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.     

Schizophrenia-like syndrome inducing agent phencyclidine failed to impair memory for temporal order in rats

Although subchronic phencyclidine (PCP) administration is recognized as a probative method to model schizophrenia-like symptoms in animals, only a few sets of data support the hypothesis of a cognitive prefrontal cortex (PFc) dysfunction in PCP-treated monkeys and rodents. Two experiments were here conducted to further test the integrity of prefrontal function in two versions of a memory for temporal order (MTO) task administered to rats. Original versions of this task elaborated by Kesner repeatedly yielded moderate to severe performance deficits in PFc lesioned rats. MTO assessment in an eight-arm radial maze consisted in a recency discrimination between two arms previously explored in the context of sequential forced choices. In Experiment 1, 16 naive Long-Evans rats were pre-trained on a variable version of the MTO task involving randomly re-mixed sequences until they reached a group criterion. Then, rats were treated daily for 21 days with PCP (10mg/kg) or saline vehicle and were tested on the same task approximately 20 h after an injection. The performance of the groups did not differ. In Experiment 2, 16 naive Long-Evans rats untrained prior to treatment received 27 daily injections of either PCP (10mg/kg) or saline vehicle and were tested, 20 h after each injection, on a constant version of the MTO task. This time, a fixed set of four sequences of successive arm entries was repeated within each daily session as well as across days. Again, prolonged PCP exposure failed to impair discrimination of temporal order despite the stability of sequential information over time. These negative results are not consistent with long-lasting hypofrontality, a major landmark of human schizophrenia, in the PCP rat model.     

Tactful or doubtful? Expectations of politeness explain the severity bias in the interpretation of probability phrases

When a statement about the occurrence of a medical condition is qualified by an expression of probability, such as the word possible, listeners interpret the probability of the condition as being higher the more severe the condition. This severity bias can have serious consequences for the well-being of patients. We argue that the bias is due to a misconception of the pragmatic function served by the expression of probability. The more severe the condition, the greater the chance that the listener construes the expression as a politeness marker rather than as an uncertainty marker. When this misconception does not occur, neither should the severity bias. An analysis of interpretations of probability expressions using a membership-function approach validates this account. We discuss the consequences of this bias for the communication of risk within and outside the medical domain.     

Delayed masking and the auditory attentional blink: A test for retrieval competition and bottleneck models

The attentional blink (AB) corresponds to a transient deficit in reporting the second (T2) of two targets embedded in a rapid sequence of distractors. The retrieval competition (Shapiro, Raymond & Arnell, 1994) and bottleneck models (Chun & Potter, 1995; Jolicoeur, 1998) predict the attenuation of the deficit with the extension of the delay between T2 and its mask. This prediction was tested using auditory sequences of nonverbal stimuli in which the T2-mask interval was systematically varied. The magnitude of the auditory AB diminished with the lengthening of the interval from 50 to 150 ms while no time-locked deficit was observed with the longest (350 ms) and the shortest (10 ms) intervals. These results suggest that presenting a mask after T2 is not sufficient to produce an auditory AB: The mask must be perceivable as an auditory event distinct from the target and occur before T2 consolidation. The present study also provides evidence that as in vision, AB deficits take place in the auditory domain when T2 is masked by interruption but not by integration. Our findings are best accounted for in terms of bottlenecked processing limitations.     

The capacity of visual short-term memory within and between hemifields

Visual short-term memory (VSTM) and attention are both thought to have a capacity limit of four items [e.g. Luck, S. J., & Vogel, E. K. (1997). The capacity of visual working memory for features and conjunctions. Nature, 309, 279-281; Pylyshyn, Z. W., & Storm, R. W. (1988). Tracking multiple independent targets: evidence for a parallel tracking mechanism. Spatial Vision, 3, 179-197.]. Using the multiple object visual tracking paradigm (MOT), it has recently been shown that twice as many items can be simultaneously attended when they are separated between two visual fields compared to when they are all presented within the same hemifield [Alvarez, G. A., & Cavanagh, P. (2004). Independent attention resources for the left and right visual hemifields (Abstract). Journal of Vision, 4(8), 29a.]. Does VSTM capacity also increase when the items to be remembered are distributed between the two visual fields? The current paper investigated this central issue in two different tasks, namely a color and spatial location change detection task, in which the items were displayed either in the two visual fields or in the same hemifield. The data revealed that only memory capacity for spatial locations and not colors increased when the items were separated between the two visual fields. These findings support the view of VSTM as a chain of capacity limited operations where the spatial selection of stimuli, which dominates in both spatial location VSTM and MOT, occupies the first place and shows independence between the two fields.     

Stability of attachment during the preschool period

Children's attachment patterns at early preschool age and 2 years later as well as factors related to stability-instability were examined in a diverse socioeconomic status French Canadian sample of 120 children. Attachment was assessed during 2 laboratory visits using separation-reunion procedures when the children were approximately 3.5 (J. Cassidy & R. S. Marvin, 1992) and 5.5 (M. Main & J. Cassidy, 1988) years old. Overall, stability of attachment, based on 4-way classification, was moderate (68%, k = .47, p = .01). Change from security to disorganization was associated with the most dramatic decline in interactive quality with mother, lowest marital satisfaction, and greatest likelihood of severe attachment-related family events, namely, loss and parental hospitalization. Families of children who changed from security to organized insecurity presented levels of caregiving and marital dissatisfaction that fell between those of stable secure children and secure children who changed toward disorganization.     

Effects of bilingual and monolingual presentations and time on concept- and language-matching tasks

Balanced Turkish-English bilingual participants viewed word pairs, presented both monolingually (English-English or Turkish-Turkish) or bilingually (English-Turkish or Turkish-English) and both for short and long durations. They made decisions on whether the simultaneously presented words in a pair were in the same language or not, or whether they denoted the same concept or not. In the short presentation condition, we found no evidence for subliminal processing. In cases in which both words were consciously identified, participants were more accurate, although not faster in the long than in the short presentation condition for both language and concept decisions. In the long presentation condition, language decisions were more accurate than concept decisions, although not faster. In addition, language decisions were not affected by whether the words were synonyms (concept identity), and concept decisions were not affected by whether the presentation was monolingual or bilingual (language identity), although in the monolingual conditions, "same" decisions were faster but not more accurate, and in the bilingual conditions a speed-accuracy trade-off was observed in that "same" decisions were faster but "different" decisions were more accurate.     

Unilateral nostril breathing in intraocular pressure of right-handed healthy subjects

The effects of unilateral forced nostril breathing on the intraocular pressures of right and left eyes was studied in 24 male and 26 female right-handed adults. In men, the forced breathing through both the right and left nostrils significantly decreased the intraocular pressures of both right and left eyes. For women, the forced breathing through right nostril did not affect the intraocular pressures of right and left eyes, and the forced breathing through left nostril also had no effect on the intraocular pressure of right eye, although it decreased the intraocular pressure of left eye significantly. These results show that unilateral forced nostril breathing decreases intraocular pressure especially in men, perhaps increasing sympathetic nervous system activity.     

From "logographic" to normal reading: the case of a deaf beginning reader

Visual word recognition of a profoundly deaf girl (AH) with developmental reading disorders was explored using an experimental technique that measures performance as a function of eye fixation within a word. AH's fixation-dependent word recognition profile revealed that she was inferring the identity of words using a "logographic" reading strategy (i. e., using salient visual features). Following this observation a special training program that enhances the understanding of grapheme-phoneme relations was applied. After few months of training, AH's reading skills improved, while her fixation-dependent performance changed to become like that of normal readers. We discuss the impact of our technique for the early diagnosis of reading impairments.