Patterns of comprehension performance in agrammatic Broca's aphasia: a test of the Trace Deletion Hypothesis

We tested the core prediction of the Trace Deletion Hypothesis (TDH) of agrammatic Broca's aphasia, which contends that such patients' comprehension performance is normal for active reversible sentences but at chance level for passive reversible sentences. We analyzed the comprehension performance of 38 Italian Broca's aphasics with verified damage to Broca's area, who completed sentence-to-picture matching tasks using active and passive reversible sentences as stimuli. The results failed to confirm the predictions made by TDH: only a small minority (15%) performed at chance on passive sentences and better than chance on active sentences. Furthermore, the distribution of the 38 subjects' performance on passive sentences differed from that predicted by the TDH since many more subjects performed at better-than-chance levels than expected. We discuss the implication of these results for claims about the distribution of language processing mechanisms in the brain.     

Does Respect for Embryos Entail Respect for Gametes?

Respect for human embryos is often defended on the basis of the potentiality argument: embryos deserve respect because they already possess potentially the features that in adults are fully actualized. Opponents of this argument challenge it by claiming that if embryos should be respected because they are potentially adults, then gametes should be respected because they are potentially embryos. This article rejects this reductio ad absurdum argument by showing that there are two different types of potentiality involved so that the transitivity of potentiality does not hold up in this case. Respect for embryos does not logically entail respect for gametes.     

The selection of grammatical features in word production: the case of plural nouns in German

Two experiments investigate the effect of number congruency using picture-word interference. Native German participants were required to name pictures of single objects (Nase 'nose') or two instances of the same object (Nasen 'noses') while ignoring simultaneously presented distractor words. Distractor words either had the same number or were different in number. In addition, the type of plural formation (same or different inflectional plural suffix) and the semantic relationship (same or different semantic category) between target and distractor were varied in Experiments 1 and 2. Results showed no effect of number congruency in either experiment. Furthermore, the type of inflectional suffix did not exert an influence on naming latencies in Experiment 1, but semantic relationship led to a significant interference effect in Experiment 2. The results indicate that selection of the number feature diacritic in noun production is not a competitive process. The implications of the results for models of lexical access are discussed.     

The absence of a gender congruency effect in romance languages: a matter of stimulus onset asynchrony?

Using the picture-word interference paradigm, H. Schriefers and E. Teruel (2000) found that in German the grammatical gender of the distractor word affects the production of phrases composed of article+picture name: Latencies were longer for picture-word pairs of different genders. However, the effect was found only at positive stimulus onset asynchronies (SOAs; i.e., when pictures were presented 75 or 150 ms earlier than word distractors). This gender congruency effect is not obtained in Romance languages. The present article examines whether in these languages, as in German, the effect appears at positive SOAs. No effect was observed in Italian and Spanish at positive SOAs. An account is proposed to explain why the gender congruency effect is obtained in Germanic (Dutch and German) but not in Romance languages.     

Displacement activities as a behavioral measure of stress in nonhuman primates and human subjects

Traditionally, research on human stress has relied mostly on physiological and psychological measures with a relatively minor emphasis on the behavioral aspects of the phenomenon. Such an approach makes it difficult to develop valid animal models of the human stress syndrome. A promising approach to the study of the behavioral correlates of stress is to analyze those behavior patterns that ethologists have named displacement activities and that, in primates, consist mostly of self-directed behaviors. In both nonhuman primates and human subjects, displacement behavior appears in situations characterized by social tension and is likely to reflect increased autonomic arousal. Pharmacological studies of nonhuman primates have shown that the frequency of occurrence of displacement behavior is increased by anxiogenic compounds and decreased by anxiolytic drugs. Ethological studies of healthy persons and psychiatric patients during interviews have found that increased displacement behavior not only correlates with a subjective feeling state of anxiety and negative affect but also gives more veridical information about the subject's emotional state than verbal statements and facial expression. The measurement of displacement activities may be a useful complement to the physiological and psychological studies aimed at analyzing the correlates and consequences of stress.     

Factors influencing assignment of pronoun antecedents

In two experiments a group of adult subjects and a group of 10 – 13 year old subjects completed sentences of the format NP1 V NP2 because Pro… The fragment, John telephoned Bill because he…, elicited completions such as had good news, which locate the impetus for telephoning in NP1 (John). The fragment, John admired Bill because he…, elicited completions such as was a fine athlete, which locate the impetus for admiring in NP2 (Bill). The assignment of the subject pronoun of the second clause as coreferential with NP1 or NP2 shows that this choice depends on a factor, direction of causality, which may be assigned to verb roots. This factor was isolated from interacting semantic and syntactic features of sentences in which the verbs occurred. Manipulation of these features resulted in greater or lesser salience of the direction of causality factor. The potential of this technique for investigation of verb semantics and for interaction of semantic, pragmatic and syntactic features in the psychological study of comprehension is discussed.     

Foreperiod and stuttering severity effects on acoustic laryngeal reaction time

An earlier paper presented a model of the laryngeal reaction time (LRT) paradigm that included several factors that appeared to affect LRT values. The present study assesses the effects of two of these factors: foreperiod and stuttering severity. The former was assessed by the use of 13 foreperiod durations. The latter was assessed by classifying experimental subjects as either mild or severe stutterers. Both factors significantly affected LRT values. More importantly, these factors demonstrated a composite effect on group LRT differences. Specifically, mild stutterers' LRT values approached normal values as foreperiod increased, whereas severe stutterers' LRT values remained significantly greater than normal values at all foreperiods. Results are discussed in terms of differential posturing and/or vibration initiation deficits underlying stutterers' delayed LRT values. We caution that acoustic measurements alone are insufficient to specify fully the nature of the underlying deficits.     

A comparison of LRT and VOT values between stutterers and nonstutterers

The experiment reported here found no significant group differences in laryngeal reaction time (LRT) and voice onset time (VOT) values. Rank-order correlations between the stutterers' LRT and VOT values were also nonsignificant. A model of the LRT paradigm is presented that (1) allows for systematic assessment of factors possibly contributing to the failure to replicate the often reported LRT group difference, and (2) is useful in examining the relationship between the LRT experimental condition and normal speaking conditions. We argue that two factors were particularly critical to our results. First, simple reaction time procedures included (1) a warning signal that preceded a response signal by a variable 1–3-sec foreperiod, and (2) a single response. We argue that foreperiod durations exceeded the stutterers' speech posture time for a known response. Second, the stuttering severity rating of our experimental group was less severe than ratings in other experiments.     

Modality-independent impairments in word processing in a deep dyslexic patient

An extensive study of the language abilities of one deep dyslexic patient, B.L., was undertaken. Tests of his ability to comprehend and produce words in the auditory, verbal, and graphic modalities revealed striking similarities in performance across modalities, such that the defining symptoms of deep dyslexic reading also held true for this patient's writing, repetition, and naming. A new dual-deficit model of deep dyslexia is presented which predicts that a variety of “deep dyslexic” syndromes may occur with or without modality-specific impairments.     

Naive beliefs in “sophisticated” subjects: misconceptions about trajectories of objects

University students were asked to solve simple problems about the trajectories of falling objects. A majority of the students revealed a variety of misconceptions about motion. However, the few basic patterns of responses produced by the subjects suggest considerable commonality in the types of naive physical “laws” people develop on the basis of everyday experience with the world.