The Baldwin Effect is a proposed mechanism by which plasticity facilitates adaptive phenotypic and genetic evolution. In particular it has been proposed to be involved in the evolution of language. Here we investigate three factors affecting the extent to which plastic traits are fixed by selection: (i) the difficulty with which traits can be acquired through plasticity, (ii) the importance of traits to fitness, and (iii) the nature of dependencies between different traits. We find that selection preferentially fixes traits that are difficult to acquire through plasticity, traits that have larger fitness benefits, and traits that affect the acquisition of, or benefits from, other traits. We conclude by discussing the implications of these findings for the evolution of language as well as non-human behaviors and reconsider the evolutionary significance of the Baldwin Effect

The quiet hum of interpersonal coordination that runs through-out social communication and interaction shows how individu-als can subtly influence one another’s behaviors, thoughts, andemotions over time. While the majority of research on co-ordination studies face-to-face interaction, recent advances incrowdsourcing afford the opportunity to conduct large-scale,real-time social interaction experiments. We take advantageof these tools to explore interpersonal coordination in a “min-imally interactive context,” distilling the richness of naturalcommunication into a tightly controlled setting to explore howpeople become coupled in their perceptual and memory sys-tems while performing a task together. Consistent with previ-ous work on postural sway and gaze, we found that individualsbecome coupled to one another’s cognitive processes withoutneeding to be co-located or fully interactive with their partner;interestingly, although participants had no information abouttheir partner and no means of direct communication, we alsofound hints that social forces can shape minimally interactivecontexts, similar to effects observed in face-to-face interaction.