Effects of an auditory model on the learning of relative and absolute timing

The effects of an auditory model on the learning of relative and absolute timing were examined. In 2 experiments, participants attempted to learn to produce a 1,000- or 1,600-ms sequence of 5 key presses with a specific relative-timing pattern. In each experiment, participants were, or were not, provided an auditory model that consisted of a series of tones that were temporally spaced according to the criterion relative-timing pattern. In Experiment 1, participants (n = 14) given the auditory template exhibited better relative- and absolute-timing performance than participants (n = 14) not given the auditory template. In Experiment 2, auditory and no-auditory template groups again were tested, but in that experiment each physical practice participant (n = 16) was paired during acquisition with an observer (n = 16). The observer was privy to all instructions as well as auditory and visual information that was provided the physical practice participant. The results replicated the results of Experiment 1: Relative-timing information was enhanced by the auditory template for both the physical and observation practice participants. Absolute timing was improved only when the auditory model was coupled with physical practice. Consistent with the proposal of D. M. Scully and K. M. Newell (1985), modeled timing information in physical and observational practice benefited the learning of the relative-timing features of the task, but physical practice was required to enhance absolute timing.     

Quantitative analysis of aphasic sentence production: further development and new data

The narrative production of patients with Broca's aphasia and age-and education-matched control subjects was analyzed using the Quantitative Production Analysis (Saffran et al., 1989), a procedure designed to provide measures of morphological and structural characteristics of aphasic production. In addition to providing data for a larger number of subjects than in the original study, we provide data on interrater and test-retest reliability. The data were also submitted to factor and cluster analyses. Two factors characterized the data and the cluster analysis yielded four sets of patients who performed differently on these factors. In particular, there is evidence that agrammatic patients can differ in their production of free and bound grammatical morphemes, substantiating earlier claims in the literature.     

Consistent and variable practice conditions: effects on relative and absolute timing

The authors conducted the present experiments to resolve the discrepancy between studies in which relative-timing learning has been found to be enhanced by consistent practice conditions and contextual interference experiments in which relative-timing learning has been found to be enhanced more by random practice than by blocked practice. There were 40 participants in Experiment 1 and 48 in Experiment 2. The results of Experiment 1 extended previous findings: The learning of the relative-timing pattern was systematically enhanced by the degree to which the practice conditions promoted movement consistency (constant > blocked > serial > random). Experiment 2 provided evidence that the discrepancy between the relative-timing effects in the 2 groups of studies was a product of the way in which relative-timing goals and feedback were presented. When the feedback was presented as segment times, random practice resulted in generally more stable relative-timing patterns during acquisition than blocked practice did. Thus, in both experiments, the learning of the relative-timing pattern was enhanced by more stable relative-timing conditions during acquisition. Absolute-timing learning, as indexed by the transfer tests, was enhanced by serial or random practice as compared with constant or blocked practice, and was relatively unaffected by feedback conditions directed at the relative-timing pattern. In terms of motor programming theory, those findings are taken as additional evidence for the disassociation of memories supporting generalized motor program (GMP) performance, as indexed by relative timing, and parameter performance, as indexed by absolute timing.     

Converging evidence for the role of relative timing in speech

In an earlier article (Tuller, Kelso, & Harris, 1982a) we suggested that the timing of consonant-related muscle activity was constrained relative to the period between onsets of muscle activity for successive vowels. Here, we reexamine those data based on reservations posed by Barry (1983). Next, we present a kinematic study of articulation that extends and strongly supports our original observations. Finally, we very briefly survey some converging lines of evidence for a functionally significant vowel-to-vowel period in speech and how this may relate to the role of temporal invariance in motor skills in general.     

Effects of syllable structure in aphasic errors: implications for a new model of speech production

Current models of word production assume that words are stored as linear sequences of phonemes which are structured into syllables only at the moment of production. This is because syllable structure is always recoverable from the sequence of phonemes. In contrast, we present theoretical and empirical evidence that syllable structure is lexically represented. Storing syllable structure would have the advantage of making representations more stable and resistant to damage. On the other hand, re-syllabifications affect only a minimal part of phonological representations and occur only in some languages and depending on speech register. Evidence for these claims comes from analyses of aphasic errors which not only respect phonotactic constraints, but also avoid transformations which move the syllabic structure of the word further away from the original structure, even when equating for segmental complexity. This is true across tasks, types of errors, and, crucially, types of patients. The same syllabic effects are shown by apraxic patients and by phonological patients who have more central difficulties in retrieving phonological representations. If syllable structure was only computed after phoneme retrieval, it would have no way to influence the errors of phonological patients. Our results have implications for psycholinguistic and computational models of language as well as for clinical and educational practices.     

Pragmatic-mode mediation of sentence comprehension among aphasic bilinguals and hispanophones

A test of sentence comprehension administered in four input-output modality combinations to a group of aphasic bilinguals and monolingual hispanophones provides evidence that aphasics tend to use pragmatic-mode (in the sense of Givón, 1979, On understanding-grammar, New York, Academic Press) strategies in approaching this task. When five factors were identified and dichotomized with respect to the pragmatic-mode-syntactic-mode dimension, the patients performed significantly better on items classified as pragmatic than on those classified as syntactic, in both languages. The results support a vertical/hierarchical view of aphasic language dissolution.     

Mimicry versus imitative modeling: Facilitating sentence production in the speech of the retarded

Two methods of language instruction administered to mentally retarded subjects at the two-word stage of language development were investigated. Subjects of the mimicry training group imitated Agent-Action-Object (AAO) constructions immediately after presentation, while subjects of the imitative modeling group first heard the AAO presentation and later produced the AAO construction in response to a verb question. Imitative modeling subjects achieved as many correct AAO responses during training and more correct responses on a generalization task and in a free play setting. They also displayed more novel response behavior (selective imitations) and spontaneously corrected productions. The results support the use of modeling procedures for inducing language production in the retarded.     

Sensitivity to relative reinforcer rate in concurrent schedules: independence from relative and absolute reinforcer duration

Twelve pigeons responded on two keys under concurrent variable-interval (VI) schedules. Over several series of conditions, relative and absolute magnitudes of reinforcement were varied. Within each series, relative rate of reinforcement was varied and sensitivity of behavior ratios to reinforcer-rate ratios was assessed. When responding at both alternatives was maintained by equal-sized small reinforcers, sensitivity to variation in reinforcer-rate ratios was the same as when large reinforcers were used. This result was observed when the overall rate of reinforcement was constant over conditions, and also in another series of concurrent schedules in which one schedule was kept constant at VI ached 120 s. Similarly, reinforcer magnitude did not affect the rate at which response allocation approached asymptote within a condition. When reinforcer magnitudes differred between the two responses and reinforcer-rate ratios were varied, sensitivity of behavior allocation was unaffected although response bias favored the schedule that arranged the larger reinforcers. Analysis of absolute response rates ratio sensitivity to reinforcement occurrred on the two keys showed that this invariance of response despite changes in reinforcement interaction that were observed in absolute response rates on the constant VI 120-s schedule. Response rate on the constant VI 120-s schedule was inversely related to reinforcer rate on the varied key and the strength of this relation depended on the relative magnitude of reinforcers arranged on varied key. Independence of sensitivity to reinforcer-rate ratios from relative and absolute reinforcer magnitude is consistent with the relativity and independence assumtions of the matching law.     

Temporal dimensions of consonant and vowel production: an acoustic and CT scan analysis of aphasic speech

This study explored a number of temporal (durational) parameters of consonant and vowel production in order to determine whether the speech production impairments of aphasics are the result of the same or different underlying mechanisms and in particular whether they implicate deficits that are primarily phonetic or phonological in nature. Detailed analyses of CT scan lesion data were also conducted to explore whether more specific neuroanatomical correlations could be made with speech production deficits. A series of acoustic analyses were conducted including voice-onset time, intrinsic and contrastive fricative duration, and intrinsic and contrastive vowel duration as produced by Broca's aphasics with anterior lesions (A patients), nonfluent aphasics with anterior and posterior lesions (AP patients), and fluent aphasics with posterior lesions (P patients). The constellation of impairments for the anterior aphasics including both the A and AP patients suggests that their disorder primarily reflects an inability to implement particular types of articulatory gestures or articulatory parameters rather than an inability to implement particular phonetic features. They display impairments in the implementation of laryngeal gestures for both consonant and vowel production. These patterns seem to relate to particular anatomical sites involving Broca's area, the anterior limb of the internal capsule, and the lowest motor cortex areas for larynx and tongue. The posterior patients also show evidence of subtle phonetic impairments suggesting that the neural instantiation of speech may require more extensive involvement, including the perisylvian area, than previously suggested.     

Concurrent-chain performance: Effects of absolute and relative terminal-link entry frequency

Six pigeons were trained in a concurrent-chain procedure with constant variable-interval 6-s variable-interval 12-s terminal links. Five groups of conditions were arranged. Within a group of conditions, the duration of one initial-link schedule was held constant and the duration of the other initial link was varied. The duration of the varied initial link was always longer than, or equal to, the constant initial-link duration. The duration of the shorter initial link was varied across groups of conditions from 5 s to 70 s. The data from each group were well described by the generalized matching law. Sensitivity (a) to the terminal-link entry ratio increased as the shorter initial-link duration increased, but appeared to reach an asymptote at shorter initial-link durations greater than 32 s. Terminal-link bias did not change with changes in shorter initial-link duration for the response-allocation data, but showed a small increase with increasing shorter initial-link duration for the time-allocation data.     

Syntactic priming of relative clause attachments: persistence of structural configuration in sentence production

Three sentence completion experiments will be reported in which participants had to generate German equivalents of "the servant of the actress who..." (NP-of-NP-RC) constructions. Target fragments (which were unconstrained as to whether the relative pronoun permitted high or low attachment) were preceded by constrained prime fragments, which were either structurally congruent with the targets (Experiments 1 and 2) or structurally incongruent with the targets (anaphoric adverbial clauses rather than relative clauses (RCs), Experiment 3). While the first two experiments established reliable repetition of RC attachments between primes and targets, Experiment 3 failed to obtain a significant priming effect, indicating that RC attachment priming is dependent on a syntactic overlap between primes and targets. The results suggest a tendency of language producers to retain hierarchical syntactic relations over consecutive trials. Current models of syntactic priming in production do not offer an explanatory mechanism for this kind of observation as they presently stand.     

Comprehension of sentence structure in anomic and conduction aphasia

Picture-pointing auditory and reading comprehension tests were administered to anomic and conduction aphasics. Subjects responded to active sentences of the present progressive form. The possible errors which a subject could make on these experimental tasks included failure to correctly interpret noun order, number, or lexical meaning. Both groups made significantly more correct responses than error responses. Of their error responses, noun-order errors significantly exceeded number and lexical errors for which no differences were observed. When compared with results previously obtained for agrammatic Broca's aphasics, no differences in the pattern of errors were identified. These results are discussed relative to current theories of syntactic processing and for the mechanisms which account for these syntactic comprehension deficits following aphasia.     

Effects of syllable frequency in speech production

In the speech production model proposed by [Levelt, W. J. M., Roelofs, A., Meyer, A. S. (1999). A theory of lexical access in speech production. Behavioral and Brain Sciences, 22, pp. 1-75.], syllables play a crucial role at the interface of phonological and phonetic encoding. At this interface, abstract phonological syllables are translated into phonetic syllables. It is assumed that this translation process is mediated by a so-called Mental Syllabary. Rather than constructing the motor programs for each syllable on-line, the mental syllabary is hypothesized to provide pre-compiled gestural scores for the articulators. In order to find evidence for such a repository, we investigated syllable-frequency effects: If the mental syllabary consists of retrievable representations corresponding to syllables, then the retrieval process should be sensitive to frequency differences. In a series of experiments using a symbol-position association learning task, we tested whether high-frequency syllables are retrieved and produced faster compared to low-frequency syllables. We found significant syllable frequency effects with monosyllabic pseudo-words and disyllabic pseudo-words in which the first syllable bore the frequency manipulation; no effect was found when the frequency manipulation was on the second syllable. The implications of these results for the theory of word form encoding at the interface of phonological and phonetic encoding; especially with respect to the access mechanisms to the mental syllabary in the speech production model by (Levelt et al.) are discussed.     

The segment as the minimal planning unit in speech production: Evidence based on absolute response latencies

A minimal amount of information about a word must be phonologically and phonetically encoded before a person can begin to utter that word. Most researchers assume that the minimum is the complete word or possibly the initial syllable. However, there is some evidence that the initial segment is sufficient based on longer durations when the initial segment is primed. In two experiments in which the initial segment of a monosyllabic word is primed or not primed, we present additional evidence based on very short absolute response times determined on the basis of acoustic and articulatory onset relative to presentation of the complete target. We argue that the previous failures to find very short absolute response times when the initial segment is primed are due in part to the exclusive use of acoustic onset as a measure of response latency, the exclusion of responses with very short acoustic latencies, the manner of articulation of the initial segment (i.e., plosive vs. nonplosive), and individual differences. Theoretical implications of the segment as the minimal planning unit are considered.     

The processing of the sounds and meanings of ongoing speech by aphasic subjects

The ability of aphasic subjects to process the sounds and meanings of ongoing speech was tested. Subjects, 10 aphasic and 20 control, heard test sentences which contained one member of phonemically similar word pairs in one of three semantic contexts: congruent, neutral, and noncongruent. Immediately after hearing a sentence, subjects were to indicate which member of the word pair had been in the sentence. All subject groups had similar overall patterns of response to the different semantic contexts. The division of aphasic subjects into groups of high and low comprehenders revealed response differences. High comprehending aphasic subjects, like control subjects, demonstrated interactive processing of the sounds and meaning of speech while low comprehending aphasic subjects did not.     

Revisiting absolute and relative judgments in the WITNESS model

The WITNESS model (Clark in Applied Cognitive Psychology 17:629–654, 2003) provides a theoretical framework with which to investigate the factors that contribute to eyewitness identification decisions. One key factor involves the contributions of absolute versus relative judgments. An absolute contribution is determined by the degree of match between an individual lineup member and memory for the perpetrator; a relative contribution involves the degree to which the best-matching lineup member is a better match to memory than the remaining lineup members. In WITNESS, the proportional contributions of relative versus absolute judgments are governed by the values of the decision weight parameters. We conducted an exploration of the WITNESS model’s parameter space to determine the identifiability of these relative/absolute decision weight parameters, and compared the results to a restricted version of the model that does not vary the decision weight parameters. This exploration revealed that the decision weights in WITNESS are difficult to identify: Data often can be fit equally well by setting the decision weights to nearly any value and compensating with a criterion adjustment. Clark, Erickson, and Breneman (Law and Human Behavior 35:364–380, 2011) claimed to demonstrate a theoretical basis for the superiority of lineup decisions that are based on absolute contributions, but the relationship between the decision weights and the criterion weakens this claim. These findings necessitate reconsidering the role of the relative/absolute judgment distinction in eyewitness decision making.     

Concurrent-schedule performance: Effects of relative and overall reinforcer rate

Six pigeons were trained to respond on two keys, each of which provided reinforcers on an arithmetic variable-interval schedule. These concurrent schedules ran nonindependently with a 2-s changeover delay. Six sets of conditions were conducted. Within each set of conditions the ratio of reinforcers available on the two alternatives was varied, but the arranged overall reinforcer rate remained constant. Each set of conditions used a different overall reinforcer rate, ranging from 0.22 reinforcers per minute to 10 reinforcers per minute. The generalized matching law fit the data from each set of conditions, but sensitivity to reinforcer frequency (a) decreased as the overall reinforcer rate decreased for both time allocation and response allocation based analyses of the data. Overall response rates did not vary with changes in relative reinforcer rate, but decreased with decreases in overall reinforcer rate. Changeover rates varied as a function of both relative and overall reinforcer rates. However, as explanations based on changeover rate seem unable to deal with the changes in generalized matching sensitivity, discrimination accounts of choice may offer a more promising interpretation.     

Influence of irrelevant information on human performance: Effects of S-R association strength and relative timing

Six experiments examined effects of stimulus-response (S-R) association strength and relative timing on the magnitude of consistency effects for irrelevant information in Stroop-like tasks. Keypresses were made to two-dimensional stimuli (a colour or location word surrounded by a coloured rectangle or arrow), with the irrelevant information presented simultaneously with or prior to the relevant information. With simultaneous presentation, irrelevant information affected performance regardless of whether its S-R association was weak or strong, if the relevant S-R association was weak (e.g., colour word to keypress). However, a weak irrelevant S-R association (location word to keypress) had little effect when paired with a strong relevant S-R association (arrow direction to keypress), except when the stimulus onset asynchrony (SOA) between the irrelevant and relevant information was 300 ms. When the relevant information was colour, the effect of an irrelevant colour word persisted at a 500-ms SOA but that of an irrelevant physical colour did not, reflecting different decay functions for irrelevant verbal and non-verbal information. The persisting effect of an irrelevant colour word was reduced by articulatory suppression and eliminated at extended SOAs of 3 s. The results indicate that whether the consistency effect patterns are symmetric or asymmetric is determined by the relative strengths of the relevant and irrelevant S-R associations, as specified by the criteria of conceptual and mode similarity. The magnitude of the consistency effect is also a function of the temporal overlap of the resulting response activation, which is determined primarily by mode similarity.