Econstudentlog

Stuff

i. How To Write Badly Well. The blog is no longer active, but there’s a lot of good stuff in the archives. A collection of good links here. Some posts from the blog that made me smile or laugh: Choose a narrator who is peripheral to the story, Select words for their impressiveness rather than their relevance, Find the bone mote, Let your characters explain themselves, Underestimate your audience.

ii. Preschool Children’s Behavioral Tendency toward Social Indirect Reciprocity.

“The tendency for genetically unrelated individuals to build large-scale cooperative networks in human societies is a major exception in the animal kingdom [1]. Researchers have suggested that the principle of indirect reciprocity–the idea that altruistic (or prosocial) behavior toward an individual is returned by another individual–is crucial in enabling these cooperative networks [2], [3]. Three different forms of indirect reciprocity exist: social indirect (downstream) [4][6], generalized (upstream) [7], [8], and generalized indirect [3]. In this study, we focus on social indirect reciprocity (SIR), which means that if A helps B, then C will help A, who acted cooperatively toward B; this is based on individuals’ evaluations of others’ prior behaviors toward third parties [4][6]. SIR is associated with social evaluation or moral judgment in humans and seems to be most important form for human prosociality. SIR is more elaborate than the other two forms of indirect reciprocity and requires individuals to recognize and select those with whom they cooperate [2], [3]. Through computer simulations and analytic models, previous studies have demonstrated that SIR could evolve when individuals act according to particular strategies [2], [6]. In all such strategies, individuals have the tendency (1) to reward helpful individuals and (2) to detect and avoid helping cheaters [2], [6].

In reality, studies with human adults have demonstrated a behavioral tendency toward SIR in the decision to cooperate or defect in game experiments [9], [10]. However, there are relatively few studies on SIR in children. Therefore, investigating whether young children have a tendency toward SIR, as well as the manner in which such reciprocity develops during the early developmental stages, will help us understand how and when this tendency, that is so fundamental in organizing cooperative interactions between adults, takes root in people’s lives.

Prosocial behavior can be observed from the first year of a child’s life [11] and becomes common between ages 1 and 2 [12]. Additionally, even 14-month-olds have been shown to be capable of helping others achieve their goals [13]. However, this early prosocial tendency does not seem to be selective with regard to recipients [14], [15]. Such selectivity begins to appear between toddlerhood and the preschool period. For example, prosocial behavior becomes selective in terms of partners’ gender and personality [11], [16], familiarity between partners [17], [18], or the existence of prior prosocial behavior from the partners, thereby suggesting that children engage in direct reciprocity [19][23]. However, this selectivity is based on the partners’ own characteristics or behavior toward the potential helper itself. In order to build cooperative relationships through SIR, children require a more elaborate selective ability based on the social evaluation of a partner’s behavior toward a third party. […]

In this study, we investigated whether preschool children, in their natural interactions, have a tendency to behave prosocially or affiliatively toward a peer after they have directly observed the peer behaving prosocially toward a third party. The results showed that bystanders performed prosocial and affiliative behaviors toward focal children more frequently after the focal children’s prosocial behavior toward third parties, compared with control situations. This indicates that 5- to 6-year-olds have a behavioral tendency toward prosocial and affiliative behaviors according to the recipient peers’ prior prosocial behavior toward another peer. […] bystanders tended to engage in prosocial and affiliative behaviors toward peers more frequently soon after observing the peers’ prosocial behavior toward other peers than in control situations, even when the possibility that bystanders had imitated the first recipient’s or other bystanders’ prosocial behavior was eliminated. […]

we conclude that preschool children have an essential behavioral tendency to establish SIR when interacting with their peers in naturalistic settings, as well as in their interactions with puppets or adult actors, as found in previous studies [27][29]. Our results, which extend the findings of previous studies [27][29], suggest that preschool children not only have the ability to evaluate partners on the basis of their prosocial behavior toward a third party, they can also use this ability in natural interactions with their peers. This study is the first to provide evidence indicating that children’s prosocial interactions can be formed for the benefits derived from exchanging prosocial behaviors according to the mechanism of SIR in natural interactions with their peers. […]

SIR arises from two aspects of motivation: reward helpful individuals and avoid helping (or punish) harmful individuals [2], [4][6]. The present study explored only the behavioral tendency related to the former aspect and did not examine the latter. Previous studies have demonstrated that a “negativity bias” (a greater impact of negative information as compared with positive information) affects the behavioral tendencies of infants [24], [28], [66]. Vaish et al. [28] has shown that 3-year-olds’ prosocial behavior decreased toward a harmful individual but did not increase toward a helpful individual. Negativity bias has also been demonstrated in nonhuman primate: capuchin monkeys avoided non-reciprocal and non-helpful individuals with intentionality rather than express a preference for reciprocal or helpful ones [63], [64].”

iii. Benford’s very strange law:

I don’t actually think this lecture is all that great, but I watched it all and figured I might as well blog it. I think I’ve written about it before, I’ve certainly read about it before. Here’s wikipedia on the subject.

iv. I couldn’t help noticing the results of a new study suggesting that alcohol consumption (/during adolescence?) may be a significant risk factor for young-onset dementia (note the hazard ratio). I assume the study will be put up on the author’s website at some point – I’m annoyed I can’t access it yet.

This is a huge study (n=488,484), so it’s the kind of thing you’ll want to check out if you want to know more about this topic. Alcohol consumption has incidentally been linked to mental decline and dementia risk for a very long time, see e.g. this publication from around the year 2001.

v. A little stuff about mitochondrial DNA and related matters, via John Hawks. Do watch the video – it’s not long. Perhaps not surprisingly, Dawkins covered related stuff in The Ancestor’s Tale.

vi. In one of his recent posts, Ed Yong tells you a little about what happens inside you when a mosquito bites.

vii. Eyjafjallajökull and 9/11: The Impact of Large-Scale Disasters on Worldwide Mobility. I’ve only just briefly skimmed this, but it looks interesting. A quote:

“We model the impact of Eyjafjallajökull and 9/11 on the WAN [worldwide air transportation network] by removing the same set of airports that were closed in response to these events (see Text S1 Sec. S2.1) together with the non-stop flights to and from these airports. Our method captures the dynamic re-routing of passengers at functional airports to avoid obstructed multi-stop connections through airports that close. At their peak, on April 16th 2010, the closures due to Eyjafjallajökull’s ash cloud interrupted 20.5% of the total traffic and closed 10.5% of all airports. The closure of American and Canadian airspace as a response to the 9/11 attacks was even more severe, removing 37.7% of air traffic and 19.6% of all airports.”

August 13, 2013 - Posted by | biology, Lectures, mathematics, papers

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