Is Dyadic Fitts' Law Task Affected by Action Observation?

According to Fitts' law, an individual's speed-accuracy tradeoff is only related to the object's properties. According to previous research, the movement time to hit the current target can be affected by the target of different size on the previous trial where the Fitts' law task is affected by trial history. However, in a dyadic context, the question is whether there is still a trial-to-trial transfer across individuals. In this study, Experiment 1 was conducted to investigate whether the current trial would be affected by the previous trial performed by the partner in a dyadic task. The results showed trial-to-trial transfer between individuals was affected by the difficulty of the action. The current movement was only affected by the previous difficult trial but not simple task. In order to investigate whether observing only novel targets would affect the current movement, we conducted Experiment 2, which showed that observing the target was not sufficient to generate effect transfer between trials. These findings suggest that the goal-directed movement can be affected by the observation of others. In addition, the effect of trial-to-trial transfer between individuals was influenced by task difficulty, which proved this effect was not a simple imitation.