Group Size Effect and Over-Punishment in the Case of Third Party Enforcement of Social Norms

One of the important topics in public choice is how people's free-riding behavior could differ by group size in collective action dilemmas. This paper experimentally studies how the strength of third party punishment in a prisoner's dilemma could differ by the number of third parties in a group. Our data indicate that as the number of third party punishers increases in a group, the average punishment intensity per third party punisher decreases. However, the decrease rate is very mild and therefore the size of total punishment in a group substantially increases with an increase in group size. As a result, third party punishment becomes a sufficient deterrent against a player selecting defection in the prisoner's dilemma when the number of third party punishers is sufficiently large. Nevertheless, when there are too many third party punishers in a group, a defector's expected payoff is far lower than that of a cooperator due to strong aggregate punishment, while some cooperators are even hurt through punishment. Therefore, the group incurs a huge efficiency loss. Such over-punishment results from third party punishers’ conditional punishment behaviors: their punishment intensity is positively correlated with their beliefs on the peers’ punitive actions. Some possible ways to coordinate punishment among peers even when group size is very large, thus enabling the efficiency loss to be mitigated, are also discussed in the paper

Voluntary Disclosure of Information and Cooperation in Simultaneous-Move Economic Interactions

This paper experimentally studies individuals’ voluntary disclosure of past behaviors and its effects in a finitely repeated two-player public goods game. The experiment data found that voluntary information disclosure strengthens cooperation under certain conditions, although a non-negligible fraction of individuals do not disclose information about the past and proceed to behave opportunistically. On closer inspection, the data revealed that the material incentives of disclosure acts differ according to the matching protocol. Specifically, disclosers receive higher payoffs than non-disclosers if the disclosers are assured to be matched with like-minded disclosers; conversely, disclosers are vulnerable to exploitation by others under random matching. These results suggest that mandatory disclosure helps enhance economic efficiency if individuals’ hiding and uncooperative behaviors are liable to precipitate a collapse in the community norms

Play it Again: Partner Choice, Reputation Building and Learning from Finitely-Repeated Dilemma Games

Often the fuller the reputational record people's actions generate, the greater their incentive to earn a reputation for cooperation. However, inability to “wipe clean” one's past record might trap some agents who initially underappreciate reputation's value in a cycle of bad behaviour, whereas a clean slate could have been followed by their “reforming” themselves. In a laboratory experiment, we investigate what subjects learn from playing a finitely repeated dilemma game with endogenous, symmetric partner choice. We find that with a high cooperation premium and good information, investment in cooperative reputation grows following exogenous restarts, although earlier end-game behaviours are observed

In Broad Daylight: Fuller Information and Higher-Order Punishment Opportunities Can Promote Cooperation

The expectation that non-cooperators will be punished can help to sustain cooperation, but there are competing claims about whether opportunities to engage in higher-order punishment (punishing punishment or failure to punish) help or undermine cooperation in social dilemmas. Varying treatments of a voluntary contributions experiment, we find that availability of higher-order punishment opportunities increases cooperation and efficiency when subjects have full information on the pattern of punishing and its history, when any subject can punish any other, and when the numbers of punishment and of contribution stages are not too unequal

State or nature? Endogenous formal versus informal sanctions in the voluntary provision of public goods

We investigate the endogenous formation of sanctioning institutions supposed to improve efficiency in the voluntary provision of public goods. Our paper parallels Markussen et al. (Rev Econ Stud 81:301–324, 2014) in that our experimental subjects vote over formal versus informal sanctions, but it goes beyond that paper by endogenizing the formal sanction scheme. We find that self-determined formal sanctions schemes are popular and efficient when they carry no up-front cost, but as in Markussen et al. informal sanctions are more popular and efficient than formal sanctions when adopting the latter entails such a cost. Practice improves the performance of sanction schemes: they become more targeted and deterrent with learning. Voters’ characteristics, including their tendency to engage in perverse informal sanctioning, help to predict individual voting

The reliability and validity of surface electromyography to study the functional status of the lumbar paraspinal muscles

The aim of this thesis is to determine whether surface electromyography (EMG) can be used as a diagnostic tool in chiropractic practice to identify the functional status of the lumbar paraspinal muscles. There were two main studies to achieve this aim. The reliability and validity of the surface EMG signal to measure the activity of paraspinal muscles during maintenance of simple static postures was evaluated. During maintenance of static postures, the raw surface EMG signal was often contaminated by an electrocardiographic (ECG) signal. Although the ECG artefact was successfully removed using two different ECG removal techniques (manual and semi-automatic), the reliability of the surface EMG signal was not significantly improved (ICC less than 0.75) for both non-normalised and normalised data. Therefore the static postures that were used in this thesis did not provide a protocol that can be used to measure the functional status of the lumbar paraspinal muscles in clinical practice. However, when muscle contraction was at a moderate level, the reliability of EMG signal became better. Walking was considered to be a possible protocol to record a reliable surface EMG signal from paraspinal muscles. Three components of the surface EMG signal were used to characterise the pattern of muscle activity during steady state walking. The narrow window technique was used to characterise the peak activation point of the activity envelope in order to capture a stationary signal from which to calculate amplitude and frequency measures. Walking is a cyclic activity. The back muscles contract rhythmically during a single gait cycle. It is possible to identify the start and end points of the activity envelope associated with the rhythmic contraction of the muscles and define the timing of the muscle activation cycle relative to heel strike. The metronome was found to be useful to control the pace of natural walking in this study. The surface EMG signal of the first recording minute (1 ~ 2 minute) was not associated with a signal that was stable in terms of the parameters that were used in this study. It wa s found that the last recording minute (9 ~ 10 minute) can be used. This suggests that it may be necessary for subjects to walk for a defined period lasting some minutes before the commencement of recording of the surface EMG. Surface EMG may be used as a tool to measure activation patterns of the low back muscles during muscle contraction associated with the support of various static postures or during the execution of dynamic movements such as walking in the real world. The static postures used in this thesis to record the surface EMG signal from the lumbar paraspinal muscles were found not to provide the basis for a reliable and valid tool. However, a walking exercise might be an alternative activity which can be used easily in clinical practice. The components of the surface EMG signal that may be used in future studies might include measures of the amplitude, frequency and timing of the surface EMG signal