Voss, M., Chambon, V., Wenke, D., Kühn, S., & Haggard, P. (2017). In and out of control: brain mechanisms linking fluency of action selection to self-agency in patients with schizophrenia. Brain, 140(8), 2226–2239. https://doi.org/10.1093/brain/awx136
Sense of agency refers to the feeling of control over one’s actions, and their consequences. It involves both predictive processes linked to action control, and retrospective ‘sense-making’ causal inferences. Schizophrenia has been associated with impaired predictive processing, but the underlying mechanisms that impair patients’ sense of agency remain unclear. We introduce a new ‘prospective’ aspect of agency and show that subliminally priming an action not only influences response times, but also influences reported sense of agency over subsequent action outcomes. This effect of priming was associated with altered connectivity between frontal areas and the angular gyrus. The effects on response times and on frontal action selection mechanisms were similar in patients with schizophrenia and in healthy volunteers. However, patients showed no effects of priming on sense of agency, no priming-related activation of angular gyrus, and no priming-related changes in fronto-parietal connectivity. We suggest angular gyrus activation reflects the experiences of agency, or non-agency, in part by processing action selection signals generated in the frontal lobes. The altered action awareness that characterizes schizophrenia may be due to impaired communication between these areas.
Stenner, M.-P., Bauer, M., Sidarus, N., Heinze, H.-J., Haggard, P., & Dolan, R.J. 2014 Subliminal action priming modulates the perceived intensity of sensory action consequences. Cognition, 30(2), 227–235.
The sense of control over the consequences of one’s actions depends on predictions about these consequences. According to an influential computational model, consistency between predicted and observed action consequences attenuates perceived stimulus intensity, which might provide a marker of agentic control. An important assumption of this model is that these predictions are generated within the motor system. However, previous studies of sensory attenuation have typically confounded motor-specific perceptual modulation with perceptual effects of stimulus predictability that are not specific to motor action. As a result, these studies cannot unambiguously attribute sensory attenuation to a motor locus. We present a psychophysical experiment on auditory attenuation that avoids this pitfall. Subliminal masked priming of motor actions with compatible prime– target pairs has previously been shown to modulate both reaction times and the explicit feeling of control over action consequences. Here, we demonstrate reduced perceived loudness of tones caused by compatibly primed actions. Importantly, this modulation results from a manipulation of motor processing and is not confounded by stimulus predictability. We discuss our results with respect to theoretical models of the mechanisms underlying sensory attenuation and subliminal motor priming.
Sidarus, N., Vuorre, M., Metcalfe, J., & Haggard, P. (2017). Investigating the prospective sense of agency: Effects of processing fluency, stimulus ambiguity, and response conflict. Frontiers in Psychology, 8, 545. https://doi.org/10.3389/fpsyg.2017.00545
How do we know how much control we have over our environment? The sense of agency refers to the feeling that we are in control of our actions, and that, through them, we can control our external environment. Thus, agency clearly involves matching intentions, actions and outcomes. The present studies investigated the possibility that processes of action selection, i.e. choosing what action to make, contribute to the sense of agency. Since selection of action necessarily precedes execution of action, such effects must be prospective. In contrast, most literature on sense of agency has focussed on the retrospective computation whether an outcome fits the action performed or intended. This hypothesis was tested in an ecologically rich, dynamic task based on a computer game. Across three experiments, we manipulated three different aspects of action selection processing: visual processing fluency, categorisation ambiguity, and response conflict. Additionally, we measured the relative contributions of prospective, action selection-based cues, and retrospective, outcome-based cues to the sense of agency. Manipulations of action selection were orthogonally combined with discrepancy of visual feedback of action. Fluency of action selection had a small but reliable effect on the sense of agency. Additionally, as expected, sense of agency was strongly reduced when visual feedback was discrepant with the action performed. The effects of discrepant feedback were larger than the effects of action selection fluency, and sometimes suppressed them. The sense of agency is highly sensitive to disruptions of action-outcome relations. However, when motor control is successful, and action-outcome relations are as predicted, fluency or dysfluency of action selection provides an important prospective cue to the sense of agency.
Sidarus, N., Vuorre, M., & Haggard, P. (2017). Integrating prospective and retrospective cues to the sense of agency: a multi-study investigation. Neuroscience of Consciousness, 2017(1), 1–10. https://doi.org/10.1093/nc/nix012
Sense of agency (SoA) refers to the experience of voluntary control over one’s own actions, and, through them, over events in the outside world. Recent accounts suggest that SoA involves an integration of various cues. These include prospective cues, for example, related to the fluency of action selection, and retrospective cues, linked to outcome monitoring. It remains unclear whether these cues may have independent effects on SoA, and, in particular, how their relative contributions may change during instrumental learning. In the present study, we explored these issues by conducting a multi-study analysis of seven published and unpublished studies on the role of prospective cues to the SoA. Our main question was how the effects of selection fluency on SoA might change as information about action–outcome contingencies is gathered. Results show that selection fluency can have a general and consistent influence on the SoA, independent of outcome monitoring. This suggests selection fluency is used as a heuristic cue, to prospectively inform our SoA. In addition, our results show that the influence of selection fluency on SoA may change systematically as action–outcome contingencies are gradually learned. We speculate that dysfluent selection may impair formation of mental associations between action and outcome.
Sidarus, N., Vuorre, M., & Haggard, P. (2017). How action selection influences the sense of agency: An ERP study. NeuroImage, 150, 1–13. https://doi.org/10.1016/j.neuroimage.2017.02.015
Sense of agency (SoA) refers to the feeling that we are in control of our actions and, through them, of events in the outside world. One influential view claims that the SoA depends on retrospectively matching the expected and actual outcomes of action. However, recent studies have revealed an additional, prospective component to SoA, driven by action selection processes. We used event-related potentials (ERPs) to clarify the neural mechanisms underlying prospective agency. Subliminal priming was used to manipulate the fluency of selecting a left or right hand action in response to a supraliminal target. These actions were followed by one of several coloured circles, after a variable delay. Participants then rated their degree of control over this visual outcome. Incompatible priming impaired action selection, and reduced sense of agency over action outcomes, relative to compatible priming. More negative ERPs immediately after the action, linked to post-decisional action monitoring, were associated with reduced agency ratings over action outcomes. Additionally, feedback-related negativity evoked by the outcome was also associated with reduced agency ratings. These ERP components may reflect brain processes underlying prospective and retrospective components of sense of agency respectively.
Sidarus, N., Chambon, V. & Haggard, P. 2013 Priming of actions increases sense of control over unexpected outcomes. Consciousness and Cognition, 22, 1403–1411.
Sense of agency (SoA) refers to the feeling that we are in control of our own actions and, through them, events in the outside world. SoA depends partly on retrospectively matching outcomes to expectations, and partly on prospective processes occurring prior to action, notably action selection.
To assess the relative contribution of these processes, we factorially varied subliminal priming of action selection and expectation of action outcomes. Both factors affected SoA, and there was also a significant interaction. Compatible action primes increased SoA more strongly for unexpected than expected outcomes. Outcome expectation had strong effects on SoA following incompatible action priming, but only weak effects following compatible action priming. Prospective and retrospective SoA may have distinct and complementary functions.
Sidarus, N., & Haggard, P. (2016). Difficult action decisions reduce the sense of agency: A study using the Eriksen flanker task. Acta Psychologica, 166, 1–11.
The sense of agency refers to the feeling that we are in control of our actions and, through them, of events in the outside world. Much research has focused on the importance of retrospectively matching predicted and actual action outcomes for a strong sense of agency. Yet, recent studies have revealed that a metacognitive signal about the fluency of action selection can prospectively inform our sense of agency. Fluent, or easy, action selection leads to a stronger sense of agency over action outcomes than dysfluent, or difficult, selection. Since these studies used subliminal priming to manipulate action selection, it remained unclear whether supraliminal stimuli affecting action selection would have similar effects.
We used supraliminal flankers to manipulate action selection in response to a central target. Experiment 1 revealed that conflict in action selection, induced by incongruent flankers and targets, led to reduced agency ratings over an outcome that followed the participant's response, relative to neutral and congruent flanking conditions. Experiment 2 replicated this result, and extended it to free choice between alternative actions. Finally, Experiment 3 varied the stimulus onset asynchrony (SOA) between flankers and target. Action selection performance varied with SOA. Agency ratings were always lower in incongruent than congruent trials, and this effect did not vary across SOAs. Sense of agency is influenced by a signal that tracks conflict in action selection, regardless of the visibility of stimuli inducing conflict, and even when the timing of the stimuli means that the conflict may not affect performance.
Chambon*, V., Sidarus*, N., & Haggard, P. (2014). From action intentions to action effects: how does the sense of agency come about? Frontiers in Human Neuroscience, 8, 320. doi:10.3389/fnhum.2014.00320
Sense of agency refers to the feeling of controlling an external event through one’s own
action. On one influential view, agency depends on how predictable the consequences
of one’s action are, getting stronger as the match between predicted and actual effect
of an action gets closer. Thus, sense of agency arises when external events that follow
our action are consistent with predictions of action effects made by the motor system
while we perform or simply intend to perform an action. According to this view, agency
is inferred retrospectively, after an action has been performed and its consequences are
known. In contrast, little is known about whether and how internal processes involved
in the selection of actions may influence subjective sense of control, in advance of the
action itself, and irrespective of effect predictability. In this article, we review several
classes of behavioral and neuroimaging data suggesting that earlier processes, linked to
fluency of action selection, prospectively contribute to sense of agency. These findings
have important implications for better understanding human volition and abnormalities of