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ABSTRACT From navigating a crowded hallway to skiing down a treacherous hill, humans are constantly making decisions while moving. Insightful past work has provided a glimpse of decision deliberation at the moment of movement onset. Yet it is unknown whether ongoing deliberation can be expressed during movement, following movement onset and prior to any decision. Here we tested the idea that an ongoing deliberation continually influences motor processes—prior to a decision—directing online movements. Over three experiments, we manipulated evidence to influence deliberation during movement. The deliberation process was manipulated by having participants observe evidence in the form of tokens that moved into a left or right target. Supporting our hypothesis we found that lateral hand movements reflected deliberation, prior to a decision. We also found that a deliberation urgency signal, which more heavily weighs later evidence, was fundamental to predicting decisions and explains past movement behaviour in a new light. Our paradigm promotes the expression of ongoing deliberation through movement, providing a powerful new window into understanding the interplay between decision and action. 

Physical collaboration between two or more individuals involves both visual and haptic feedback. Here, we investigated how visual and haptic feedback is used to estimate the movements of a partner during a collaboration task. Our experimental and computational modeling results parsimoniously support the notion that greater visual accuracy is more important than faster yet noisier haptic feedback when estimating the state of a partner. 

We present experiments on the motion of swimming microbes in a laminar, hyperbolic flow. We test a theory that predicts the existence of swimming invariant manifolds (SwIMs) that act as invisible, one-way barriers that block the motion of the microbes. The flow is generated in a cross-channel in a PDMS cell, driven by syringe pumps. The swimming microbes are euglena and tetraselmis, both single-celled, eukaryotic algae. The algae are not ideal smooth-swimmers: there is significant rocking in their motion with occasional tumbles and a swimming speed that can vary. The experiments show that the swimming algae are bound very effectively by the predicted SwIMs. The different shapes and swimming behavior of the euglena and tetraselmis affect the distribution of swimming angles, with the elongated euglena having a larger probability of swimming in a direction parallel to the outflow directions. The differences in swimming orientation affect the ability of the microbes to penetrate the manifolds that act as barriers to passive tracers. The differing shapes of the euglena and tetraselmis also affect probabilities for the microbes to escape in one direction or the other along the outflow.