We propose and test a model of loyalty in games. Players can mutually maintain loyalty by working towards a common goal that is pareto-superior to any Nash equilibrium without it. Loyalty imposes a psychological cost on defecting in an ongoing cooperation, which is thus sustained. We distinguish loyalty from reciprocity and explain how it complements guilt aversion with two dynamic games from a field experiment conducted in a Pakistani factory. The evidence supports the validity of loyalty, which has a stronger (...) effect within than between groups. (shrink)

Some researchers have attributed deviations from selfish behavior to fairness. Violations of fairness theories, however, are observed in experimental dictator games with transfer rates greater than 1 (a transfer of x from the dictator yields an income of tx for the beneficiary, where x < tx): the dictator’s final income is less than the beneficiary’s. We theoretically propose that dictator giving also involves altruism, further supporting our claim with empirical evidence from four separate samples of dictator game experiments. Our nonlinear (...) specification allows the relative measurement of the independent motives in dictator behavior. (shrink)

This article examines, experimentally, whether inequality affects the social capital of trust in non-market and market settings. We consider three experimental treatments, one with equality, one with inequality but no knowledge of the income of other agents, and one with inequality and knowledge. Inequality, particularly when it is known, has a corrosive effect on trusting behaviours in this experiment. Agents appear to be less sensitive to known relative income differentials in markets than they are in the non-market settings, but trust (...) in markets appears generally more vulnerable to the introduction of inequality than in the non-market setting. (shrink)

This article examines, experimentally, whether inequality affects the social capital of trust in non-market and market settings. We consider three experimental treatments, one with equality, one with inequality but no knowledge of the income of other agents, and one with inequality and knowledge. Inequality, particularly when it is known, has a corrosive effect on trusting behaviours in this experiment. Agents appear to be less sensitive to known relative income differentials in markets than they are in the non-market settings, but trust (...) in markets appears generally more vulnerable to the introduction of inequality than in the non-market setting. (shrink)

Bone marrow is the main site for hematopoiesis in adults. It acts as a niche for hematopoietic stem cells (HSCs) and contains non‐hematopoietic cells that contribute to stem cell dormancy, quiescence, self‐renewal, and differentiation. HSC also exist in resting spleen of several species, although their contribution to hematopoiesis under steady‐state conditions is unknown. The spleen can however undergo extramedullary hematopoiesis (EMH) triggered by physiological stress or disease. With the loss of bone marrow niches in aging and disease, the spleen as (...) an alternative tissue site for hematopoiesis is an important consideration for future therapy, particularly during HSC transplantation. In terms of harnessing the spleen as a site for hematopoiesis, here the remarkable regenerative capacity of the spleen is considered with a view to forming additional or ectopic spleen tissue through cell engraftment. Studies in mice indicate the potential for such grafts to support the influx of hematopoietic cells leading to the development of normal spleen architecture. An important goal will be the formation of functional ectopic spleen tissue as an aid to hematopoietic recovery following clinical treatments that impact bone marrow. For example, expansion or replacement of niches could be considered where myeloablation ahead of HSC transplantation compromises treatment outcomes. (shrink)