Essays on Asymmetries in Contest

This thesis is concerned with the effects of asymmetries in ability and social preferences in contests and conflict networks. Standard models find that asymmetries monotonically decrease total and individual efforts. I demonstrate that this result does not necessarily hold when players are embedded in complex networks, have preferencesregardingthefairnessofthecontestortheoutcomesofothers, and when real subjects play these games in the lab. Chapter 1 formulates a network of bilateral contests in which locally unique equilibria always exist, and global uniqueness is possible. I find that an increase of one player’s ability can increase her effort and the effort of the entire network. If one player targets a specific opponent, other players follow. Chapter 2 imposes a budget constraint on this model. Most findings are robust to this modelling choice. This allows an investigation of topics like the effects of heterogeneity on team performance and the effect of asymmetries in the number of conflicts a player and her rivals are involved in. Chapter 3 documents that there exists no agreed way for implementing social preferences in contests. I derive four possible versions and critically assess their properties. When costs are considered, the magnitude of predicted overspreading and overbidding is reduced. Mild asymmetry can result in higher effort from the high ability player. In chapter 4, I present a pilot experiment in which social identities, with and without a hierarchy, are induced. We find that identities with such a hierarchy can trigger more aggressive play. To structure these findings, I suggest a foundational model of social preferences that relates them to social identity, where ‘close’ players are treated with altruism and ‘distant’ players are treated with spite

Prosocial behavior among human workers in robot-augmented production teams : a field-in-the-lab experiment

Human-machine interaction has raised a lot of interest in various academic disciplines, but it is still unclear how human-human interaction is affected when robots join the team. Robotics has already been integral to manufacturing since the 1970s. With the integration of AI, however, they are increasingly working alongside humans in shared spaces. We conducted an experiment in a learning factory to investigate how a change from a human-human work context to a hybrid human-robot work context affects participants\u27 valuation of their production output as well as their pro-sociality among each other. Learning factories are learning, teaching, and research environments in engineering university departments. These factory environments allow control over the production environment and incentives for participants. Our experiment suggests that the robot\u27s presence increases sharing behavior among human workers, but there is no evidence that rewards earned from production are valued differently. We discuss the implications of this approach for future studies on human-machine interaction

Don't Fear the Robots: Automatability and Job Satisfaction

We analyse the correlation between job satisfaction and automatability - the degree to which an occupation can be or is at risk of being replaced by computerised equipment. Using multiple survey datasets matched with various measures of automatability from the literature, we find that there is a negative and statistically significant correlation that is robust to controlling for worker and job characteristics. Depending on the dataset, a one standard deviation increase in automatability leads to a drop in job satisfaction of about 0.73% to 1.85% for the average worker. Unlike other studies, we provide evidence that it is not the fear of losing the job that mainly drives this result, but the fact that monotonicity and low perceived meaning of the job drive both automatability as well as low job satisfaction

Generalising Conflict Networks

We investigate the behaviour of agents in bilateral contests within arbitrary network structures when valuations and efficiencies are heterogenous. These parameters are interpreted as measures of strength. We provide conditions for when unique, pure strategy equilibria exist. When a player starts attacking one player more strongly, others join in on fighting the victim. Different efficiencies in fighting make players fight those of similar strength. Centrality of a player (having more enemies) makes a player weaker and her opponents are more likely to attack with more effort

Prosocial behavior among human workers in robot-augmented production teams—A field-in-the-lab experiment

IntroductionHuman-machine interaction has raised a lot of interest in various academic disciplines, but it is still unclear how human-human interaction is affected when robots join the team. Robotics has already been integral to manufacturing since the 1970s. With the integration of AI, however, they are increasingly working alongside humans in shared spaces.MethodsWe conducted an experiment in a learning factory to investigate how a change from a human-human work context to a hybrid human-robot work context affects participants' valuation of their production output as well as their pro-sociality among each other. Learning factories are learning, teaching, and research environments in engineering university departments. These factory environments allow control over the production environment and incentives for participants.ResultsOur experiment suggests that the robot's presence increases sharing behavior among human workers, but there is no evidence that rewards earned from production are valued differently.DiscussionWe discuss the implications of this approach for future studies on human-machine interaction

Use of Rotorod as a Method for the Qualitative Analysis of Walking in Rat

The rotorod test, in which animals walk on a rotating drum, is widely used to assess motor status in laboratory rodents. Performance is measured by the duration that an animal stays up on the drum as a function of drum speed. Here we report that the task provides a rich source of information about qualitative aspects of walking movements. Because movements are performed in a fixed location, they can readily be examined using high-speed video recording methods. The present study was undertaken to examine the potential of the rotorod to reveal qualitative changes in the walking movements of hemi-Parkinson analogue rats, produced by injection of 6-hydroxydopamine (6-OHDA) into the right nigrostriatal bundle to deplete nigrostriatal dopamine (DA). Beginning on the day following surgery and then periodically over the next two months, the rats were filmed from frontal, lateral, and posterior views as they walked on the rotorod. Behavior was analyzed by frame-by-frame replay of the video records. Rating scales of stepping behavior indicated that the hemi-Parkinson rats were chronically impaired in their posture and in the use of the limbs contralateral to the DA-depletion. The contralateral limbs not only displayed postural and movement abnormalities, they participated less in initiating and sustaining propulsion than did the ipsilateral limbs. These findings not only reveal new deficits secondary to unilateral DA-depletion, but also show that the rotorod can provide a robust tool for the qualitative analysis of movement

Different Pattern of Immunoglobulin Gene Usage by HIV-1 Compared to Non-HIV-1 Antibodies Derived from the Same Infected Subject

A biased usage of immunoglobulin (Ig) genes is observed in human anti-HIV-1 monoclonal antibodies (mAbs) resulting probably from compensation to reduced usage of the VH3 family genes, while the other alternative suggests that this bias usage is due to antigen requirements. If the antigen structure is responsible for the preferential usage of particular Ig genes, it may have certain implications for HIV vaccine development by the targeting of particular Ig gene-encoded B cell receptors to induce neutralizing anti-HIV-1 antibodies. To address this issue, we have produced HIV-1 specific and non-HIV-1 mAbs from an infected individual and analyzed the Ig gene usage. Green-fluorescence labeled virus-like particles (VLP) expressing HIV-1 envelope (Env) proteins of JRFL and BaL and control VLPs (without Env) were used to select single B cells for the production of 68 recombinant mAbs. Ten of these mAbs were HIV-1 Env specific with neutralizing activity against V3 and the CD4 binding site, as well as non-neutralizing mAbs to gp41. The remaining 58 mAbs were non-HIV-1 Env mAbs with undefined specificities. Analysis revealed that biased usage of Ig genes was restricted only to anti-HIV-1 but not to non-HIV-1 mAbs. The VH1 family genes were dominantly used, followed by VH3, VH4, and VH5 among anti-HIV-1 mAbs, while non-HIV-1 specific mAbs preferentially used VH3 family genes, followed by VH4, VH1 and VH5 families in a pattern identical to Abs derived from healthy individuals. This observation suggests that the biased usage of Ig genes by anti-HIV-1 mAbs is driven by structural requirements of the virus antigens rather than by compensation to any depletion of VH3 B cells due to autoreactive mechanisms, according to the gp120 superantigen hypothesis

Serendipity and the SDSS: Discovery of the Largest Known Planetary Nebula on the Sky

Investigation of spectra from the Sloan Digital Sky Survey reveals the presence of a region of ionized gas of >2 degrees diameter centered approximately at alpha = 10^h 37^m delta = -00^o 18' (J2000) (Galactic coordinates l=248, b=+48). [OIII] 4959,5007 emission is particularly strong and emission from H-alpha and [NII] 6548,6583 is also detectable over a substantial area on the sky. The combination of emission line ratios, the close to zero heliocentric radial velocity and the morphology of the structure are consistent with an identification as a very nearby planetary nebula. The proximity of the hot, DO white dwarf PG1034+001 further strengthens this interpretation. The object is: i) the largest planetary nebula on the sky, ii) certainly closer than any planetary nebula other than Sh 2--216, iii) the first to be unambiguously associated with a DO white dwarf. A parallax distance for PG1034+001 would establish whether the structure is in fact the closest, and one of the physically largest, planetary nebula known.Comment: 12 pages including 4 figures. ApJ Letters in pres

Induction of Antibodies in Rhesus Macaques That Recognize a Fusion-Intermediate Conformation of HIV-1 gp41

A component to the problem of inducing broad neutralizing HIV-1 gp41 membrane proximal external region (MPER) antibodies is the need to focus the antibody response to the transiently exposed MPER pre-hairpin intermediate neutralization epitope. Here we describe a HIV-1 envelope (Env) gp140 oligomer prime followed by MPER peptide-liposomes boost strategy for eliciting serum antibody responses in rhesus macaques that bind to a gp41 fusion intermediate protein. This Env-liposome immunization strategy induced antibodies to the 2F5 neutralizing epitope 664DKW residues, and these antibodies preferentially bound to a gp41 fusion intermediate construct as well as to MPER scaffolds stabilized in the 2F5-bound conformation. However, no serum lipid binding activity was observed nor was serum neutralizing activity for HIV-1 pseudoviruses present. Nonetheless, the Env-liposome prime-boost immunization strategy induced antibodies that recognized a gp41 fusion intermediate protein and was successful in focusing the antibody response to the desired epitope