Stimulus awareness is necessary for both instrumental learning and instrumental responding to previously learned stimuli.

Instrumental conditioning is a crucial part of adaptive behaviour, allowing agents to selectively interact with stimuli in their environment. Recent evidence suggests that instrumental conditioning cannot proceed without stimulus awareness. However, whether accurate unconscious instrumental responding can emerge from consciously acquired knowledge of the stimulus-action-outcome contingencies is unknown. We studied this question using instrumental trace conditioning, where participants learned to make approach/avoid decisions in two within-subject modes: conscious (stimuli in plain view) and unconscious (visually masked). Both tasks were followed by an unconscious-only instrumental performance task. We show that even when the contingencies are reliably learned in the conscious mode, participants fail to act upon them in the unconscious responding task. We also replicate the previous results that no instrumental learning occurs in the unconscious mode. Consequently, the absence of stimulus awareness not only precludes instrumental conditioning, but also precludes any kind of instrumental responding to already known stimuli. This suggests that instrumental behaviour is entirely supported by conscious awareness of the world, and corroborates the proposals that consciousness may be necessary for adaptive behaviours requiring selective action.

General and anxiety-linked influences of acute serotonin reuptake inhibition on neural responses associated with attended visceral sensation.

Ordinary sensations from inside the body are important causes and consequences of our affective states and behaviour, yet the roles of neurotransmitters in interoceptive processing have been unclear. With a within-subjects design, this experiment tested the impacts of acute increases of endogenous extracellular serotonin on the neural processing of attended internal sensations and the links of these effects to anxiety using a selective serotonin reuptake inhibitor (SSRI) (20 mg CITALOPRAM) and a PLACEBO. Twenty-one healthy volunteers (fourteen female, mean age 23.9) completed the Visceral Interoceptive Attention (VIA) task while undergoing functional magnetic resonance imaging (fMRI) with each treatment. The VIA task required focused attention on the heart, stomach, or visual sensation. The relative neural interoceptive responses to heart sensation [heart minus visual attention] (heart-IR) and stomach sensation [stomach minus visual attention] (stomach-IR) were compared between treatments. Visual attention subtraction controlled for the general effects of CITALOPRAM on sensory processing. CITALOPRAM was associated with lower interoceptive processing in viscerosensory (the stomach-IR of bilateral posterior insular cortex) and integrative/affective (the stomach-IR and heart-IR of bilateral amygdala) components of interoceptive neural pathways. In anterior insular cortex, CITALOPRAM reductions of heart-IR depended on anxiety levels, removing a previously known association between anxiety and the region's response to attended heart sensation observed with PLACEBO. Preliminary post hoc analysis indicated that CITALOPRAM effects on the stomach-IR of the amygdalae corresponded to acute anxiety changes. This direct evidence of general and anxiety-linked serotonergic influence on neural interoceptive processes advances our understanding of interoception, its regulation, and anxiety.

Feasibility of unconscious instrumental conditioning: A registered replication.

The extent to which high-level, complex functions can proceed unconsciously has been a topic of considerable debate. While unconscious processing has been demonstrated for a range of low-level processes, from feature integration to simple forms of conditioning and learning, theoretical contributions suggest that increasing complexity requires conscious access. Here, we focus our attention on instrumental conditioning, which has been previously shown to proceed without stimulus awareness. Yet, instrumental conditioning also involves integrating information over a large temporal scale and distinct modalities in order to deploy selective action, constituting a process of substantial complexity. With this in mind, we revisit the question of feasibility of instrumental conditioning in the unconscious domain. Firstly, we address the theoretical and practical considerations relevant to unconscious learning in general. Secondly, we aim to replicate the first study to show instrumental conditioning in the absence of stimulus awareness (Pessiglione et al., 2008), following the original design and supplementing the original crucial analyses with a Bayesian approach (Experiment 1). We found that apparent unconscious learning took place when replicating the original methods directly and according to the tests of awareness used. However, we could not establish that the full sample was unaware in a separate awareness check. We therefore attempted to replicate the effect yet again with improved methods to address the issues related to sensitivity and immediacy (Experiment 2), including an individual threshold-setting task and a trial-by-trial awareness check permitting exclusion of individual aware trials. Here, we found evidence for absence of unconscious learning. This result provides evidence that instrumental conditioning did not occur without stimulus awareness in this paradigm, supporting the view that complex forms of learning may rely on conscious access. Our results provides support for the proposal that perceptual consciousness may be necessary for complex, flexible processes, especially where selective action and behavioural adaptation are required.

Awareness is required for autonomic performance monitoring in instrumental learning: Evidence from cardiac activity.

Performance monitoring is a vital aspect of successful learning and decision-making. Performance errors are reflected in the autonomic nervous system, indicating the need for behavioral adjustment. As part of this response, errors cause a pronounced deceleration in heart rate, compared to correct decisions, and precede explicit awareness of stimulus-response outcome contingencies. However, it is unknown whether those signals are present and able to inform instrumental learning without stimulus awareness, where explicit performance monitoring is disabled. With mixed evidence for unconscious instrumental learning, determining the presence or absence of autonomic signatures of performance monitoring can shed light on its feasibility. Here, we employed an unconscious instrumental conditioning task, where successful learning is evidenced by increased approach responses to visually masked rewarding stimuli, and avoidance of punishing stimuli. An electrocardiogram (ECG) assessed cardiac activity throughout the learning process. Natural fluctuations of awareness under masking permitted us to contrast learning and cardiac deceleration for trials with, versus without, conscious stimulus awareness. Our results demonstrate that on trials where participants did not consciously perceive the stimulus, there was no differentiation in cardiac response between rewarding and punishing feedback, indicating an absence of performance monitoring. In contrast, consciously perceived stimuli elicited the expected error-related deceleration. This result suggests that, in unconscious instrumental learning, the brain might be unable to acquire knowledge of stimulus values to guide correct instrumental choices. This evidence provides support for the notion that consciousness might be required for flexible adaptive behavior, and that this may be mediated through bodily signals.

Sensorimotor predictions shape reported conscious visual experience in a breaking continuous flash suppression task.

Accounts of predictive processing propose that conscious experience is influenced not only by passive predictions about the world, but also by predictions encompassing how the world changes in relation to our actions-that is, on predictions about sensorimotor contingencies. We tested whether valid sensorimotor predictions, in particular learned associations between stimuli and actions, shape reports about conscious visual experience. Two experiments used instrumental conditioning to build sensorimotor predictions linking different stimuli with distinct actions. Conditioning was followed by a breaking continuous flash suppression task, measuring the speed of reported breakthrough for different pairings between the stimuli and prepared actions, comparing those congruent and incongruent with the trained sensorimotor predictions. In Experiment 1, counterbalancing of the response actions within the breaking continuous flash suppression task was achieved by repeating the same action within each block but having them differ across the two blocks. Experiment 2 sought to increase the predictive salience of the actions by avoiding the repetition within blocks. In Experiment 1, breakthrough times were numerically shorter for congruent than incongruent pairings, but Bayesian analysis supported the null hypothesis of no influence from the sensorimotor predictions. In Experiment 2, reported conscious perception was significantly faster for congruent than for incongruent pairings. A meta-analytic Bayes factor combining the two experiments confirmed this effect. Altogether, we provide evidence for a key implication of the action-oriented predictive processing approach to conscious perception, namely that sensorimotor predictions shape our conscious experience of the world.