Enantioselective Construction of Chiral THIQUINOL and Its Derivatives via Chiral Phosphoric Acid Catalysis.

The first catalytic enantioselective construction of chiral THIQUINOL and its derivatives has been accomplished through a chiral phosphoric-acid-catalyzed direct aza-Friedel-Crafts reaction of 3,4-dihydroisoquinolines with 2-naphthols/anthracen-2-ols/phenanthren-9-ol. This method offers a powerful and straightforward synthetic route toward chiral THIQUINOL derivatives with good to excellent yields and enantioselectivities. These structural motifs are crucial chiral components for further transformations into established or potential chiral ligands and catalysis.

The Learning Signal in Perceptual Tuning of Speech: Bottom Up Versus Top-Down Information.

Cognitive systems face a tension between stability and plasticity. The maintenance of long-term representations that reflect the global regularities of the environment is often at odds with pressure to flexibly adjust to short-term input regularities that may deviate from the norm. This tension is abundantly clear in speech communication when talkers with accents or dialects produce input that deviates from a listener's language community norms. Prior research demonstrates that when bottom-up acoustic information or top-down word knowledge is available to disambiguate speech input, there is short-term adaptive plasticity such that subsequent speech perception is shifted even in the absence of the disambiguating information. Although such effects are well-documented, it is not yet known whether bottom-up and top-down resolution of ambiguity may operate through common processes, or how these information sources may interact in guiding the adaptive plasticity of speech perception. The present study investigates the joint contributions of bottom-up information from the acoustic signal and top-down information from lexical knowledge in the adaptive plasticity of speech categorization according to short-term input regularities. The results implicate speech category activation, whether from top-down or bottom-up sources, in driving rapid adjustment of listeners' reliance on acoustic dimensions in speech categorization. Broadly, this pattern of perception is consistent with dynamic mapping of input to category representations that is flexibly tuned according to interactive processing accommodating both lexical knowledge and idiosyncrasies of the acoustic input.

Simultaneous tracking of coevolving distributional regularities in speech.

Speech processing depends upon mapping variable acoustic speech input in a manner that reflects the long-term regularities of the native language. Yet, these mappings are flexible such that introduction of short-term distributional regularities in speech input, like those arising from foreign accents or talker idiosyncrasies, leads to rapid adjustments in the effectiveness of acoustic dimensions in signaling phonetic categories. The present experiments investigate whether the system is able to track simultaneous short-term distributional statistics present in speech input or if, instead, the global regularity jointly defined by these distributions dominates. Three experiments establish that adult listeners are able to track distinct simultaneously evolving regularities across time, given information to support the "binning" of acoustic instances. Both voice quality and visual information to indicate talker supported tracking of coevolving distributional regularities, even when the regularities are opposing and even when the acoustic speech tokens contributing to the distinct distributions are identical. This indicates that reweighting of perceptual dimensions in response to short-term regularities in speech input is not simply an accumulation of acoustic instances. Rather, the system is able to track multiple context-sensitive regularities simultaneously, with rapid context-dependent adaptive adjustments in how acoustic speech input maps to phonetic categories. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The Activation of Embedded Words in Spoken Word Recognition.

The current study investigated how listeners understand English words that have shorter words embedded in them. A series of auditory-auditory priming experiments assessed the activation of six types of embedded words (2 embedded positions × 3 embedded proportions) under different listening conditions. Facilitation of lexical decision responses to targets (e.g., pig) associated with words embedded in primes (e.g., hamster) indexed activation of the embedded words (e.g., ham). When the listening conditions were optimal, isolated embedded words (e.g., ham) primed their targets in all six conditions (Experiment 1a). Within carrier words (e.g., hamster), the same set of embedded words produced priming only when they were at the beginning or comprised a large proportion of the carrier word (Experiment 1b). When the listening conditions were made suboptimal by expanding or compressing the primes, significant priming was found for isolated embedded words (Experiment 2a), but no priming was produced when the carrier words were compressed/expanded (Experiment 2b). Similarly, priming was eliminated when the carrier words were presented with one segment replaced by noise (Experiment 3). When cognitive load was imposed, priming for embedded words was again found when they were presented in isolation (Experiment 4a), but not when they were embedded in the carrier words (Experiment 4b). The results suggest that both embedded position and proportion play important roles in the activation of embedded words, but that such activation only occurs under unusually good listening conditions.

Perceptual learning of speech under optimal and adverse conditions.

Humans have a remarkable ability to understand spoken language despite the large amount of variability in speech. Previous research has shown that listeners can use lexical information to guide their interpretation of atypical sounds in speech (Norris, McQueen, & Cutler, 2003). This kind of lexically induced perceptual learning enables people to adjust to the variations in utterances due to talker-specific characteristics, such as individual identity and dialect. The current study investigated perceptual learning in two optimal conditions: conversational speech (Experiment 1) versus clear speech (Experiment 2), and three adverse conditions: noise (Experiment 3a) versus two cognitive loads (Experiments 4a and 4b). Perceptual learning occurred in the two optimal conditions and in the two cognitive load conditions, but not in the noise condition. Furthermore, perceptual learning occurred only in the first of two sessions for each participant, and only for atypical /s/ sounds and not for atypical /f/ sounds. This pattern of learning and nonlearning reflects a balance between flexibility and stability that the speech system must have to deal with speech variability in the diverse conditions that speech is encountered.

The Perception and Representation of Segmental and Prosodic Mandarin Contrasts in Native Speakers of Cantonese.

Previous research has found that a speaker's native phonological system has a great influence on perception of another language. In three experiments, we tested the perception and representation of Mandarin phonological contrasts by Guangzhou Cantonese speakers, and compared their performance to that of native Mandarin speakers. Despite their rich experience using Mandarin Chinese, the Cantonese speakers had problems distinguishing specific Mandarin segmental and tonal contrasts that do not exist in Guangzhou Cantonese. However, we found evidence that the subtle differences between two members of a contrast were nonetheless represented in the lexicon. We also found different processing patterns for non-native segmental versus non-native tonal contrasts. The results provide substantial new information about the representation and processing of segmental and prosodic information by individuals listening to a closely-related, very well-learned, but still non-native language.

Processing fluency of the forms and sounds of Chinese characters.

The goal of this study is to investigate whether different types of structures and lexical tones of Chinese characters cause different processing fluency. In Experiment 1, participants' explicit affective assessments of Chinese characters with different structures, frequencies, and lexical tones were analyzed. Results indicated that participants showed explicit preferences and dispreferences to different structures and lexical tones. In Experiment 2, participants' implicit responses to different structures and lexical tones were investigated using a metaphor experimental paradigm. Results were consistent with the major findings of Experiment 1. In Experiments 3 and 4, participants' recognition of words of different structures and lexical tones were analyzed. Results revealed that participants had a better memory for Surround structure characters when stimuli were visually presented and for Tone 3 when stimuli were auditorily presented. Finally, the significance and implications of this study are discussed.