I notice that all previous rounds have resulted in ties, which suggests my opponent might be mirroring my moves. If that's the case, choosing rock will result in another tie. However, if they're trying to predict my next move, they might expect me to continue a pattern. The sequence so far (rock, paper, scissors, paper) doesn't show a clear pattern, but they might anticipate me choosing scissors next to follow paper. In that case, playing rock would be advantageous as it would beat their scissors. I'm choosing rock to test whether they're mirroring or predicting.