Ernestus, M.

Janse, E.

MPG.PuRe

Esther Janse1,2 & Mirjam Ernestus3,11Max Planck Institute for Psycholinguistics, Nijmegen; 2Utrecht inst. of Linguistics OTS, Utrecht University, 3Center for Language Studies, Radboud University Nijmegen, The Netherlands Esther.Janse@mpi.nlUse of linguistic knowledge in the recognition of reduced words:effects of age and high-frequency hearing loss1. Older adults only relied more on following-word context than young adults in how fast they recognised complex adjectivesCONCLUSIONSMaterials and manipulations• Task: repeat third word of each phrase; be as fast and as accurate as possible• Fixedness manipulation: target presented either in fixed-expression or non-fixed- expression context (rotated over targets on two experimental lists)• Speech presented at 80 dB SPL for all listener groupsReduced speech•‘Reduced’ pronunciations are ubiquitous in casual speech (e.g., 'onry' for 'ordinary')• Many reduced words only identified accurately when presented in their original neighbouring-words context (cf. Ernestus et al., 2002).Context effects on word recognition and aging• Older adults benefit more from semantic context in spoken-word recognition than young adults (Nittrouer & Boothroyd, 1990; Pichora-Fuller et al., 1995). • However, this claim mainly based on (high-predictability) contexts of Sentence-Perception-In-Noise materials.Focus here: Fixed-expression contexts→ Conditional probability of words in word combinations (role of linguistic experience)→ Following-word context may facilitate ‘late’ word recognition, as in recognition of ‘promised’ in promised land vs. promised lampREDUCED SPEECH AND AGING1. Do older adults rely more on following-word context than young adults for spoken-word recognition?2. Are there any interactions with the morphological complexity of the target word because longer words can be more reduced? RESEARCH QUESTIONS• 56 highly-educated older adults (M= 71 years (SD=6, 61-86), average PTA over 1, 2, and 4 kHz in best ear is 28 dB; SD= 14)• 24 normal-hearing young adults (M= 21 years)• 24 normal-hearing young adults (M= 21 years) who were presented with low-pass filtered speech stimuliParticipantsWORD IDENTIFICATION EXPERIMENTRESULTSFigure 1. Word recognition accuracy in fixed and non-fixed expression conditions for the three listener groups.Simple target words Complex target words* main effect of Fixedness * main effect of Fixedness* no interaction Fixedness x Listener Group * Fixedness x Listener Group (effect smaller for filtered group) Figure 2. Word recognition RT (from target word onset) in fixed and non-fixed expression conditions for three listener groups. (Error bars = 1 SD).Simple target words Complex target words* main effect of Fixedness * main effect of Fixedness* Fixedness x Listener Group * Fixedness x Listener Group(effect smaller for filtered group) (effect larger for older adults) Individual differences among older adults (accuracy and RTs)•Hearing sensitivity predicts performance•But no interaction between Hearing sensitivity and FixednessProcedureNative-Dutch speaker produced Dutch phrases in a fast and slurred way48 four-word phrase pairs (‘to the promised lamp/land’)• 24 of which with simple adjective (‘fat’)• 24 of which with complex adjective (‘promised’)96 filler four-word phrases without fixed expressionsCross-splicing: initial-three-words part (including target word) of non-fixed expression used in both fixed and non-fixed condition3. Does low-pass filtering the speech stimuli bring about a greater reliance on following-word context in young adults?Filtering: Low-pass filter: -20 dB/octave dampening above 1 kHzNote: only one group of young adults were presented with filtered stimuliAccuracyResponse Latencies2. Complex adjectives have more unstressed vowels and thus more room for reduction. Greater knowledge on transitional probabilities may be particularly useful for more reduced and thus less intelligible words.3. Signal degradation does not bring about a greater reliance on this type of context: - not in young adults: smaller effects in filtered-speech condition- not among older adults: those with more hearing loss did not show greater effect of fixed-expression contextComplex adjectives405060708090100Young Adults Young_Filtered Older AdultsAccuracy (%)FixedNon-fixedSimple adjectives405060708090100Young Adults Young_Filtered Older AdultsAccuracy (%)FixedNon-fixedSimple adjectives600800100012001400160018002000Young Adults Young_Filtered Older AdultsRT (ms)FixedNon-fixedComplex adjectives600800100012001400160018002000Young Adults Young_Filtered Older AdultsRT (ms)FixedNon-fixed010203040506070250 500 1000 2000 4000 8000Hearing threshold (dB HL)Frequency (Hz)young (both groups)filter functionolder adults4pSC2

Use of linguistic knowledge in the recognition of reduced speech: Effects of age and high-frequency hearing loss

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