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标题: The Evolution of Norms [打印本页]

作者: 春天的风筝    时间: 2009-4-23 08:49     标题: The Evolution of Norms

Paul R. Ehrlich is with the Department of Biological Sciences, Stanford University (Stanford, California, United States of America). Simon A. Levin is with the Department of Ecology and Evolutionary Biology, Princeton University (Princeton, New Jersey, United States of America).
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Over the past century and a half, we have made enormous progress in assembling a coherent picture of genetic evolution〞that is, changes in the pools of genetic information possessed by populations, the genetic differentiation of populations (speciation) (see summaries in [1,2]), and the application of that understanding to the physical evolution of Homo sapiens and its forebears ([3]; e.g., [4,5]). But human beings, in addition to being products of biological evolution, are〞vastly more than any other organisms〞also products of a process of ※cultural evolution.§ Cultural evolution consists of changes in the nongenetic information stored in brains, stories, songs, books, computer disks, and the like. Despite some important first steps, no integrated picture of the process of cultural evolution that has the explanatory power of the theory of genetic evolution has yet emerged.2 b$ d, k$ k% R$ n

0 M7 Q. _6 y) o* X* M0 x, ^* BMuch of the effort to examine cultural evolution has focused on interactions of the genetic and cultural processes (e.g., [6], see also references in [7]). This focus, however, provides a sometimes misleading perspective, since most of the behavior of our species that is of interest to policy makers is a product of the portion of cultural evolution [8] that occurs so rapidly that genetic change is irrelevant. There is a long-recognized need both to understand the process of human cultural evolution per se and to find ways of altering its course (an operation in which institutions as diverse as schools, prisons, and governments have long been engaged). In a world threatened by weapons of mass destruction and escalating environmental deterioration, the need to change our behavior to avoid a global collapse [9] has become urgent. A clear understanding of how cultural changes interact with individual actions is central to informing democratically and humanely guided efforts to influence cultural evolution. While most of the effort to understand that evolution has come from the social sciences, biologists have also struggled with the issue (e.g., p. 285 of [10], [11–16], and p. 62 of [17]). We argue that biologists and social scientists need one another and must collectively direct more of their attention to understanding how social norms develop and change. Therefore, we offer this review of the challenge in order to emphasize its multidisciplinary dimensions and thereby to recruit a broader mixture of scientists into a more integrated effort to develop a theory of change in social norms〞and, eventually, cultural evolution as a whole.6 _" x5 x$ n$ U* x8 O4 G

3 P/ n  o% k0 W7 rWhat Are the Relevant Units of Culture$ f% t* q/ e6 U( d

+ G0 f8 O4 g# _Norms (within this paper understood to include conventions or customs) are representative or typical patterns and rules of behavior in a human group [18], often supported by legal or other sanctions. Those sanctions, norms in themselves, have been called ※metanorms§ when failure to enforce them is punished [17,19,20]. In our (liberal) usage, norms are standard or ideal behaviors ※typical§ of groups. Whether these indeed represent the average behaviors of individuals in the groups is an open question, and depends on levels of conformity. Conformity or nonconformity with these norms are attributes of individuals, and, of course, heterogeneity in those attributes is important to how norms evolve. Norms and metanorms provide a cultural ※stickiness§ (p. 10 of [21]) or viscosity that can help sustain adaptive behavior and retard detrimental changes, but that equally can inhibit the introduction and spread of beneficial ones. It is in altering normative attitudes that changes can be implemented.; t7 N. k+ S7 @1 P# }$ M

2 ^/ o% j+ b1 {Here, we review the daunting problem of understanding how norms change, discuss some basic issues, argue that progress will depend on the development of a comprehensive quantitative theory of the initiation and spread of norms (and ultimately all elements of culture), and introduce some preliminary models that examine the spread of norms in space or on social networks. Most models of complex systems are meant to extract signal from noise, suppressing extraneous detail and thereby allowing an examination of the influence of the dominant forces that drive the dynamics of pattern and process. To this end, models necessarily introduce some extreme simplifying assumptions.5 c8 _, d+ H" ^4 H/ }# W
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Early attempts to model cultural evolution have searched for parallels of the population genetic models used to analyze genetic evolution. A popular analogy, both tempting and facile, has been that there are cultural analogues of genes, termed ※memes§ [22,23], which function as replicable cultural units. Memes can be ideas, behaviors, patterns, units of information, and so on. But the differences between genes and memes makes the analogy inappropriate, and ※memetics§ has not led to real understanding of cultural evolution. Genes are relatively stable, mutating rarely, and those changes that do occur usually result in nonfunctional products. In contrast, memes are extremely mutable, often transforming considerably with each transmission. Among humans, genes can only pass unidirectionally from one generation to the next (vertically), normally through intimate contact. But ideas (or ※memes§) now regularly pass between individuals distant from each other in space and time, within generations, and even backwards through generations. Through mass media or the Internet, a single individual can influence millions of others within a very short period of time. Individuals have no choice in what genes they incorporate into their store of genetic information, and the storage is permanent. But we are constantly filtering what will be added to our stored cultural information, and our filters even differentiate according to the way the same idea is presented [24,25]. People often deliberately reduce the store of data (for example, when computer disks are erased, old books and reprints discarded, etc.), or do so involuntarily, as when unreinforced names or telephone numbers are dropped from memory. Such qualitative differences, among others, ensure that simple models of cultural evolution based on the analogy to genetic evolution will fail to capture a great deal of the relevant dynamics. A model framework addressed to the specific challenges of cultural evolution is needed.
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; T* J! @& m& s" x, cIn the models discussed below, the most basic assumption is that the spread (or not) of norms shares important characteristics with epidemic diseases. In particular, as with diseases, norms spread horizontally and obliquely [14], as well as vertically, through infectious transfer mediated by webs of contact and influence. As with infectious diseases, norms may wax and wane, just as the popularity of norms is subject to sudden transitions [3]. On the other hand, there are unique features of cultural transmission not adequately captured by disease models, in particular the issue of ※self-constructed§ knowledge, which has long been a source of interest, and the development of problem-solving models in psychology ([26, 27]; D. Prentice, personal communication). New syntheses are clearly required.2 Y; O3 I+ L' A' T0 E8 P; a

5 M$ @5 p! f- O; n" kMicroscopic Dynamic
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Substantial progress has been made toward the development of a mathematical theory of cultural transmission, most notably by Cavalli-Sforza and Feldman [14], and Boyd and Richerson [11]. Cavalli-Sforza and Feldman consider the interplay between heritable genetic change and cultural change. This is an important question, addressed to the longer time scale, with a view to understanding the genetic evolution of characteristics that predispose individuals to act in certain ways in specified situations. For many of the phenomena of interest, however, individual behaviors have not evolved specifically within the limited context of a single kind of challenge, but in response to a much more general class of problems. Efforts to provide genetic evolutionary explanations for human decisions today within the narrow contexts in which they occur may be frustrated because generalized responses to evolutionary forces in the distant past have lost optimality, or even adaptive value. Extant human behaviors for example may be the relics of adaptations to conditions in the distant past, when populations were smaller and technology less advanced. Attempts to understand them as adaptive in current contexts may therefore be futile. Thus, we prefer to take the genetic determinants of human behavior (that, for example, we react strongly to visual stimuli) as givens, and to ask rather how those initial conditions shape individual and social learning [3]. Similar efforts have been undertaken by others, such as Henrich and Boyd [28] and Kendal et al. [20].
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: c& ^+ {' u8 y* a/ N9 G. f, AThe sorts of models put forth by Cavalli-Sforza and Feldman, Boyd and Richerson, and others are a beginning towards the examination of a colossal problem. To such approaches, we must add efforts to understand ideation (how an idea for a behavior that becomes a norm gets invented in first place), and filtering (which ideas are accepted and which are rejected). How many ideas just pop up in someone's brain like a mutation How many are slowly assembled from diverse data in a single mind How many are the result of group ※brainstorming§ How, for example, did an idea like the existence of an afterlife first get generated Why do ideas spread, and what facilitates or limits that spread What determines which ideas make it through transmission filters Why are broadly held norms, like religious observance, most often not universal (why, for instance, has atheism always existed [29,30]) Ideas may be simply stated, or argued for, but transmission does not necessarily entail the reception or adoption of behaviors based on the idea, e.g., [31]. What we accept, and what gets stored in long-term memory, is but a tiny sample of a bombardment of candidate ideas, and understanding the nature and origin of filters is obviously one key to understanding the life spans of ideas and associated behaviors once generated.
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The Emergence of Higher-Level Structure: Some Simple Models, s+ C- W$ \0 `% w2 k

4 T& k  G+ X0 W0 k, eOur filters usually are themselves products of cultural evolution, just as degrees of resistance of organisms to epidemics are products of genetic evolution. Filters include the perceived opinions of others, especially those viewed as members of the same self-defined social group, which collectively attempt to limit deviance [32–34]. ※Conformist transmission,§ defined as the tendency to imitate the most frequent behavior in the population, can help stabilize norms [28] and indeed can be the principal mechanism underlying the endogenous emergence of norms. The robustness of norms can arise either from the slow time scales on which group norms shift, or from the inherent resistance of individuals to changing their opinions. In the simplest exploration of this, Durrett and Levin (unpublished data) have examined the dynamics of the ※threshold§ voter model, in which individuals change their views if the proportion of neighbors with a different opinion exceeds a specified threshold. Where the threshold is low, individuals are continually changing their opinions, and groups cannot form (Figure 1A). In contrast, at high thresholds, stickiness is high〞opinions rarely change〞and the system quickly becomes frozen (Figure 1B). Again, groups cannot form. In between, however, at intermediate thresholds (pure conformist transmission), groups form and persist (Figure 1C). In the simplest such models in two dimensions, unanimity of opinions will eventually occur, but only over much longer time periods than those of group formation (see also [20]). When the possibility of innovation (mutation) is introduced in a model that considers linkages among traits and group labels, and where individuals can shift groups when their views deviate from group norms sufficiently, multiple opinions and multiple groups can persist, essentially, indefinitely (Figure 1D).
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(A) Long-term patterning in the dynamics of two opinions for the threshold voter model with a low threshold.5 M# |/ ]1 V# p$ V

. C4 ~) k5 s! j1 B0 T- m# j7 l(B) Long-term patterning in the dynamics of two opinions for the threshold voter model with a high threshold. Note the existence of small, frozen clusters.1 i  A6 x$ |7 M: y4 y( ]
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(C) Long-term patterning in the dynamics of two opinions for the threshold voter model with an intermediate threshold. Note the clear emergence of group structure.* X8 ^- Z+ [# B: O9 Q

3 `7 l* q6 x% F1 Y+ z(D) Long-term patterning in a model of social group formation, in which individuals imitate the opinions of others in their (two) groups, and others of similar opinions, and may switch groups when their views deviate from group norms.
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3 o# H$ b4 P" H/ @# P; AThe formation of groups is the first step in the emergence of normative behavior; the work of Durrett and Levin shows that this can occur endogenously, caused by no more than a combination of ideation and imitation. The existence of a threshold helps to stabilize these groups, and to increase stickiness; furthermore, if threshold variation is permitted within populations, these thresholds can coevolve with group dynamics. What will the consequences be for the size distribution of groups, and for their persistence Will group stability increase, while average size shrinks What will be the consequences of allowing different individuals to have different thresholds, or of allowing everyone's thresholds to change with the size of the group When payoffs reward individuals who adhere to group norms, and when individuals have different thresholds, will those thresholds evolve The answers to such questions could provide deep insights into the mechanisms underlying the robustness of norms, and are ripe for investigation through such simple and transparent mathematical models.
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Modeling may also shed light on why some norms (like fashions) change so easily, while others (like foot binding in imperial China) persist over centuries, and more generally on how tastes and practices evolve in societies. Norms in art and music change rapidly and with little apparent effort at persuasion or coercion. But three-quarters of a century of communism barely dented the religious beliefs of many Russians, despite draconian attempts to suppress them [35], and several centuries of science have apparently not affected the belief of a large number of Americans in angels and creationism (e.g., [36,37]). Then there are the near-universal norms, such as the rules against most types of physical assault or theft within groups that, although they vary in their specifics, are interpreted as necessary to preserve functional societies. Group-selection explanations for such phenomena (e.g., [12]) are, we argue, neither justified nor necessary (see also pp. 221–225 of [38], [39]). Such behaviors can emerge from individual-based models, simply involving rewards to individuals who belong to groups.
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There are degrees: the evolution of cooperation is facilitated by tight interactions, for example when individuals interact primarily with their nearest neighbors [40,41], and the payoffs that come to individuals from such cooperation can enhance the tightness of interactions and the formation of groups. This easily explains why mutually destructive behaviors, like murder, are almost universally proscribed. Group benefits can emerge, and can enhance these effects, but it is neither necessary nor likely that group selection among groups for these behaviors overrides individual selection within groups when these groups are not composed of closely related individuals [42].
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Simple models could address such things as the role of contagion in cultural evolution, recognized in one of the first works on psychology [43] in the context of religious revivals and belief, as what has been described as ※pious contagion§ (p. 10 of [30]). But models must also address issues such as the roles of authority or moral entrepreneurs (individuals engaged in changing a norm) [32], to say nothing of the impacts of advertising and the norm-changing efforts of the entertainment and other industries. In reality, we are intentioned agents who act with purpose. In maturing, we master the norms that have been evolved over a long period, but to which we may adapt in different ways and even (in the case of moral entrepreneurs) strive to change.8 N4 U$ J; f/ v) X/ V* ~

0 Y2 K0 ?8 `- F' }' b4 z3 LFor a moral entrepreneur, a group that is too small may have little influence and be not worth joining. But large groups may be too difficult to influence, so also may not be worth joining. For such individuals, there is likely an optimal group size, depending on the change the individual wants to effect. Groups also introduce ancillary benefits of membership that change the equation. Such considerations influence decisions such as whether to join a third party effort in a political campaign; understanding the interplay between individual decisions and the dynamics of party sizes is a deeply important and fascinating question, with strong ecological analogies. Groups, collectively, must also wrestle with the costs and benefits of increasing membership, thereby enhancing influence while potentially diminishing consensus and hence the perceived benefits to members.: K( h. a0 K- T3 B

2 v- S  O5 }+ R9 z; l( D2 DInnovation and Conservatism
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Cultural evolution, like biological evolution, contains what we like to call the ※paradox of viscosity.§ Evolving organisms must balance the need to change at an appropriate rate in response to varying environmental conditions against the need to maintain a functioning phenome. This trade-off between conservatism and adaptability, between stability and exploration, is one of the central problems in evolutionary theory. For example, how much change can there be in the genes required to maintain adaptation in a caterpillar without lethally affecting the structure and functioning of the butterfly (p. 303 of [44]) Conservatism in religion might be explained by the lack of empirical tests of religious ideas. But even in military technology and tactics, where empirical tests are superabundant, changes are slower than might be expected. For example, the British high command in World War I did not react rapidly to the realities of barbed wire, massed artillery, and machine guns [45]. Even so, the conservatism of the generals may be overrated [46].) c+ D8 R9 W6 c" E+ y
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Macroscopic Dynamics) T. s- [6 u+ g( E
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We have thus far examined the evolution of norms in isolation〞as how the views of individuals (and thus the constituents of a pool of nongenetic information) change through time. But everywhere in common discourse and technical literature, it is assumed that norms are bundled into more or less discrete packages we call cultures, and that those packages themselves evolve. Recall that everyday notions such as that American culture of the 1990s was very different from that of the 1960s, that Islamic culture did not undergo the sort of reformation that convulsed Christian culture (for example, [47]), and that Alexander the Great carried Greek culture throughout the Mediterranean and as far east as Persia. The problem of defining ※cultures§ in cultural evolution seems analogous to that of defining ※species§ (or other categories) in genetic evolution. There has been a long and largely fruitless argument among taxonomists over the latter [48], and an equally fruitless debate in anthropology (and biology) on the definition of culture [39, 49–57].
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/ R% H) M6 r4 c& gAgain, we suggest that the parsing of the various influences that create and sustain norms and cultures are ripe for theoretical modeling, but it must begin to incorporate the full richness on multiple scales of space, time, and complexity. Durrett and Levin [3] develop a model integrating the dynamics of clusters of linked opinions and group membership; appropriate extensions would allow group characteristics to evolve as well, but on slower time scales. The oversimplicity of models of symmetric imitation on regular grids, as represented in our simple models, must give way to those that incorporate fitnesses and feedbacks, as well as asymmetries and power brokers, on more complex networks of interaction [58].! i3 f1 p$ G) e& z4 K: i% E
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Challenges and Hypotheses" n: b. O  z. _  j7 W
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One of the major challenges for those interested in the evolution of norms is, at the most elementary level, defining a norm. This is related to another general problem of defining exactly what is changing in cultural evolution〞which we might call the ※meme dilemma§ in honor of Dawkins' regrettably infertile notion. A second major challenge is discovering the mechanism(s) by which truly novel ideas and behaviors are generated and spread. A third is discovering the most effective ways of changing norms.  P( Y. b% X+ ~9 A# I  L9 a6 |$ @
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We've got a long way to go before being able to meet those challenges. One place to start is to begin formulating hypotheses about the evolution of norms that can be tested with historical data, modeling, or even (in some cases) experiments. Some hypotheses we believe worth testing (and some of which may well be rejected) are given in Box 1.2 Z2 R! }' X% o8 A8 H: S* X

4 m, g9 D; u9 J7 w  o, Y6 H0 PBox 1. Sample Hypotheses about the Evolution of Norms
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Hypothesis 1. Evolution of technological norms will generally be more rapid than that of ethical norms.
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Technological changes are generally tested promptly against environmental conditions〞a round wheel wins against a hexagonal one every time, and the advantages of adopting it are clear to all. Ethical systems, on the other hand cannot often be tested against one another, and the standards of success are not only generally undetermined, they often vary from observer to observer and are the subject of ongoing controversy among philosophers.
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' m, ~; s7 d( ^, vHypothesis 2. In societies with nonreligious art, the evolution of norms in art will be more rapid than those in religion.
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9 O8 R' w4 s3 t0 d* [. z) jWe hypothesize that art is less important to the average individual than his or her basic system of relating to the world, and conservatism in the latter would be culturally adaptive (leading to success within a culture).
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Hypothesis 3. Military norms will change more in defeated nations than victorious ones.
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8 Y( `0 [. \) L6 n' O; ?* b9 [Was the Maginot Line and the generally disastrous performance of the French army in 1940 an example of a more general rule Does success generally breed conservatism
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Hypothesis 4. The spread of a norm is not independent of the spread of others, but depends on the spread of other norms (norm clusters).
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3 n  S% o  Y. T& q: N8 _4 fDoes, for example, empathy decrease with social stratification
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& I, I3 i+ P1 C% f  ~Hypothesis 5. Susceptibility to the spread of norms is negatively correlated with level of education.
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Are the less educated generally more conformist, or does the spread of norms depend almost entirely on the character of the norm% |8 D6 v9 J% X* g! o

7 o! B- X$ u  w. U; K0 z  r& RHypothesis 6. Horizontal transmission will show less stickiness than vertical transmission.# D/ A  \) ~) k
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This conjecture is based on anecdotal observations that norms like using hula hoops come and go and are primarily horizontally transmitted, and religious values and other high-viscosity points of view are mostly vertically transmitted (p. 129 of [14], [59])./ t8 `/ m0 I/ D5 G, a

( a7 A& L$ z+ {* PBox 1. Sample Hypotheses about the Evolution of Norms8 S& [0 [* Q: }0 [- s
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Hypothesis 1. Evolution of technological norms will generally be more rapid than that of ethical norms.
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  S- G3 g" U% x& D3 i& ]! o- ^# sTechnological changes are generally tested promptly against environmental conditions〞a round wheel wins against a hexagonal one every time, and the advantages of adopting it are clear to all. Ethical systems, on the other hand cannot often be tested against one another, and the standards of success are not only generally undetermined, they often vary from observer to observer and are the subject of ongoing controversy among philosophers.# z& W/ Y' I, N' E

; v  H+ n. f2 \- ?2 LHypothesis 2. In societies with nonreligious art, the evolution of norms in art will be more rapid than those in religion.# h! H0 [, j; k. N- O& g
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We hypothesize that art is less important to the average individual than his or her basic system of relating to the world, and conservatism in the latter would be culturally adaptive (leading to success within a culture).' e* f! J7 s# A0 C% L; |
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Hypothesis 3. Military norms will change more in defeated nations than victorious ones.
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% n) H, b5 y) E- a( n2 n$ c, zWas the Maginot Line and the generally disastrous performance of the French army in 1940 an example of a more general rule Does success generally breed conservatism% D4 ~; |; w5 W0 n9 a! ?

, }! B( I. N/ s" o9 FHypothesis 4. The spread of a norm is not independent of the spread of others, but depends on the spread of other norms (norm clusters).
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" m0 o& d1 D5 [Does, for example, empathy decrease with social stratification# B. L; x. |* g: q
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Hypothesis 5. Susceptibility to the spread of norms is negatively correlated with level of education.* {- a- `5 u! ?* B* K' N* j
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Are the less educated generally more conformist, or does the spread of norms depend almost entirely on the character of the norm" i/ e. m* ~; a- C+ V( P

! C8 y# A6 d8 c$ v9 @Hypothesis 6. Horizontal transmission will show less stickiness than vertical transmission.
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This conjecture is based on anecdotal observations that norms like using hula hoops come and go and are primarily horizontally transmitted, and religious values and other high-viscosity points of view are mostly vertically transmitted (p. 129 of [14], [59]).0 t" G6 |, _$ J  w5 i( L3 O1 q

( R4 A3 J: D6 A$ mIn this essay we have tried to be provocative rather than exhaustive. There is a welter of issues we have not even attempted to address, including: (1) asymmetries of power in the spread of norms, (2) the role of networks, (3) the efficacy of persuasion as opposed to imitation, (4) the cause of thresholds in the change of norms, (5) the genesis of norms during child development, (6) the connection between attitudes and actions, (8) competition among norms from different cultures; and (9) the question, can norms exist ※free of people§ in institutions Institutions certainly may emerge as independent structures, stabilized by laws and customs that are enforced to varying degrees through formal punishment or social pressure. Can such norms persist long even when adherence to them is disappearing The interplay between the dynamics of individual behaviors and normative rules, operating on different time (and other) scales, may be the key, we argue, to understanding sudden phase transitions that can transform the cultural landscape.5 O5 J5 W0 _2 n+ R  `

: ]6 P. Z8 y  A% M' oWe hope that, by being provocative, we can interest more evolutionists, behavioral biologists, and ecologists in tackling the daunting but crucial problems of cultural evolution. Few issues in science would seem to be more pressing if civilization is to survive.
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Acknowledgments
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We have received helpful critical comments from Kenneth Arrow, John Bonner, Samuel Bowles, Kai Chan, Gretchen Daily, Partha Dasgupta, Adrian deFroment, Anne Ehrlich, Marcus Feldman, Michelle Girvan, Ann Kinzig, Deborah Prentice, and Will Provine. Amy Bordvik provided invaluable assistance in preparing the manuscript for publication.
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References1 E- {, @1 N. }2 i
7 X! ?6 X9 P5 j
Ridley M (1996) Evolution. Cambridge (Massachusetts): Blackwell Science. 719 p.2 s* A, o" f3 q

' M7 ?  E, f/ jFutuyma DJ (1998) Evolutionary biology. Sunderland (Massachusetts): Sinauer Associates. 763 p.
/ a3 z+ ]" f- c8 l/ D; W4 v
7 l4 p& K$ T/ _. i& E- g% |% h  v, r! mDurrett R, Levin SA (2005) Can stable social groups be maintained by homophilous imitation alone J Econ Behav Organ In press.' E  C2 X  H# \4 x. m3 n5 m
2 L& Z+ n9 |4 s7 A( Q
Klein RG (1999) The human career: Human biological and cultural origins. Chicago (Illinois): University of Chicago Press. 840 p.
3 b$ S: v, c  v9 K7 P$ B8 J+ ?% M5 k# `1 z
Cavalli-Sforza LL, Feldman MW (2003) The application of molecular genetic approaches to the study of human evolution. Nat Genet 33:266–275 (Suppl).& x% ^/ p# J0 ~3 M9 y/ G
- T/ s  ]0 Q2 e/ }' r; e- S# T* X
Hewlett BS, Silvestri AD, Guglielmino CR (2002) Semes and genes in Africa. Curr Anthropol 43:313–321.
( a5 ]( C  ?9 z8 d) o$ D
1 o4 M) d: |. ~6 FDanchin E, Giraldeau L, Valone T, Wagner R (2004) Public information: From nosy neighbors to cultural evolution. Science 305:487–491.1 V( D1 F0 z  v1 G+ h1 F/ }
# v5 w9 {+ M% c( |% `6 s+ d3 M
Ehrlich PR, Feldman MW (2003) Genes and cultures: What creates our behavioral phenome Curr Anthropol 44:87–107.
) C4 R( f  y: H9 k# g
3 w+ ~$ s! Q& P' ^' WDiamond J (2005) Collapse: How societies choose to fail or succeed. New York: Viking. 592 p.+ P3 y3 @) z! ^. D- U9 {

' H, _$ S3 o- x3 dEhrlich PR, Holm RW (1963) The process of evolution. New York: McGraw-Hill. 347 p.# S' V( N; |; w& `' r
1 k( F& m- x4 B. \' t$ ~
Boyd R, Richerson PJ (1985) Culture and the evolutionary process. Chicago (Illinois): University of Chicago Press. 331 p.8 A" `6 ~* k$ P  d. t

1 f5 R! T) H- J8 ^9 jWilson DS (2002) Darwin's cathedral: Evolution, religion, and the nature of society. Chicago: University of Chicago Press. 268 p.0 W( l' J2 E+ V

' h* {- _  s$ A; @Cavalli-Sforza LL, Feldman MW (1973) Cultural versus biological inheritance: Phenotypic transmission from parent to children (A theory of the effect of parental phenotypes on children's phenotype). Am J Hum Genet 25:618–637.# B7 B) w  m6 D, q* ~/ S

$ G0 c0 [! w4 {, r' bCavalli-Sforza LL, Feldman MW (1981) Cultural transmission and evolution: A quantitative approach. Princeton (New Jersey): Princeton University Press. 388 p.
. p1 B: i" f- R' A+ i& K! [! f
+ _% H0 j3 H+ Z/ r- V2 K" l8 pOrnstein R, Ehrlich P (1989) New world new mind: Moving toward conscious evolution. New York: Doubleday. 302 p.& u5 r) L2 I. [9 Q* h. `5 F$ X( ]/ l

; x; |7 o/ Y6 j) sLevin SA (1999) Fragile dominion: Complexity and the commons. Reading (Massachusetts): Perseus Books. 250 p.. q- ^+ w; f: I4 Q  B

8 z, B: G1 W& @3 q/ nEhrlich PR (2000) Human natures: Genes, cultures, and the human prospect. Washington (D. C.): Island Press. 531 p.
/ m6 p' B6 [$ J* r8 B2 B: ]
. p$ ^% T" t3 \( C7 L( H/ ^Sumner WG (1911) Folkways: A study of the social importance of usages, manners, customs, mores, and morals. Boston (Massachusetts): Ginn & Co. 692 p.+ q3 l4 l* l2 m: Z( Q% |1 W6 B

" M& _0 }1 h9 f( c* V" q5 ZBowles S, Gintis H (2004) The evolution of strong reciprocity: Cooperation in heterogeneous populations. Theor Popul Biol 65:17–28.6 N# s  X+ ?! ]; C
" c1 C# x1 X7 C5 c* k. `
Kendal J, Feldman MW, Aoki K (2005) Cultural coevolution of norm adoption and enforcement when punishers are rewarded or non-punishers are punished. Morrison Work Pap 102:1–22.; }+ Y5 g: w" W

- @% a+ h) T. [! M' g7 U3 l# y) KKuper A (1999) Culture: The anthropologists' account. Cambridge (Massachusetts): Harvard University Press. 299 p.
4 g4 h5 t0 \1 T7 p: ~. k* ~; b5 S! T1 g5 M6 e  _$ T
Dawkins R (1976) The selfish gene. New York: Oxford University Press. 224 p.  c5 I2 h( A9 i9 r) N1 l

/ C5 p& G9 g9 W1 i/ wBlackmore S (1999) The meme machine. Oxford (United Kingdom): Oxford University Press. 288 p.
! ~! n- c* C+ l7 \
- t3 M* N* k( x" c. nTversky A, Kahneman D (1981) The framing of decisions and the psychology of choice. Science 211:453–458.
' E& h5 R  S( }& Q% P% @  P# d0 f1 o* O" s( P
Tversky A, Kahneman D (1986) Rational choice and the framing of decisions. J Bus 59:S251–S278.# w8 m( |6 B8 v0 g+ D
& ?! N! U4 b; W& P0 s) R7 ~2 S
Shweder RA (1982) Beyond self-constructed knowledge: The study of culture and morality. Merrill Palmer Q 28:41–69.
  k4 C! B" _7 O- p: z5 e$ x
* h, L; V' z( pShweder RA (1991) Thinking through cultures: Expeditions in cultural psychology. Cambridge (Massachusetts): Harvard University Press. 404 p.: J. a# j8 G9 m. D1 R
& b! V2 p7 ~7 `$ e8 b+ C
Henrich J, Boyd R (2001) Why people punish defectors: Weak conformist transmission can stabilize costly enforcement of norms in cooperative dilemmas. J Theor Biol 208:79–89.) m9 \/ [$ |& L1 o! m$ [

( s8 u% Z% X5 R- zCollins R (1998) The sociology of philosophies: A global theory of intellectual change. Cambridge (Massachusetts): Belknap Press. 1098 p.
4 O. q2 T3 U  U, b! c! N- F  k4 F% B! v$ j  P: `! v1 ~  p
Stark R, Finke R (2000) Acts of faith: Explaining the human side of religion. Berkeley (California): University of California Press. 343 p.
: V: [9 ]. ~  U( U
* D* Z2 _& B* {8 I0 {, N& wRogers EM (1995) Diffusion of innovations. New York: Free Press. 519 p.
) l+ Q( U- S0 D" A* `
* j* K: Z+ i7 e, M2 h, `Becker HS (1963) Outsiders: Studies in the sociology of deviance. London: Free Press of Glencoe. 179 p.' @. W9 t( A3 w6 o: |

. A6 e8 a2 V0 T; {3 u- HStark R (1996) The rise of Christianity: A sociologist reconsiders history. Princeton (New Jersey): Princeton University Press. 288 p./ Z* c) @. l% Q6 F# i: x2 p0 ?* K0 R
8 t( }  E8 P( c5 [; n) v
Adler PA, Adler P, editors (2002) Constructions of deviance: Social power, context, and interaction. Belmont (California): Wadsworth Thomson Learning. 508 p.
. D0 N+ Y; h% K. N2 z; W9 D# ~" i6 ]8 ^9 c
Greeley AM (1994) A religious revival in Russia. J Sci Study Relig 33:253–272.
+ B1 ^9 b3 w' o7 i: o
7 |2 m! o- H% O# _Pigliucci M (2002) Denying evolution: Creationism, scientism, and the nature of science. Sunderland: Sinauer Associates. 275 p.
( r  V( s9 E. @! d+ O9 U
6 h$ B- ]6 d) G% c/ A7 zJacobs A (2004) Georgia takes on &evolution* as &monkeys to man* idea. New York Times Sect A: 13.3 x! p3 c4 @+ u7 M4 _$ M

& f3 v) t# S1 |; v/ _1 C4 ILaland KN, Odling-Smee FJ, Feldman MW (2000) Group selection: A niche construction perspective. Evolutionary origins of morality: Cross-disciplinary perspectives In: Katz LD, editor. Bowling Green (Ohio): Imprint Academic. pp 221–225.5 S! H* ]# _6 [( c- v

- Y/ m/ A" U7 `/ ^& u, [Palmer CT, Frederickson BE, Tilley CF (1997) Categories and gatherings: Group selection and the mythology of cultural anthropology. Ethol Sociobiol 18:291–308.
4 p8 A& M0 [7 a8 x' b1 |! g' G$ ]. S2 h) m
Durrett R, Levin SA (1994) Stochastic spatial models: A user's guide to ecological applications. Philos Trans R Soc Lond B Biol Sci 343:329–350.7 @$ s" N' w" {2 a
$ |! Y7 M5 i/ m6 M
Nowak MA, Bonhoeffer S, May RM (1994) Spatial games and the maintenance of cooperation. Proc Natl Acad Sci U S A 91:4877–4881.
' i; r2 j3 T: o! f1 x7 u
6 }0 W% Q  e0 X& I, p+ K1 H1 eWright S (1980) Genic and organismic selection. Evolution 34:825–843.
6 h& A/ r) a: p4 ~+ t; A- K& s0 x( o$ f) U2 e- t) a6 h( c
Shaftesbury AAC (1978 [1711]) Characteristics of men, manners, opinions, times. Hildesheim (Germany): Georg Olms Verlag. 321 p.  n( v; T' J" B; ~+ {8 w

$ D( f( @! |: ?" B8 M# N7 S. bEhrlich PR, Hanski I (2004) On the wings of checkerspots: A model system for population biology. Oxford: Oxford University Press. 480 p.
3 O. p2 e. }; }7 ]) p
3 N2 ]  M! S3 N. P$ _Clark A (1965) The donkeys. New York: Award Books. 192 p.# L0 T8 y' U) k! l; b$ s

' d6 D/ h; a* J- [Stevenson D (2004) Cataclysm: The first world war as political tragedy. New York: Basic Books. 564 p.) j9 V3 {: z7 B3 u! Y' T! a
1 N1 N; q: P# s. H: ~
Harris S (2004) The end of faith: Religion, terror, and the future of reason. New York: W.W. Norton & Co. 256 p.
5 I: y7 M, c) x8 i! x9 n0 m; X; t! J% Q0 f( _
Ehrlich PR (2005) Twenty-first century systematics and the human predicament. Proceedings Calif Acad Sci 56:122–140 Suppl 1.' y7 v% f/ R0 R8 M7 h1 \: L

1 v- z7 H& [, I4 y. N! p3 W2 D9 [6 KKroeber AL, Parsons T (1958) The concepts of culture and of social system. Am Sociol Rev 23:582–583.6 o7 _& D- M" O, K) n, q

/ G3 L0 ]3 P" X4 i! L& \7 uKeesing R (1974) Theories of culture. Annu Rev Anthropol 3:73–97.
9 D, s6 D, _% `8 q# O+ a
: w1 x( d+ K/ M0 i+ D. TMoore JT (1974) The culture concept as ideology. American Ethnologist 1:537–549.6 |- u  Y7 H9 L' A; e" B
0 F: s* E; P5 u8 Y: p8 n
Drummond L (1980) The cultural continuum: A theory of intersystems. Man 15:352–374.
0 m5 a5 d5 [  J- s+ W7 x4 f# `$ B; R1 P! f# p
Kahn J (1989) Culture, demise or resurrection Crit Anthropol 9:5–25.
) n, W1 V, h" Y. _. e  o; d: Q9 s, d$ v' S% ^( K  q
Durham WH (1991) Coevolution: Genes, culture, and human diversity. Stanford (California): Stanford University Press. 629 p.
( ^- V3 s4 A" \% L3 m8 ]& Y" {- K5 w5 l
Brightman R (1995) Forget culture: Replacement, transcendence, relexification. Cult Anthropol 10:509–546.% ?3 O! Q+ o6 {5 z# n6 {
# b& z) k) q- @6 b
Borofsky R, Barth F, Shweder R, Rodseth L, Stolzenberg N (2001) When: A conversation about culture. Am Anthropol 103:432–446.- G4 W( Y! X' U3 A! P

4 E- E, s' U% S9 x. KMesoudi A, Whiten A, Laland KN (2004) Is human cultural evolution darwinian Evidence reviewed from the perspective of the origin of species. Evolution 58:1–11.
$ G/ r: c6 q' J* }  k
2 t- @* y/ [; Q( @$ zNakamaru M, Levin SA (2004) Spread of two linked social norms on complex interaction networks. J Theor Biol 230:57–64.
8 R( n( g! z' X$ t7 l; p, f3 V5 M. I  t
Guglielmino CR, Viganotti C, Hewlett B, Cavalli-Sforza L (1995) Cultural variation in Africa: Role of mechanisms of transmission and adaptation. Proc Natl Acad Sci U S A 92:7585–7589.(Paul R. Ehrlich, Simon A.)
作者: 橙味绿茶    时间: 2015-6-28 21:01

是楼主原创吗  
作者: txxxtyq    时间: 2015-7-1 18:09

来几句吧  
作者: 大小年    时间: 2015-7-3 10:54

这样的贴子,不顶说不过去啊  
作者: bluesuns    时间: 2015-7-6 15:01

围观来了哦  
作者: beautylive    时间: 2015-8-6 16:43

看或者不看,贴子就在这里,不急不忙  
作者: nauticus    时间: 2015-8-18 20:25

真是天底下好事多多  
作者: 张佳    时间: 2015-9-9 12:25

观看中  
作者: 123456zsz    时间: 2015-9-11 14:01

帮顶  
作者: 舒思    时间: 2015-9-12 05:10

这贴?不回都不行啊  
作者: 橙味绿茶    时间: 2015-9-12 14:01

看看..  
作者: immail    时间: 2015-9-22 18:09

病毒转染干细胞
作者: 橙味绿茶    时间: 2015-9-23 14:18

很好!很强大!  
作者: dypnr    时间: 2015-10-4 13:00

干细胞产业是朝阳产业
作者: 123456zsz    时间: 2015-10-9 14:54

肿瘤干细胞
作者: tempo    时间: 2015-11-28 19:27

彪悍的人生不需要解释。  
作者: awen    时间: 2015-12-22 16:35

HOHO~~~~~~  
作者: 龙水生    时间: 2015-12-29 16:18

呵呵 哪天得看看 `~~~~  
作者: tuanzi    时间: 2016-2-1 14:10

自己知道了  
作者: awen    时间: 2016-2-2 21:35

真是佩服得六体投地啊  
作者: lalala    时间: 2016-2-22 16:00

先顶后看  
作者: 安生    时间: 2016-2-22 17:09

照你这么说真的有道理哦 呵呵 不进沙子馁~~~  
作者: 我学故我思    时间: 2016-2-25 08:35

活着,以死的姿态……  
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好帖子,要顶!
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我想要`~  
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留个脚印```````  
作者: chongchong    时间: 2016-5-28 11:10

顶下再看  
作者: awen    时间: 2016-7-13 11:35

鉴定完毕.!  
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努力,努力,再努力!!!!!!!!!!!  
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给我一个女人,我可以创造一个民族;给我一瓶酒,我可以带领他们征服全世界 。。。。。。。。。  
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间充质干细胞
作者: dongmei    时间: 2016-10-19 19:08

干细胞治疗  
作者: 罗马星空    时间: 2016-10-24 08:55

帮你项项吧  
作者: ladybird    时间: 2016-11-1 12:35

哈哈,有意思~顶顶 ,继续顶顶。继续顶哦  
作者: lab2010    时间: 2016-11-20 15:18

HOHO~~~~~~  
作者: bioprotein    时间: 2016-11-21 16:09

偶真幸运哦...  
作者: dglove    时间: 2016-11-25 16:10

每天都会来干细胞之家看看
作者: Whole    时间: 2016-12-26 15:17

不错,看看。  
作者: 坛中酒    时间: 2017-1-5 17:10

这个贴好像之前没见过  
作者: DAIMAND    时间: 2017-1-6 16:23

干细胞治疗  
作者: 蚂蚁    时间: 2017-1-21 07:52

知道了 不错~~~  
作者: 三星    时间: 2017-1-26 03:21

支持一下  
作者: 科研人    时间: 2017-1-31 11:27

加油啊!!!!顶哦!!!!!  
作者: myylove    时间: 2017-2-9 07:26

干细胞研究非常有前途
作者: tuting    时间: 2017-2-12 06:28

神经干细胞
作者: qibaobao    时间: 2017-2-24 15:42

干细胞研究还要面向临床
作者: pcr    时间: 2017-2-25 04:27

这年头,分不好赚啊  
作者: HongHong    时间: 2017-2-26 09:43

支持~~顶顶~~~  
作者: 张佳    时间: 2017-3-4 17:24

哈哈 我支持你
作者: 咕咚123    时间: 2017-3-29 09:54

谢谢干细胞之家提供资料
作者: 温暖暖    时间: 2017-4-25 19:40

淋巴细胞
作者: 命运的宠儿    时间: 2017-5-1 16:19

原来这样也可以  
作者: SCISCI    时间: 2017-5-3 09:10

这样的贴子,不顶说不过去啊  
作者: 舒思    时间: 2017-5-4 14:35

一楼的位置好啊..  
作者: whyboy    时间: 2017-5-11 04:39

谢谢分享了!  
作者: ringsing    时间: 2017-5-11 15:59

看或者不看,贴子就在这里,不急不忙  
作者: 龙水生    时间: 2017-5-22 09:26

21世纪,什么最重要——我!  
作者: 杏花    时间: 2017-5-25 03:59

皮肤干细胞
作者: Greatjob    时间: 2017-5-31 03:35

说的不错  
作者: 123456zsz    时间: 2017-6-6 22:18

终于看完了~~~  
作者: lab2010    时间: 2017-8-18 18:50

这个站不错!!  
作者: 石头111    时间: 2017-8-30 17:52

我的啦嘿嘿  
作者: lab2010    时间: 2017-9-15 12:27

想都不想,就支持一下  
作者: 石头111    时间: 2017-10-10 02:29

谁都不容易啊 ~~  
作者: 小丑的哭泣    时间: 2017-10-15 12:57

哈哈 瞧你说的~~~  
作者: immail    时间: 2017-10-19 23:59

干细胞分化技术
作者: sky蓝    时间: 2017-10-23 20:57

青春就像卫生纸。看着挺多的,用着用着就不够了。  
作者: 若天涯    时间: 2017-10-24 22:26

哈哈 瞧你说的~~~  
作者: netlover    时间: 2017-12-11 07:53

回答了那么多,没有加分了,郁闷。。  
作者: mk990    时间: 2017-12-16 12:01

就为赚分嘛  
作者: 依旧随遇而安    时间: 2017-12-25 05:51

进行溜达一下  
作者: 快乐小郎    时间: 2018-4-11 04:34

加油啊!!!!顶哦!!!!!  
作者: 20130827    时间: 2018-4-13 05:57

我帮你 喝喝  
作者: dr_ji    时间: 2018-5-9 08:27

dc-cik nk  
作者: dglove    时间: 2018-5-12 10:01

哈哈,看的人少,回一下  
作者: 三好学生    时间: 2018-5-18 06:22

厉害!强~~~~没的说了!  
作者: heart10    时间: 2018-5-24 07:46

顶顶更健康,越顶吃的越香。  
作者: 碧湖冷月    时间: 2018-6-16 23:10

回个帖子支持一下!
作者: 红旗    时间: 2018-7-4 04:00

一楼的位置好啊..  
作者: htc728    时间: 2018-7-6 17:58

嘿...反了反了,,,,  
作者: leeking    时间: 2018-8-11 02:16

顶你一下,好贴要顶!  
作者: heart10    时间: 2018-8-25 02:26

生殖干细胞
作者: dr_ji    时间: 2018-8-30 02:30

哈哈,看的人少,回一下  
作者: nauticus    时间: 2018-8-31 06:04

谢谢分享了!  
作者: txxxtyq    时间: 2018-9-22 08:18

自己知道了  
作者: aakkaa    时间: 2018-9-28 00:58

神经干细胞
作者: xuguofeng    时间: 2018-10-12 12:43

心脏干细胞
作者: s06806    时间: 2018-10-31 17:53

顶一个先  
作者: s06806    时间: 2018-11-9 03:50

干细胞之家是国内最好的干细胞网站了
作者: 三好学生    时间: 2018-11-23 20:01

肿瘤干细胞
作者: highlight    时间: 2018-11-25 00:16

我在努力中  
作者: 小丑的哭泣    时间: 2018-12-1 17:08

脂肪干细胞
作者: 安安    时间: 2018-12-6 20:04

干细胞研究还要面向临床
作者: heart10    时间: 2019-1-1 09:01

哈哈,这么多的人都回了,我敢不回吗?赶快回一个,很好的,我喜欢  
作者: yukun    时间: 2019-1-7 07:08

我顶啊。接着顶  
作者: abc987    时间: 2019-1-20 00:43

不管你信不信,反正我信  
作者: 桦子    时间: 2019-1-23 14:41

人气还要再提高  
作者: 考拉    时间: 2019-2-20 02:08

设置阅读啊  
作者: dglove    时间: 2019-3-4 12:00

(*^__^*) 嘻嘻……  
作者: tian2006    时间: 2019-3-30 02:20

我回不回呢 考虑再三 还是不回了吧 ^_^  




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