Task specificity in age-related slowing: word production versus conceptual comparison.

We analyzed age-related slowing in 29 younger (M = 22 years) and 30 older adults (M = 70 years) who performed a conceptual comparison task, a naming task, and a simple reaction time task. Both vocal and manual responses were elicited in all except the naming task. Results did not support the hypothesis that there is greater age-related slowing in comparison tasks than in production tasks. In contrast, we found an interaction between age and response modality in the conceptual comparison task. Response latencies of younger participants were shorter in the manual modality whereas those of older participants were shorter in the vocal modality. In the simple reaction time task manual responses were faster in the two age groups. These findings are discussed in relation to models assuming task-specific slowing factors.

Why do picture naming latencies increase with age: general slowing, greater sensitivity to interference, or task-specific deficits?

To test different hypotheses about age-related slowing of word and picture naming, response latencies of young and older adults were compared in 2 experiments using the same 4 tasks: picture naming, written word pronunciation, and picture and word categorization. In each case, the target word or picture was presented with a distractor word that had to be ignored. Analyses showed the expected main effects of age, modality, and interference conditions but no consistent interaction between age and other factors. More particularly, age-related slowing was similar in word and picture processing and interference was proportional to overall speed of responding. Thus, no support was found for the hypotheses assuming either declining inhibitory mechanisms or task-specific deficits in older adults. These results were discussed in relation to characteristics of the experimental tasks.

A meta-analytic procedure shows an age-related decline in picture naming: comments on Goulet, Ska, and Kahn (1994).

In the conclusion of their review of the literature, Goulet, Ska, and Kahn (1994) found no clear evidence that picture-naming accuracy declines with advancing age. However, another conclusion can be drawn if one considers the subset of studies in which means and standard deviations of picture-naming accuracy are reported for different age groups: below 50, between 50 and 69, and from 70 years of age upwards. A meta-analysis of these data showed that naming accuracy was similar in the younger and the intermediate groups but that the performance of the older group was significantly different from that of the younger groups. Thus, the problem of inconsistencies in research findings can be resolved when meta-analytic methods are used.

The behavioural cues of familiarity during social interactions among human adults: A review of the literature and some observations in normal and demented elderly subjects.

The present paper deals with the non-verbal expression of individual recognition in normal and pathological populations. In the first part, the literature on non-verbal communication is surveyed with a selective attention given to observational studies comparing encounters between friends and between strangers in young adult subjects. To begin with, it is shown that in some cases external observers can discriminate above chance level silent films showing interactions between familiar and unfamiliar persons. Then, potential cues enabling such a performance are searched for by analysis of familiarity effects on interpersonal distance, touching gesture, visual and postural orientation, and facial or manual movements expressing affiliation or reticence. Finally, these observations are discussed in relation to several underlying processes: learning of interaction rules, involvement of an affiliative motivational system, and regulation of arousal. The problem of assessing the directionality of the familiarity effects is also raised. The second part of the paper addresses the issue of non-verbal expression of recognition in subjects who show impaired person recognition in the verbal modality. A pilot study compares the behaviour of older institutionalised women, either normal or suffering from senile dementia of the Alzheimer's type, during conversations with a member of the medical team and with another unfamiliar person. The methodological problems raised by the planning of the experimental situation are discussed.

The operativity effect in naming: a re-analysis.

According to Howard Gardner (1973), operativity, i.e. the extent to which it is possible to act with or upon an object, influences picture naming by aphasic subjects. In the present study, this influence is analysed with three purposes: (1) to replicate the Gardner's observation, (2) to avoid methodological biases and to extend the analyses, and (3) to look for alternative explanations. Sixty-four pictures corresponding to high- and low-frequency nouns rated as high or low in operativity were presented to 18 aphasic subjects. Frequency and operativity were found to significantly affect naming performance. More particularly, fewer semantic paraphasias were observed in confrontation with operative items and fewer phonemic paraphasias in the production of frequent nouns. However, the influence of operativity on the reduction of errors disappeared when age-of-acquisition and picture familiarity were introduced as co-variables. These dimensions were found to be better predictors of aphasic performance than operativity.

On fluency measures in aphasic speech.

This study was conducted with two purposes. First, to examine the extent to which fluency measures are affected by conditions of speech production. The speech of an unselected sample of 18 aphasic subjects was collected in two situations: conversation and description of short picture stories. Words were uttered at a reduced rate in the story descriptions, which were also characterized by a greater use of verbs. However, the ranking of the subjects on the different measures of fluency was correlated in the two situations. The second aim was to analyze the relationship between different fluency measures: mean silence duration, speech tempo, subjective evaluation of fluency, and the use of grammatical morphemes. Rankings of the subjects on these measures were compared. The different indicators of fluency were positively correlated with each other. Moreover, clinical evaluations of fluency by Belgian and American clinicians were correlated with the objective measures. However, fluency measures did not correlate with the percentage of content words. Thus, reduction of fluency did not seem to be related to a selective loss of function words.

A case of prosopagnosia with some preserved covert remembrance of familiar faces.

This paper presents the detailed analysis of a case of prosopagnosia in a 54-year-old male farmer following bioccipital vascular disease. In-depth clinical investigations confirmed the diagnosis of prosopagnosia and revealed the absence of any associated defect, except for a slight aspecific disturbance of the short-term memory. Further study of this case indicated that the trouble was not concerned with the class of complex visual stimuli, was not even concerned with facial expressions or unknown faces, was not a perceptual defect, but was related mainly to the operation of individualization. The memory hypothesis was thus retained and supported. Moreover, exploration of the difficulty indicated that the deficiency was limited to defective access to conscious information concerning faces and information associated with these faces (name, context, etc.), effectively stored in memory.

Decoding paralinguistic signals: effect of semantic and prosodic cues on aphasics' comprehension.

A matching task between sentences voiced with joyful, angry, or sad intonation and pictures of facial expressions representing the same emotions is proposed to 27 aphasics and 20 normal subjects. Semantic contents are either meaningless, neutral, or affectively loaded. In the affective-meaning condition, content is redundant with prosody or conflicting with it. Results are 1. a greater number of nonprosodic choices in the aphasic group; 2. an identical influence of the congruence/conflict variable on aphasic and control subjects; 3. an identical influence of the semantic content of the conflict sentences on both groups. Aphasic impairment is interpreted as purely quantitative, since affective semantic content influences the decoding of the sentences.