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We study a dynamic game in which players compete for a prize. In a waiting game with two-sided private information about strength levels, players choose fighting, fleeing, or waiting. Players earn a “deterrence value” on top of the prize if their opponent escapes without a battle. We show that this value is a key determinant of the type of equilibrium. For intermediate values, sorting takes place, with weaker players fleeing before others fight. Time then helps to reduce battles. In an experiment, we find support for the key theoretical predictions and document suboptimal predatory fighting.

We investigate a mechanism that facilitates the provision of public goods in a network formation game. We show how competition for status encourages a core player to realize efficiency gains for the entire group. In a laboratory experiment we systematically examine the effects of group size and exogenously monetarized status rents. The experimental results provide very clear support for the concept of challenge-freeness, a refinement that predicts when a repeated game equilibrium will be played, and if so which one. Two control treatments allow us to reject the possibility that these observations are driven by social preferences, independently of the competition for status.

Economic preferences may be shaped by exposure to sex hormones around birth. Prior studies of economic preferences and numerous other phenotypic characteristics use digit ratios (2D : 4D), a purported proxy for prenatal testosterone exposure, whose validity has recently been questioned. We use direct measures of neonatal sex hormones (testosterone and oestrogen), measured from umbilical cord blood ( n = 200) to investigate their association with later-life economic preferences (risk preferences, competitiveness, time preferences and social preferences) in an Australian cohort (Raine Study Gen2). We find no significant associations between testosterone at birth and preferences, except for competitiveness, where the effect runs opposite to the expected direction. Point estimates are between 0.05–0.09 percentage points (pp) and 0.003–0.14 s.d. We similarly find no significant associations between 2D : 4D and preferences ( n = 533, point estimates 0.003–0.02 pp and 0.001–0.06 s.d.). Our sample size allows detecting effects larger than 0.11 pp or 0.22 s.d. for testosterone at birth, and 0.07 pp or 0.14 s.d. for 2D : 4D ( α = 0.05 and power = 0.90). Equivalence tests show that most effects are unlikely to be larger than these bounds. Our results suggest a reinterpretation of prior findings relating 2D : 4D to economic preferences, and highlight the importance of future large-sample studies that permit detection of small effects.

Economic preferences may be shaped by exposure to sex hormones around birth. Prior studies of economic preferences and numerous other phenotypic characteristics use digit ratios (2D:4D), a purported proxy for prenatal testosterone exposure, whose validity has recently been questioned. We use direct measures of neonatal sex hormones (testosterone and estrogen), measured from umbilical cord blood (n=200) to investigate their association with later-life economic preferences (risk preferences, competitiveness, time preferences and social preferences) in an Australian cohort (Raine Study Gen2). We find no significant associations between testosterone at birth and preferences, except for competitiveness, where the effect runs opposite to the expected direction. Point estimates are between 0.05-0.09 percentage points (pp) and 0.003-0.14 SD. We similarly find no significant associations between 2D:4D and preferences (n=533, point estimates 0.003-0.02 pp and 0.001-0.06 SD). Our sample size allows detecting effects larger than 0.11 pp or 0.22 SD for testosterone at birth, and 0.07 pp or 0.14 SD for 2D:4D (α=0.05 and power=0.90). Equivalence tests show that most effects are unlikely to be larger than these bounds. Our results suggest a reinterpretation of prior findings relating 2D:4D to economic preferences, and highlight the importance of future large-sample studies that permit detection of small effects.

Recent theoretical work suggests that a form of Kantian morality has evolutionary foundations. To investigate the relative importance of Kantian morality and social preferences, we run laboratory experiments on strategic interaction in social dilemmas. Using a structural model, we estimate social preferences and morality concerns both at the individual level and the aggregate level. We observe considerable heterogeneity in social preferences and Kantian morality. A finite mixture analysis shows that the subject pool is well described as consisting of two types. One exhibits a combination of inequity aversion and Kantian morality, while the other combines spite and Kantian morality.

Evolutionary explanations of anger as a commitment device hinge on two key assumptions. The first is that it is predictable, ex ante, whether someone will get angry when feeling that he or she has been badly treated. The second is that anger is associated with destructive behavior. We test the validity of these two assumptions. We collected photos of responders in an ultimatum game before they were informed about the game that they would be playing, and we filmed responders with webcams during play. We then showed pairs of photos consisting of one responder who rejected and one responder who accepted (a low offer) to an independent group of observers. We find that observers are better than chance at detecting who rejected the low offer; they do 10% better than random guessing would. We also find that anger at receiving a low offer is associated with rejection. Data and the online appendix are available at https://doi.org/10.1287/mnsc.2017.2727 . This paper was accepted by Uri Gneezy, behavioral economics.

The emotion that someone expresses has consequences for how that person is treated. We study whether people display emotions strategically. In two laboratory experiments, participants play task delegation games in which managers assign a task to one of two workers. When assigning the task, managers see pictures of the workers and we vary whether getting the task is desirable or not. We find that workers strategically adapt their emotional expressions to the incentives they face, and that it indeed pays off to do so. Yet, workers do not exploit the full potential of the strategic display of emotions.

We study a dynamic game in which players compete for a prize. In a waiting game with two-sided private information about strength levels, players choose between fighting, fleeing, or waiting. Players earn a “deterrence value” on top of the prize if their opponent escapes without a battle. We show that this value is a key determinant of the type of equilibrium. For intermediate values, sorting takes place with weaker players fleeing before others fight. Time then helps to reduce battles. In an experiment, we find support for the key theoretical predictions, and document suboptimal predatory fighting.

We investigate the effects of power on cooperation in repeated social dilemma settings. Groups of five players play either multi-player trust games or VCM-games on a fixed network. Power stems from having the authority to allocate funds raised through voluntary contributions by all members and/or from having a pivotal position in the network (centrality). We compare environments with and without ostracism by allowing players in some treatments to exclude others from further participation in the network. Our results show that power matters but that its effects hinge strongly on the type involved. Reminiscent of the literature on leadership, players with authority often act more cooperatively than those without such power. Nevertheless, when possible, they are quickly ostracized from the group. Thus, this kind of power is not tolerated by the powerless. In stark contrast, centrality leads to less cooperative behavior and this free riding is not punished; conditional on cooperativeness, players with power from centrality are less likely to be ostracized than those without. Hence, not only is this type of power tolerated, but so is the free riding it leads to.

We investigate a mechanism that facilitates the provision of public goods in a network formation game. We show how competition for status encourages a core player to realize efficiency gains for the entire group. In a laboratory experiment we systematically examine the effects of group size and status rents. The experimental results provide very clear support for a competition for status dynamic that predicts when, and if so which, repeated game equilibrium is reached. Two control treatments allow us to reject the possibility that the supergame effects we observe are driven by social preferences.

Evolutionary explanations of anger as a commitment device hinge on two key assumptions. The first is that it is observable ex-ante whether someone will get angry when feeling badly treated. The second is that anger is associated with destructive behavior. We test the validity of these assumptions by studying whether observers are able to detect who rejected a low offer in an ultimatum game. We collected photos and videos of responders in an ultimatum game before they were informed about the game that they would be playing. We showed pairs of photos or videos, consisting of one responder who rejected a low offer and one responder who accepted a low offer, to an independent group of observers. We find support for the two assumptions. Observers do better than chance at detecting who rejected the low offer, especially for rejecters who get angry at low offers.

We investigate contributions to the provision of public goods on a network when efficient provision requires the formation of a star network. We provide a theoretical analysis and study behavior in a controlled laboratory experiment. In a 2x2 design, we examine the effects of group size and the presence of (social) benefits for incoming links. We find that social benefits are highly important. They facilitate convergence to equilibrium networks and enhance the stability and efficiency of the outcome. Moreover, in large groups social benefits encourage the formation of superstars: star networks in which the core contributes more than expected in the stage-game equilibrium. We show that this result is predicted by a repeated game equilibrium.

We investigate contributions to the provision of public goods on a network when efficient provision requires the formation of a star network. We provide a theoretical analysis and study behavior is a controlled laboratory experiment. In a 2x2 design, we examine the effects of group size and the presence of (social) benefits for incoming links. We find that social benefits are highly important. They facilitate convergence to equilibrium networks and enhance the stability and efficiency of the outcome. Moreover, in large groups social benefits encourage the formation of superstars: star networks in which the core contributes more than expected in the stage-game equilibrium. We show that this result is predicted by a repeated game equilibrium.

We describe the preliminary design of the proposed Heterodyne Instrument for FIRST (HIFI). The instrument will have a continuous frequency coverage over the range from 480 to 1250 GHz in five bands, while a sixth band will provide coverage for 1410 - 1910 GHz and 2400 - 2700 GHz. The first five bands will use SIS mixers and varactor frequency multipliers while in the sixth band a laser photomixer local oscillator will pump HEB mixers. HIFI will have an instantaneous bandwidth of 4 GHz, analyzed in parallel by two types of spectrometers: a pair of wide-band spectrometers (WBS), and a pair of high- resolution spectrometer (HRS). The wide-band spectrometer will use acousto-optic technology with a frequency resolution of 1 MHz and a bandwidth of 4 GHz for each of the two polarizations. The HRS will provide two combinations of bandwidth and resolution: 1 GHz bandwidth at 200 kHz resolution, and at least 500 MHz at 100 kHz resolution. The HRS will be divided into 4 or 5 sub-bands, each of which can be placed anywhere within the full 4 GHz IF band. The instrument will be able to perform rapid and complete spectral line surveys with resolving powers from 103 up to 107 (300 - 0.03 km/s) and deep line observations.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The x-ray multi-mirror (XMM) mission is the second of four cornerstone projects of the ESA long-term program for space science, Horizon 2000. The payload comprises three co- aligned high-throughput, imaging telescopes with a FOV of 30 arcmin and spatial resolution less than 20 arcsec. Imaging CCD-detectors (EPIC) are placed in the focus of each telescope. Behind two of the three telescopes, about half the x-ray light is utilized by the reflection grating spectrometer (RGS). The x-ray instruments are co-aligned and measure simultaneously with an optical monitor (OM). The RGS instruments achieve high spectral resolution and high efficiency in the combined first and second order of diffraction in the wavelength range between 5 and 35 angstrom. The design incorporates an array of reflection gratings placed in the converging beam at the exit from the x-ray telescope. The grating stack diffracts the x-rays to an array of dedicated charge-coupled device (CCD) detectors offset from the telescope focal plane. The cooling of the CCDs is provided through a passive radiator. The design and performance of the instrument are described below.

The emotion that someone expresses has consequences for how that person is treated. We study whether people display emotions strategically. In two laboratory experiments, participants play task delegation games in which managers assign a task to one of two workers. When assigning the task, managers see pictures of the workers and we vary whether getting the task is desirable or not. We find that workers strategically adapt their emotional expressions to the incentives they face, and that it indeed pays off to do so. Yet, workers do not exploit the full potential of the strategic display of emotions.