We randomly selected half of the population to be targeted and then periodically after 10 frames (~2.5 s) illuminated these specific colonies for 2 frames (~0.5 s) using cyan light that Volvox are known to be responsive to (Figure \ref{153302}). The velocities for each colony were tracked throughout the experiment. Notably, analysis of Volvox motion over time showed that only targeted cells saw clear changes in velocity (slowing down) when illuminated in a punctuated fashion (Figures \ref{902527} and \ref{523227}).