Motor Conflict: Revealing Involuntary Conditioned Motor Preparation Using Transcranial Magnetic Stimulation

Preparing actions to achieve goals, overriding habitual responses, and substituting actions that are no longer relevant are aspects of motor control often assumed to be driven by deliberate top-down processes. In the present study, we investigated whether motor control could come under involuntary control of environmental cues that have been associated with specific actions in the past. We used transcranial magnetic stimulation (TMS) to probe corticospinal excitability as an index of motor preparation, while participants performed a Go/No-Go task (i.e., an action outcome or no action outcome task) and rated what trial was expected to appear next (Go or No-Go). We found that corticospinal excitability during a warning cue for the upcoming trial closely matched recent experience (i.e., cue–outcome pairings), despite conflicting with what participants expected would appear. The results reveal that in an action–outcome task, neurophysiological indices of motor preparation show changes that are consistent with participants learning to associate a preparatory warning cue with a specific action, and are not consistent with the action that participants explicitly anticipate making. This dissociation with conscious expectancy ratings reveals that conditioned responding and motor preparation can operate independently of conscious expectancies about having to act.

Mackintosh lecture-: Association and cognition: Two processes, one system

This article argues that the dual-process position can be a useful first approximation when studying human mental life, but it cannot be the whole truth. Instead, we argue that cognition is built on association, in that associative processes provide the fundamental building blocks that enable propositional thought. One consequence of this position is to suggest that humans are able to learn associatively in a similar fashion to a rat or a pigeon, but another is that we must typically suppress the expression of basic associative learning in favour of rule-based computation. This stance conceptualises us as capable of symbolic computation but acknowledges that, given certain circumstances, we will learn associatively and, more importantly, be seen to do so. We present three types of evidence that support this position: The first is data on human Pavlovian conditioning that directly support this view. The second is data taken from task-switching experiments that provide convergent evidence for at least two modes of processing, one of which is automatic and carried out "in the background." And the last suggests that when the output of propositional processes is uncertain, the influence of associative processes on behaviour can manifest.

Saving the Perruchet effect: A role for the strength of the association in associative learning

In a partial reinforcement schedule where a cue repeatedly predicts the occurrence of a target in consecutive trials, reaction times to the target tend to decrease in a monotonic fashion, while participants' expectancies for the target decrease at the same time. This dissociation between reaction times and expectancies-the so-called Perruchet effect-challenges the propositional view of learning, which posits that human conditioned responses result from conscious inferences about the relationships between events. However, whether the reaction time pattern reflects the strength of a putative cue-target link, or only non-associative processes, such as motor priming, remains unclear. To address this issue, we implemented the Perruchet procedure in a two-choice reaction time task and compared reaction time patterns in an Experimental condition, in which a tone systematically preceded a visual target, and in a Control condition, in which the onset of the two stimuli were uncoupled. Participants' expectancies regarding the target were recorded separately in an initial block. Reaction times decreased with the succession of identical trials in both conditions, reflecting the impact of motor priming. Importantly, reaction time slopes were steeper in the Experimental than in the Control condition, indicating an additional influence of the associative strength between the two stimuli. Interestingly, slopes were less steep for participants who showed the gambler's fallacy in the initial block. In sum, our results suggest the mutual influences of motor priming, associative strength, and expectancies on performance. They are in line with a dual-process model of learning involving both a propositional reasoning process and an automatic link-formation mechanism.

Three Ways That Non-associative Knowledge May Affect Associative Learning Processes

Associative learning theories offer one account of the way animals and humans assess the relationship between events and adapt their behavior according to resulting expectations. They assume knowledge about event relations is represented in associative networks, which consist of mental representations of cues and outcomes and the associative links that connect them. However, in human causal and contingency learning, many researchers have found that variance in standard learning effects is controlled by "non-associative" factors that are not easily captured by associative models. This has given rise to accounts of learning based on higher-order cognitive processes, some of which reject altogether the notion that humans learn in the manner described by associative networks. Despite the renewed focus on this debate in recent years, few efforts have been made to consider how the operations of associative networks and other cognitive operations could potentially interact in the course of learning. This paper thus explores possible ways in which non-associative knowledge may affect associative learning processes: (1) via changes to stimulus representations, (2) via changes to the translation of the associative expectation into behavior (3) via a shared source of expectation of the outcome that is sensitive to both the strength of associative retrieval and evaluation from non-associative influences.

Automaticity and Conscious Control in Single and Choice Response Time Versions of the Perruchet Effect

The Perruchet effect refers to a dissociation between conscious expectation of an event and the strength or speed of the response elicited by that event, which is revealed through sequential analyses of consecutive trials. For instance in a cued go/no-go task, over a run of consecutive go responses, participants perform the go task with increasing speed but display decreasing expectancy of the go response when asked to rate the likelihood of its occurrence, in line with a gambler's fallacy. The effect has conventionally been shown in procedures that measure expectancy and responding in separate blocks of trials (separate measurement) or measure both on the same trial (concurrent measurement). Here we directly compared the trends produced in separate and concurrent measurement procedures, using single response and two-choice response procedures. While the single response showed the same trends regardless of measurement style, the Perruchet dissociation disappeared when concurrent measurement was used with the choice response task. Furthermore, in the concurrent measurement versions of both tasks, those participants who produced a consistent gambler's fallacy did not show the standard effects of positive recency that underpin the Perruchet effect in response time. The results suggest that explicit expectation of events and facilitation based on recent trial history have dissociable but competing effects on response performance.

Rapidly measuring the speed of unconscious learning: amnesics learn quickly and happy people slowly

Background

We introduce a method for quickly determining the rate of implicit learning.

Methodology/Principal Findings

The task involves making a binary prediction for a probabilistic sequence over 10 minutes; from this it is possible to determine the influence of events of a different number of trials in the past on the current decision. This profile directly reflects the learning rate parameter of a large class of learning algorithms including the delta and Rescorla-Wagner rules. To illustrate the use of the method, we compare a person with amnesia with normal controls and we compare people with induced happy and sad moods.

Conclusions/Significance

Learning on the task is likely both associative and implicit. We argue theoretically and demonstrate empirically that both amnesia and also transient negative moods can be associated with an especially large learning rate: People with amnesia can learn quickly and happy people slowly.