ABSTRACT We used event‐related potentials ( ERPs ) to determine the time course of mechanisms underlying strategy selection. Participants had to select the better strategy on multiplication problems (i.e., 51 × 27) to find approximate products. They could choose between rounding up and rounding down both operands to their nearest decades. Two types of problems were tested, homogeneous problems (e.g., 34 × 61) and heterogeneous problems (e.g., 61 × 36). Homogeneous problems are easier to solve because both operands are close to the lowest or the upper decades. Behavioral data revealed that participants selected the better strategy more often on homogeneous problems. ERPs showed that homogeneous problems elicited more positive cerebral activities than heterogeneous problems in the 0–200 and 800–1,000 ms windows, and more negative cerebral activities than heterogeneous problems in the 400–600 ms window. These findings have important theoretical implications for our understanding of the mechanisms underlying strategy selection.
Abstract The concept of “monitoring” refers to our ability to control our actions on-line. Monitoring involved in speech production is often described in psycholinguistic models as an inherent part of the language system. We probed the specificity of speech monitoring in two psycholinguistic experiments where electroencephalographic activities were recorded. Our focus was on a component previously reported in nonlinguistic manual tasks and interpreted as a marker of monitoring processes. The error negativity (Ne, or error-related negativity), thought to originate in medial frontal areas, peaks shortly after erroneous responses. A component of seemingly comparable properties has been reported, after errors, in tasks requiring access to linguistic knowledge (e.g., speech production), compatible with a generic error-detection process. However, in contrast to its original name, advanced processing methods later revealed that this component is also present after correct responses in visuomotor tasks. Here, we reported the observation of the same negativity after correct responses across output modalities (manual and vocal responses). This indicates that, in language production too, the Ne reflects on-line response monitoring rather than error detection specifically. Furthermore, the temporal properties of the Ne suggest that this monitoring mechanism is engaged before any auditory feedback. The convergence of our findings with those obtained with nonlinguistic tasks suggests that at least part of the monitoring involved in speech production is subtended by a general-purpose mechanism.
Bains pointed out that some of our nonwords were in fact real words and that an algorithm using only information about single letters and their positions achieves the same level of accuracy as baboons in discriminating words from nonwords. We clarify the operational definition of words and nonwords in our study and point out possible limits of the proposed algorithm.
This study investigated the visual information that children and adults consider while switching or maintaining object-matching rules.Eye movements of 5-and 6-year-old children and adults were collected with two versions of the Advanced Dimensional Change Card Sort, which requires switching between shape-and color-matching rules.In addition to a traditional integrated version with bidimensional objects (e.g., a blue bear), participants were tested on a dissociated version with pairs of unidimensional objects as stimuli (e.g., a noncolored bear beside a blue patch) so that fixations on the relevant and irrelevant dimensions of the stimuli could be distinguished.The fixation times were differentially distributed depending on whether children had to switch or maintain matching rules.Trial type differences in fixation times were primarily observed for the cues and the relevant and irrelevant dimensions of the stimuli, whereas responses options were seldom fixated even by the youngest children.In addition, the shape modality of the stimulus was more fixated than the color modality whether or not shape was relevant.Finally, the fixation patterns were modulated by age.These results suggest that switch costs are more related to selection of the relevant dimension on the stimulus than to response selection and point to age-related differences in strategies underlying flexible behavior.
