, position)were applied to the graves of children (Crawford2000: 176). An example using archaeologicalmethods to determine the state of childhood isthe study of infanticide (cited in Mays2000: 180). To identifY infanticide in a particularcommunity, research can be completed on burialpractices combined with observing peaks in ageat death near the time of birth (Mays 2000: 181).The practice of infanticide may indicate thebelief that newborns were not consideredpersons. This is a notion that is not all thatuncommon. In fact, Tooley (1983) argued thatuntil an infant has a concept of self, it is not aperson; as such, infanticide is acceptable (Mays2000: 181). In other cultures, reaching milestonesmay have been required before an infant/childwas considered a person/member of thecommunity, such as eating solid foods, walking,teething or receiving a name (Mays 2000: 182).Whatever the reason, information on both burialplace and birthrates may provide insight into thelives of children.

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Children have the power to influenceadults. In psychological studies, it has beenfound that experiences with child interaction, andnot necessarily with the adult's own child,caused the adults in the study to: change valuesor priorities; recall forgotten or repressedmemories from their own childhood; becomemore creative and more cognitively flexible; andobserve the world with wonder and curiosity(Dillon 2002: 267). Psychology suggests that thereason for this strong influence of children onadults is related to genetic stratification; a theorywhereby earlier modes of knowledge are notreplaced by new ones, but coexist along aparallel line instead. As such, there are functionaland multiple modes of knowledge existingwithin an adult. It is also theorized that theinfluence of children is due to dynamicintersubjectivity. This theory suggestsdevelopment in adults does not move in a singleline; instead, it reunites knowledge acquiredfrom infancy and childhood with that knowledgegained in adolescence and adulthood (Dillon2002:273). These psychological theories showhow children affect the lives of the adults aroundthem, be it how they remember their own past orhow they think as an adult.

Furthermore, children are not merelysmaller versions of adults; rather, they maintaintheir own sense of identity, world-view, prioritiesand social networks (Wilkie 2000: I00, Crawford2000). As such we cannot simply apply adultbeliefs, social practices and behaviours acrossthe population as a whole. More importantly,when conducting an excavation, it must beremembered that, "children contribute to thearchaeological record whether or not we arecompetent to recognize them" (Chamberlain1997:249 emphasis original).

The children of today are the adults andleaders of tomorrow; as such, understanding thesort of childhood they experienced not onlyallows bioarchaeologists to better understand thissegment of society, but it also allowsbioarchaeologists to understand why changesmay have occurred. While LEH may onlyprovide a glimpse into the past, it does provideand excellent starting point to fully investigatethe lives of children.

AcknowledgementsI would like to acknowledge Lisa Hodgetts andthe anonymous reviewers for their helpful

comments. I would also like to extend my thanksto Barbara Little for her assistance.

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