Nolin David A
Department of Anthropology, University of California, Davis.
Evol Hum Behav. 2012 Jul 1;33(4):334-345. doi: 10.1016/j.evolhumbehav.2011.11.003.
Costly signaling has been proposed as a possible mechanism to explain food sharing in foraging populations. This sharing-as-signaling hypothesis predicts an association between sharing and status. Using exponential random graph modeling (ERGM), this prediction is tested on a social network of between-household food-sharing relationships in the fishing and sea-hunting village of Lamalera, Indonesia. Previous analyses (Nolin 2010) have shown that most sharing in Lamalera is consistent with reciprocal altruism. The question addressed here is whether any additional variation may be explained as sharing-as-signaling by high-status households. The results show that high-status households both give and receive more than other households, a pattern more consistent with reciprocal altruism than costly signaling. However, once the propensity to reciprocate and household productivity are controlled, households of men holding leadership positions show greater odds of unreciprocated giving when compared to households of non-leaders. This pattern of excessive giving by leaders is consistent with the sharing-as-signaling hypothesis. Wealthy households show the opposite pattern, giving less and receiving more than other households. These households may reciprocate in a currency other than food or their wealth may attract favor-seeking behavior from others. Overall, status covariates explain little variation in the sharing network as a whole, and much of the sharing observed by high-status households is best explained by the same factors that explain sharing by other households. This pattern suggests that multiple mechanisms may operate simultaneously to promote sharing in Lamalera and that signaling may motivate some sharing by some individuals even within sharing regimes primarily maintained by other mechanisms.
代价高昂的信号传递被认为是一种可能的机制，用以解释觅食群体中的食物分享行为。这种将分享视为信号传递的假说预测，分享行为与地位之间存在关联。利用指数随机图模型（ERGM），在印度尼西亚拉马勒拉的渔业和海上狩猎村庄中，针对家庭间食物分享关系的社会网络对这一预测进行了检验。先前的分析（诺林，2010年）表明，拉马勒拉的大多数分享行为符合互惠利他主义。这里要探讨的问题是，高地位家庭的分享行为是否可以被解释为一种信号传递，从而带来额外的差异。结果显示，高地位家庭的给予和接受都比其他家庭更多，这种模式与互惠利他主义比与代价高昂的信号传递更为一致。然而，一旦控制了互惠倾向和家庭生产力，与非领导者家庭相比，担任领导职位的男性家庭进行单向给予的可能性更大。领导者这种过度给予的模式与将分享视为信号传递的假说相符。富裕家庭则呈现相反的模式，给予较少而接受比其他家庭更多。这些家庭可能以食物以外的其他形式进行回报，或者他们的财富可能吸引他人的讨好行为。总体而言，地位协变量对整个分享网络的差异解释甚少，高地位家庭的许多分享行为，用解释其他家庭分享行为的相同因素来解释最为恰当。这种模式表明，在拉马勒拉可能有多种机制同时运作以促进分享行为，并且信号传递可能促使一些个体进行分享，即便在主要由其他机制维持的分享模式中也是如此。
