The agent's response can be modeled as a sample from a probability distribution over the possible sequences.
for one session, given the visual input v t and conversation history H the agent's response a t can be generated by sampling from a distribution of the speaking action The agent interacts with the teacher by outputting the utterance a t and receives feedback from the teacher in the next step, with w t+1 a sentence as verbal feedback and r t+1 reward feedback (with positive values as encouragement while negative values as discouragement, according to a t , as described in Section 3).