scholarly journals Market Sentiment: A Tragedy of the Commons

2011 ◽  
Vol 101 (3) ◽  
pp. 402-405 ◽  
Author(s):  
Tarek A Hassan ◽  
Thomas M Mertens

We present a model in which investors decide whether or to what degree they want to allow their behavior to be influenced by “market sentiment.” Investors who choose to insulate their decisions from market sentiment earn higher expected returns, but incur a small mental cost. We show that if information is moderately dispersed across investors, even a very small mental cost may result in a significant amount of sentiment in equilibrium: Individuals who choose to be swayed by sentiment increase uncertainty about the future and make it less costly for others to be swayed by sentiment as well.

2014 ◽  
Vol 6 (1) ◽  
pp. 38-55 ◽  
Author(s):  
Stephen Leslie Wearing ◽  
Paul A. Cunningham ◽  
Stephen Schweinsberg ◽  
Chantelle Jobberns

Australia has long tried to portray itself as an environmentally responsible state and has consistently been a strong supporter of Whale Watching as an alternative to the practice of commercial and ‘scientific’ whaling. This paper explores whale watching in an effort to determine the economic and social viability of it as a sustainable marine tourism activity —and whether in the future the whale and the tourist can coexist or will the latter as with previous human activities such as whaling yet again create a ‘tragedy of the commons’ and displace the former. As an ecotourism product, whale watching holds the potential for sustainable practice, one that is both ecological and profitable. Responsible whale watching is seen as a clean, green industry that simultaneously supports local economies and promotes whale education and conservation. The question is can it live up to these expectations?


Erkenntnis ◽  
2020 ◽  
Author(s):  
H. Orri Stefánsson

AbstractThose who are risk averse with respect to money, and thus turn down some gambles with positive monetary expectations, are nevertheless often willing to accept bundles involving multiple such gambles. Therefore, it might seem that such people should become more willing to accept a risky but favourable gamble if they put it in context with the collection of gambles that they predict they will be faced with in the future. However, it turns out that when a risk averse person adopts the long-term perspective, she faces a decision-problem that can be analysed as a noncooperative game between different “time-slices” of herself, where it is in the interest of each time-slice (given its prediction about other slices) to turn down the gamble with which it is faced. Hence, even if a risk averse but rational person manages to take the long-term perspective, she will, in the absence of what Hardin called “mutual coercion”, end up in a situation analogous to the “tragedy of the commons”.


2014 ◽  
Author(s):  
David J. Hardisty ◽  
Howard Kunreuther ◽  
David H. Krantz ◽  
Poonam Arora

2021 ◽  
Author(s):  
Jaime G. Lopez ◽  
Mohamed S. Donia ◽  
Ned S. Wingreen

AbstractPlasmids are autonomous genetic elements that can be exchanged between microorganisms via horizontal gene transfer (HGT). Despite the central role they play in antibiotic resistance and modern biotechnology, our understanding of plasmids’ natural ecology is limited. Recent experiments have shown that plasmids can spread even when they are a burden to the cell, suggesting that natural plasmids may exist as parasites. Here, we use mathematical modeling to explore the ecology of such parasitic plasmids. We first develop models of single plasmids and find that a plasmid’s population dynamics and optimal infection strategy are strongly determined by the plasmid’s HGT mechanism. We then analyze models of co-infecting plasmids and show that parasitic plasmids are prone to a “tragedy of the commons” in which runaway plasmid invasion severely reduces host fitness. We propose that this tragedy of the commons is averted by selection between competing populations and demonstrate this effect in a metapopulation model. We derive predicted distributions of unique plasmid types in genomes—comparison to the distribution of plasmids in a collection of 17,725 genomes supports a model of parasitic plasmids with positive plasmid–plasmid interactions that ameliorate plasmid fitness costs or promote the invasion of new plasmids.


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