Search

Hintergrund Bisherige Verhaltensstudien verweisen auf unterschiedliche Rollen für Konsonanten und Vokale im frühkindlichen Lexikonerwerb, wobei Säuglinge ab einem Alter von etwa 8 Monaten eine Präferenz für Konsonanten in der Wortverarbeitung zeigen [ref:1], [ref:2]. [zum vollständigen Text gelangen Sie über die oben angegebene URL]

This project will examine the cognitive process of perceptual anchoring in response to auditorily presented non-linguistic (pitch discrimination) and linguistic stimuli (phoneme discrimination) in participants with unilateral circumscribed acquired brain-lesions and a neurotypical otherwise matched control group. We include equal numbers of participants with single either right or left hemisphere lesions. Using dichotic presentation (signal vs. noise) either to the left or right ear, lateralisation issues will be addressed. We formulate three research questions: (i) does anchoring for the non-linguistic and linguistic paradigm correlate or dissociate between left- and right ear presentation; (ii) do brain lesions modulate perceptual anchoring and does this depend on the lesion side (left versus right hemisphere); (iii) does the patholinguistic profile correlate with modulations of anchoring in people with an acquired brain lesion. The experiment will comprise two tasks: A pitch discrimination task and a selective adaptation task which modulates the perception of the phonetic boundary between /b/ and /d/. In the non-linguistic pitch discrimination task, participants hear 70 pairs of tones per block, and are asked to indicate which tone is higher. There will be an anchor condition, in which the first tone will always be 1000 Hz and the second tone will be chosen based on the adaptive procedure. This is contrasted to a no-anchor condition, in which both tones will vary in frequency, with the first tone being randomly chosen from a frequency range of 800-1250 Hz and the second tone being determined based on the adaptive procedure. A two-down, one-up adaptive staircase procedure will be used to target 79% correct on the psychometric function (Levitt, 1971), with step size decreasing every 4 reversals from 50% to 28.6% to 9.1 % to 4,8% of the previous ratio of frequency difference. Initial frequency difference between tones will be 50% of the frequency of the first tone (log-transformed). Tone duration will be 40 ms and interstimulus interval (ISI) will be 500 ms. Before the start of the main experiment, participants will perform a test run to ensure correct understanding of the task and sufficient hearing performance. On each ear, 10 anchor-trials will be presented with the starting frequency difference of the main experiment (i.e., 50% of the frequency of the first tone, log-transformed). In the selective adaptation task (= linguistic anchoring) a continuum of 20 syllables between the endpoints /ba/ and /da/ created by Stephens and Holt (2011) will be used. In an initial pre-test at the beginning of each selective adaptation task, participants will be presented with each step of the continuum twice (i.e., 40 syllables in total). They will perform a forced choice decision regarding their perception of /ba/ or /da/. This pre-test will be followed by four rounds of an adaptation-test procedure: Participants will hear 70 instances of the prototypical endpoints of the continuum (either /ba/ or /da/). This has been shown to shift the phonetic boundary closer to the prototypical exemplar. In the ensuing identification phase the 18 intermediate steps of the continuum will be presented and participants will again perform the forced choice decision. Both adaptors (/ba/ and /da/) will be presented alternatingly (two times each per block), with the first two selective adaptation blocks starting with one adaptor and the last two selective adaptation blocks starting with the second adaptor. Stimuli will be presented dichotically (signal/white noise). The structure of the experiment will be the following: • 4 blocks of the selective adaptation block (ear 1) • Frequency discrimination block (ear 1, anchor or no-anchor) • 4 blocks of the selective adaptation block (ear 2) • Frequency discrimination block (ear 2, anchor or no-anchor) - clinical testing - • 4 blocks of the selective adaptation block (ear 1) • Frequency discrimination block (ear 1, anchor or no-anchor) • 4 blocks of the selective adaptation block (ear 2) • Frequency discrimination block (ear 2, anchor or no-anchor) Order of ears, first adaptor in the selective adaptation task and of anchor and no-anchor blocks will be counterbalanced across participants for each participant group (participants with right-hemisphere lesions, participants with left-hemisphere lesions, control participants).

Processing grammatical dependencies between distant speech elements is central to human language (e.g. he sings). Successful learning of these so-called non-adjacent dependencies has been shown repeatedly in both adults and infants, often with the use of an artificial grammar, which allows conclusions exclusively about the processing of grammatical structure devoid of meaning (Friederici, Mueller, & Oberecker, 2011; Frost & Monaghan, 2016; Santelmann & Jusczyk, 1998). Mueller, Friederici & Männel (2012) have shown that infants readily detect non-adjacent dependencies (NADs) coded over syllables (AXB) in an auditory artificial language and that this ability is related to individual differences in pitch processing. It remains an open question, however, whether the syllable is the relevant linguistic unit in this rule extraction process or whether smaller segments, that is consonants or vowels, are the relevant units guiding NAD learning. The consonant-vowel hypothesis brought forth by Nespor, Peña, & Mehler (2003) suggests an advantage for vowels over consonants for the coding of grammatical rules. Further, it is an open question whether the link between auditory processing and rule extraction observed by Mueller et al. (2012) is characteristic for pitch processing only or whether it generalizes to other auditory processes, such as intensity perception. Encountering a similar link based on intensity processing in the present study would support the general idea of a close interrelation, if not a dependency, between efficient auditory sensory processes (e.g. memory-related) and successful rule extraction. At an even more general level, this could hint at an adept domain-general cognitive mechanism relevant for several kinds of learning. Thus, the present study aims to test whether 8- to 10-month-old German-learning infants show differences between the detection of NADs coded over consonants and those coded over vowels, and whether individual differences in NAD extraction are related to intensity perception. Here, a similar experimental design will be employed as the one used by Mueller et al. (2012), namely an oddball paradigm. Participants will be auditorily presented with sequences of the form AXB, whereby each letter constitutes a CV syllable. Each AXB sequence contains a dependency between either the vowels (e.g. bo-kä-wu, lo-wa-su) or the consonants (e.g. ge-mi-kä, gu-lö-ke) of the A and B syllables, while the remaining elements, including the middle X syllable, are variable. We will use an oddball paradigm in which frequent standard items will be interspersed with two types of infrequent deviants: rule deviants violating the vowel- or consonant-based NAD, and intensity deviants, which are played at a lower sound pressure level than the standards. Throughout exposure, participants’ brain response to both standards and deviants will be recorded via electroencephalography (EEG).

Infants show impressive speech decoding abilities and detect acoustic regularities that highlight the syntactic relations of a language, often coded via non-adjacent dependencies (NADs, e.g., is singing). It has been claimed that infants learn NADs implicitly and associatively through passive listening and that there is a shift from effortless associative learning to a more controlled learning of NADs after the age of 2 years, potentially driven by the maturation of the prefrontal cortex. To investigate if older children are able to learn NADs, Lammertink et al. (2019) recently developed a word-monitoring serial reaction time (SRT) task and could show that 6–11-year-old children learned the NADs, as their reaction times (RTs) increased then they were presented with violated NADs. In the current study we adapted their experimental paradigm and tested NAD learning in a younger group of 52 children between the age of 4–8 years in a remote, web-based, game-like setting (whack-a-mole). Children were exposed to Italian phrases containing NADs and had to monitor the occurrence of a target syllable, which was the second element of the NAD. After exposure, children did a “Stem Completion” task in which they were presented with the first element of the NAD and had to choose the second element of the NAD to complete the stimuli. Our findings show that, despite large variability in the data, children aged 4–8 years are sensitive to NADs; they show the expected differences in r RTs in the SRT task and could transfer the NAD-rule in the Stem Completion task. We discuss these results with respect to the development of NAD dependency learning in childhood and the practical impact and limitations of collecting these data in a web-based setting., Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe; 766