Figure 1

Experimental task and learning data.

The top panel provides a schematic of the experimental procedure. The lower left panel depicts mean probability of choosing a High option in a High/Low decision across participants on consecutive blocks of 6 decisions in each of the three experiments (error bars denote standard errors). The shaded area indicates probability below 80%, the threshold used to infer that participants learned to choose the High option and the dashed line indicates 50%, the choice probability expected by chance. The lower right panel is a bubble plot of sensitivity to relative reward measured by the log₂ probability of choosing a High option. As relative reward increased (the horizontal axis), more participants reliably chose the High choice in High/Low decisions. The size of each point is determined by the number of participants that obtained that value controlled for the number of participants in that experiment (i.e., probability density of that value within each experiment). The shaded area and black dashed line correspond to the same values as in the left panel. The blue dashed line indicates the mean log₂ probability at each level of relative reward.