A method for quantifying focused versus overview behavior in AOI sequences

We present a new measure for evaluating focused versus overview eye movement behavior in a stimulus divided by areas of interest. The measure can be used for overall data, as well as data over time. Using data from an ongoing project with mathematical problem solving, we describe how to calculate the measure and how to carry out a statistical evaluation of the results.     

The role of personal values and basic traits in perceptions of the consequences of immigration: a three-nation study

Using data from Italy, Spain, and Germany (N= 1,569), this study investigated the role of basic values (universalism and security) and basic traits (openness and agreeableness) in predicting perceptions of the consequences of immigration. In line with Schwartz's (1992) theory, we conceptualized security as having two distinct components, one concerned with safety of the self (personal security) and the other with harmony and stability of larger groups and of society (group security). Structural equation modelling revealed that universalism values underlie perceptions that immigration has positive consequences and group security values underlie perceptions that it has negative consequences. Personal security makes no unique, additional contribution. Multi-group analyses revealed that these associations are invariant across the three countries except for a stronger link between universalism and perceptions of the consequences of immigration in Spain. To examine whether values mediate relations of traits to perceptions of immigration, we used the five-factor model. Findings supported a full mediation model. Individuals' traits of openness and agreeableness explained significant variance in security and universalism values. Basic values, in turn, explained perceptions of the consequences of immigration.     

A bilingual advantage in visual language discrimination in infancy

The origins of the bilingual advantage in various cognitive tasks are largely unknown. We tested the hypothesis that bilinguals' early capacities to track their native languages separately and learn about the properties of each may be at the origin of such differences. Spanish-Catalan bilingual and Spanish or Catalan monolingual infants watched silent video recordings of French-English bilingual speakers and were tested on their ability to discern when the language changed from French to English or vice versa. The infants' performance was compared with that of previously tested French-English bilingual and English monolingual infants. Although all groups of monolingual infants failed to detect the change between English and French, both groups of bilingual infants succeeded. These findings reveal that bilingual experience can modulate the attentional system even without explicit training or feedback. They provide a basis for explaining the ontogeny of the general cognitive advantages of bilinguals.     

Sleep-dependent consolidation of procedural motor memories in children and adults: the pre-sleep level of performance matters

In striking contrast to adults, in children sleep following training a motor task did not induce the expected (offline) gain in motor skill performance in previous studies. Children normally perform at distinctly lower levels than adults. Moreover, evidence in adults suggests that sleep dependent offline gains in skill essentially depend on the pre-sleep level of performance. Against this background, we asked whether improving children's performance on a motor sequence learning task by extended training to levels approaching those of adults would enable sleep-associated gains in motor skill in this age group also. Children (4-6 years) and adults (18-35 years) performed on the motor sequence learning task (button-box task) before and after ~2-hour retention intervals including either sleep (midday nap) or wakefulness. Whereas one group of children and adults, respectively, received the standard amount of 10 blocks of training before retention intervals of sleep or wakefulness, a further group of children received an extended training on 30 blocks (distributed across 3 days). A further group of adults received a restricted training on only two blocks before the retention intervals. Children after standard training reached lowest performance levels, whereas in adults performance after standard training was highest. Children with extended training and adults after reduced training reached intermediate performance levels. Only at these intermediate performance levels did sleep induce significant gains in motor sequence skill, whereas performance did not benefit from sleep in the low-performing children or in the high-performing adults. Spindle counts in the post-training nap were correlated with performance gains at retrieval only in the adults benefitting from sleep. We conclude that, across age groups, sleep induces the most robust gain in motor skill at an intermediate pre-sleep performance level. In low-performing children sleep-dependent improvements in skill may be revealed only after enhancing the pre-sleep performance level by extended training.     

Multiple mechanisms for recency with vowels and consonants

Three experiments were conducted to test the hypothesis that the difference in recency effect between vowel-contrasting and stop-contrasting lists of syllables in immediate ordered recall can be explained by item discriminability and regular short-term memory mechanisms, without any recourse to echoic memory or precategorical acoustic storage (PAS). In Experiment 1, the short-term memory mechanisms were manipulated by reducing amount of output interference and length of retention interval. The partial-report technique was used. The most important finding was the usual final-position recency effect (difference in recall between the fifth and sixth serial positions) for the vowel lists but not for the stop lists, regardless of the type of report. Thus the PAS theory could not be rejected. In Experiments 2 and 3, the last item was differentiated from the other items of the list, either by lengthening the interstimulus interval between the last and the next-to-last (Experiment 2) or by increasing the intensity of the last item (Experiment 3). In both cases, an increase of the final-position recency effect was found even for stop lists. Since a drop in recall errors was also obtained for the fourth item when its intensity was increased (von Restorff effect), this final-position recency effect for stop lists is likely to be due to item discriminability, and not to echoic memory for the last item. Item discriminability appeared to be the critical factor.     

Anxiety, perceptual and motor skills in an underwater environment

This research has analyzed the perceptual and motor skills in an underwater environment at 30 m of 24 subjects differing in diving experience. The State-Trait Anxiety Inventory, Form X-1, was administered to evaluate possible changes in anxiety associated with hyperbaric conditions during the perceptual and motor task. Analysis indicates that in comparison with experienced divers, less experienced divers showed a performance decrement. No changes in anxiety were observed.     

The processing of negative sentences in fluent aphasics: semantic and pragmatic aspects.

This paper examines the processing of negative sentences with respect to their truth value in fluent aphasic subjects. Three groups of 25 subjects each (men and women) were studied: the first group consisted of fluent aphasics, the second consisted of right temporal lobe-damaged subjects, and the third of normal subjects. An experiment of sentence verification was carried out. A quantitative study of reaction time (RT) and a qualitative study of the types of answers were carried out. The results show that the fluent aphasics were impaired in their logical-semantic processing of negative sentences and showed a predilection for the affirmative in answering strategies. The right temporal lobe-damaged subjects showed differences only in respect to the normal subjects in the RT, but not in answering strategies. The results suggest that in Wernicke's Aphasics there is a tendency to substitute a type of contextual-pragmatic processing for the logical-semantic processing.     

Splitting focal attention.

The study was based on the inverse relationship between the effect of attention on reaction time (RT) and the size of the area over which focal attention is allocated. Independent occurrence of this in 2 locations in the opposite hemifields would be evidence of attention splitting. In Experiment 1, in which the 2 locations were denoted by empty boxes, there was an inverse relationship between size of the stimulated box and RT. Experiment 2 replicated the finding with different stimulation conditions. In Experiment 3, no relationship was found between RT and length of a cuing line. In Experiment 4, in which attention was manipulated by central cues, there was an effect of box size on valid and neutral trials but not invalid trials. Observers could split focal attention and manipulate simultaneously 2 independent attentional foci on objects located in the opposite hemifields.     

Neurotoxicity of Kainate to the Hippocampus is not Accrued by Aging, Stress and Exogenous Corticosterone in Wistar Kyoto and Spontaneously Hypertensive Rats

It has been reported that a high corticosterone milieu can exacerbate various experimental insults to the nervous system, in particular to the hippocampus. However, in many of these studies the above milieu was attained by injecting corticosterone in doses (e.g. 10 mg/rat) producing supraphysiological concentrations. In the present study we have investigated whether high plasma corticosterone levels, such as those associated with aging or stress, potentiate a hippocampal excitotoxic insult. Male Wistar Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR) at the age of 6, 12, 18 and 24 months (only WKY for the oldest age) were used. As in other strains, aging in these rats was marked by an increase in basal plasma corticosterone levels. Rats were infused in the dorsal hippocampus with kainic acid (0.035 μg/hippocampus) and the neuronal injury was evaluated within the areas CA3 and CA4. Results indicated that neither aging nor the hypertensive condition affected kainic acid neurotoxicity. In order to study the effect of stress, rats were stressed twice a day, with alternate types of stressors to avoid possible habituation, 3 days prior to and 3 days following the kainic acid infusion. Using this experimental paradigm the hippocampal damage in stressed rats was of the same degree as in non-stressed controls. In a complementary set of experiments, 6 month old WKY and SHR rats were injected with corticosterone (10 mg/rat s.c.). Four hours after administration plasma corticosterone levels in the range of 60-70 μg/100 ml were found. Moreover, a time-course study showed a plasma corticosterone peak in the range of 240 μg/100 ml. Daily corticosterone administration for 3 days before and 3 days after kainic acid infusion potentiated the hippocampal damage in 6 months old SHR but not in the WKY. These results demonstrate that elevation of corticosterone levels within physiological range does not exacerbate hippocampal kainate neurotoxicity and that pharmacological doses of glucocorticoid hormone, which produces plasma levels well above those observable in any physiopathological condition, might, with some strain dependency, potentiate a hippocampal neurotoxic insult.