Stroop interference depends also on the level of automaticity of the to-be-interfered process.

The size of the Stroop effect is usually taken as dependent on the level of practice of the more automatized of two competing processes (e.g., reading in the standard Stroop task), possibly modulated in children by the age-dependent ability to inhibit nonrelevant information.

What Mechanisms Underlie Implicit Statistical Learning? Transitional Probabilities Versus Chunks in Language Learning.

In a prior review, Perrruchet and Pacton (2006) noted that the literature on implicit learning and the more recent studies on statistical learning focused on the same phenomena, namely the domain-general learning mechanisms acting in incidental, unsupervised learning situations. However, they also noted that implicit learning and statistical learning research favored different interpretations, focusing on the selection of chunks and the computation of transitional probabilities aimed at discovering chunk boundaries, respectively. This paper examines the state of the debate 12 years later.

Familiar units prevail over statistical cues in word segmentation.

In language acquisition research, the prevailing position is that listeners exploit statistical cues, in particular transitional probabilities between syllables, to discover words of a language. However, other cues are also involved in word discovery. Assessing the weight learners give to these different cues leads to a better understanding of the processes underlying speech segmentation.

Dissociating conscious expectancies from automatic-link formation in an electrodermal conditioning paradigm.

The key point of a paradigm initially proposed by Perruchet (Pavlov J Biol Sci 20:163-170, 1985) to dissociate conscious expectancies from automatic-link formation in classical conditioning settings is the use of a partial reinforcement schedule, in which the unconditioned stimulus (US) follows the conditioned stimulus (CS) only half of the time on average. Given (pseudo) randomization, the whole sequence comprises runs of CS alone and runs of CS-US pairs of various lengths. When the preceding run goes from a long sequence of CS alone to a long sequence of CS-US pairs (via shorter sequences), associative strength should grow up, whereas conscious expectancy should decrease.

Dissociating conscious expectancies from automatic link formation in associative learning: a review on the so-called Perruchet effect.

A long-running debate in the literature on conditioning in humans focuses on the question of whether conditioned responses are the product of automatic link formation processes governed by the standard laws of simple associative learning, or the consequence of participants' inferences about the relationships between the 2 related events, E1 and E2, which would lead E1 to generate a conscious expectancy of E2. A paradigm aimed at dissociating the predictions of the 2 accounts was proposed by Perruchet (1985). In this paradigm, E2 randomly follows E1 only half of the time on average, a probability that is known to participants.

Is an attention-based associative account of adjacent and nonadjacent dependency learning valid?

Pacton and Perruchet (2008) reported that participants who were asked to process adjacent elements located within a sequence of digits learned adjacent dependencies but did not learn nonadjacent dependencies and conversely, participants who were asked to process nonadjacent digits learned nonadjacent dependencies but did not learn adjacent dependencies. In the present study, we showed that when participants were simply asked to read aloud the same sequences of digits, a task demand that did not require the intentional processing of specific elements as in standard statistical learning tasks, only adjacent dependencies were learned. The very same pattern was observed when digits were replaced by syllables.

How does Stroop interference change with practice? A reappraisal from the musical Stroop paradigm.

Most earlier studies investigating the evolution of the Stroop effect with the amount of reading practice have reported data consistent with an inverted U-shaped curve, whereby the Stroop effect appears early during reading acquisition, reaches a peak after 2 or 3 years of practice, and then continuously decreases until adulthood. The downward component of the curve suggests that skilled performers would be able to control their performance better than less-skilled performers. However, in these studies, the level of reading practice entirely coincides with age due to obvious practical and ethical constraints, and it is possible that the observed reduction in the Stroop interference is due to a growing ability of older children to inhibit nonrelevant information.

About the unidirectionality of interference: insight from the musical Stroop effect.

The asymmetry of interference in a Stroop task usually refers to the well-documented result that incongruent colour words slow colour naming (Stroop effect) but incongruent colours do not slow colour word reading (no reverse Stroop effect). A few other studies have suggested that, more generally, a reverse Stroop effect can be occasionally observed but at the expense of the Stroop effect itself, as if interference was inherently unidirectional, from the stronger to the weaker of the two competing processes. We describe here a situation conducive to a pervasive mutual interference effect.

New evidence for chunk-based models in word segmentation.

There is large evidence that infants are able to exploit statistical cues to discover the words of their language. However, how they proceed to do so is the object of enduring debates. The prevalent position is that words are extracted from the prior computation of statistics, in particular the transitional probabilities between syllables.

Is the musical stroop effect able to keep its promises? A reply to Akiva-Kabiri and Henik (2014), Gast (2014), Moeller and Frings (2014), and Zakay (2014).

Grégoire, Perruchet, and Poulin-Charronnat (2013) claimed that the Musical Stroop task, which reveals the automaticity of note naming in musician experts, provides a new tool for studying the development of automatisms through extensive training in natural settings. Many of the criticisms presented in the four commentaries published in this issue appear to be based on a misunderstanding of our procedure, or questionable postulates. We maintain that the Musical Stroop Effect offers promising possibilities for further research on automaticity, with the main proviso that the current procedure makes it difficult to tease apart facilitation and interference.

The musical Stroop effect. Opening a new avenue to research on automatisms.

The usual color-word Stroop task, as well as most other Stroop-like paradigms, has provided invaluable information on the automaticity of word reading. However, investigating automaticity through reading alone has inherent limitations. This study explored whether a Stroop-like effect could be obtained by replacing word reading with note naming in musicians.

Challenging prior evidence for a shared syntactic processor for language and music.

A theoretical landmark in the growing literature comparing language and music is the shared syntactic integration resource hypothesis (SSIRH; e.g., Patel, 2008), which posits that the successful processing of linguistic and musical materials relies, at least partially, on the mastery of a common syntactic processor.

Centre-embedded structures are a by-product of associative learning and working memory constraints: evidence from baboons (Papio Papio).

Influential theories have claimed that the ability for recursion forms the computational core of human language faculty distinguishing our communication system from that of other animals (Hauser, Chomsky, & Fitch, 2002). In the present study, we consider an alternative view on recursion by studying the contribution of associative and working memory processes. After an intensive paired-associate training with visual shapes, we observed that baboons spontaneously ordered their responses in keeping with a recursive, centre-embedded structure.

Exploiting multiple sources of information in learning an artificial language: human data and modeling.

This study investigates the joint influences of three factors on the discovery of new word-like units in a continuous artificial speech stream: the statistical structure of the ongoing input, the initial word-likeness of parts of the speech flow, and the contextual information provided by the earlier emergence of other word-like units. Results of an experiment conducted with adult participants show that these sources of information have strong and interactive influences on word discovery. The authors then examine the ability of different models of word segmentation to account for these results.

Generating constrained randomized sequences: item frequency matters.

All experimental psychologists understand the importance of randomizing lists of items. However, randomization is generally constrained, and these constraints-in particular, not allowing immediately repeated items-which are designed to eliminate particular biases, frequently engender others. We describe a simple Monte Carlo randomization technique that solves a number of these problems.

The influence of temporal factors on automatic priming and conscious expectancy in a simple reaction time task.

In a previous study, we reported a dissociation between subjective expectancy and motor behaviour in a simple associative learning task (Perruchet, Cleeremans, & Destrebecqz, 2006). According to previous conditioning studies (Clark, Manns, & Squire, 2001), this dissociation is observed when the to-be-associated events coterminate and thus overlap in time (a training regimen called delay conditioning), but not when they are separated by a temporal delay (trace conditioning). In this latter situation indeed, there tends to be a direct relationship between subjective expectancy and behaviour.

Implicit learning of nonlocal musical rules: a comment on Kuhn and Dienes (2005).

In a recent study, G. Kuhn and Z. Dienes (2005) reported that participants previously exposed to a set of musical tunes generated by a biconditional grammar subsequently preferred new tunes that respected the grammar over new ungrammatical tunes.

A role for backward transitional probabilities in word segmentation?

A number of studies have shown that people exploit transitional probabilities between successive syllables to segment a stream of artificial continuous speech into words. It is often assumed that what is actually exploited are the forward transitional probabilities (given XY, the probability that X will be followed by Y), even though the backward transitional probabilities (the probability that Y has been preceded by X) were equally informative about word structure in the languages involved in those studies. In two experiments, we showed that participants were able to learn the words from an artificial speech stream when the only available cues were the backward transitional probabilities.

Does unconscious thought improve complex decision making?

In a recent study, Dijksterhuis et al. (Science 311:1005, 2006) reported that participants were better at solving complex decisions after a period of unconscious thought relative to a period of conscious thought. They interpreted their results as an existence proof of powerful unconscious deliberation mechanisms.

gSRT-Soft: a generic software application and some methodological guidelines to investigate implicit learning through visual-motor sequential tasks.

Serial reaction time tasks and, more generally, the visual-motor sequential paradigms are increasingly popular tools in a variety of research domains, from studies on implicit learning in laboratory contexts to the assessment of residual learning capabilities of patients in clinical settings. A consequence of this success, however, is the increased variability in paradigms and the difficulty inherent in respecting the methodological principles that two decades of experimental investigations have made more and more stringent. The purpose of the present article is to address those problems.

An attention-based associative account of adjacent and nonadjacent dependency learning.

In 5 experiments, results showed that when participants are faced with materials embedding relations between both adjacent and nonadjacent elements, they learn exclusively the type of relations they had to actively process in order to meet the task demands, irrespective of the spatial contiguity of the paired elements. These results are consonant with current theories positing that attention is a necessary condition for learning. More important, the results provide support for a more radical conception, in which the joint attentional processing of 2 events is also a sufficient condition for learning the relation between them.

Do distractors interfere with memory for study pairs in associative recognition?

In an associative recognition task, distractors generally consist of a rearrangement of the items composing the study pairs. This makes it possible that processing the distractors generates retroactive interference on memory for the study pairs. In Experiment 1, we explored this possibility in a yes/no recognition test concerning previously learned arbitrary associations between visual symbols and auditory syllables.

Dissociating the effects of automatic activation and explicit expectancy on reaction times in a simple associative learning task.

After repeated associations between two events, E1 and E2, responses to E2 can be facilitated either because participants consciously expect E2 to occur after E1 or because E1 automatically activates the response to E2, or because of both. In this article, the authors report on 4 experiments designed to pit the influence of these 2 factors against each other. The authors found that the fastest responses to a target in a reaction time paradigm occurred when automatic activation was highest and conscious expectancy lowest.

Implicit learning and statistical learning: one phenomenon, two approaches.

The domain-general learning mechanisms elicited in incidental learning situations are of potential interest in many research fields, including language acquisition, object knowledge formation and motor learning. They have been the focus of studies on implicit learning for nearly 40 years. Stemming from a different research tradition, studies on statistical learning carried out in the past 10 years after the seminal studies by Saffran and collaborators, appear to be closely related, and the similarity between the two approaches is strengthened further by their recent evolution.