The Small Worlds and Floyd's algorithms: a way to study scientific collaboration

Many proposals from the analysis of social networks focused on the study of scientific collaboration have been made recently. The Small Worlds theory seems to be the most efficient to study the inner features of the scientific community. Those researches have demonstrated that small communities are based on some key individuals who connect some groups which, on the contrary, would be disconnected. One of the disadvantages from the perspective of the analysis of networks is the lack of researches of particular nodes. With the implementation of a pseudocode algorithm of Floyd, we try to avoid this. To study how a small community is formed and, as a research of one case, we observe the invisible college which is formed when connecting the fifteen most productive authors of the Journal of Personality and Social Psychology .     

Individual differences in the linguistic competence of referential and expressive subjects

The aim of this work was to examine individual differences in referential and expressive style through a longitudinal study. The composition of the first 50 words, communicative gestures, the conversational style of dyads and the percentage of vocabulary produced from 12 to 24 month-olds were analyzed. The vocabulary was collected through interviews to parents and sessions of mother-infant interaction in the laboratory. Significant differences in the proportion of common nouns and frozen phrases between referential and expressive children in the frequency of communicative gestures and style conversation were found. Thus, referential children and their mothers used more pointing gestures than the expressive children and their mothers. Additionally, mothers of referential children used completing more frequently.     

Subtypes of drug-addicts in treatment: empirical support for a distinction between Type A and Type B

This study examines the possibility of replicating and generalizing a multidimensional typology of drug-addicts by means of the evaluation of 320 participants who were receiving outpatient treatment for their problem of addiction. A two-stage cluster analysis was performed, revealing the existence of two typologies of consumers, called type A and Type B. The participants classified as Type B showed various indicators of chronicity (higher mean age, higher unemployment rate), more severity of their problem of drug consumption and of medical aspects, employment support, legal, family/social and psychiatric problems in comparison with Type A. Participants from the latter group reported active employment as their main source of income and they had consumed drugs for fewer years. However, they presented more severity associated with alcohol consumption. In view of these data, Type A is called functional drug-addict and Type B chronic drug-addict. Once the groups of drug-addicts were delimited, a more specific characterization was made, taking seven problem areas into account: medical, employment support, alcohol, drugs, legal, family/social, and psychiatric areas. As a general conclusion, more psychosocial severity was observed in Type B as compared with Type A. Lastly, the implications and usefulness of grouping drug-addicts into typologies is discussed.     

The effects of metabolic stress and vagotomy on emotional learning in an animal model of anxiety

The aim of the present study is to evaluate the role of the blood glucose (BG) level in emotional learning in the elevated plus maze (EPM), an animal model of anxiety. In Experiment 1, male Wistar rats were submitted to different EPM trial lengths (1- or 5-min). Blood samples were withdrawn before and after the maze exploration, through a polyethylene cannula chronically implanted into the jugular vein. In Experiment 2, the animals received either saline or 2-deoxy-D-glucose, a glucoprivic drug (2-DG, 250 or 500 mg kg(-1)) by i.p. route, 30 min before a 5-min EPM exposure and were retested in the maze (Trial1/Trial2 EPM procedure) 24 h later. In an independent group of rats, blood samples were withdrawn 0, 5, 15, and 30 min after 2-DG administration, through the jugular vein, to determine BG. In Experiment 3, the animals underwent a vagotomy and were tested in a Trial1/Trial2 EPM procedure four weeks later. The results showed that rats exploring the EPM for 5 min displayed increased fear and higher hyperglycemia than those exploring the EPM for 1 min. In addition, rats submitted to 5-min EPM Trial1 length displayed higher level of fear on Trial2, as well as higher percentage of shortening of the %Open arm entries and %Open arm time from Trial1 to Trial2, which characterizes the occurrence of emotional learning. In contrast, rats previously vagotomized or treated with 2-DG (500 mg kg(-1)) showed the same level of fear on both EPM trials and a low percentage of shortening, from Trial1 to Trial2, of the %Open arm entries and %Open arm time, indicating poor emotional learning. The data is discussed regarding the role of glycaemia in emotional learning in the EPM.     

Memories of the terrorist attacks of September 11, 2001: a study of the consistency and phenomenal characteristics of flashbulb memories

In this study, I investigated students' memories of the terrorist attacks of September 11, 2001, carried out by Al Qaeda terrorists against the World Trade Center in New York and the Pentagon in Washington. Participants completed on two occasions (2 weeks and 8 months after the events took place) a memory questionnaire that included an assessment of the phenomenal richness of their memories. The results showed that the participants remembered very well the circumstances in which they first heard about the terrorist attacks, that they were very confident about this information, and that these memories were characterized by a high phenomenal richness. Over time, there was a decrease in all of these variables, but people's ratings of phenomenology and confidence were still very high.     

The effect of content and physical properties of affective pictures on emotional responses

The aim of this research was to study the influence of both the emotional content and the physical characteristics of affective stimuli on the psychophysiological, behavioral and cognitive indexes of the emotional response. We selected 54 pictures from the IAPS, depicting unpleasant, neutral, and pleasant contents, and used two picture sizes as experimental conditions (120 x 90 cm and 52 x 42 cm). Sixty-one subjects were randomly assigned to each experimental condition. We recorded the startle blink reflex, skin conductance response, heart rate, free viewing time, and picture valence and arousal ratings. In line with previous research (e.g., Bradley, Codispoti, Cuthbert, and Lang, 2001), our data showed an effect of the affective content on all the measurements recorded. Importantly, effects of the size of the affective pictures on emotional responses were not found, indicating that the emotional content is more important than the formal properties of the stimuli in evoking the emotional response.     

Psychological processes and family variables as prosocial behavior predictors in a sample of Spanish adolescents

A review of personal and family variables that regulate prosocial behavior is based on a sample of 1,433 Spanish adolescents (ages 9 to 13; 743 boys and 690 girls) who were assessed on the Prosocial Reasoning Objective Measure, the Physical and Verbal Aggression Scale, the Emotional Instability Scale, the State-Trait Anger Inventory, the Child's Report of Parental Behavior Inventory, the Prosocial Behavior Scale, and the Index of Empathy for Children and Adolescents. Discriminant analyses showed that empathy, self-control in anger-provoking situations, and affection in family relationships are the best predictors of prosocial behavior.     

Fragment difficulty in priming on word-completion tests

Word-fragment completion is a frequently used test in implicit memory research. In this test priming is the relevant variable. Priming is obtained by subtracting the proportion of nonstudied word fragments correctly completed (called "completion difficulty baseline") from the studied word fragments correctly completed. Since completion difficulty can spuriously vary greatly between experimental conditions, its effect on magnitude of priming is studied. Normative frequency of occurrence of target words was considered because their influence over performance is known. In an experiment using a word-fragment completion test, participants' completion of fragments at three levels of completion difficulty and two levels of frequency was tested. Analysis showed that completion difficulty had a significant effect on global priming. The priming magnitude was higher for Difficult and Moderately Difficult fragments than for Easy ones. An interaction between fragment difficulty and normative word frequency was observed. When the fragments were easy to complete, the expected effect of higher priming for low-frequency words than for high-frequency words was not observed.     

Distinct mechanisms for planning keypress and reaching responses: a developmental study

This study examined developmental effects in the ability to use precue information for the planning of keypress and reaching responses. Participants from four age groups (7, 9, 13, and 21 year olds) performed a spatial precuing task either by pressing one of four response keys (keypress task) or by reaching directly toward one of the four target locations on the screen (reaching task). Reaction time data revealed striking age differences in the ability to use advance information in the keypress task, not in the reaching task. This dissociation confirms the hypothesis that distinct and separate mechanisms govern the planning of indirect keypress and direct reaching responses.     

Inattentional blindness for negative relationships in human causal learning

The present study focuses on the effect of selective attention on causal learning. Three effects of the level of attention to predictive symptoms in positive and negative contingency learning tasks are reported. First, participants accurately detected a positive relationship between an incidental cue and a contingent outcome, although judgements were slightly lower than those for the attended cue. Second, participants were unable to detect negative relationships between incidental cues and outcomes, which suggests a major role of selective attention in this type of learning. Third, participants retrieved the frequency of each trial type more accurately in the attended conditions than in the incidental conditions. These findings show how attention guides and constrains human causal learning and reveal an inattentional blindness effect for negative contingency learning.