Associations Among Anxiety Disorders and Non-anxiety Disorders,Functional Impairment and Medication in Children and Adolescents

This is a study of comorbid anxiety disorders and how they affect the clinical picture of comorbid cases. The sample consisted of 576 Spanish children aged 8 to 17 years receiving psychiatric outpatient consultation that were evaluated using a semi-structured diagnostic interview for both parents and children. A specific association of homotypic comorbidity among anxiety disorders that was independent of the presence of other disorders was found. There was heterotypic comorbidity between anxiety and depressive disorders, ADHD, anorexia and tic disorders. Relationships between non-anxiety disorders were, in general, independent of anxiety, but anxiety moderated the relationship between ADHD-Conduct disorder and Conduct disorder-enuresis. Comorbid anxiety increased difficulties in social interaction, was related with higher global impairment and had an impact on consultation and medication. Anxiety disorder comorbidity should be well recognized in order not to disregard the treatment of all present disorders.     

Algebraic logic for classical conjunction and disjunction

In this paper we study the relations between the fragment L of classical logic having just conjunction and disjunction and the variety D of distributive lattices, within the context of Algebraic Logic. We prove that these relations cannot be fully expressed either with the tools of Blok and Pigozzi's theory of algebraizable logics or with the use of reduced matrices for L. However, these relations can be naturally formulated when we introduce a new notion of model of a sequent calculus. When applied to a certain natural calculus for L, the resulting models are equivalent to a class of abstract logics (in the sense of Brown and Suszko) which we call distributive. Among other results, we prove that D is exactly the class of the algebraic reducts of the reduced models of L, that there is an embedding of the theories of L into the theories of the equational consequence (in the sense of Blok and Pigozzi) relative to D, and that for any algebra A of type (2,2) there is an isomorphism between the D-congruences of A and the models of L over A. In the second part of this paper (which will be published separately) we will also apply some results to give proofs with a logical flavour for several new or well-known lattice-theoretical properties.Dedicated to our master, Francesc d'A. Sales, on his 75th birthday     

Factor structure of items from the personality Adjective Check List in a sample of normal adolescents

We present the results of a principal-components analysis of the Personality Adjective Check List (PACL) at the item level, rather than at the scale level. The PACL was constructed by Strack (1987) to evaluate the personality scales proposed by Millon (1981). Data were obtained from a sample of normal adolescents. A scree test was applied to determine the number of factors to be extracted, and the retained factors were then rotated using a varimax procedure. Using the data from this second analysis, congruence coefficients were calculated by correlating the factor weights from the two analyses of men and women. Results reveal the existence in the whole sample of five unipolar personality factors, which we have called: Aggressive, Conscientious, Inhibited, Impulsive and Gregarious. These are not similar to those obtained from a sample of normal adults.     

Inferences by exclusion in the great apes: the effect of age and species

This study investigated the ability of chimpanzees, gorillas, orangutans, and bonobos to make inferences by exclusion using the procedure pioneered by Premack and Premack (Cognition 50:347–362, 1994) with chimpanzees. Thirty apes were presented with two different food items (banana vs. grape) on a platform and covered with identical containers. One of the items was removed from the container and placed between the two containers so that subjects could see it. After discarding this item, subjects could select between the two containers. In Experiment 1, apes preferentially selected the container that held the item that the experimenter had not discarded, especially if subjects saw the experimenter remove the item from the container (but without seeing the container empty). Experiment 3 in which the food was removed from one of the containers behind a barrier confirmed these results. In contrast, subjects performed at chance levels when a stimulus (colored plastic chip: Exp. 1; food item: Exp. 2 and Exp. 3) designated the item that had been removed. These results indicated that apes made inferences, not just learned to use a discriminative cue to avoid the empty container. Apes perceived and treated the item discarded by the experimenter as if it were the very one that had been hidden under the container. Results suggested a positive relationship between age and inferential ability independent of memory ability but no species differences.This contribution is part of the special issue “Animal Logics” (Watanabe and Huber 2006).     

Unwilling versus unable: infants' understanding of intentional action

Infants experienced a female adult handling them toys. Sometimes, however, the transaction failed, either because the adult was in various ways unwilling to give the toy (e.g., she teased the child with it or played with it herself) or else because she was unable to give it (e.g., she accidentally dropped it). Infants at 9, 12, and 18 months of age reacted with more impatience (e.g., reaching, looking away) when the adult was unwilling to give them the toy than when she was simply unable to give it. Six-month-olds, in contrast, showed no evidence of this differentiation. Because infants' behavioral responses were appropriately adapted to different kinds of intentional actions, and because the adult's actions sometimes produced results that did not match her goal (when having accidents or failed attempts), these findings provide especially rich evidence that infants first begin to understand goal-directed action at around 9 months of age.     

Piagetian conservation of discrete quantities in bonobos (Pan paniscus), chimpanzees (Pan troglodytes), and orangutans (Pongo pygmaeus)

This study investigated whether physical discreteness helps apes to understand the concept of Piagetian conservation (i.e. the invariance of quantities). Subjects were four bonobos, three chimpanzees, and five orangutans. Apes were tested on their ability to conserve discrete/continuous quantities in an over-conservation procedure in which two unequal quantities of edible rewards underwent various transformations in front of subjects. Subjects were examined to determine whether they could track the larger quantity of reward after the transformation. Comparison between the two types of conservation revealed that tests with bonobos supported the discreteness hypothesis. Bonobos, but neither chimpanzees nor orangutans, performed significantly better with discrete quantities than with continuous ones. The results suggest that at least bonobos could benefit from the discreteness of stimuli in their acquisition of conservation skills.     

How does cognition evolve? Phylogenetic comparative psychology

Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution.     

Are monkeys able to plan for future exchange?

Whether or not non-human animals can plan for the future is a hotly debated issue. We investigate this question further and use a planning-to-exchange task to study future planning in the cooperative domain in two species of monkeys: the brown capuchin (Cebus apella) and the Tonkean macaque (Macaca tonkeana). The rationale required subjects to plan for a future opportunity to exchange tokens for food by collecting tokens several minutes in advance. Subjects who successfully planned for the exchange task were expected to select suitable tokens during a collection period (5/10?min), save them for a fixed period of time (20/30?min), then take them into an adjacent compartment and exchange them for food with an experimenter. Monkeys mostly failed to transport tokens when entering the testing compartment; hence, they do not seem able to plan for a future exchange with a human partner. Three subjects did however manage to solve the task several times, albeit at very low rates. They brought the correct version of three possible token types, but rarely transported more than one suitable token at a time. Given that the frequency of token manipulation predicted transport, success might have occurred by chance. This was not the case, however, since in most cases subjects were not already holding the token in their hands before they entered the testing compartment. Instead, these results may reflect subjects' strengths and weaknesses in their time-related comprehension of the task.     

Great apes infer others’ goals based on context

In previous studies claiming to demonstrate that great apes understand the goals of others, the apes could potentially have been using subtle behavioral cues present during the test to succeed. In the current studies, we ruled out the use of such cues by making the behavior of the experimenter identical in the test phase of both the experimental and control conditions; the only difference was the preceding “context.” In the first study, apes interpreted a human’s ambiguous action as having the underlying goal of opening a box, or not, based on that human’s previous actions with similar boxes. In the second study, chimpanzees learned that when a human stood up she was going to go get food for them, but when a novel, unexpected event happened, they changed their expectation—presumably based on their understanding that this new event led the human to change her goal. These studies suggest that great apes do not need concurrent behavioral cues to infer others’ goals, but can do so from a variety of different types of cues—even cues displaced in time.     

The Effect of Plausible Versus Implausible Balance Scale Feedback on the Expectancies of 3- to 4-Year-Old Children

Previous studies (Case, 1985 Case , R. ( 1985 ). Intellectual development: Birth to adulthood . New York , NY : Academic . [Google Scholar]; Siegler, 1981 Siegler , R. S. ( 1981 ). Developmental sequences within and between concepts . Monographs of the Society for Research in Child Development , 46 , 1 – 84 . [Google Scholar]) have shown that children under the age of 5 years have little understanding of balance scales when required to encode the influence of weight or distance from the fulcrum. More recently, however, Halford, Andrews, Dalton, Boag, and Zielinski (2002 Halford , G. S. , Andrews , G. , Dalton , C. , Boag , C. , & Zielinski , T. ( 2002 ). Young children's performance on the balance scale: The influence of relational complexity . Journal of Experimental Child Psychology , 81 , 417 – 445 .[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) noted that an understanding based on weight alone is present even in 2-year-olds. In all these experiments, weight was varied using multiple objects of the same weight. Consequently, the children's decisions could have been based upon visual features (size, number) without necessarily taking the weight into account. The present study investigated whether young children are able to correctly encode the relevance of weight in influencing the behavior of a balance scale. We studied how well 3- to 4-year-old children learn to use one of two different weights (of equal appearance) to tip the scale. In the plausible condition, the heavy weight produced the desired outcome. In the implausible condition, the light weight caused the scale to tip. Only 4-year-olds' performance differed between conditions by learning more effectively in the plausible than the implausible condition. Our results suggest that children younger than 4 years of age have not yet developed clear expectations of the role of weights on the movements of a balance scale.