Test phase: Grand-average ERPs for grammatical (solid line) and ungrammatical (dashed line) target tones in the Strongly Metrical (left side) group and Isochronous group (right side).

<p>Each site represents the mean of the five electrodes included in the ROI (LF, left frontal; LC, left central; LP, left parietal; RF, right frontal; RC, right central; RP, right parietal). Grey rectangles indicate time windows of ascending (light grey) and descending (dark grey) part of the N2 chosen for the analyses.</p

Test phase: Difference waves (ungrammatical minus grammatical target tones) for the Isochronous group (dashed line) and Strongly Metrical group (solid line).

<p>Each site represents the mean of the five electrodes included in the ROI (LF, left frontal; LC, left central; LP, left parietal; RF, right frontal; RC, right central; RP, right parietal). Only for visualization purposes waveforms are presented with a 10 Hz low-pass filter. Grey rectangles indicate time windows of ascending (light grey) and descending (dark grey) part of the N2 chosen for the analyses.</p

Exposure phase: Grand-average ERPs for in-tune (solid line) and mistuned (dashed line) target tones in the Strongly Metrical group (left) and Isochronous group (right).

<p>Each site represents the mean of the five electrodes included in the ROI (LF, left frontal; LC, left central; LP, left parietal; RF, right frontal; RC, right central; RP, right parietal). Grey rectangles indicate time windows of the N2 (230–330 ms), P3a (350–550 ms) and P3b (550–900 ms) chosen for the analyses.</p

Exposure phase: Difference waves (mistuned minus in-tune target tones) for the Isochronous group (dashed line) and Strongly Metrical group (solid line).

<p>Each site represents the mean of the five electrodes included in the ROI (LF, left frontal; LC, left central; LP, left parietal; RF, right frontal; RC, right central; RP, right parietal). Only for visualization purposes waveforms are presented with a 10 Hz low-pass filter. Grey rectangles indicate time windows of the N2 (230–330 ms), P3a (350–550 ms) and P3b (550–900 ms) chosen for the analyses.</p

Metrical Presentation Boosts Implicit Learning of Artificial Grammar

<div><p>The present study investigated whether a temporal hierarchical structure favors implicit learning. An artificial pitch grammar implemented with a set of tones was presented in two different temporal contexts, notably with either a strongly metrical structure or an isochronous structure. According to the Dynamic Attending Theory, external temporal regularities can entrain internal oscillators that guide attention over time, allowing for temporal expectations that influence perception of future events. Based on this framework, it was hypothesized that the metrical structure provides a benefit for artificial grammar learning in comparison to an isochronous presentation. Our study combined behavioral and event-related potential measurements. Behavioral results demonstrated similar learning in both participant groups. By contrast, analyses of event-related potentials showed a larger P300 component and an earlier N2 component for the strongly metrical group during the exposure phase and the test phase, respectively. These findings suggests that the temporal expectations in the strongly metrical condition helped listeners to better process the pitch dimension, leading to improved learning of the artificial grammar.</p></div

Percentages of correct responses for strongly metrical and isochronous exposure groups for each participant represented by a black dot.

<p>Grey triangles represent the average performance for each group, the dotted line represents chance level performance.</p