This study explored the contexts in which native Japanese listeners have difficulty identifying prosodic focus. Using a 4AFC identification task, we compared native Japanese listeners’ focus ...identification accuracy in different lexical accent × focus location conditions using resynthesised speech stimuli, which varied only in fundamental frequency. Experiment 1 compared the identification accuracy in lexical accent × focus location conditions using both natural and resynthesised stimuli. The results showed that focus identification rates were similar with the two stimulus types, thus establishing the reliability of the resynthesised stimuli. Experiment 2 explored these conditions further using only resynthesised stimuli. Narrow foci bearing the lexical pitch accent were always more correctly identified than unaccented ones, whereas the identification rate for final focus was the lowest among all focus locations. From these results, we argue that the difficulty of focus perception in Japanese is attributed to (i) the blocking of PFC by unaccented words, and (ii) similarity in F0 contours between lexical pitch accent and narrow focus, including in particular the similarity between downstep and PFC. Focus perception is therefore contingent on other concurrent communicative functions which may sometimes take precedence in a +PFC language.
Disentangling the roles of phonological well-formedness and lexical attestedness in phonotactic processing has proven challenging. In this study, we present results from a passive listening ERP study ...showing that English speakers exhibit distinct neural responses to CCVC nonce words according to the phonological well-formedness and attestedness (in English) of the onset cluster. Clusters with poor sonority sequencing evoked an N400 effect compared to those without poor sonority sequencing, regardless of whether the well-formed clusters were attested in English. In contrast, unattested clusters, regardless of whether they were well-formed or ill-formed in terms of sonority sequencing, evoked a late positivity compared to attested clusters. The results suggest that listeners first perform a phonological analysis on potential words before submitting them to a lexical search.
The thesis aimed to update the traditional understanding of the speech chain with recent proposals on communicative behaviour from theoretical and computational neuroscience. For a generative brain ...that engages in active (Bayesian) inference, speech perception itself is considered as a form of predictive processing. Experiments presented in this thesis were designed to answer the questions of ‘what’, ‘how’, and ‘where’: 1. What constitutes an auditory prediction error, and is it selective to a specific sound type? 2. How is surprise minimisation implemented in hierarchical cortical networks for auditory and speech perception? 3. Where – at what level in cognition and linguistic knowledge – could predictions for speech perception come from? Study 1 answered the first question – of ‘what’ – by collecting passive Mismatch Negativity responses to speech and non-speech sounds. This was recorded as subjects ignored the auditory stimuli. It was hypothesised that if speech-specific auditory prediction errors existed, certain aspects of MMN – a change detection response – would be selective to sound type and to speech category. Source-analyses of the same EEG data in Study 1 provided clues to the question of ‘how’. To address ‘where’, Study 2 considered attentional modulations to the effect of categorical processing recorded in passive brain responses, and tested for a prelexical locus of speech-specific prediction and prior knowledge. Auditory-evoked brain responses were recorded in both Ignore and Attend conditions to acoustically identical stimuli from three subject groups of varying levels of familiarity to a certain speech category. Stimuli manipulation in an accompanying behavioural discrimination task allowed for the monitoring of top-down lexical influences. Findings from this project will provide a way to reframe existing theoretical debates in speech processing on topics such as speech-specific auditory processing (against non-speech sounds), categorical perception, and pre-lexical abstraction within spoken word recognition.
The thesis aimed to update the traditional understanding of the speech chain with recent proposals on communicative behaviour from theoretical and computational neuroscience. For a generative brain ...that engages in active (Bayesian) inference, speech perception itself is considered as a form of predictive processing. Experiments presented in this thesis were designed to answer the questions of ‘what’, ‘how’, and ‘where’: 1. What constitutes an auditory prediction error, and is it selective to a specific sound type? 2. How is surprise minimisation implemented in hierarchical cortical networks for auditory and speech perception? 3. Where – at what level in cognition and linguistic knowledge – could predictions for speech perception come from? Study 1 answered the first question – of ‘what’ – by collecting passive Mismatch Negativity responses to speech and non-speech sounds. This was recorded as subjects ignored the auditory stimuli. It was hypothesised that if speech-specific auditory prediction errors existed, certain aspects of MMN – a change detection response – would be selective to sound type and to speech category. Source-analyses of the same EEG data in Study 1 provided clues to the question of ‘how’. To address ‘where’, Study 2 considered attentional modulations to the effect of categorical processing recorded in passive brain responses, and tested for a prelexical locus of speech-specific prediction and prior knowledge. Auditory-evoked brain responses were recorded in both Ignore and Attend conditions to acoustically identical stimuli from three subject groups of varying levels of familiarity to a certain speech category. Stimuli manipulation in an accompanying behavioural discrimination task allowed for the monitoring of top-down lexical influences. Findings from this project will provide a way to reframe existing theoretical debates in speech processing on topics such as speech-specific auditory processing (against non-speech sounds), categorical perception, and pre-lexical abstraction within spoken word recognition.
Summary
Traditional species diversity measures do not make distinctions among species. Faith's phylogenetic diversity (PD), which is defined as the sum of the branch lengths of a phylogenetic tree ...connecting all species, takes into account phylogenetic differences among species and has found many applications in various research fields. In this paper, we extend Faith's PD to represent the total length of a phylogenetic tree from any fixed point on its main trunk.
Like species richness, Faith's PD tends to be an increasing function of sampling effort and thus tends to increase with sample completeness. We develop in this paper the ‘PD accumulation curve’ (an extension of the species accumulation curve) to depict how PD increases with sampling size and sample completeness.
To make fair comparisons of Faith's PD among several assemblages based on sampling data from each assemblage, we derive both theoretical formulae and analytic estimators for seamless rarefaction (interpolation) and extrapolation (prediction). We develop a lower bound of the undetected PD for an incomplete sample to guide the extrapolation; the PD estimator for an extrapolated sample is generally reliable up to twice the size of the empirical sample.
We propose an integrated curve that smoothly links rarefaction and extrapolation to standardize samples on the basis of sample size or sample completeness. A bootstrap method is used to obtain the unconditional variances of PD estimators and to construct the confidence interval of the expected PD for a fixed sample size or fixed degree of sample completeness. This facilitates comparison of multiple assemblages of both rarefied and extrapolated samples.
We illustrate our formulae and estimators using empirical data sets from Australian birds in two sites. We discuss the extension of our approach to the case of multiple incidence data and to incorporate species abundances.
Integrating the palliative care approach into care home service to address the complex care needs of older adults with frailty or advanced diseases has been increasingly recognized. However, such a ...service is underdeveloped in Hong Kong owing to socio-cultural and legal concerns. We adopted a modified Delphi study design to identify the key components for the delivery of palliative and end-of-life care in care home settings for the local context. It was an iterative staged method to assimilate views of experts in aged care, palliative care, and care home management. A multidisciplinary expert panel of 18 members consented to participate in the study. They rated their level of agreement with 61 candidate statements identified through a scoping review in two rounds of anonymous surveys. The steering group revised the statements in light of the survey findings. Eventually, the finalized list included 28 key statements concerning structure and process of care in seven domains, namely policy and infrastructure, education, assessment, symptom management, communication, care for dying patients, and family support. The findings of this study underscored concerns regarding the feasibility of statements devised at different levels of palliative care development. This list would be instrumental for regions where the development of palliative and end-of-life care services in care home setting is at an initial stage.
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