straight movement.

In the scenario $S_2$, a controller which learned all the three subtasks, namely foraging, phototaxis and obstacle avoidance, was not evolved. From the pool of controllers found during the 400 evaluations, some of the evolved controllers learned only obstacle avoidance while some others learned foraging and phototaxis. No controller learned all the tasks. Scenario $S_3$ had two subtasks which are switched based on the two conditions: 1) Condition $C_1$, when the light source is turned ON, and the robot had to push the pucks towards the light while also avoiding obstacles. 2) Condition $C_2$, wherein the light source is turned OFF and the robot had to learn to avoid obstacles and to repel the pucks encountered. The conditions $C_1$ and $C_2$ were triggered asynchronously. The duration for which each condition lasted was kept such that a minimum of 5 consecutive controller evaluations could take place under each condition. This asynchronous switching made it impractical for a single controller to learn the whole task. We may thus conclude that it is difficult for a single monolithic controller to learn all the tasks described herein.\

**Real-Robot Experiments** We performed 10 trials for each of the scenarios[^1]. The value of $\epsilon$ 