Personality matters: A quantitative comparison of asocial and social behaviors in the zebrafish (Danio rerio)

Abstract

Fine inter-individual behavioral differences have significant consequences for an organism’s behavioral flexibility between social contexts. I developed a mathematically robust system of characterizing individual zebrafish personalities along the shy-bold continuum by analyzing the fine movement trajectories of zebrafish during asocial and social exploration tasks. Based on these methods, zebrafish were assigned unique SB (shyness/boldness) scores for each of the asocial and social conditions. These methods are potentially the first to use identical techniques and scoring systems for assigning personalities across multiple social environments. Using such consistent and quantitative methodology resulted in more controlled ways of measuring personality across social environments, enabling this study to draw more concrete conclusions about the effect of social context on individual behavior. This study found that individual behavioral adaptation to a social environment is defined by linear relationships with asocial personality and inter-individual personality differences. Relative boldness status within a pair predicted the magnitude and direction of these relationships. Thus, social behavior modification is influenced by absolute personality traits and relative behavioral differences. Furthermore, when zebrafish were sorted into groups, a group’s profile of member personalities affected its overall behavior. Those characterized by high boldness and substantial personality diversity lost their shoal cohesion during a choice task. Individual personality has meaningful ramifications across social contexts, influencing social roles and group dynamics in ways that can affect success and survival.