Carole Berger

A case study of developmental phonological dyslexia: Is the attentional deficit in the perception of rapid stimuli sequences amodal?

The attentional blink (AB) refers to a decrease in accuracy that occurs when participants are required to detect the second of two rapidly sequential targets displayed randomly in a stream of distracters. Dyslexic individuals have been shown to exhibit a prolonged AB in the visual modality, interpreted as evidence of sluggish attentional shifting (SAS). However, the amodal SAS theory predicts that the disorder should further extend to the auditory modality, then resulting in a phonological disorder as typically found in developmental dyslexia. Otherwise, it has been demonstrated that a visual attention (VA) span deficit contributes to the poor reading outcome of dyslexic individuals, independently of their phonological skills. The present study assesses the amodality assumption of the SAS theory together with questioning its relation with the VA span deficit. For this purpose, visual and auditory ABs were explored in a well compensated young adult, LL, who exhibits a pure phonological dyslexia characterised by poor pseudo-word processing and poor phonological skills but preserved VA span. The investigation revealed two different kinds of deficits in LL. Her AB was prolonged and marginally deeper in the visual modality whereas a primarily deeper in amplitude and a subtle prolonged AB was found in the auditory modality. The atypical performance patterns of LL in both modalities suggest that her perceptual attention disorder is amodal as predicted by the SAS theory. This amodal disorder was here reported in a dyslexic participant with a phonological disorder, well in accordance with the hypothesis that sluggish auditory attention shifting contributes to difficulties in phoneme awareness and literacy acquisition. Furthermore, prolonged VA blink was observed in the absence of VA span disorder, thus suggesting that visual attentional shifting and VA span might be distinct mechanisms, contributing independently to reading acquisition and developmental dyslexia.

Dimensional and overall similarity classifications in haptics: A developmental study

The developmental change from global towards dimensional classifications, usually observed in vision, was investigated in haptics with stimuli varying according to their size and roughness. Children aged 5 and 9 years old and adults were presented with a free classification task allowing either an overall similarity sorting or a dimensional sorting. In two experiments, the discriminability of the stimuli along one or both dimensions was varied. Results showed that although more overall similarity classifications were observed in children than in adults, this kind of classification was never dominant (i.e., it was nerve chosen more frequently than would be predicted by chance). In addition to these developmental effects, effects due to the magnitude of stimulus difference were observed: A stimulus tended to be matched with the standard especially if it was slightly different from it or if the other comparison objects were much more different from this standard. This appeared in the first experiment testing dimensional versus overall similarity matching, and in the second experiment testing dimensional size versus dimensional roughness matching. These results were discussed with reference to the characteristics of haptic exploratory procedures.

Dynamic categorization and slot-filler representation in 4- and 6-year-old children

This experiment was aimed at studying both the role of narrow/contextualized categories in the acquisition/organization of conceptual knowledge and the dynamics of categorization decisions. A forced-choice categorization task contrasting thematic and taxonomic responding was used in 4- and 6-year-old children. Before response alternatives were presented, a conceptual organization was pre-activated by means of a matching between the target stimulus and a thematically related, taxonomically related or slot-filler related object. Although taxonomic sorting was prominent overall, it varied as a function of age and of the nature of the pre-activated relation. Responses in accordance with the thematic or taxonomic activations occurred similarly in 4- and 6-year-old children. Age-related effects were however at work in the case of a slot-filler activation: 4-year-old children considered the contextual/contiguity relations between the stimuli but did not weight the equivalence relations (i.e., same occurrence of responses based on the kind of object in the slot-filler and in the thematic activation conditions). More diversified processes appeared to be at work in 6-year-old children. Slot-filler categories were this time considered throughout both their contextual/contiguity structure and their equivalence relations. Results were discussed in terms of availability of conceptual organizations, flexibility abilities, dynamic categorization and preferences. The focus was on implication of slot-filler representations in the construction of conceptual knowledge and in the development of categorization. An important point was to determine whether the age-related changes observed in the slot-filler activation condition could be consistent with Nelsons ( 1983 ) idea that slot-fillers would help passing from a schema-based to a conventional superordinate organization.

Audio-Visual Perception of Gender by Infants Emerges Earlier for Adult-Directed Speech

Early multisensory perceptual experiences shape the abilities of infants to perform socially-relevant visual categorization, such as the extraction of gender, age, and emotion from faces. Here, we investigated whether multisensory perception of gender is influenced by infant-directed (IDS) or adult-directed (ADS) speech. Six-, 9-, and 12-month-old infants saw side-by-side silent video-clips of talking faces (a male and a female) and heard either a soundtrack of a female or a male voice telling a story in IDS or ADS. Infants participated in only one condition, either IDS or ADS. Consistent with earlier work, infants displayed advantages in matching female relative to male faces and voices. Moreover, the new finding that emerged in the current study was that extraction of gender from face and voice was stronger at 6 months with ADS than with IDS, whereas at 9 and 12 months, matching did not differ for IDS versus ADS. The results indicate that the ability to perceive gender in audiovisual speech is influenced by speech manner. Our data suggest that infants may extract multisensory gender information developmentally earlier when looking at adults engaged in conversation with other adults (i.e., ADS) than when adults are directly talking to them (i.e., IDS). Overall, our findings imply that the circumstances of social interaction may shape early multisensory abilities to perceive gender.

Is the impairment in temporal allocation of visual attention in children with ADHD related to a developmental delay or a structural cognitive deficit

We investigated the temporal allocation of visual attention in 11-year-old children with attention-deficit/hyperactivity disorder (ADHD) by comparing their attentional blink (AB) parameters (duration, amplitude and minimum performance) with those observed in three groups of healthy control participants (8-year-olds, 11-year-olds and adults). The AB is a marker of impaired ability to detect a second target following the identification of a first target when both appear randomly within a rapid sequence of distractor items. Our results showed developmental effects; with age, the AB duration decreased and the AB minimum moved to shorter lag times. Importantly, 11-year old children with ADHD presented much the same similar AB patterns (in terms of duration and minimum position) as the healthy 8-year-old controls. Our results support the hypothesis whereby impaired allocation of temporal selective attention in children with ADHD is due to a developmental delay and not a specific cognitive deficit.

Age-Related Changes in Temporal Allocation of Visual Attention: Evidence From the Rapid Serial Visual Presentation (RSVP) Paradigm

The present study explored the temporal allocation of attention in groups of 8-year-old children, 10-year-old children, and adults performing a rapid serial visual presentation task. In a dual-condition task, participants had to detect a briefly presented target (T2) after identifying an initial target (T1) embedded in a random series of distractors. A single-condition control task required participants to detect T2 without first identifying T1. The attentional blink (AB) reflects impairments in T2 detection due to the previous identification of T1. Although the amplitude of the AB (difference in T2 detection performance between the single task and the dual task) was found to be similar across age groups, its temporal expression (as a function of the T1–T2 lag) differed across age groups. Our results revealed age-related changes a) in the duration of the first lag(s) sparing effect (longer in the younger age groups), b) in the peak position of the AB (temporal displacement toward later lags in the younger age groups), and c) in the width of the AB (T2 impairments occurring for T1–T2 intervals of 400 ms and 500 ms in 8-year-old children, 300 ms in 10-year-old children, and 200 ms and 300 ms in adults). We discuss these differences in terms of changes in the efficiency of perceptual selection and inhibitory processes (attentional gating mechanisms) during development.

Children's consideration of relevant and non-relevant facial features in kinship detection

The aim of this study was to clarify the understanding of biological inheritance in children (ages 5, 7, 9 and 11) and adults by using a new methodological approach. In a perceptual task, participants were asked to match the photo of a newborns face with the one of his/her mothers face, shown along with two other non-kin female faces. The non-kin female faces were either neutral, since they had no perceptual similarity to the newborns face (control condition), or shared with the target newborns face a salient perceptual facial feature irrelevant to kin detection, e.g., head orientation, open/closed eyes or mouth (experimental condition). Results showed that children could efficiently detect the mothers face by the age of 9 (control condition). Difficulties ignoring irrelevant salient perceptual properties occurred up to age 9 (experimental condition). We discussed whether these results could correspond to progressive conceptual changes in the understanding of inheritance.