Phonological priming effects on speech onset latencies and viewing times in object naming

An earlier experiment (Meyer, Sleiderink, & Levelt, 1998) had shown that speakers naming object pairs usually inspected the objects in the required order of mention (left object first) and that the viewing time for the left object depended on the word frequency of its name. In the present experiment, object pairs were presented simultaneously with auditory distractor words that could be phonologically related or unrelated to the name of the object to be named first. The speech onset latencies and the viewing times for that object were shorter after related distractors than after unrelated distractors. Since this phonological priming effect, like the word frequency effect, most likely arises during wordform retrieval, we conclude that the shift of gaze from the first to the second object is initiated after the word form of the first object’s name has been accessed.     

Sublexical and lexical representations in speech production: effects of phonotactic probability and onset density

Phonotactic probability, neighborhood density, and onset density were manipulated in 4 picture-naming tasks. Experiment 1 showed that pictures of words with high phonotactic probability were named more quickly than pictures of words with low phonotactic probability. This effect was consistent over multiple presentations of the pictures (Experiment 2). Manipulations of phonotactic probability and neighborhood density showed only an influence of phonotactic probability (Experiment 3). In Experiment 4, pictures of words with sparse onsets were named more quickly than pictures of words with dense onsets. The results of these experiments provide additional constraints on the architecture and processes involved in models of speech production, as well as constraints on the connections between the recognition and production systems.     

Fundamental frequency as a cue to postvocalic consonantal voicing: Some data from speech perception and production

Several recent studies by Lehiste have reported that changes in fundamental frequency (F0) can serve as a cue to perceived vowel length and, furthermore, that the perceived lengthening of the vowel can influence perception of the voicing feature of stop consonants in syllable-final position. In Experiment 1, we replicated Lehiste’s basic results for stop consonants in final position. Experiment 2 extended these results to postvocalic fricatives. The final consonant in syllables of intermediate vowel duration was more often perceived as voiced when F0 was falling than when F0 was monotone. In Experiment 3, we examined the F0 contours produced by eight talkers before postvocalic stop consonants and fricatives in natural speech for minimal pairs of words differing in voicing. The amount of change of F0 over the vowel was no greater before voiced than voiceless consonants, suggesting that the earlier perceptual effects cannot be explained by appealing to regularities observed in the production of F0 contours in vowels preceding postvocalic consonants.     

Semantic effects in naming perceptual identification but not in delayed naming: implications for models and tasks

Previous research has demonstrated that the subjective danger and usefulness of words affect lexical decision times. Usually, an interaction is found: Increasing danger predicts faster reaction times (RTs) for words low on usefulness, but increasing danger predicts slower RTs for words high on usefulness. The authors show the same interaction with immediate auditory naming. The interaction disappeared with a delayed auditory naming control experiment, suggesting that it has a perceptual basis. In an attempt to separate input (signal to ear) from output (brain to muscle) processes in word recognition, the authors ran 2 auditory perceptual identification experiments. The interaction was again significant, but performance was best for words high on both danger and usefulness. This suggests that initial demonstrations of the interaction were reflecting an output approach/withdraw response conflict induced by stimuli that are both dangerous and useful. The interaction cannot be characterized as a tradeoff of speed versus accuracy.     

Embodied grounding of memory: Toward the effects of motor execution on memory consolidation

Behavioural and neuroscientific research has provided evidence for a strong functional link between the neural motor system and lexical–semantic processing of action-related language. It remains unclear, however, whether the impact of motor actions is restricted to online language comprehension or whether sensorimotor codes are also important in the formation and consolidation of persisting memory representations of the word's referents. The current study now demonstrates that recognition performance for action words is modulated by motor actions performed during the retention interval. Specifically, participants were required to learn words denoting objects that were associated with either a pressing or a twisting action (e.g., piano, screwdriver) and words that were not associated to actions. During a 6–8-minute retention phase, participants performed an intervening task that required the execution of pressing or twisting responses. A subsequent recognition task revealed a better memory for words that denoted objects for which the functional use was congruent with the action performed during the retention interval (e.g., pepper mill–twisting action, doorbell–pressing action) than for words that denoted objects for which the functional use was incongruent. In further experiments, we were able to generalize this effect of selective memory enhancement of words by performing congruent motor actions to an implicit perceptual (Experiment 2) and implicit semantic memory test (Experiment 3). Our findings suggest that a reactivation of motor codes affects the process of memory consolidation and emphasizes therefore the important role of sensorimotor codes in establishing enduring semantic representations.     

Behavioral,subjective, and electroencephalographic indices of sleep onset latency and sleep duration

Electrographic (EEG, EOG, EMG) indices have been used for some decades in the definition of the stages of sleep and more recently in the diagnosis of sleep-related disorders, e.g., insomnia, despite the lack of detailed information concerning the precise relationship between such electrographic indices and behavioral and subjective criteria of sleep. Evaluation of the relationship between EEG, behavioral, and self-report measures of sleep onset latency and sleep duration was conducted using 17 young normal sleepers. The behavioral measure was provided by an apparatus which records subjects' button-press responses to an auditory stimulus presented at various interstimulus intervals (2, 5, and random 1, 2, 5, 7, and 10 min). The behavioral and stage 2 EEG estimates of sleep onset latency (SOL) and sleep duration (SD) were almost identical. The stage 1 EEG provided the shortest estimate of SOL; the self-report measure, the longest. The SD measures were in reverse order. There were no significant differences among the three interstimulus interval conditions (2, 5, and random min). Average response rates to the 50-dB chime were 100% during wakefulness, 81% during EEG stage 1, and 8% during EEG stage 2. Almost all stage 2 responding occurred during the first 5 min of each stage 2 period. The validity of electrographic indices as sleep criteria and the implications of the findings for the formulation of an adequate definition of sleep and its clinical measurement are discussed.     

The influence of syllable onset complexity and syllable frequency on speech motor control

Functional imaging studies have delineated a "minimal network for overt speech production", encompassing mesiofrontal structures (supplementary motor area, anterior cingulate gyrus), bilateral pre- and postcentral convolutions, extending rostrally into posterior parts of the inferior frontal gyrus (IFG) of the language-dominant hemisphere, left anterior insula as well as bilateral components of the basal ganglia, the cerebellum, and the thalamus. In order to further elucidate the specific contribution of these cerebral regions to speech motor planning, subjects were asked to read aloud visually presented bisyllabic pseudowords during functional magnetic resonance imaging (fMRI). The test stimuli systematically varied in onset complexity (CCV versus CV) and frequency of occurrence (high-frequency, HF versus low-frequency, LF) of the initial syllable. A cognitive subtraction approach revealed a significant main effect of syllable onset complexity (CCV versus CV) at the level of left posterior IFG, left anterior insula, and both cerebellar hemispheres. Conceivably, these areas closely cooperate in the sequencing of subsyllabic aspects of the sound structure of verbal utterances. A significant main effect of syllable frequency (LF versus HF), by contrast, did not emerge. However, calculation of the time series of hemodynamic activation within the various cerebral structures engaged in speech motor control revealed this factor to enhance functional connectivity between Broca's area and ipsilateral anterior insula.     

Orthographic and phonological facilitation in speech production: new evidence from picture naming in Chinese

Picture naming is facilitated when a target picture (e.g. of a cat) is accompanied by a form-related context word (e.g. CAP) relative to an unrelated word (e.g. PEN). Because in alphabetic languages phonological and orthographic similarity are confounded, Chinese, a logographic language, has been employed to study these two effects in isolation. The results obtained suggest that the orthographic facilitation effect is localized at an earlier processing level than the phonological facilitation effect. In the present study we examine this issue again, using an experimental design in which the context words in the related and unrelated conditions are optimally matched. In contrast to the earlier studies Experiments 1 and 2 fail to show differences in the time course of the two context effects. Moreover, Experiment 3 provides direct evidence against an early, conceptual locus of orthographic facilitation. Our findings indicate that in Chinese language production both orthographically and phonologically related context words have their effect at the rather late level of word-form encoding.     

The effects of speech production and speech comprehension on simulated driving performance

We performed two experiments comparing the effects of speech production and speech comprehension on simulated driving performance. In both experiments, participants completed a speech task and a simulated driving task under single‐ and dual‐task conditions, with language materials matched for linguistic complexity. In Experiment 1, concurrent production and comprehension resulted in more variable velocity compared to driving alone. Experiment 2 replicated these effects in a more difficult simulated driving environment, with participants showing larger and more variable headway times when speaking or listening while driving than when just driving. In both experiments, concurrent production yielded better control of lane position relative to single‐task performance; concurrent comprehension had little impact on control of lane position. On all other measures, production and comprehension had very similar effects on driving. The results show, in line with previous work, that there are detrimental consequences for driving of concurrent language use. Our findings imply that these detrimental consequences may be roughly the same whether drivers are producing speech or comprehending it. Copyright © 2005 John Wiley & Sons, Ltd.     

Earwitnesses: effects of speech duration,retention interval and acoustic environment

An experiment was conducted to investigate the reliability of voice lineups. More specifically, the experiment was designed to look into the effects of retention interval (an immediate test or after a week), speech duration (30 or 70 s) and acoustic environment (indoors or indoors and outdoors) on speaker identification accuracy. In addition, the relation between confidence assessments of both participants and test assistant on the one hand and identification accuracy was explored. A total of 361 participants heard the target voice in one of four exposure conditions (short or long text and speech samples recorded only indoors or indoors and outdoors). Half the participants were tested immediately after exposure to the target voice and half 1 week later. The results show that the target was correctly identified in 42% of cases. In the target‐absent condition there were 51% false alarms. Acoustic environment did not affect identification accuracy. There was an interaction between speech duration and retention interval in the target‐absent condition. When listeners were tested after a week, they made fewer false identifications if the speech sample was long. No effects were found when participants were tested immediately. Only the confidence scores of the test assistant had predictive value. Taking the confidence score of the test assistant into account therefore increases the diagnostic value of the identity parade. Copyright © 2004 John Wiley & Sons, Ltd.     

Effect of learning on production of duration in variable motor conditions

It has been suggested that increasing proprioceptive feedback and ensuring its consistency from trial to trial favours timing accuracy. The progressive acquisition of a timing performance with isometric and anisometric responses was investigated in conditions of 'inconsistent feedback', with two different methods: counting seconds or not. Subjects gripped the handle of a dynamometer during precisely 5 seconds in 4 randomly distributed conditions: 'Weak' or 'Strong' constant force, 'Slow' or 'Rapid' variable force. A first group produced the durations without counting and a second group counted seconds either mentally or aloud. Learning was examined in 4 successive blocks of trials. Average produced durations did not differ as a function of group, but the variability was reduced when subjects counted seconds. In both groups, the constant force conditions induced more accurate responses than the variable force conditions in the first block of trials. 'Slow' and 'Rapid' conditions were respectively associated with overestimation and under-estimation of response duration. These trends diminished progressively with learning. Both groups yielded sequential effects linked to duration and independent of condition. These data suggest that, whether subjects counted or not, learning was not based on condition-specific proprioceptive feedback. It may involve the elaboration of an internal temporal reference common to all conditions.     

The effects of delayed and displaced visual feedback on motor control

Developments in television technology have made possible new approaches to the study of the role of visual feedback in motor control. In two experiments using a special videodisc recording and playback system, the effects of delaying for 66 msec a subject's view of his own hand during a target-directed movement was investigated. The observed effects of such visually delayed feedback compared to spatially distorted feedback produced by prisms led to three major conclusions: (a) despite the behavioral similarity (overshooting) induced by the two kinds of altered feedback, the role of each in the visual-motor control loop is different; (b) adaptation to and the after effect of the two kinds of altered feedback are based on different control mechanisms (c) the processing and use of visual information in hand control requires less time than previous experiments have indicated.     

Tactile apparent movement: The effects of interstimulus onset interval and stimulus duration

The effects of variations in stimulus duration and interstimulus onset interval on ratings of tactile apparent movement were determined for seven Ss with stimulators of very small diameter. Judgments of successiveness and simultaneity were also obtained. It was found that apparent movement increased as a power function of increases in stimulus duration. The function relating tactile apparent movement and stimulus duration was shown to be similar to that obtained by Kolers (1964) for visual apparent movement, lnterstimulus onset interval also had a marked effect on apparent movement, and the optimal interval was influenced by stimulus duration in a manner similar to that reported by Sherrick and Rogers (1966).     

The effects of onset and offset warning and post-target stimuli on the saccade latency of children and adults

Two studies, involving children (mean age = 10 years) and adults, investigated the effects of visual stimulus onsets and offsets on the latency of saccades to peripheral targets. Saccade latency was reduced when foveal stimulus onsets or offsets preceded the target. When stimulus onset occurred 100 msec after target onset, the stimulus interfered with responding, with this interference effect significantly greater for children than for adults. When stimuli were presented in the peripheral visual field facilitation and interference effects were similar for children and adults. These results were interpreted as indicating that oculomotor processes are similar in children and adults while the stimulus intake processes that follow stimulus onset at the point of fixation have a greater interference effect on children's than on adults' eye movements.     

Testing the embodied account of object naming: A concurrent motor task affects naming artifacts and animals

Embodied theories of object representation propose that the same neural networks are involved in encoding and retrieving object knowledge. In the present study, we investigated whether motor programs play a causal role in the retrieval of object names. Participants performed an object-naming task while squeezing a sponge with either their right or left hand. The objects were artifacts (e.g. hammer) or animals (e.g. giraffe) and were presented in an orientation that favored a grasp or not. We hypothesized that, if activation of motor programs is necessary to retrieve object knowledge, then concurrent motor activity would interfere with naming manipulable artifacts but not non-manipulable animals. In Experiment 1, we observed naming interference for all objects oriented towards the occupied hand. In Experiment 2, we presented the objects in more ‘canonical orientations’. Participants named all objects more quickly when they were oriented towards the occupied hand. Together, these interference/facilitation effects suggest that concurrent motor activity affects naming for both categories. These results also suggest that picture-plane orientation interacts with an attentional bias that is elicited by the objects and their relationship to the occupied hand. These results may be more parsimoniously accounted for by a domain-general attentional effect, constraining the embodied theory of object representations. We suggest that researchers should scrutinize attentional accounts of other embodied cognitive effects.     

Attentional deployment in visual half-field tasks: the effect of cue position on word naming latency

Divided visual-field research suggests that attentional factors may contribute to the left hemisphere's (LH) superiority for language processing. The LH's parallel recognition strategy, specialised for whole word encoding, is largely unaffected by the distribution of spatial attention. In contrast, the right hemisphere's (RH) serial, letter-by-letter strategy places far greater demands on attentional resources. By manipulating spatial attention, the present study gauged the effect of cueing the beginning vs. the end of the word on LH and RH naming latency. Results indicated no effect of cue position on LH performance, consistent with research indicating that the LH enjoys an attentional advantage, deploying attention in parallel across the stimulus. As anticipated, the RH showed a facilitatory effect of beginning cue, which draws spatial attention to the initial letter cluster, enabling efficient implementation of the RH's sequential strategy. These findings suggest that differences in attentional deployment contribute to hemispheric asymmetries for word recognition.     

Sequencing, speech production, and selective effects of aging on phonological and morphological speech errors

To test age-linked predictions of node structure theory (NST) and other theories, young and older adults performed a task that elicited large numbers of phonological and morphological speech errors. Stimuli were visually presented words containing either /p/ or /b/, and participants changed the /p/ to /b/ or vice versa and produced the resulting word as quickly as possible. For example, the correct response was "bunk" for the stimulus PUNK, and "ripped" for RIBBED. Consistent with NST predictions, the elicited speech errors exhibited selective effects of aging. Some error types decreased with aging. For example, young adults produced more nonsequential substitution errors (as a percentage of total errors) than older adults (e.g., intended bills misproduced as "gills"). However, other error types remained constant or increased with aging. For example, older adults produced more omission errors than young adults, especially omissions involving inflectional endings (e.g. intended ripped misproduced as "np"). In addition, older adults exhibited special difficulties with 2 types of phonological and morphological sequencing processes.     

Sample-duration effects on pigeons' delayed matching as a function of predictability of duration

Three experiments assessed the impact of sample duration on pigeons' delayed matching as a function of whether or not the samples themselves signaled how long they would remain on. When duration was uncorrelated with the sample appearing on each matching trial, the typical effect of duration was observed: Choice accuracy was higher with long (15-s) than with short (5-s) durations. By contrast, this difference either disappeared or reversed when the 5- and 15-s durations were correlated with the sample stimuli. Sample duration itself cued comparison choice by some birds in the latter (predictable) condition when duration was also correlated with the reinforced choice alternatives. However, even when duration could not provide a cue for choice, pigeons matched predictably short-duration samples as accurately as, or more accurately than, predictably long-duration samples. Moreover, this result was observed independently of whether the contextual conditions of the retention interval were the same as, or different from, those of the intertrial interval. These results strongly support the view that conditional stimulus control by the samples is partly a function of their conditioned reinforcing properties, as determined by the relative reduction in overall delay to reinforcement that they signal.     

The contribution of the insula to motor aspects of speech production: a review and a hypothesis

Based on clinical and functional imaging data, the left anterior insula has been assumed to support prearticulatory functions of speech motor control such as the "programming" of vocal tract gestures. In order to further elucidate this model, a recent functional magnetic resonance imaging (fMRI) study of our group (Riecker, Ackermann, Wildgruber, Dogil, & Grodd, 200) investigated both overt (aloud) and covert (silent) production of highly overlearned word strings ("automatic speech"), based on the suggestion that "inner speech" might provide a "window" into preparatory motor activities (Jeannerod, 1994). As a control condition, subjects were asked to reproduce a nonlyrical tune. In contrast to hemodynamic responses within motor cortex and cerebellum, activation of the intrasylvian cortex turned out to be bound to overt task performance. Rather than prearticulatory processes, these findings suggest the left insula to contribute to the actual coordination of the up to 100 muscles engaged in articulation and phonation. Conceivably, the association of speech production with intrasylvian cortex might have evolved within the framework of phylogenetically older connections between the insula and limbic structures, on the one hand, and nonspeech functions of the upper midline musculature such as swallowing, on the other. Whereas (overt) speech tasks predominantly elicit activation within left anterior insula, reproduction of a nonlyrical tune yielded an opposite response pattern. Conceivably, the opposite distributional pattern of speaking and singing at the level of intrasylvian cortex reflects operation of the two hemispheres across different time domains ("double filtering by frequency theory": left hemisphere=segmental information, right hemisphere=intonation contours of verbal utterances and musical melodies; ). In line with this suggestion, a further study of our group (Ackermann et al., 2001) provided first evidence that differential hemispheric filtering might be bound to insular cortex.