Sung-Joo Lim

Max Planck Institute for Human Cognitive and Brain Sciences | CBS

Musical training has been associated with enhanced neural processing of sounds, as measured via the frequency following response (FFR), implying the potential for human subcortical neural plasticity. We conducted a large-scale multi-site preregistered study (n > 260) to replicate and extend the findings underpinning this important relationship. We...

The task of processing speech masked by concurrent speech/noise can pose a substantial challenge to listeners. However, performance on such tasks may not directly reflect the amount of listening effort they elicit. Changes in pupil size and neural oscillatory power in the alpha range (8-12 Hz) are prominent neurophysiological signals known to refle...

Re-directing attention to objects in working memory can enhance their representational fidelity. However, how this attentional enhancement of memory representations is implemented across distinct, sensory and cognitive-control brain network is unspecified. The present fMRI experiment leverages psychophysical modelling and multivariate auditory-patt...

A perceptual adaptation deficit often accompanies reading difficulty in dyslexia, manifesting in poor perceptual learning of consistent stimuli and reduced neurophysiological adaptation to stimulus repetition. However, it is not known how adaptation deficits relate to differences in feedforward or feedback processes in the brain. Here we used elect...

Speech is processed less efficiently from discontinuous, mixed talkers than one consistent talker, but little is known about the neural mechanisms for processing talker variability. Here, we measured psychophysiological responses to talker variability using electroencephalography (EEG) and pupillometry while listeners performed a delayed recall of...

A perceptual adaptation deficit often accompanies reading difficulty in dyslexia, manifesting in poor perceptual learning of consistent stimuli and reduced neurophysiological adaptation to stimulus repetition. However, it is not known how adaptation deficits relate to differences in feedforward or feedback processes in the brain. Here we used elect...

Speech is processed less efficiently from discontinuous, mixed talkers than one consistent talker, but little is known about the neural mechanisms for processing talker variability. Here, we measured psychophysiological responses to talker variability using electroencephalography (EEG) and pupillometry while listeners performed a delayed recall of...

Re-directing attention to objects in working memory can enhance their representational fidelity. However, how this attentional enhancement of memory representations is implemented across distinct, sensory and cognitive-control brain network is unspecified. The present fMRI experiment leverages psychophysical modelling and multivariate auditory-patt...

Measuring the listening effort exerted by an individual to understand speech under auditory masking conditions can provide vital information not available from speech intelligibility scores alone. The goal of this study was to compare the amount of listening effort elicited in young, normal-hearing subjects during an intelligible speech masking con...

No PDF available ABSTRACT Listeners process speech from mixed talkers less efficiently than from one continuous talker. An auditory streaming framework may help explain this effect: talker discontinuity may disrupt listeners' attentional focus, decreasing speech processing efficiency. In two experiments, we examined how auditory interruption of a s...

No PDF available ABSTRACT Perceptual adaptation to a talker allows listeners to efficiently resolve inherent ambiguities present in the speech signal introduced by the lack of a one-to-one mapping between acoustic signals and intended phonemic categories across talkers. In ideal listening environments, preceding speech context enhances perceptual a...

Speech processing is slower when listening to speech from multiple talkers compared to one continuous talker. Prior studies of talker variability mostly compared listening to long blocks of a continuous talker versus blocks where talkers constantly switch. It is thus unclear whether differences in processing efficiency are better understood as faci...

Speech processing is faster for one continuous talker than mixed talkers. However, it is unknown whether listeners’ expectations about talker continuity affect this facilitation. We measured response times during three speeded word identification experiments that manipulated listeners’ expectations about talker continuity. First, we manipulated exp...

Significance Humans are born as “universal listeners.” However, over the first year, infants’ perception is shaped by native speech categories. How do these categories naturally emerge without explicit training or overt feedback? Using fMRI, we examined the neural basis of incidental sound category learning as participants played a videogame in whi...

Speech processing is slower and less accurate when listeners encounter speech from multiple talkers compared to one continuous talker. However, interference from multiple talkers has been investigated only using immediate speech recognition or long-term memory recognition tasks. These tasks reveal opposite effects of speech processing time on speec...

Speech learning involves discovering appropriate functional speech units (e.g., speech categories) embedded in a continuous stream of speech. However, speech category learning has been mostly investigated with isolated sound tokens. Here, we used a videogame to encourage incidental learning of speech categories from continuous speech input (Lim et...

Talker adaptation is known to facilitate immediate speech recognition. However, it is unclear whether and how talker adaptation also facilitates working memory for speech. Using electroencephalography (EEG) during a delayed recall of digit span task, we investigated whether talker adaptation facilitates working memory performance. We also investiga...

Humans can be cued to attend to an item in memory, which facilitates and enhances the perceptual precision in recalling this item. Here, we demonstrate that this facilitating effect of attention-to-memory hinges on the overall degree of memory load. The benefit an individual draws from attention-to-memory depends on her overall working memory perfo...

Dopamine underlies important aspects of cognition, and has been suggested to boost cognitive performance. However, how dopamine modulates the large-scale cortical dynamics during cognitive performance has remained elusive. Using functional MRI during a working memory task in healthy young human listeners, we investigated the effect of levodopa (l-d...

Dopamine underlies important aspects of cognition, and has been suggested to boost cognitive performance. However, how dopamine modulates the large-scale cortical dynamics during cognitive performance has remained elusive. Using functional MRI during a working memory task in healthy young human listeners (N=22), we investigated the effect of levodo...

Human alpha (~10 Hz) oscillatory power is a prominent neural marker of cognitive effort. When listeners attempt to process and retain acoustically degraded speech, alpha power enhances. It is unclear whether these alpha modulations reflect the degree of acoustic degradation per se or the degradation-driven demand to a listener's attentional control...

Significance statement: Can selective attention improve the representational precision with which objects are held in memory? And if so, what are the neural mechanisms that support such improvement? These issues have been rarely examined within the auditory modality, in which acoustic signals change and vanish on a milliseconds time scale. Introdu...

Language learning requires that listeners discover acoustically variable functional units like phonetic categories and words from an unfamiliar, continuous acoustic stream. Although many category learning studies have examined how listeners learn to generalize across the acoustic variability inherent in the signals that convey the functional units...

Listeners must accomplish two complementary perceptual feats in extracting a message from speech. They must discriminate linguistically-relevant acoustic variability and generalize across irrelevant variability. Said another way, they must categorize speech. Since the mapping of acoustic variability is language-specific, these categories must be le...

Human speech perception rapidly adapts to maintain comprehension under adverse listening conditions. For example, with exposure listeners can adapt to heavily accented speech produced by a non-native speaker. Outside the domain of speech perception, adaptive changes in sensory and motor processing have been attributed to cerebellar functions. The p...

Cognitive neuroscientists studying sound and speech learning have successfully used videogames as a research vehicle. Neuroscientists and game developers worked together to produce a game built to entice participants to longer periods of play, while enabling researchers to easily configure presentation parameters in support of future studies. A spa...

Although speech categories are defined by multiple acoustic dimensions, some are perceptually weighted more than others and there are residual effects of native-language weightings in non-native speech perception. Recent research on nonlinguistic sound category learning suggests that the distribution characteristics of experienced sounds influence...

Over the course of language development, infants learn native speech categories and word boundaries from speech input. Although speech category learning and word segmentation learning occur in parallel, most investigations have focused on one, assuming somewhat mature develop of the other. To investigate the extent to which listeners can simultaneo...

Previous research demonstrates the sensitivity of adults and infants to the statistical regularity of input distributions defining speech categories [D. L. Grieser and P. K. Kuhl, Dev. Psychol. 25, 577–588 (1989)] and even non‐human animals exhibit such sensitivity [Kluender et al., J. Acoust. Soc. Am. 104, 3568–3580 (1998)]. Speech categories’ str...

Adults have difficulty learning non-native speech categories, presenting an opportunity to study adult learning and plasticity with non-native speech categorization. Long-term training within laboratory-based response-feedback paradigms has produced modest non-native category learning in previous studies. The current study investigates the effectiv...

When should instruction provide or withhold assistance? In three empirical studies, we have investigated whether worked examples, a high- assistance approach, studied in conjunction with tutored problems to be solved, a mid-level assistance approach, can lead to better learning. Contrary to prior results with untutored problem solving, a low-assist...

Our work explores the assistance dilemma: when should instruction provide or withhold assistance? In three separate but very similar studies, we have investigated whether worked examples, a high-assistance approach, studied in conjunction with tutored problems to be solved, a mid-level assistance approach, can lead to better learning. Contrary to p...

In this work we are investigating the learning benefits of e-Learning principles (a) within the context of a web-based intelligent tutor and (b) in the "wild," that is, in real classroom (or homework) usage, outside of a controlled laboratory. In the study described in this paper, we focus on the benefits of politeness, as originally formulated by...

Previous studies have demonstrated the learning benefit of per- sonalized language and worked examples. However, previous investigators have primarily been interested in how these interventions support students as they problem solve with no other cognitive support. We hypothesized that personalized language added to a web-based intelligent tutor an...