Cognitive control: a role for implicit learning?

We investigated the influence of implicit learning on cognitive control. In a sequential Stroop task, participants implicitly learned a sequence placed on the color of the Stroop words. In Experiment 1, Stroop conflict was lower in sequenced than in random trials (learning-improved control).

On the automaticity of pure perceptual sequence learning.

We investigated the automaticity of implicit sequence learning by varying perceptual load in a pure perceptual sequence learning paradigm. Participants responded to the randomly changing identity of a target, while the irrelevant target location was structured. In Experiment 1, the target was presented under low or high perceptual load during training, whereas testing occurred without load.

Target-flanker discriminability affects conflict size but not sustained suppression.

On successive trials, repetitions of irrelevant information often tend to reduce congruency effects as compared to alternations of irrelevant information. The preferred explanation for this congruency modulation is the sustained-suppression hypothesis, suggesting that suppression of the irrelevant information on a given trial perseveres into the subsequent trial. However, in contrast to the generality of this idea, this modulation is only stable when the irrelevant information contains spatial features, which coincided in the existing research with large conflict sizes and response conflicts.

Testing the attention shift hypothesis as an account for the flanker sequence-based congruency modulation in spatial flanker tasks.

Smaller Simon effects when stimulus locations are repeated on successive trials rather than alternated have been explained by the attention shift hypothesis, suggesting that shifts of attention result in interfering response codes. We investigated whether the attention shift hypothesis can also explain smaller flanker effects for repeated flankers than for alternated flankers, which occur only with directional information. In 3 peripheral letter identification tasks, target locations were cued by partial or complete flanker stimuli.

Congruency reversals in an accessory signal Simon task with auditory and visual stimuli.

In visual two-choice reaction-time tasks, a Simon-like effect occurs when a peripheral accessory signal is presented shortly before or together with the response signal. However, the effect reverses when the peripheral signal appears shortly after the response signal. This pattern also occurs when the peripheral signal appears relative to a go (nogo) signal, with the relevant signal presented well in advance.

Practice-induced and sequential modulations of the Simon effect.

People react more quickly and more accurately to stimuli presented in locations corresponding to the response, as compared with noncorresponding locations, even when stimulus location is irrelevant (Simon effect [SE]). The explanation that SEs are caused by the automatic priming of a corresponding response has been questioned, because of the many exceptions to the effect. We replicated practice-induced and sequential modulations of the SE in two experiments--first, by training participants with blocks of location-relevant stimuli, and second, by mixing location-relevant and location-irrelevant trials.

Intact first- and second-order implicit sequence learning in secondary-school-aged children with developmental dyslexia.

We examined the influence of task complexity on implicit sequence learning in secondary-school-aged children with developmental dyslexia (DD). This was done to determine whether automatization problems in reading extend to the automatization of all skill and depend on the complexity of the to-be-learned skill. A total of 28 dyslexic children between 12 and 15 years and 28 matched control children carried out two serial reaction time tasks using a first-order conditional (FOC) and second-order conditional (SOC) sequence.