Ulrike Schild

How space-number associations may be created in preliterate children: six distinct mechanisms

The directionality of space-number association (SNA) is shaped by cultural experiences. It usually follows the culturally dominant reading direction. Smaller numbers are generally associated with the starting side for reading (left side in Western cultures), while larger numbers are associated with the right endpoint side. However, SNAs consistent with cultural reading directions are present before children can actually read and write. Therefore, these SNAs cannot only be shaped by the direction of children’s own reading/writing behavior. We propose six distinct processes – one biological and five cultural/educational – underlying directional SNAs before formal reading acquisition: (i) Brain lateralization, (ii) Monitoring adult reading behavior, (iii) Pretend reading and writing, and rudimentary reading and writing skills, (iv) Dominant attentional directional preferences in a society, not directly related to reading direction, (v) Direct spatial-numerical learning, (vi) Other spatial-directional processes independent of reading direction. In this mini-review, we will differentiate between these processes, elaborate when in development they might emerge, discuss how they may create the SNAs observed in preliterate children and propose how they can be studied in the future.

Electrophysiological indices of word fragment priming allow characterizing neural stages of speech recognition.

Spoken word onset syllables (prime fragments) have been used to track neurophysiological processing of following written words (targets). Between 300 and 400 ms event-related potentials (ERPs) over the left hemisphere were more positive for targets that did not match their preceding prime fragments (e.g., hun-dragon) compared to matching targets (e.g., dra-dragon). This P350 effect has been related to the activation of modality independent neural word form representations. In the present experiment we set out to characterize neural word processing specific to the auditory domain. Spoken word onset syllables (prime fragments) were followed by spoken words (targets). Reduced amplitudes for matching targets were found for the N100 and the T-complex (100-300 ms), for the P350 (300-400 ms) and for a central negativity starting at 300 ms. The early potentials possibly index the priming of speech sound processing. The P350 replicates previous work with written words. This constitutes further evidence for shared neural word form representations in auditory and visual word recognition. The central negativity might be related to the rapid phonological matching of prime and target; or to the immediate testing of phonological expectations in speech recognition.

Neuronal spoken word recognition: The time course of processing variation in the speech signal

Recent neurobiological studies revealed evidence for lexical representations that are not specified for the coronal place of articulation (PLACE; Friedrich, Eulitz, & Lahiri, 2006; Friedrich, Lahiri, & Eulitz, 2008). Here we tested when these types of underspecified representations influence neuronal speech recognition. In a unimodal auditory–auditory word fragment priming experiment target words either had initial coronal PLACE (e.g., tiger) or had initial noncoronal PLACE (e.g., pony). Prime-target pairs were either identical (e.g., ti-tiger, po-pony), differed in initial PLACE (e.g., pi-tiger, to-pony), or were unrelated. Event-related Potentials for identical and related targets started to differ from unrelated targets at 100 ms, indicating early perceptual processing. Different effects for coronal vs. noncoronal variation were observed starting at 200 ms. Results are related to recent neurocognitive research on compensation for assimilation of PLACE (e.g., rainbow realised as *raimbow). A time line of processing PLACE variation at multiple stages is proposed and parallel processing of specified and underspecified representations at the lexical level is discussed.

Learning to read shapes the activation of neural lexical representations in the speech recognition pathway

It has been demonstrated that written and spoken language processing are tightly linked. Here we focus on the development of this relationship at the time children start reading and writing. We hypothesize that the newly acquired knowledge about graphemes shapes lexical access in neural spoken word recognition. A group of preliterate children (six years old) and two groups of beginning readers (six and eight years old) were tested in a spoken word identification task. Using word onset priming we compared behavioural and neural facilitation for target words in identical prime-target pairs (e.g., mon-monster) and in prime target pairs that varied in the first speech sound (e.g., non-monster, Variation condition). In both groups of beginning readers priming was less effective in the Variation condition than in the Identity condition. This was indexed by less behavioural facilitation and enhanced P350 amplitudes in the event related potentials (ERPs). In the group of preliterate children, by contrast, both conditions did not differ. Together these results reveal that lexical access in beginning readers is based on more acoustic detail than lexical access in preliterate children. The results are discussed in the light of bidirectional speech and print interactions in readers.

Phoneme-free prosodic representations are involved in pre-lexical and lexical neurobiological mechanisms underlying spoken word processing

Highlights • We hypothesize that prosody and phoneme information is processed independently.• We tested this by applying word onset priming and analyzing event-related potentials.• ERPs for prosody and phoneme overlap differed in timing and distribution.• Both effects did not interact, suggesting that both cues are used independently.• Our results are evidence for phoneme-free prosodic processing in speech recognition.

ERP correlates of word onset priming in infants and young children

Highlights • Word onset priming appears to be a powerful method for investigating early lexico-phonological processes.• Based on word onsets, infants seem to make phonological predictions about word forms.• Adult-like word form access seems to develop only after the second year of life.

Processing of syllable stress is functionally different from phoneme processing and does not profit from literacy acquisition

Speech is characterized by phonemes and prosody. Neurocognitive evidence supports the separate processing of each type of information. Therefore, one might suggest individual development of both pathways. In this study, we examine literacy acquisition in middle childhood. Children become aware of the phonemes in speech at that time and refine phoneme processing when they acquire an alphabetic writing system. We test whether an enhanced sensitivity to phonemes in middle childhood extends to other aspects of the speech signal, such as prosody. To investigate prosodic processing, we used stress priming. Spoken stressed and unstressed syllables (primes) preceded spoken German words with stress on the first syllable (targets). We orthogonally varied stress overlap and phoneme overlap between the primes and onsets of the targets. Lexical decisions and Event-Related Potentials (ERPs) for the targets were obtained for pre-reading preschoolers, reading pupils and adults. The behavioral and ERP results were largely comparable across all groups. The fastest responses were observed when the first syllable of the target word shared stress and phonemes with the preceding prime. ERP stress priming and ERP phoneme priming started 200 ms after the target word onset. Bilateral ERP stress priming was characterized by enhanced ERP amplitudes for stress overlap. Left-lateralized ERP phoneme priming replicates previously observed reduced ERP amplitudes for phoneme overlap. Groups differed in the strength of the behavioral phoneme priming and in the late ERP phoneme priming effect. The present results show that enhanced phonological processing in middle childhood is restricted to phonemes and does not extend to prosody. These results are indicative of two parallel processing systems for phonemes and prosody that might follow different developmental trajectories in middle childhood as a function of alphabetic literacy.