Monthly Archives: September 2009

Social cues, mentalizing and the neural processing of speech accompanied by gestures

Body orientation and eye gaze influence how information is conveyed during face-to-face communication. However, the neural pathways underpinning the comprehension of social cues in everyday interaction are not known. In this study we investigated the influence of addressing vs. non-addressing body orientation on the neural processing of speech accompanied by gestures.

While in an fMRI scanner, participants viewed short video clips of an actor speaking sentences with object- (O; e.g. shape) or person-related content (P; e.g. saying goodbye) accompanied by iconic (e.g. circle) or emblematic gestures (e.g. waving), respectively. The actor’s body was oriented either toward the participant (frontal, F) or toward a third person (lateral, L) not visible.

For frontal vs. lateral actor orientation (F>L), we observed activation of bilateral occipital, inferior frontal, medial frontal, right anterior temporal and left parietal brain regions. Additionally, we observed activity in the occipital and anterior temporal lobes due to an interaction effect between actor orientation and content of the communication (PF>PL)>(OF>OL).

Our findings indicate that social cues influence the neural processing of speech- gesture utterances. Mentalizing (the process of inferring the mental state of another individual) could be responsible for these effects. In particular, socially relevant cues seem to activate regions of the anterior temporal lobes if abstract person-related content is communicated by speech and gesture. These new findings illustrate the complexity of interpersonal communication, as our data demonstrate that multisensory information pathways interact at both perceptual and semantic levels.

from Neuropsychologia

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Right visual field advantage in parafoveal processing: Evidence from eye-fixation-related potentials

Readers acquire information outside the current eye fixation. Previous research indicates that having only the fixated word available slows reading, but when the next word is visible, reading is almost as fast as when the whole line is seen. Parafoveal-on-foveal effects are interpreted to reflect that the characteristics of a parafoveal word can influence fixation on a current word. Prior studies also show that words presented to the right visual field (RVF) are processed faster and more accurately than words in the left visual field (LVF). This asymmetry results either from an attentional bias, reading direction, or the cerebral asymmetry of language processing. We used eye-fixation-related potentials (EFRP), a technique that combines eye-tracking and electroencephalography, to investigate visual field differences in parafoveal-on-foveal effects. After a central fixation, a prime word appeared in the middle of the screen together with a parafoveal target that was presented either to the LVF or to the RVF. Both hemifield presentations included three semantic conditions: the words were either semantically associated, non-associated, or the target was a non-word. The participants began reading from the prime and then made a saccade towards the target, subsequently they judged the semantic association. Between 200 and 280 ms from the fixation onset, an occipital P2 EFRP-component differentiated between parafoveal word and non-word stimuli when the parafoveal word appeared in the RVF. The results suggest that the extraction of parafoveal information is affected by attention, which is oriented as a function of reading direction.

from Brain and Language

Does phonological short-term memory causally determine vocabulary learning? Toward a computational resolution of the debate

The relationship between nonword repetition ability and vocabulary size and vocabulary learning has been a topic of intense research interest and investigation over the last two decades, following the demonstration that nonword repetition accuracy is predictive of vocabulary size (Gathercole & Baddeley, 1989). However, the nature of this relationship is not well understood. One prominent account posits that phonological short-term memory (PSTM) is a causal determinant both of nonword repetition ability and of phonological vocabulary learning, with the observed correlation between the two reflecting the effect of this underlying third variable (e.g., Baddeley, Gathercole, & Papagno, 1998). An alternative account proposes the opposite causality: that it is phonological vocabulary size that causally determines nonword repetition ability (e.g., Snowling, Chiat, & Hulme, 1991). We present a theory of phonological vocabulary learning, instantiated as a computational model. The model offers a precise account of the construct of PSTM, of performance in the nonword repetition task, of novel word form learning, and of the relationship between all of these. We show through simulation not only that PSTM causally affects both nonword repetition accuracy and phonological vocabulary size, but also that phonological vocabulary size causally affects nonword repetition ability. The plausibility of the model is supported by the fact that its nonword repetition accuracy displays effects of phonotactic probability and of nonword length, which have been taken as evidence for causal effects on nonword repetition accuracy of phonological vocabulary knowledge and PSTM, respectively. Thus the model makes explicit how the causal links posited by the two theoretical perspectives are both valid, in the process reconciling the two perspectives, and indicating that an opposition between them is unnecessary.

from the Journal of Memory and Language

Age-related changes in the functional neuroanatomy of overt speech production

Alterations of existing neural networks during healthy aging, resulting in behavioral deficits and changes in brain activity, have been described for cognitive, motor, and sensory functions. To investigate age-related changes in the neural circuitry underlying overt non-lexical speech production, functional MRI was performed in 14 healthy younger (21–32 years) and 14 healthy older individuals (62–84 years). The experimental task involved the acoustically cued overt production of the vowel /a/ and the polysyllabic utterance /pataka/. In younger and older individuals, overt speech production was associated with the activation of a widespread articulo-phonological network, including the primary motor cortex, the supplementary motor area, the cingulate motor areas, and the posterior superior temporal cortex, similar in the /a/ and /pataka/ condition. An analysis of variance with the factors age and condition revealed a significant main effect of age. Irrespective of the experimental condition, significantly greater activation was found in the bilateral posterior superior temporal cortex, the posterior temporal plane, and the transverse temporal gyri in younger compared to older individuals. Significantly greater activation was found in the bilateral middle temporal gyri, medial frontal gyri, middle frontal gyri, and inferior frontal gyri in older vs. younger individuals. The analysis of variance did not reveal a significant main effect of condition and no significant interaction of age and condition. These results suggest a complex reorganization of neural networks dedicated to the production of speech during healthy aging.

from Neurobiology of Aging

Measures of Hearing Threshold and Temporal Processing across the Adult Lifespan

Psychophysical data on hearing sensitivity and various measures of supra-threshold auditory temporal processing are presented for large groups of young (18-35 y), middle-aged (40-55 y) and older (60-89 y) adults. Hearing thresholds were measured at 500, 1414 and 4000 Hz. Measures of temporal processing included gap-detection thresholds for bands of noise centered at 1000 and 3500 Hz, stimulus onset asynchronies for monaural and dichotic temporal-order identification for brief vowels, and stimulus onset/offset asynchronies for the monaural temporal masking of vowel identification. For all temporal-processing measures, the impact of high-frequency hearing loss in older adults was minimized by a combination of low-pass filtering the stimuli and use of high presentation levels. The performance of the older adults was worse than that of the young adults on all measures except gap-detection threshold at 1000 Hz. Middle-aged adults performed significantly worse than the young adults on measures of threshold sensitivity and three of the four measures of temporal-order identification, but not for any of the measures of temporal masking. Individual differences are also examined among a group of 124 older adults. Cognition and age were found to be significant predictors, although only 10-27% of the variance could be accounted for by these predictors.

from Hearing Research

Older Adults’ Recognition of Bodily and Auditory Expressions of Emotion

This study compared young and older adults’ ability to recognize bodily and auditory expressions of emotion and to match bodily and facial expressions to vocal expressions. Using emotion discrimination and matching techniques, participants assessed emotion in voices (Experiment 1), point-light displays (Experiment 2), and still photos of bodies with faces digitally erased (Experiment 3). Older adults’ were worse at least some of the time in recognition of anger, sadness, fear, and happiness in bodily expressions and of anger in vocal expressions. Compared with young adults, older adults also found it more difficult to match auditory expressions to facial expressions (5 of 6 emotions) and bodily expressions (3 of 6 emotions).

from Psychology and Aging

We Can Work It Out: Age Differences in Relational Pronouns, Physiology, and Behavior in Marital Conflict

This study examined the relationship that personal pronouns spoken during a marital conversation have with the emotional qualities of those interactions and with marital satisfaction. Middle-aged and older couples (N = 154) engaged in a 15-min conflict conversation during which physiology and emotional behavior were continuously monitored. Verbatim transcripts of the conversations were coded into 2 lexical categories: (a) we-ness (we-words), pronouns that focus on the couple; (b) separateness (me/you-words), pronouns that focus on the individual spouses. Analyses revealed that greater we-ness was associated with a number of desirable qualities of the interaction (lower cardiovascular arousal, more positive and less negative emotional behavior), whereas greater separateness was associated with a less desirable profile (more negative emotional behavior, lower marital satisfaction). In terms of age differences, older couples used more we-ness words than did middle-aged couples. Further, the associations between separateness and marital satisfaction were strongest for older wives. These findings indicate that the emotional aspects of marital quality are expressed in the natural language of couples engaged in conversation.

from Psychology and Aging

Body Schemantics: On the role of the body schema in embodied lexical-semantic representations

Words denoting manipulable objects activate sensorimotor brain areas, likely reflecting action experience with the denoted objects. In particular, these sensorimotor lexical representations have been found to reflect the way in which an object is used. In the current paper we present data from two experiments (one behavioral and one neuroimaging) in which we investigate whether body schema information, putatively necessary for interacting with functional objects, is also recruited during lexical processing. To this end, we presented participants with words denoting objects that are typically brought towards or away from the body (e.g., cup or key, respectively). We hypothesized that objects typically brought to a location on the body (e.g., cup) are relatively more reliant on body schema representations, since the final goal location of the cup (i.e., the mouth) is represented primarily through posture and body co-ordinates. In contrast, objects typically brought to a location away from the body (e.g., key) are relatively more dependent on visuo-spatial representations, since the final goal location of the key (i.e., a keyhole) is perceived visually. The behavioral study showed that prior planning of a movement along an axis towards and away from the body facilitates processing of words with a congruent action semantic feature (i.e., preparation of movement towards the body facilitates processing of cup.). In an fMRI study we showed that words denoting objects brought towards the body engage the resources of brain areas involved in the processing information about human bodies (i.e., the extra-striate body area, middle occipital gyrus and inferior parietal lobe) relatively more than words denoting objects typically brought away from the body. The results provide converging evidence that body schema are implicitly activated in processing lexical information.

from Neuropsychologia

Aging and Fluency-Based Illusions in Recognition Memory

We examined age-related differences in susceptibility to fluency-based memory illusions. The results from 2 experiments, in which 2 different methods were used to enhance the fluency of recognition test items, revealed that older and young adults did not differ significantly in terms of their overall susceptibility to this type of memory illusion. Older and young adults were also similar in that perceptual fluency did not influence recognition memory responses when there was a mismatch in the sensory modality of the study and test phases. Likewise, a more conceptual fluency manipulation influenced recognition memory responses in both older and young adults regardless of the match in modality. Overall, the results indicate that older adults may not be more vulnerable than young adults to fluency-based illusions of recognition memory. Moreover, young and older adults appear to be comparable in their sensitivity to factors that modulate the influence of fluency on recognition decisions.

from Psychology and Aging

Aging, Hearing Acuity, and the Attentional Costs of Effortful Listening

A dual-task interference paradigm was used to investigate the effect of perceptual effort on recall of spoken word lists by young and older adults with good hearing and with mild-to-moderate hearing loss. In addition to poorer recall accuracy, listeners with hearing loss, especially older adults, showed larger secondary task costs while recalling the word lists even though the stimuli were presented at a sound intensity that allowed correct word identification. Findings support the hypothesis that extra effort at the sensory–perceptual level attendant to hearing loss has negative consequences to downstream recall, an effect that may be further magnified with increased age.

from Psychology and Aging

Eye Movements and the Perceptual Span in Older and Younger Readers

The size of the perceptual span (or the span of effective vision) in older readers was examined with the moving window paradigm (G. W. McConkie & K. Rayner, 1975). Two experiments demonstrated that older readers have a smaller and more symmetric span than that of younger readers. These 2 characteristics (smaller and more symmetric span) of older readers may be a consequence of their less efficient processing of nonfoveal information, which results in a riskier reading strategy.

from Psychology and Aging

Older Adults’ Recognition of Bodily and Auditory Expressions of Emotion

This study compared young and older adults’ ability to recognize bodily and auditory expressions of emotion and to match bodily and facial expressions to vocal expressions. Using emotion discrimination and matching techniques, participants assessed emotion in voices (Experiment 1), point-light displays (Experiment 2), and still photos of bodies with faces digitally erased (Experiment 3). Older adults’ were worse at least some of the time in recognition of anger, sadness, fear, and happiness in bodily expressions and of anger in vocal expressions. Compared with young adults, older adults also found it more difficult to match auditory expressions to facial expressions (5 of 6 emotions) and bodily expressions (3 of 6 emotions).

from Psychology and Aging

We Can Work It Out: Age Differences in Relational Pronouns, Physiology, and Behavior in Marital Conflict

This study examined the relationship that personal pronouns spoken during a marital conversation have with the emotional qualities of those interactions and with marital satisfaction. Middle-aged and older couples (N = 154) engaged in a 15-min conflict conversation during which physiology and emotional behavior were continuously monitored. Verbatim transcripts of the conversations were coded into 2 lexical categories: (a) we-ness (we-words), pronouns that focus on the couple; (b) separateness (me/you-words), pronouns that focus on the individual spouses. Analyses revealed that greater we-ness was associated with a number of desirable qualities of the interaction (lower cardiovascular arousal, more positive and less negative emotional behavior), whereas greater separateness was associated with a less desirable profile (more negative emotional behavior, lower marital satisfaction). In terms of age differences, older couples used more we-ness words than did middle-aged couples. Further, the associations between separateness and marital satisfaction were strongest for older wives. These findings indicate that the emotional aspects of marital quality are expressed in the natural language of couples engaged in conversation.

from Psychology and Aging

We Can Work It Out: Age Differences in Relational Pronouns, Physiology, and Behavior in Marital Conflict

This study examined the relationship that personal pronouns spoken during a marital conversation have with the emotional qualities of those interactions and with marital satisfaction. Middle-aged and older couples (N = 154) engaged in a 15-min conflict conversation during which physiology and emotional behavior were continuously monitored. Verbatim transcripts of the conversations were coded into 2 lexical categories: (a) we-ness (we-words), pronouns that focus on the couple; (b) separateness (me/you-words), pronouns that focus on the individual spouses. Analyses revealed that greater we-ness was associated with a number of desirable qualities of the interaction (lower cardiovascular arousal, more positive and less negative emotional behavior), whereas greater separateness was associated with a less desirable profile (more negative emotional behavior, lower marital satisfaction). In terms of age differences, older couples used more we-ness words than did middle-aged couples. Further, the associations between separateness and marital satisfaction were strongest for older wives. These findings indicate that the emotional aspects of marital quality are expressed in the natural language of couples engaged in conversation.

from Psychology and Aging

Can the Error Detection Mechanism Benefit from Training the Working Memory? A Comparison between Dyslexics and Controls — An ERP Study

Based on the relationship between working memory and error detection, we investigated the capacity of adult dyslexic readers’ working memory to change as a result of training, and the impact of training on the error detection mechanism.

Methodology
27 dyslexics and 34 controls, all university students, participated in the study. ERP methodology and behavioral measures were employed prior to, immediately after, and 6 months after training. The CogniFit Personal Coach Program, which consists of 24 sessions of direct training of working memory skills, was used.

Findings
Both groups of readers gained from the training program but the dyslexic readers gained significantly more. In the dyslexic group, digit span increased from 9.84±3.15 to 10.79±3.03. Working memory training significantly increased the number of words per minute read correctly by 14.73%. Adult brain activity changed as a result of training, evidenced by an increase in both working memory capacity and the amplitude of the Error-related Negativity (ERN) component (24.71%). When ERN amplitudes increased, the percentage of errors on the Sternberg tests decreased.

Conclusions
We suggest that by expanding the working memory capacity, larger units of information are retained in the system, enabling more effective error detection. The crucial functioning of the central-executive as a sub-component of the working memory is also discussed.

from PLoS ONE