Temporally selective attention supports speech processing in 3- to 5-year-old children

Abstract

Recent event-related potential (ERP) evidence demonstrates that adults employ temporally selective attention to preferentially process the initial portions of words in continuous speech. Doing so is an effective listening strategy since word-initial segments are highly informative. Although the development of this process remains unexplored, directing attention to word onsets may be important for speech processing in young children who would otherwise be overwhelmed by the rapidly changing acoustic signals that constitute speech. We examined the use of temporally selective attention in 3- to 5-year-old children listening to stories by comparing ERPs elicited by attention probes presented at four acoustically matched times relative to word onsets: concurrently with a word onset, 100 ms before, 100 ms after, and at random control times. By 80 ms, probes presented at and after word onsets elicited a larger negativity than probes presented before word onsets or at control times. The latency and distribution of this effect is similar to temporally and spatially selective attention effects measured in adults and, despite differences in polarity, spatially selective attention effects measured in children. These results indicate that, like adults, preschool aged children modulate temporally selective attention to preferentially process the initial portions of words in continuous speech.

Fig. 1

Experimental paradigm. Children listened to stories with linguistic attention probes (a 50 ms excerpt of the syllable “ba”) presented during acoustically matched portions of the narrative at four times: concurrently with word onsets, 100 ms before word onsets, 100 ms after word onsets, and at random control times. Images corresponding to the story were presented on a computer monitor.

Fig. 2

Electrode array. Approximate scalp location of the 128 recording electrodes. Measurements were taken from the 60 electrodes shown in black and combined into 30 pairs arranged in a 5 (Left/Right position) × 6 (Anterior/Posterior position) grid.

Fig. 3

Word onset versus control times. ERPs elicited by probes presented at word onsets (solid line) and at random control times (dotted line). Data are shown from eight medial, anterior electrode sites indicated on the electrode map. Probes played at word onset elicited a more negative response from 80 to 140 ms and from 200 to 350 ms. Differences in mean amplitude (control minus word onset) in both time windows are shown in the topographic plots.

Fig. 4

Attention before and after word onsets. ERPs elicited by probes presented at word onsets (solid line), 100 ms before word onsets (dotted line), and 100 ms after word onsets (dashed line). Data are shown from eight medial, anterior electrode sites indicated on the electrode map. During the early positivity, probes presented at and after word onset elicited a more negative waveform than probes played before word onset. During the later time window, probes presented at word onset elicited a more negative response than all other conditions.

Fig. 5

Latency bin analysis. Mean amplitude difference between probes presented at word onset versus control times in staggered 50 ms time windows beginning 0–200 ms after probe onset. Data shown are from left medial and anterior electrode sites (indicated by shaded region on the electrode map) recorded from 3- to 5-year-old children in the current study (gray bars) and adults (black bars) in a similar paradigm (Astheimer and Sanders, 2009). Brackets indicate time windows with significant differences (p < .05) between word onset and control times (upper gray bracket = children in the current study, lower black bracket = adults in previous experiment).