Training differences predict dogs' (Canis lupus familiaris) preferences for prosocial others.

Humans evaluate other agents' behavior on a variety of different dimensions, including morally, from a very early age. For example, human infants as young as 6-months old prefer prosocial over antisocial others and demonstrate negative evaluations of antisocial others in a variety of paradigms (Hamlin et al. in Nature 450(7169):557, 2007; Dev Sci 13(6):923-929, 2010; Proc Natl Acad Sci 108(50):19931-19936, 2011).

Learning about the Ellsberg Paradox reduces, but does not abolish, ambiguity aversion.

Ambiguity aversion-the tendency to avoid options whose outcome probabilities are unknown-is a ubiquitous phenomenon. While in some cases ambiguity aversion is an adaptive strategy, in many situations it leads to suboptimal decisions, as illustrated by the famous Ellsberg Paradox. Behavioral interventions for reducing ambiguity aversion should therefore be of substantial practical value.

Early development of spatial-numeric associations: evidence from spatial and quantitative performance of preschoolers.

Numeric magnitudes often bias adults' spatial performance. Partly because the direction of this bias (left-to-right versus right-to-left) is culture-specific, it has been assumed that the orientation of spatial-numeric associations is a late development, tied to reading practice or schooling. Challenging this assumption, we found that preschoolers expected numbers to be ordered from left-to-right when they searched for objects in numbered containers, when they counted, and (to a lesser extent) when they added and subtracted.

Cognitive constraints on how economic rewards affect cooperation.

Cooperation often fails to spread in proportion to its potential benefits. This phenomenon is captured by prisoner's dilemma games, in which cooperation rates appear to be determined by the distinctive structure of economic incentives (e.g.