Infant visual habituation and parental psychological distress

Research is equivocal concerning the relationship between parental psychological distress and infant cognitive functioning. Four potential limitations of the literature are addressed: reliance on mothers' but not fathers' psychological distress, use of categorical measures of psychological distress, use of standardized measures of infant cognitive functioning, and failure to take into account potential gender differences. Ninety‐nine twin pairs and both their mothers and fathers were assessed. Infants cognitive functioning was assessed using an infant‐controlled habituation–recovery–dishabituation task. Maternal and paternal psychological distress was assessed using the Symptom Check List‐90‐Revised. No gender differences were obtained for infant visual information‐processing abilities or parental psychological distress. Maternal and paternal psychological distress was related to female visual encoding abilities only. It was concluded that parental psychological distress might degrade parent–infant interactions. Characteristics of girls when faced with parents exhibiting psychiatric difficulties may exacerbate difficulties of parent–infant interactions, thereby hindering the full development of cognitive abilities involved in the process of habituation. A need exists to examine the relationship between parental psychological distress and infant visual attention separately for girls and boys. ©2001 Michigan Association for Infant Mental Health.     

Levels of processing with free and cued recall and unilateral temporal lobe epilepsy

This study investigates the role of the temporal lobes in levels-of-processing tasks (phonetic and semantic encoding) according to the nature of recall tasks (free and cued recall). These tasks were administered to 48 patients with unilateral temporal epilepsy (right "RTLE"=24; left "LTLE"=24) and a normal group (n=24). The results indicated that LTLE patients were impaired for semantic processing (free and cued recall) and for phonetic processing (free and cued recall), while for RTLE patients deficits appeared in free recall with semantic processing. It is suggested that the left temporal lobe is involved in all aspects of verbal memory, and that the right temporal lobe is specialized in semantic processing. Moreover, our data seem to indicate that RTLE patients present a retrieval processing impairment (semantic condition), whereas the LTLE group is characterized by encoding difficulties in the phonetic and semantic condition.     

MANULEX: A grade-level lexical database from French elementary school readers

This article presents MANULEX, a Web-accessible database that provides grade-level word frequency lists of nonlemmatized and lemmatized words (48,886 and 23,812 entries, respectively) computed from the 1.9 million words taken from 54 French elementary school readers. Word frequencies are provided for four levels: first grade (G1), second grade (G2), third to fifth grades (G3-5), and all grades (G1-5). The frequencies were computed following the methods describedby Carroll, Davies, and Richman (1971) and Zeno, Ivenz, Millard, and Duwuri (1995), with four statistics at each level (F, overall word frequency;D, index of dispersion across the selectedreaders;U, estimated frequencyper million words; andSFI, standard frequency index). The database also provides the number of letters in the word and syntactic category information. MANULEX is intended to be a useful tool for studying language development through the selection of stimuli based on precise frequency norms. Researchers in artificial intelligence can also use it as a source of information on natural language processing to simulate written language acquisition in children. Finally, it may serve an educational purpose by providing basic vocabulary lists.     

Alzheimer's disease disrupts arithmetic fact retrieval processes but not arithmetic strategy selection

Three groups of healthy younger adults, healthy older adults, and probable AD patients, performed an addition/number comparison task. They compared 128 couples of additions and numbers (e.g., 4 + 9 15) and had to identify the largest item for each problem by pressing one of two buttons located under each item. Manipulations of problem characteristics (i.e., problem difficulty and splits between correct sums and proposed numbers) enabled us to examine strategy selection and specific arithmetic fact retrieval processes. Results showed that arithmetic facts retrieval processes, which were spared with aging, were impaired in AD patients. However, AD patients were able to switch between strategies across trials according to problem characteristics as well as healthy older adults, and less systematically than healthy younger adults. We discuss implications of these findings for further understanding AD-related differences in arithmetic in particular, and problem solving in general.     

Effects of sleep deprivation on Color-Word, Emotional, and Specific Stroop interference and on self-reported anxiety

The aim of this study was principally to assess the impact of sleep deprivation on interference performance in short Stroop tasks (Color-Word, Emotional, and Specific) and on subjective anxiety. Subjective sleepiness and performance on a psychomotor sustained attention task were also investigated to validate our protocol of sleep deprivation. Twelve healthy young subjects were tested at four-hourly intervals through a 36-h period of wakefulness under a constant routine protocol. Analyses of variance for repeated measurements revealed that self-assessment of sleepiness on a visual analogue scale as well as mean reaction time performance on the sustained attention task, both for the first minute and for 10 min of testing, were worsened by sleep deprivation. Analyses revealed an increase in self-reported anxiety scores on the STAI questionnaire but did not reveal any significant effect after sleep deprivation either on indexes of interference or on accuracy in Stroop tasks. However, analyses showed sensitivity to circadian effect on verbal reaction times in the threat-related (Emotional) and sleep-related (Specific) Stroop tasks. We concluded that 36 h of prolonged wakefulness affect self-reported anxiety and Emotional Stroop task resulting in a cognitive slowing. Moreover, total sleep deprivation does not affect interference control in any of the three short Stroop tasks.     

The discrimination of temporal fine structure in call-like harmonic sounds by birds

Thresholds for discriminating changes in the temporal fine structure of call-like, harmonic sounds were measured in zebra finches (Taeniopygia guttata) and budgerigars (Melopsittacus undulatus). Birds could detect changes in periods as short as 1.225 ms at near 100% accuracy even when spectral and envelope cues were identical, as in time-reversed stimuli. Humans performed poorly on such stimuli, paralleling results from previous studies. Bird thresholds were in the range of those reported in neurophysiological studies of the songbird high vocal center (HVC) to temporally modified conspecific songs. Taken together, these results show that birds can hear differences in temporal fine structure in their natural vocalizations that go beyond human capabilities, but whether these abilities have communicative relevance remains to be seen.     

Decision making and interference in the domestic cat (Felis catus)

Domestic cats (Felis catus) received a task in which an obstacle was introduced at the time they were ready to reach for 1 among 2 or 3 baited targets. The results revealed that when the initially chosen direction (i.e., before the introduction of the obstacle) and the new one were orthogonal, the cats reassessed distance, angular deviation, and visibility once they had turned around the obstacle (Experiments 1, 2, and 3). Then the cats chose a different target than the one that would have been chosen had there been no obstacle. When both the initially chosen and the new direction matched (Experiment 4), the cats kept intact their initial decision. The discussion focuses on the nature of the representational system of the cat. The discussion also emphasizes comparisons with dogs (i.e., cooperative hunters).