Reproduction process in Hunter-fisher-gatherers Multi Agents Simulation J

Reproduction process in Hunter-fisher-gatherers: Multi Agents Simulation J. Estévez Universitat Autònoma de Barcelona A. Vila Spanish National Research Council (CSIC) IMF- CSIC

1. POSTING THE QUESTION

EXTANT HUMAN SPECIES REPRODUCTIVE POTENTIAL IS VERY HIGH 1 United Nations Demographic Yearbook ('51). CRUDE ANNUAL RATES OF INCREASE*1000 Hutterites (1941 -1950) 41. 5 Israel (1948 ) 20. 2 Algeria (Moslem) (1940) 19. 3 Jamaica (1948) 17. 7 United States (1948) 14. 3

THE EXEMPLE OF THE HUTERITES The ANNUAL GROWING RATE of Huterites Implies that they could completelly fill up the whole African continent with a density of one person per square meter in just 750 years 750 YEARS 100 YEARS 40, 000. 00 800, 000, 000. 00 35, 000. 00 700, 000, 000. 00 30, 000. 00 600, 000, 000. 00 25, 000. 00 500, 000, 000. 00 20, 000. 00 400, 000, 000. 00 15, 000. 00 300, 000, 000. 00 10, 000. 00 200, 000, 000. 00 5, 000. 00 100, 000, 000. 00 1 2 3 4 5 6 7 8 9 101112131415161718192021 1 4 7101316192225283134374043464952555861646770737679828588919497

EXTANCT HUNTER-GATHERER HAVE: Social norms that emphasize the management of reproduction Very different growing rates and sometimes an impressive capacity for recovery The PREHISTORY of HUNTER-GATHERER SHOWS: Long term demographic stability

Annual grow +0. 7% (Ache), – 0. 2% (Agta), +1. 3% (Hadza) +0. 26% (!Kung) The mean for agta women was 7 live children a 26% could die before 15. The maximum potential fertility was 14, 5. 1990 1930 COAST SALISH POPULATION RECOVERY

MODERN HG SHOW VERY DIFFERENT GROWING RATES AND SOMETIMES AN IMPRESSIVE CAPACITY OF RECOVERY

What is “NATURAL” is the ABILITY to procreate, but NOT the FACT of PROCREATE. The set of variables on which depends natural fertility can be and are indeed socially modified.

THE “FACT” The process of social reproduction is regulated by SOCIAL NORMS which direct all parts of the process: prior to pregnancy, childbirth, feeding and care, education… Each part involves labor (social relationships), products, spaces, etc. like any other process.

HOW Demographic grow can be be managed (reduced) by: Demographic grow can managed (reduced) by: Demographic grow can be managed (reduced) by: Controlling intercourse o Controlling intercourse fertile women. infantile. regulating the availability of mortality of INTENTIONALLY increasing reducingthe biased managed in HRAFS 48% of contact between men infantile mortality o Increasing societiesfemale and women. recognize o lowering theagainstof women (food taboos, prolonged breastinfanticide fertility a 11% that do not practice it. feeding…) is managed mostly by parents (mothers) Infanticide o with norms of celibacy and abstinence. o with frightening morals and rituals o …

Simulations show the great impact of such practices

HOMINIDAE BIOLOGICAL DYNAMICS CO-EVOLUTIONATED DISEASES DEPREDATION STARVATION CARRYING CAPACITY

HUMAN SOCIAL DYNAMICS CO-EVOLUTIONATED MIGRATION ILLNESS FIRE-TECNOLOGY DEPREDATION MUTUAL AID STARVATION SHARING TECNOLOGICAL DEVELOPMENT CARRYING CAPACITY

HUMAN SOCIAL DYNAMICS EFFORT INVESTMENT IN SOCIAL NORMS: STRUCTURAL VIOLENCE: N MI GR TIO A INTENSIFICATION CARRYING CAPACITY SEXUAL RESTRICTIONS SOCIAL DIVISION OF LABOR STRATEGIES INEQUALITY REDISTRIBUTEDPUNISHMENT INFANTICIDE HOMICIDE-WAR

Modern HG Societies throughout history will have learned from their accumulated experience and have developed strategies and norms with which they have successfully managed their reproduction and sustainability.

HOW WAS IT IMPLEMENTED? Our thesis is: Through the sexual division of labor. Subsequently asymetry between men and women can be easely stablished. It is also easy to justificate advoquing biological diferences. Thus division of labor is not a biological bias but the historical consequence of reproductive strategies to manage the demographic variable in those societies

It may have been the functional social alternative at a “given” moment It is clearly evident in most CR ethnographic societies.

WHEN, HOW AND WHY IN EVERY CASE are now archaeological questions. This is the aim of our research

WHAT’ S OUR AIM We propose first to verify thesis that -The axis that determines the development of HG societies depends on reproduction and -that the control is exercised a decisive through social norms. -

Reproduction processes are ultimately dependent on exposure to fertilization. This variable is fully regulated socially. The social relations of reproduction and how they are articulated are the basis for social explanation. We can simulate its operation by - Multiagent Systems. - Significant sample constituted by a broad spectrum of ethnographic societies.

THEREFORE Ethnoarchaeology to observe the realization of these rules in a archaeological record. Agent based simulation

1986 -2005 Ethnoarchaeology of yamana and sel’knam sites 2008 -2010: Mechanisms of Autoregulation and Social Control generating Social Norms. 2011 - 2014: Ethnoarchaeological Approach to Reproduction in H-Gatherer Societies.

ANALYSIS OF 4 ETNOGRAPHIC CASE STUDIES SW ALASKA (Inupiat) NW coast of America (Coast Salish) Fueguian canoe people(Yamana) Terrestrial HG of T. Fuego (Selknam ) Yolgnu of North Australia Based mainly on the earliest ethnographic accounts

M. A. SIMULATION Simulation of the effect of social norms on the reproduction of HG groups: Fueguian Coast Salish Yolnu Based mainly on the first ethnographic accounts

HOW Schematizing the life course of men and women Extracting and standartizing the norms and rules involved and affecting the reproduction rates. Simulating the effect of norms on societies of agents with biological and reputation (prestige and punishment) impulses.

1 ST STEP- SCHEMATIZING

infant 3 boy Adoles cent fertile 4 Ciexaus ENVIRONMENT HAZARDS Sexual segregation pairing single paired marriage married birth widowed +2 Kina poly gam my divorced disease accident death Yamana boy

infant 2 4 boy ENVIRONMENT HAZARDS Sexual segregation 7 pairing Adoles cent fertile paired single Hain widowi ng birth +1 married marriage divorce poly gam my disease accident Abandon ment death Selk’nam boy divorced widowed

infant girl 3 4 ENVIRONMENT HAZARDS Sexual segregation pairing Adoles cent menarc he single paired Ciexaus marriage ± 13 married widowi ng widowed Fertility rate embarrac e abortion PREGNANT birth disease accident death Yamana girl

infant 2 girl 4 7 ENVIRONMENT HAZARDS Sexual segregation pairing Adoles cent menarc he paired single ± 13 Fertility rate abortion embarrac e widowi ng PREGNANT widowed birth marriage married divorce disease accident death Abandon ment Selk’nam girl divorced

2. OBJECTIVE EVALUATION OF THE EFFECTIVENESS OF SOCIAL NORMS FOR THE MANAGEMENT OF REPRODUCTION: Demographic growth can be managed (reduced) by: Controlling intercourse o regulating the availability of fertile women. o reducing contact between men and women. o lowering the fertility of women (food taboos, prolonged breastfeeding…) o with norms of celibacy and abstinence o with frightening morals and rituals o … Increasing biased female infantile mortality

4. METHODOLOGY: AGENT-BASED SIMULATION TO TEST THE EFFECTS OF SOCIAL NORMS ON DEMOGRAPHY “Agent -based models, simulated over time, can elucidate the relationship between individual or group (human) decisions and the social structures which both results from and constrain those decisions” Cathy A. Small (2000). THE AIM IS NOT TO SIMULATE A WHOLE SOCIAL SYSTEM BUT TO TEST THE EFFECT OF THE DIFFERENT PARAMETERS INVOLVED

Ethnological studies Demografic and biologial reproduction studies Information about the social norms and behaviour Individuals’ biological general behaviour Current climate, biological and ethological studies Information about the environment and resources Paleontological studies Extensive list of social norms Agent simulation system Environment & resources Normative behaviour list of relevant social norms List of generalized social norms

Biological laws (community) Age fertility distribution, Age dead rate Community: agents list Individual Agent Attributes Environment, family, name, sex, parents, genes XY, health, libido, boldness, rulesrespect , reputation, social status, biological status, Engine program (Java) Community: new agents list Current Individual Agent Attributes Capsules Biological laws ponderation: i. e. : breasting time ammenorrea, accident rate by age… Norms Preconditions (trigger) Limitations consequences Stats: mortality rate, fecundity, health rates, norm acomplishment rate, deliveries, infanticides, number of children…

OUTPUTS 9000 8000 7000 120% 6000 tot null 5000 tot newborn 4000 tot infants tot adolescent 3000 tot adults 2000 Fgirlkilled 100% 80% F killed 60% M killed 40% tot newborn 20% 1000 1 22 43 64 85 106 127 148 169 190 0% 1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 0 adults females/males 120% 100% 80% 60% 40% 20% 1 12 23 34 45 56 67 78 89 100 111 122 133 144 155 166 177 188 199 0%

OUTPUTS mean grow rate for previous 10 years 0. 04 Annual grow rates 0. 03 1. 22 1. 2 0. 02 1. 18 0. 01 1. 16 1. 14 17 24 31 38 45 52 59 66 73 80 87 94 101 108 115 122 129 136 143 150 157 164 171 178 185 192 0 1. 12 1. 1 -0. 01 1. 08 -0. 02 1. 06 INDIVIDUAL’S STORIES -0. 03 LINEAGES 17 27 37 47 57 67 77 87 97 107 117 127 137 147 157 167 177 187 197 1. 04 deads by 5 years age cohorts 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 3500 3000 Population 2500 Births 2000 Deads 1500 males Abortions 1000 females total 1 22 43 64 85 106 127 148 169 190 500 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

5. EXAMPLE AND TESTED PARAMETERS: USING YAMANA NORMS q YAMANA NORMS SIMULATION Versus NO restrictions –or- MORE restrictive NORMS q POLYGAMY q INFANTICIDE BECAUSE LOW HEALTH q FEMALE INFANTICIDE BECAUSE EXCESS GIRLS q q

EMERGING PATTERNS NO SOCIAL RULES (300 years) mean of growth index for 10 years There are biological cycles of 30 aprox. years

RESULTS global population (after 100 years x 30 essays) No infanticide, no restrictions poligamy No infanticide monogamy Infanticide 4 th girl Infanticide 3 th girl Maximal restrictions

Mean for 10 years growing rate 1. 3 1. 25 1. 2 min 3 girls 4 girls increase in 10 years 1. 15 no infan no polig no restrict no poligam max potent poligam 1. 1 max repr no poligam 1. 05 1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97 101 105 109 113 117 121 125 129 133 137 141 145 149 153 157 161 165 169 173 177 181 1

1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97 101 105 109 113 117 121 125 129 133 137 141 145 149 153 157 161 165 169 173 177 181 Mean for 10 years growing rate 1. 3 1. 25 1. 2 1. 15 min 4 girls max repr no poligam 1. 1 1. 05 1

Num. of women with n children 450 400 350 num childs born 300 minimal 3 girls 250 4 girls no infanticide 200 no infantici no polig no restrictions with poligamy max potential with poligamy 150 max pot without polig 100 50 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Num. of women with n children 450 400 350 300 250 num childs born minimal 4 girls 200 max pot without polig 150 100 50 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

4 s fa n in g ici irls de tic id poli m e g ax po no no p te nt res olig tri ia m l wit c po ax h lig p po t w olig ith am ou y tp ol ig nt fa 0 no 5000 Males gir l Females AL 7. 00 30000 3 10000 IM 20000 IN ig ol tp y lig am ou ith tw po po po lig po 25000 M ax ith ric st re no lig po gir ls 35000 in m lw ia nt te po no e id tic fa n in 4 ici de nt fa in gir ls ABSOLUTE NUM. of males & females no ax m no no 3 AL IM IN M DEMOGRAPHIC PATTERNS Mean NUM. of chidren born & alive 8. 00 6. 00 5. 00 4. 00 15000 3. 00 childs born 2. 00 CH. Alive 1. 00 0. 00

SOME MORE CONCLUSIONS In a small population a catastrophic growing rate is hard to perceive along 100 years. Thus REPRODUCTION IS VERY DIFFICULT TO MANAGE consciously and strategies will arise The more restrictive rules the less variability along the experiments.

SOME MORE CONCLUSIONS Polygyny is an effective method to reduce reproduction. Infanticide is the last resort strategy to manage efficiently demographic growing potential of modern humans but the most effective Restrictive social norms and structural violence (for instance, female infanticide) would require of an ideological justification.

FINAL REMARK HG do not consciously attempt to create an optimal pattern of norms for sustainability in reproduction. Nonetheless, such patterns occur and are typical, but how did they get the solution? We are still working to test our answer to this question.

These are some results of te Reseach Project HAR 2011 -24356 ETHNO-ARCHAEOLOGICAL ANALYSIS OF REPRODUCTION IN HUNTER-GATHERER SOCIETIES With the participation of M. Gándara (INAH- Mexico), I. Davidson (UNE- Australia), C. Grier (WSU- USA), M. Pérez (ESPOL- Equador), J. Salius (UAB), M. Blake UBC- Canada), E. Mansur (CONICET- Argentina), Alfredo Prieto (Ud. M-Chile).