What physical processes govern the movement of microscopic structures capable of interacting with their environment? The answer lies in two mechanisms: self-propulsion, to escape unfavorable locations; and slow diffusion, to move toward more advantageous ones. This is the finding of scientists Jacopo Romano and Andrea Gambassi from SISSA-Scuola Internazionale Superiore di Studi Avanzati in their new study published in Physical Review Letters.