Action enhances predicted touch

Abstract

It is widely believed that predicted action outcomes are perceptually attenuated. The present experiments determined whether predictive mechanisms in fact generate attenuation, or instead enhance perception -via neural 'sharpening' mechanisms assumed to operate in sensory cognition domains outside of action. We manipulated probabilistic expectations in a force judgement task. Participants produced actions and rated the intensity of concurrent tactile forces. Experiment 1 confirmed previous findings that action outcomes are perceived less intensely than similar passive stimulation, but demonstrated more intense perception when reducing the contribution of non-predictive gating processes. Experiments 2 and 3 manipulated prediction explicitly and found that expected outcomes are perceived more, not less, intensely than unexpected outcomes. These findings challenge a central tenet of prominent motor control theories and demonstrate that sensorimotor prediction operates via qualitatively similar mechanisms to other prediction and regardless of the sensory domain.

Predictive attenuation of touch and tactile gating are distinct perceptual phenomena

“…In contrast, the active inference account can sufficiently explain the tactile gating effect; i.e., the reduction in the precision of somatosensory input on the moving limb during the movement. A recent study 64 suggested that action prediction does not produce somatosensory attenuation but enhancement and argued that the attenuation observed in all earlier experiments is actually due to nonpredictive gating processes. This claim cannot be supported based on several observations and arguments.…”

“…A recent study 64 suggested that action prediction does not produce somatosensory attenuation but enhancement and argued that the attenuation observed in all earlier experiments is actually due to nonpredictive gating processes. This claim cannot be supported based on several observations and arguments.…”

“…In contrast, gating relates to somatosensory exafference, that is, external touches occurring during our voluntary movement. Nevertheless, somatosensory research, including very recent studies and review articles, e.g., 41,42,[58][59][60][61][62][63][64] , often treats the two phenomena as a single generalized suppression strategy of the brain and uses the terms attenuation and gating interchangeably. If the two phenomena are indeed different, this false equivalence is detrimental for understanding human sensorimotor control.…”

Action biases perceptual decisions toward expected outcomes.

“…Such suppression mechanisms are thought to attenuate tactile sensations during action regardless of whether they are predicted effects of action or not and are thought to be mediated by spinal mechanisms (Seki & Fetz, 2012), and comparable mechanisms may similarly attenuate sensory processing in a non-predictive fashion across modalities in humans and other animals (Crapse & Sommer, 2008). Importantly, recent experiments in touch suggest that when confounds related to sensory suppression are removed, action predictions may influence perception in a qualitatively similar fashion irrespective of sensory modality (Thomas, Yon, de Lange & Press, 2020).…”

Enhanced metacognition for unexpected action outcomes

“…1a). These accounts share a family resemblance to Bayesian models of perception 9,[12][13][14] , which assume it is adaptive for sensory representations to be weighted towards predicted outcomesmaking us more likely to see, hear or feel sensory events that we expect to occur [15][16][17][18] . Analogously to Bayesian of models of perception, Bayesian models of metacognition suggest that top-down predictions 'sharpen' internal representations of expected events, leading to more sensitive metacognition about predicted signals 11,19 .…”