Cognitive performance and morning levels of salivary cortisol and alpha-amylase in children reporting high vs. low daily stress perception

The aim of the present study was to assess the effects of daily stress perception on cognitive performance and morning basal salivary cortisol and alpha-amylase levels in healthy children aged 9-12. Participants were classified by whether they had low daily perceived stress (LPS, n = 27) or a high daily perceived stress (HPS, n = 26) using the Children Daily Stress Inventory (CDSI). Salivary cortisol and alpha-amylase were measured at awakening and 30 minutes later. Cognitive performance was assessed using the Cognitive Drug Research assessment system. The HPS group exhibited significantly poorer scores on speed of memory (p < .05) and continuity of attention (p < .05) relative to the LPS group. The HPS group also showed significantly lower morning cortisol levels at awakening and at +30 minutes measures in comparison with the LPS group (p < .05), and mean morning cortisol levels were negatively correlated with speed of memory (p < .05) in the 53 participants. No significant differences were observed between both groups in alpha-amylase levels. These findings suggest that daily perceived stress in children may impoverish cognitive performance via its modulating effects on the HPA axis activity.     

A comparison of the peers method and traditional methodologies, and risk behaviors in studies of the prevalence of drug consumption in a population of female, Chilean students

The present study investigates drug consumption and risk behaviors among female students between 8th and 12th grade in two communities in the city of Santiago, Chile. Based on studies of university populations, we hypothesize that the students' reports of their consumption of licit drugs will tend to be consistent with their actual use of said drugs using two methods to investigate consumption, while their consumption of illicit drugs will be susceptible, and will tend to be under-reported when evaluated through traditional self-report measures. In order to compare the two methods, a cross-sectional study was designed that would compare reported drug consumption, first using the peers method, and then by means of traditional self-report in a group of 350 students. The results show that women's reports of licit drug consumption converge using the two methods, while as earlier suggested, women's illicit drug consumption was found to be under-reported when traditional methodologies were used.     

The role of interference produced by conflicting associations in contextual control

In 2 experiments, participants completed a computer task in which they judged the probability of outcomes occurring (e.g., flowers growing, a bug infestation) given cues (e.g., treatment of soil with a fictitious garden product). In each 2-phase experiment, cue X was associated with 1 outcome in Phase 1 and with a 2nd outcome in Phase 2. When the outcome in Phase 1 (e.g., X led to a bug infestation) was replaced in Phase 2 (e.g., X led to flowers growing), contextual control was observed (Experiments 1 and 2). Information learned in each phase was less likely to be retrieved when the cue was tested in a context different from the 1 where training occurred. When the 2nd outcome did not conflict with information acquired in the 1st phase (e.g., X led to flowers and bugs), no contextual control was observed (Experiment 2). Acquiring a 2nd association to X resulted in contextual control only when it conflicted with an association learned earlier. The authors discuss the role of interference produced when conflicting information is acquired in establishing contextual control.     

A Study on Late Closure in Spanish: Principle-grounded vs. Frequency-based Accounts of Attachment Preferences

A much-debated issue in current research on sentence parsing concerns the resolution of attachment ambiguities. Parsing theories differ on the procedures used to guide on-line attachment decisions: principle-grounded theories (e.g. garden-path/ construal) propose universal principles that minimize processing load; frequency-based accounts (such as linguistic tuning) claim that attachment decisions are shaped by readers' previous experience with their particular language; lexically based models, in turn, assert that attachment choices are determined by the properties of individual lexical items in the sentence. This paper reports six studies on late closure in the resolution of attachment ambiguities in Spanish: a questionnaire study on attachment preferences and three self-paced reading experiments where ambiguous PPs could be attached as arguments of two VP-hosts in NP-VP1-NPVP2-PP structures. The results show a clear preference towards low attachment (late closure), thus supporting principle-grounded theories. In addition, two corpus studies were carried out to obtain records of relative frequencies of the attachment choices involved in the experiments. A coarse-grained measure revealed that, in accordance with linguistic tuning, low-attachment structures are more common in Spanish NP-VP1-NP-VP2-PP sentences. However, a fine-grained count showed that low-attachment preferences cannot be explained by arguing that the specific verbs positioned lower on the tree (VP2) are more likely to take an extra argument than those located at a higher position (VP1), as lexical models would assume.     

Effect of irrelevant information on the processing of relevant information: Facilitation and/or interference? The influence of experimental design

Previous studies have provided conflicting evidence concerning the question of whether irrelevant information can facilitate the processing of relevant information in a choice reaction time task. Results of the present study demonstrated that indications of facilitation and/or interference were dependent on the context in which baseline trials were administered. Three groups of 24 subjects pressed a left-.or right-hand key in response to the onset of an X or 0 that was accompanied by a monaural or binaural tone. The monaural toneprovided an irrelevant directional cue since, oia some trials, it was ipsilateral to the correct response (corresponding trials), while, on other trials, it was contralateral Inoncorrasponding trials). When binaural (baseline) trials were presented in the same block as the monaural trials, data suggested that the directional cue produced both facilitation and interference. However, when baseline trials were presented in one block, and corresponding and noncorresponding trials were mixed together in another block, data suggested an interference effect only. The difference was attributed to differences in the degree of stimulus uncertainty within a block of trials.     

The role of variability in the property listing task

It is generally believed that concepts can be characterized by their properties (or features). When investigating concepts encoded in language, researchers often ask subjects to produce lists of properties that describe them (i.e., the Property Listing Task, PLT). These lists are accumulated to produce Conceptual Property Norms (CPNs). CPNs contain frequency distributions of properties for individual concepts. It is widely believed that these distributions represent the underlying semantic structure of those concepts. Here, instead of focusing on the underlying semantic structure, we aim at characterizing the PLT. An often disregarded aspect of the PLT is that individuals show intersubject variability (i.e., they produce only partially overlapping lists). In our study we use a mathematical analysis of this intersubject variability to guide our inquiry. To this end, we resort to a set of publicly available norms that contain information about the specific properties that were informed at the individual subject level. Our results suggest that when an individual is performing the PLT, he or she generates a list of properties that is a mixture of general and distinctive properties, such that there is a non-linear tendency to produce more general than distinctive properties. Furthermore, the low generality properties are precisely those that tend not to be repeated across lists, accounting in this manner for part of the intersubject variability. In consequence, any manipulation that may affect the mixture of general and distinctive properties in lists is bound to change intersubject variability. We discuss why these results are important for researchers using the PLT.