Worth Your Weight: Experimental Evidence on the Benefits of Obesity in Low-Income Countries

Macchi, Elisa. 2023. “Worth Your Weight: Experimental Evidence on the Benefits of Obesity in Low-Income Countries." American Economic Review, 113 (9): 2287-2322. (DOI: 10.1257/aer.20211879)

Abstract

I study the economic value of obesity—a status symbol in poor countries associated with raised health risks. Randomizing decision-makers in Kampala, Uganda to view weight-manipulated portraits, I find that obesity is perceived as a reliable signal of wealth but not of beauty or health. Thus, leveraging a real-stakes experiment involving professional loan officers, I show that being obese facilitates access to credit. The large obesity premium, comparable to raising borrower self-reported earnings by over 60 percent, is driven by asymmetric information and drops significantly when providing more financial information. Notably, obesity benefits and wealth-signaling value are commonly overestimated, suggesting market distortions.

The Impact of Microfinance on Pro-Social Behaviors: Experimental Evidence of Public Goods Contributions in Uganda

The Impact of Microfinance on Pro-Social Behaviors: Experimental Evidence of Public Goods Contributions in Uganda

Date:	2016-06
By:	Bryan McCannon (West Virginia University, Department of Economics) Zachary Rodriguez (Saint Bonaventure University, School of Business)
URL:	http://d.repec.org/n?u=RePEc:wvu:wpaper:16-13&r=net
	We ask whether access to microfinance loans by the poor has a spillover effect on their pro†social behaviors. An experimental field study in southern, rural Uganda is conducted using free riding in public goods contributions as an assessment. We document higher levels of contributions by those who have previously received a microloan. This effect cannot be explained by changes in social norms, income effects, or sample selection bias. The results suggest that exposure to microfinance promotes social preferences.
Keywords:	experiment, field study, free riding, microfinance, public goods, social norm, social preference, Uganda

Laboratory Evidence on Face-to-Face: Why Experimental Economics is of Interest to Regional Economists*

Björn Frank (2012) “Laboratory Evidence on Face-to-Face: Why Experimental Economics is of Interest to Regional Economists." International Regional Science Review, June 13, 2012. doi: 10.1177/0160017612449017. working paper PDF; Journal Web. **；

Notes by yinung

此文提及 death of distance" (Cairncross, 2001) or “death of geography" 意思是

…the shrinking costs for transportation, especially transportation of messages’ pure in formation content.

必需有 face-to-face 溝通的原因是

… widely agreed that communication often must be face-to-face in order to be effective. But why?

1. nonverbal 和 verbal 同時發生，減少誤解(Storper and Venables, 2004; Winger, 2005, sections 4 – 6; and Hildrum, 2007, p. 469 with further references).

2. 比較有意義 （？？？待了解）

3. 發現想看到的，也發現原來沒想看到的隱含事務

4. buzzing (流言???)

5. face-to-face 溝通成本高，可視為建立長期關係之投資

6. 建立互信的必要條件

以上是理論，經濟實驗 （不含心理實驗）之證據為此文之回顧重點

匿名實驗結果有時不具參考性，此文同意此觀點 （至少用 email 溝通知道名字）

幾個與 face-to-face 相關因素

1. 即時回應之效果 and 冷淨作用 Cooling effects: effect of spontaneity (decision time)  in Sec. 2
2. trust 和合作受到 face-to-face 之影響 in Sec. 3
3. 細節因素，如 smiling 和 eye contact  在 f2f 中之角色

冷靜效果

..experiment on the effect of a substantive cooling off period in an experiment was invented by Oechssler, Roider and Schmitz (2008).

在 ultimatum game 中，8:2 和 5：5 的分餅被提出，看對手是否接受。24小時後，接受的決定可以被修改。餅獎金大小分別有 2，5，8 euros. Cooling off period 並未導致拒絕率大幅降低 (from 42.6% to 39.4%) ，且不顯著。但將 reward 變大 （期望值相同，用 lottery 方式），則拒絕率顯著大幅下降 fom 27.7% to 20.5%.

增加決策時間之壓力也有同樣的效果 （提高拒絕率） increased time pressure might well increase the rejection rate by Sutter, Kocher and Strauß (2003). 決策時間減少 (100秒 mm> 10 秒)，拒絕率增加從 40.3 to 78.2％。 Cappelletti, Güth and Ploner (2008) 也有類似的發現 （180秒 vs 30 秒）。情感區 (affective system) 和 (deliberative system) 在大腦中並不相同。

Implications:

在 UG 中，拒絕率上升，代表效率下降。出價者將會喜歡拒絕率降低 (因此可降低 offer); 反之，回應者將喜歡拒絕率上升。故，出價者將偏好 face-to-face 溝通。不過要注意的是 UG 是單向一次 negotiation, 一般的談判會有雙向回應

建立互信 ＆ 合作

Valley, Moag and Bazerman (1998)

（註： 有時互信和合作很難區分 see ）

兩人買賣股票，出價B

只有 seller 知道 V； Seller 會接受 if B>V; seller 得到 (B-V);

Buyer 只知 V～uniform(0,100), 真實 V 要等 Buyer 買到以後才知道。真實價值 ＝ 1.5V; buyer 得到 (1.5V-B);

Buyer 問 seller V=?, 但 seller 可以 lie; 不過 face-to-face 之下，seller 顯著地比較不可能 lie （face-to face 只有 1 of 14, 7% lie; 電話 55％ lie; 不匿名witten 33% lie). 有些 face-to-face 的 buyer 並沒有問 seller V；

結果發現 face-to-face 導致比較多的 Pareto improving deals.

Pareto deals (雙方皆獲益)：

face-to-face: 51.7% (out of n=21) 成交; 顯著大於 written comm. 但不顯著大於 telephone comm.

written comm.: 22.2% (未成交 52％ 接近理論值）

telephone comm.: 38.1%

Non-Pareto deals (buy’s loss):

face-to-face: 23.8%

written comm.: 25.9%

telephone comm.: 47.6%

Frohlich and Oppenheimer (1998) PD game （應是 public good game)

5人一組玩多人 PD game 共 15 回合; 前 8 回合用 (a) 事先沒有 comm.; (b) email (c) face-to-face;

每人在每回合決定貢獻 0～10 給 group, 留下其餘。

S=5人貢獻之加總； 每人皆領回 0.4S

理論：每人皆貢獻 10， 則 S ＝ 50，每人皆領回 0.4S = 20; 若每人皆貢獻 0， 則每人只得 10；

實驗結果

各 treatment 之平均貢獻 (前 8回合）

(a) 沒有 comm: 2.9

(b) email: 7.6

(c) face-to-face: 9.99

9回合以後（皆沒有 comm.)

Contributions in groups with previous face-to-face communication quickly collapse to the level of the e-mail-groups.

face-to-face 效果持續多久？

一回合就夠了？ (Brosig, Ockenfels and Weimann, 2003; Bochet et al., 2006)

Rocco (1998).

6人一組玩28回合的 public good game；在第 10，15，20加入 face-to-face comm.;

每一回合貢獻 x of 13 tokens; 全部人之貢獻加總= S; 每人之 Payoffs = ？？？

face-to-face comm. 有助於 maximize group welfare 在後半段實驗； Email comm. 並沒有較高的合作；但實驗前一天 email comm. 的人 face-to-face 之後，卻有類似的效果。

Bochet et al. (2006)

4人10回合的 PG game；比較 5分鐘的實驗前 face-to-face vs 第 1，4，7回合 online 討論 in a chat room；

實驗結果

兩者差異沒有後大, 其平均貢獻：

chat room: 81.4%

face-to-face: 96.2%

但在第10回合有 drop, chat romm ->52.1%; face-to-face -> 78.1

Naquin, Kurtzberg and Belkin (2008),

玩 threshold PG game; 4 人一組；若至少有 3人 捐出 1 張餐券，則每人獲兩張 ￥7餐券 2 張；

比較 非匿名之 email 和 face-to-face 決策：

email: 35.8% of the participants 捐出

face-to-face: 69.9%

其它溝通媒介

Brosig, Ockenfels and Weimann (2003)

4人一組，10回合 PG game; 其貢獻 of endowment

audio comm.: 48%

anonymous: 57%

video comm: 93%

face-to-face: 97% (後兩者顯著高於前兩者)

照片 出現 10 秒： 貢獻率低於 anonymous

Face-to-face 可能隱含的影響因素

Smiling

Scharlemann et al. (2001) 在 trust game 中，發現微笑有助於合作

 Player 1 — [$1, 0.5]
|
Player 2 — [0.8, 1.25]
|
Player 1 — [1.20, 1.20]

Player 1 是受試者，Player 2 是電腦但 show 照片 (treatment 是否微笑，取自相片資料庫)，只要 Player 1 選擇 trust 策略，則電腦 (Player 2) 必定也用 trust 回應。結果發現， Player 1 之回應

沒有微笑： 55.0% 選擇 trust 策略
有微笑：     68.3%
(是否顯著待查)

eye contact

Burnham and Hare (2007)

4人一組，6回合 PG game (對手不重覆); 其貢獻 of endowment ~ (0, 10，相當於 2 美金), 總貢獻*2 均分給 4 人.

實驗組看到金屬臉但具有人類眼睛的影像 (MIT 發明的 “Kismet” robot), 實驗結果：

所有人和6回合平均
看到眼睛：5.39
匿名：        4.17

Haley and Fessler (2005)
玩 dictator game, 分$10美金, 實驗組看到眼睛圖片，對照組看到 label, 結果

Player 1 分給 Player 2
看到眼睛：3.79
沒有看到眼睛：2.45

Bateson, Nettle and Roberts (2006) 在現地實驗中也發現，eye contact 會讓貢獻較多錢

在48位大學職員喝咖啡處貼眼睛海報 or 花海報各幾週，自願投幣奉獻 (honesty box) 金額

在貼眼睛海報的時候，自願投幣奉獻金額顯著較高。

Frey and Bohnet (1995) 在 PD game 中讓受試者選擇合作和背叛，合作率

visual contact + talking : 78%
visual contact + no talking ： 23%
匿名：12%

Wichman (1970) 在 PD game 中讓受試者選擇合作和背叛; 70回合，固定對手，合作率

無限制的 face-to-face: 87%
互聽到聲音： 72.1%
只有 visual contact: 47.7%
匿名40.7％

Abstract

The notion of face-to-face contacts has recently become very popular as a reason why firms still locate in proximity to others after the “death of distance.” Controlled laboratory experiments provide direct and reliable evidence on the importance of face-to-face contacts. It is the purpose of this article to survey and to organize new and developing string of literature with a special focus on its importance for regional economics. However, the article might also serve to alert more experimentalists to the importance of their work for current regional science, of which they seem not to be aware.

References (部份）

• 冷卻效果
  Oechssler, Jörg, Andreas Roider and Patrick Schmitz (2008), Cooling-Off in Negotiations – Does It Work?, mimeo: http://ideas.repec.org/p/cpr/ceprdp/6807.html
• 決策時間長短 in Ultimatum game
  Sutter, Matthias, Martin Kocher and Sabine Strauß (2003), Bargaining under time pressure in an experimental ultimatum game, Economics Letters 81, 341–347.
• Cappelletti, Dominique, Werner Güth and Matteo Ploner (2008), Being of two minds: an ultimatum experiment investigating affective processes, mimeo.
• 其它
  Bateson, Melissa, Daniel Nettle and Gilbert Roberts (2006), Cues of being watched enhance cooperation in a real-world setting, Biology Letters 2, 412–414.
• Bochet, Olivier, Talbot Page, and Louis Putterman (2006), “Communication and Punishment in Voluntary Contribution Experiments," Journal of Economic Behavior and Organization, 60, 11-26.
• Bohnet, Iris and Bruno S. Frey (1999), The sound of silence in prisoner’s dilemma and dictator games, Journal of Economic Behavior & Organization 38, 43-57.
• Brosig, Jeannette, Axel Ockenfels and Joachim Weimann (2003), The effect of communication media on cooperation, German Economic Review 4, 217-241.
• Burnham, Terence C. and Brian Hare (2007), Engineering Human Cooperation. Does Involuntary Neural Activation Increase Public Goods Contributions?, Human Nature 18, 88-108.
• Frey, Bruno S. and Iris Bohnet (1995), Institutions Affect Fairness: Experimental Investigations, Journal of Institutional and Theoretical Economics 151, 286-303.
• Frohlich, Norman and Joe Oppenheimer (1998), Some consequences of e-mail vs. face-to-face communication in experiment, Journal of Economic Behavior & Organization 35, 389-403.
• Haley, Kevin J. and Daniel M.T. Fessler (2005), Nobody’s watching? Subtle cues affect generosity in an anonymous economic game, Evolution and Human Behavior 26, 245–256.
• Naquin, Charles E., Terri R. Kurtzberg and Liuba Y. Belkin (2008), E-Mail Communication and Group Cooperation in Mixed Motive Contexts, forthcoming: Social Justice Research,
• Rocco, Elena (1998), Trust Breaks Down in Electronic Contexts but Can Be Repaired by Some Initial Face-to-Face Contact, Proceedings of the SIGCHI conference on Human factors in computing systems 1998, 496-502.
• Scharlemann, Jörn P.W., Catherine C. Eckel, Alex Kacelnik and Rick K. Wilson (2001), The value of a smile: Game theory with a human face, Journal of Economic Psychology 22, 617-640.
• Valley, Kathleen L., Joseph Moag and Max H. Bazerman (1998), ‘A matter of trust’: Effects of communication on the efficiency and distribution of outcomes, Journal of Economic Behavior and Organization 34, 211-238.
• Valley, Kathleen, Leigh Thompson, Robert Gibbons and Max H. Bazerman (2002), How Communication Improves Efficiency in Bargaining Games, Games and Economic Behavior 38, 127-155.
• Wichman, Harvey (1970), Effects of Isolation and Communication on Cooperation in a Two-Person Game, Journal of Personality and Social Psychology，16, 114-120. http://psycnet.apa.org/journals/psp/16/1/114/; DOI;

暫記

PD game
Frey and Bohnet (1995) J Inst. & Theo. Econ.
(合作率)
visual contact + talking : 78%
visual contact + no talking ： 23%
匿名：12%
Wichman (1970) J Per & Soc Psy
(合作率)
無限制的 face-to-face: 87%
互聽到聲音： 72.1%
只有 visual contact: 47.7%
匿名40.7％
UG
Oechssler, Roider and Schmitz (2008)
時間減少
Sutter, Kocher and Strauß (2003) EL
Cappelletti, Güth and Ploner (2008) mimeo

dictator game
Haley and Fessler (2005)

Trust game
Valley, Moag and Bazerman (1998) JEBO
Scharlemann et al. (2001) (smiling 在 trust game 中) JEPsy

Public good game
Frohlich and Oppenheimer (1998) JEBO
Rocco (1998) Proceedings of the SIGCHI conference
Bochet et al. (2006) JEBO
Brosig, Ockenfels and Weimann (2003) GER
Burnham and Hare (2007) (眼睛 contact) Human Nature

Bateson, Nettle and Roberts (2006) 在現地實驗(自助咖啡投幣)

Does Market Experience Eliminate Market Anomalies?*

List, John A. 2003. “Does Market Experience Eliminate Market Anomalies?” Quarterly Journal of Economics 118 (1): 41–71.

==notes by yinung==

主要結論有三

First, consistent with previous studies, I observe a significant endowment effect in the pooled data.

Second, I find sharp evidence that suggests market experience matters: across all consumer types, marketlike experience and the magnitude of the endowment effect are inversely related.

In addition, within the group of subjects who have intense trading experience (dealers and experienced
nondealers), I find that the endowment effect becomes negligible. Both of these observations extend quite well to statements of value in auctions, where offers and bids are significantly different for naive consumers, but statistically indistinguishable for experienced consumers.

===無母數統計： Fisher exact test===

R 的 vcd package 可以進行此檢定， see https://sites.google.com/site/rlearningsite/analysis/catagory/twoway

==Original Abstract==

This study examines individual behavior in two well-functioning marketplaces to investigate whether market experience eliminates the endowment effect. Field evidence from both markets suggests that individual behavior converges to the neoclassical prediction as market experience increases. In an experimental test of whether these observations are due to treatment (market experience) or selection (e.g., static preferences), I find that market experience plays a significant role in eliminating the endowment effect. I also find that these results are robust to institutional change and extend beyond the two marketplaces studied. Overall, this study provides strong evidence that market experience eliminates an important market anomaly.

Mechanism Experiments and Policy Evaluations

Ludwig, Jens, Jeffrey R. Kling, and Sendhil Mullainathan. 2011. “Mechanism Experiments and Policy Evaluations." Journal of Economic Perspectives, 25(3): 17–38.

DOI:10.1257/jep.25.3.17

Abstract Randomized controlled trials are increasingly used to evaluate policies. How can we make these experiments as useful as possible for policy purposes? We argue greater use should be made of experiments that identify the behavioral mechanisms that are central to clearly specified policy questions, what we call “mechanism experiments." These types of experiments can be of great policy value even if the intervention that is tested (or its setting) does not correspond exactly to any realistic policy option.

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See also Journal of Economic Perspectives Vol. 25, Issue 3 — Summer 2011

(2) Why Economists Should Conduct Field Experiments and 14 Tips for Pulling One Off

John A. List

In this introduction to the symposium, I first offer an overview of the spectrum of experimental methods in economics, from laboratory experiments to the field experiments that are the subject of this symposium. I then offer some thoughts about the potential gains from doing economic research using field experiments and my own mental checklist of 14 steps to improve the chances of carrying out an economics field experiment successfully.

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(4) The Role of Theory in Field Experiments

David Card, Stefano DellaVigna and Ulrike Malmendier

We classify all published field experiments in five top economics journals from 1975 to 2010 according to how closely the experimental design and analysis are linked to economic theory. We find that the vast majority of field experiments (68 percent) are Descriptive studies that lack any explicit model; 18 percent are Single Model studies that test a single model-based hypothesis; 6 percent are Competing Models studies that test competing model-based hypotheses; and 8 percent are Parameter Estimation studies that estimate structural parameters in a completely specified model. We also classify laboratory experiments published in these journals over the same period and find that economic theory has played a more central role in the laboratory than in the field. Finally, we discuss in detail three sets of field experiments—on gift exchange, on charitable giving, and on negative income tax—that illustrate both the benefits and the potential costs of a tighter link between experimental design and theoretical underpinnings.

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(5) Field Experiments with Firms

Oriana Bandiera, Iwan Barankay and Imran Rasul

We discuss how the use of field experiments sheds light on long-standing research questions relating to firm behavior. We present insights from two classes of experiments—within and across firms—and draw common lessons from both sets. Field experiments within firms generally aim to shed light on the nature of agency problems. Along these lines, we discuss how field experiments have provided new insights on shirking behavior and the provision of monetary and nonmonetary incentives. Field experiments across firms generally aim to uncover firms’ binding constraints by exogenously varying the availability of key inputs such as labor, physical capital, and managerial capital. We conclude by discussing some of the practical issues researchers face when designing experiments and by highlighting areas for further research.

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