Presentations

Abstract

Serial naming deficits have been identified as core symptoms of developmental dyslexia. A prominent hypothesis is that naming delays are due to inefficient phonological encoding, yet the exact nature of this underlying impairment remains largely underspecified. Here we used recordings of eye movements and word onset latencies to examine at what processing level the dyslexic naming deficit emerges: localized at an early stage of lexical encoding or rather later at the level of phonetic or motor planning. 23 dyslexic and 25 control adult readers were tested on a serial object naming task for 30 items and an analogous reading task, where phonological neighborhood density and word-frequency were manipulated. Results showed that both word properties influenced early stages of phonological activation (first fixation and first-pass duration) equally in both groups of participants. Moreover, in the control group any difficulty appeared to be resolved early in the reading process, while for dyslexic readers a processing disadvantage for low-frequency words and for words with sparse neighborhood also emerged in a measure that included late stages of output planning (eye-voice span). Thus, our findings suggest suboptimal phonetic and/or articulatory planning in dyslexia.

Abstract

Speech segmentation requires flexible mechanisms to remain robust to features such as speech rate and pronunciation. Recent hypotheses suggest that low-frequency neural oscillations entrain to ongoing syllabic and phrasal rates, and that neural entrainment provides a speech-rate invariant means to discretize linguistic tokens from the acoustic signal. How this mechanism functionally operates remains unclear. Here, we test the hypothesis that neural entrainment reflects temporal predictive mechanisms. It implies that neural entrainment is built on the dynamics of past speech information: the brain would internalize the rhythm of preceding speech to parse the ongoing acoustic signal at optimal time points. A direct prediction is that ongoing neural oscillatory activity should match the rate of preceding speech even if the stimulation changes, for instance when the speech rate suddenly increases or decreases. Crucially, the persistence of neural entrainment to past speech rate should modulate speech perception. We performed an MEG experiment in which native Dutch speakers listened to sentences with varying speech rates. The beginning of the sentence (carrier window) was either presented at a fast or a slow speech rate, while the last three words (target window) were displayed at an intermediate rate across trials. Participants had to report the perception of the last word of the sentence, which was ambiguous with regards to its vowel duration (short vowel /ɑ/ – long vowel /aː/ contrast). MEG data was analyzed in source space using beamformer methods. Consistent with previous behavioral reports, the perception of the ambiguous target word was influenced by the past speech rate; participants reported more /aː/ percepts after a fast speech rate, and more /ɑ/ after a slow speech rate. During the carrier window, neural oscillations efficiently tracked the dynamics of the speech envelope. During the target window, we observed oscillatory activity that corresponded in frequency to the preceding speech rate. Traces of neural entrainment to the past speech rate were significantly observed in medial prefrontal areas. Right superior temporal cortex also showed persisting oscillatory activity which correlated with the observed perceptual biases: participants whose perception was more influenced by the manipulation in speech rate also showed stronger remaining neural oscillatory patterns. The results show that neural entrainment lasts after rhythmic stimulation. The findings further provide empirical support for oscillatory models of speech processing, suggesting that neural oscillations actively encode temporal predictions for speech comprehension.

Abstract

Previous research indicates that general cognitive abilities, such as attention or executive control, contribute to language processing (Hartsuiker & Barkhuysen, 2006; Jongman et al., 2014; Shao et al., 2013). Potential effects of language-specific abilities, such as vocabulary, on language processing in adult native speakers have been examined less extensively. Goals: a) develop and assess measures of vocabulary size in Dutch native speakers, and b) investigate the relationship between individual differences in vocabulary and language processing.

Abstract

Listeners are continuously exposed to a broad range of speech rates. Earlier work has shown that listeners perceive phonetic category boundaries relative to contextual speech rate. It has been suggested that this process of speech rate normalization occurs across talker changes. This would predict that the speech rate of talker A influences perception of the rate of another talker B. We assessed this hypothesis by testing effects of speech rate on the perception on the Dutch vowel continuum /A/-/a:/. One participant group was exposed to 'neutral' speech from talker A intermixed with fast speech from talker B. Another group listened to the same speech from talker A, but to slow speech from talker B. We observed a difference in perception of talker A depending on the speech rate of talker B: A's 'neutral' speech was perceived as slow when B spoke faster. These findings corroborate the idea that speech rate normalization occurs across talkers, but they challenge the assumption that listeners average over speech rates from multiple talkers. Instead, they suggest that listeners contrast talker-specific rates.

Abstract

Natural conversations are characterized by smooth transitions of turns between interlocutors. For instance, speakers often respond to questions or requests within half a second. As planning the first word of an utterance can easily take a second or more, this suggests that utterance planning often overlaps with listening to the preceding speaker's utterance. A specific proposal concerning the temporal coordination of listening and speech planning has recently been made by Levinson and Torreira (2016, Frontiers in Psychology; Levinson, 2016, Trends in Cognitive Sciences). They propose that speakers initiate their speech planning as soon as they have understood the speech act and gist of the preceding utterance. However, direct evidence for simultaneous listening and speech planning is scarce. I will first review studies demonstrating that both comprehending spoken utterances and planning them require processing capacity and that these processes can substantially interfere with each other. These data suggest that concurrent speech planning and listening should be cognitively quite challenging. In the second part of the talk I will turn to studies examining directly when utterance planning in dialogue begins. These studies indicate that (regrettably) there are probably no hard-and-fast rules for the temporal coordination of listening and speech planning. I will argue that (regrettably again) we need models that are far more complex than Levinson and Torreira's proposal to understand how listening and speech planning are coordinated in conversation

Abstract

We show that language users readily learn the probabilities of novel lexical cues to syntactic information (verbs biasing towards a prepositional object dative vs. double-object dative and words biasing towards a verb vs. noun reading) and use these biases in a subsequent production task. In a one-hour exposure phase participants read 12 novel lexical items, embedded in 30 sentence contexts each, in their native language. The items were either strongly (100%) biased towards one grammatical frame or syntactic category assignment or unbiased (50%). The next day participants produced sentences with the newly learned lexical items. They were given the sentence beginning up to the novel lexical item. Their output showed that they were highly sensitive to the biases introduced in the exposure phase.
Given this rapid learning and use of novel lexical cues, this paradigm opens up new avenues to test sentence processing theories. Thus, with close control on the biases participants are acquiring, competition between different frames or category assignments can be investigated using reaction times or neuroimaging methods.
Generally, these results show that language users adapt to the statistics of the linguistic input, even to subtle lexically-driven cues to syntactic information.

Abstract

If message and sentence planning are closely linked processes, planning scope may vary depending on what speakers want to say and how they say it. We compared speakers’ gaze pattern to pictures in displays eliciting sentences like “The lion and the tiger are above the basket” when speakers were a) more familiar or less familiar with the spatial layout of these displays, and b) more familiar or less familiar with the phrasal structures used in these sentences. Familiarity with spatial layout was induced by presenting prime trials with a similar or dissimilar layout of pictures (“The bell and the nail are above/below the crutch”) before the target trial, and familiarity with sentence structure was manipulated via structural priming (prime trials elicited sentences like “The bell and the nail are above the crutch” or “The bell is above the nail and the crutch”). When describing pictures on target trials, speakers looked earlier at the second object (tiger) when they were familiar with both the spatial layout and sentence structure, but speech onsets were reduced (structural priming) only when both spatial layout and sentence structure were repeated. The results show that linguistic planning is facilitated by congruence between message-level and sentence-level structure.

Abstract

Studies of lexical access in speech planning often use priming or interference paradigms, where a target picture is combined with a written prime or distracter word. A difficulty in interpreting the results of studies using interference paradigms with clearly visible distracters is that effects arising during lexical access cannot be distinguished from effects arising during self-monitoring. A difficulty with using masked priming paradigms is that the effects tend to be small and fragile. We report a series of picture naming experiments using both the conventional masked priming procedure and the sandwich priming procedure first used in lexical decision experiments by Lupker and masked prime the participants are briefly (i.e., 33 ms) presented the name of the target picture. Although neither categorically nor phonologically related primes significantly affected picture naming in the traditional masked priming experiments, in the sandwich priming experiments: (a) categorically related primes (e.g. “dog-cat”) interfered more than unrelated distracters with picture naming and (b) phonologically related primes (“mat-cat”) facilitated picture naming. The theoretical implications of these findings will be discussed. Lupker, S.J., & Davis, C.J. (2009). Sandwich priming: A method for overcoming the limitations of masked priming by reducing lexical competition effects. Journal of Experimental Psychology: Learning, Memory, & Cognition, 35, 618-639.

Abstract

Models of the mental representation of morphologically complex words traditionally fall into one of two categories, Single-Route or Dual-Route models. The former further distinguish between Full-Listing (e.g. Butterworth, 1983) and Decomposition (e.g. Taft & Forster, 1976), while the latter assume different systems governing the access of mono- vs. polymorphemic words (e.g. Pinker & Prince, 1994; Pinker & Ullman, 2002). One of the main arguments against decomposition and continuous online computations is the cognitive resources this process would require. Turning this reasoning around, taxing someone's working memory capacities should then uniquely affect the computation of bimorphemic verb forms. We tested this hypothesis on 48 Dutch native speakers with a lexical decision task, comparing reaction times for Dutch regular past tense forms to frequency-matched irregular past tense forms, both under low and under high cognitive load. We found that frequency influenced reactions to monomorphemic but not to bimorphemic forms (F(1, 47) = 4.734, p = .035), favoring a listing account for the former but a computational procedure for the latter forms. This interaction, however, was present only for a certain group of people (F(1, 23) = 6.279, p = .02), namely those whose reaction times were hardly affected by the load manipulation and who thus may be thought of as having larger working memory capacities. On the other hand, participants who showed a strong load effect had no interaction between number of morphemes and frequency (F(1, 23) = .575, ns), indicating that they process monomorphemic and bimorphemic forms in a similar manner. It seems that cognitive capacities influence the storage of and access to polymorphemic verb forms. While people with greater working memory skills use these resources to compute morphologically complex inflections on-line, people with smaller cognitive capacities seem to rely on a list-like storage for bimorphemic forms as well.

Abstract

Speakers clearly differ in how quickly they can retrieve words from the mental lexicon, but little is known about the sources of this variability. The present study investigated the relationship between speakers’ executive control abilities and their speed of picture naming. In two experiments, adult speakers of British English named line drawings of objects and actions. Three main components of executive control - updating, shifting of attention, and inhibiting - were assessed using the operation-span, number-letter shifting, and stop-signal task, respectively (see Myake et al.,2000 ). Reaction times (RT) to action and object pictures were highly correlated. Ex-Gaussian analyses of the RT distributions showed that the speakers’ updating scores correlated with the tau parameter of the RT distributions, i.e. predicted the proportions of slow responses in action and object naming. The inhibiting scores correlated with the mean RTs, whereas the scores obtained in the number-letter shifting task were uncorrelated to the RTs. These results indicate that the executive control abilities of updating and inhibiting contribute to the speed of naming objects and actions. Theories of word production may require modification to take account of these findings.

Abstract

a bitter rain – two silences beneath the one umbrella Is the connotative meaning of texts readily available or is it gleaned at an extra cognitive cost? The eye-movements of 31 English native speakers (10 male, mean age 21 years) were recorded while reading 24 haiku, 12 in the original/symbolic version, and 12 in a modified version where the most symbolic word (the keyword ‘bitter’ in the example) was replaced by a more literal word (‘loud’) reducing the text’s symbolic purport. The effects of keyword substitutions were measured globally, comparing total reading times for the two haiku types, and locally, examining the first pass gaze durations and dwell times on a word closely connected to the keyword, the referent ‘silences’, and on the last word, ‘umbrella’, to examine wrap-up processes. First pass duration showed no effects of the substitution. However, dwell time on referents and last-word regions, and total reading time were significantly longer for the original than for the altered haiku, suggesting that the connotative meaning of the texts was not available immediately but only through re-reading of the texts. The implications of these findings are discussed in relation to the literature on the processing of inferences in symbolic texts.

Abstract

a bitter rain – two silences beneath the one umbrella Is the connotative meaning of a text readily available or is it accessed only after re-examining a text? Thirtyone English native speakers (10 male, mean age 21) read 24 haiku, 12 in their original/symbolic version and 12 in a version in which the most symbolic word (the keyword "bitter" in the example above) was replaced by a more literal word ("loud"), reducing the text’s symbolic purport. Participants' eye movements were recorded using the eye-tracker EyeLink 1000. The effect of the word substitution was measured globally, by comparing the total reading times for the two haiku types, and locally, by examining first pass duration and dwell time on a word closely connected to the keyword (the referent, "silences") and on the last word ("umbrella"), as this might show wrap-up processes. First pass durations showed no effects of the substitution. However, total reading time and dwell time on both the referent and the last-word regions were significantly longer for haiku with the original keyword than for haiku with the altered keyword. These findings suggest that the texts’ connotative meaning was not available immediately but only through re-reading of the texts.

Abstract

When children learn their native language, they have to deal with a confusing array of dependencies between various elements in an utterance. Some of these dependencies may be adjacent to one another whereas others can be separated by considerable intervening material. In this study, we investigate whether both types of dependencies can be learned together, similarly to the task facing young children. Statistical learning of adjacent dependencies (probability = .17) and non-adjacent dependencies (probability = 1.0) was assessed in two experiments using a modified serial-reaction-time task. The results showed (i) increasing online sensitivity to both dependency types during training, (ii) better nonadjacency than adjacency learning, and (iii) nonadjacency learning being highly correlated with adjacency learning, suggesting that adjacency and non-adjacency learning can occur in parallel and might be subserved by a common statistical learning mechanism. An overnight break between two training sessions helped the online learning performance of slower learners to approach that of faster learners, but the same amount of training without such a break (a 15-min interval) did not, suggesting that memory consolidation may play a role in statistical learning of complex statistical patterns, especially for slower learners.