How to stay perfect: the role of memory and behavioural traits in an experienced problem and a similar problem

When animals encounter a task they have solved previously, or the same problem appears in a different apparatus, how does memory, alongside behavioural traits such as persistence, selectivity and flexibility, enhance problem-solving efficiency? We examined this question by first presenting grey squirrels with a puzzle 22 months after their last experience of it (the recall task). Squirrels were then given the same problem presented in a physically different apparatus (the generalisation task) to test whether they would apply the previously learnt tactics to solve the same problem but in a different apparatus. The mean latency to success in the first trial of the recall task was significantly different from the first exposure but not different from the last exposure of the original task, showing retention of the task. A neophobia test in the generalisation task suggested squirrels perceived the different apparatus as a different problem, but they quickly came to apply the same effective tactics as before to solve the task. Greater selectivity (the proportion of effective behaviours) and flexibility (the rate of switching between tactics) both enhanced efficiency in the recall task, but only selectivity enhanced efficiency in the generalisation task. These results support the interaction between memory and behavioural traits in problem-solving, in particular memory of task-specific tactics that could enhance efficiency. Squirrels remembered and emitted task-effective tactics more than ineffective tactics. As a result, they consistently changed from ineffective to effective behaviours after failed attempts at problem-solving.     

Can dogs defy gravity? A comparison with the human infant and a non-human primate

We conducted four experiments with 56 adult dogs (Canis lupus familiaris) involving tasks where food was dropped through an opaque tube connected either vertically or diagonally to one of two or three goal boxes. In the first experiment, modelled after studies with children and primates, the dogs first searched significantly more often in the location directly beneath the drop-off point (a gravity bias), although this box was not connected with the tube. These results are comparable to those of human infants and cotton-top tamarins. Experiments 2–4 tested which problem solving strategy the dogs applied to find the food. Results show that they do not understand the physical mechanism of the tube itself, and they apply one of three search strategies: search the gravity box (the one below the drop-off box); search the box in the middle; learn the correct location of the goal box. When the goal box was in the same location the dogs learned to search there over trials, that is, they learned to ‘defy gravity’, but when the location of the goal box changed over trials they showed no learning. These findings are compared with those from human infants and cotton-top tamarins: like these species, the dogs can learn to overcome a gravity bias, but only when the reward is to be found in a consistent location.     

Book review

STADDON, J. E. R. (Ed.). Limits to Action: The Allocation of Individual Behavior. New York: Academic Press. 1980. Pp xix+308. £13.60/$24.00.     

Norms and screening utility of the Dutch version of the Children's Depression Inventory in clinical and nonclinical youths

This study aimed to (a) assess relationships between the Children's Depression Inventory (CDI) and DSM-oriented depression and anxiety scales of the Youth Self Report, (b) develop reliable norms for the CDI, and (c) determine CDI cutoff scores for selecting youngsters at risk for depression and anxiety. A total of 3,073 nonclinical and 511 clinically referred children and adolescents from The Netherlands and Belgium were included. Results showed that CDI scores were significantly related to DSM-oriented symptoms of both depression and anxiety. CDI scores correlated highly with depression symptoms and moderately with anxiety symptoms. Norms for the CDI were determined by means of multiple regression analysis and depended on sex, age, and country. CDI cutoff scores for selecting individuals at risk for depression and anxiety as measured by the DSM-oriented depression and anxiety scales of the Youth Self Report were determined by means of multiple regression analysis and receiver operating characteristic analysis. A CDI score of 16 was found to have the most optimal balance between sensitivity and specificity for depression, whereas a score of 21 provided the best sensitivity and specificity for anxiety in a subsample of children. We conclude that the CDI is an effective instrument for screening depression and to a lesser extent anxiety in primary and secondary care centers, before applying further assessment of high-risk individuals.     

Working Memory and Motor Activity: A Comparison Across Attention-Deficit/Hyperactivity Disorder,Generalized Anxiety Disorder,and Healthy Control Groups

Converging findings from recent research suggest a functional relationship between attention-deficit/hyperactivity disorder (ADHD)-related hyperactivity and demands on working memory (WM) in both children and adults. Excessive motor activity such as restlessness and fidgeting are not pathognomonic symptoms of ADHD, however, and are often associated with other diagnoses such as generalized anxiety disorder (GAD). Further, previous research indicates that anticipatory processing associated with anxiety can directly interfere with storage and rehearsal processes of WM. The topographical similarity of excessive motor activity seen in both ADHD and anxiety disorders, as well as similar WM deficits, may indicate a common relationship between WM deficits and increased motor activity. The relationship between objectively measured motor activity (actigraphy) and PH and visuospatial WM demands in adults with ADHD (n = 21), adults with GAD (n = 21), and healthy control adults (n = 20) was examined. Although all groups exhibited significant increases in activity from control to WM conditions, the ADHD group exhibited a disproportionate increase in activity, while activity exhibited by the GAD and healthy control groups was not different. Findings indicate that ADHD-related hyperactivity is uniquely related to WM demands, and appear to suggest that adults with GAD are no more active relative to healthy control adults during a cognitively demanding laboratory task.     

Strengths and Subjective Wellbeing in Adolescence: Strength-Based Parenting and the Moderating Effect of Mindset

Recent research suggests that strength-based parenting—the tendency for parents to see and encourage children to use their strengths—relates to lower stress and higher life satisfaction in adolescents. The current study tests whether strength-based parenting, in conjunction with a teenager’s strengths use, influences the teenager’s subjective wellbeing, and whether a growth mindset moderates the relationship between strength-based parenting and strengths use. Three hundred and sixty three adolescents (M _age = 13.74, 51% female) completed questionnaire measures of strength-based parenting, strengths use, subjective wellbeing (life satisfaction, positive affect, and negative affect), Extraversion, Neuroticism, and two aspects of growth mindset. A hierarchical regression using latent variables found that strengths use and strength-based parenting were both significant independent predictors of subjective wellbeing, over and above the effects of extraversion and neuroticism. A mediation analysis found that strengths use partially mediated the relationship between strength-based parenting and subjective wellbeing. Finally, a novel measure of strengths mindset significantly moderated the relationship between strength-based parenting and strengths use. These results suggest that adolescents who see their parents as strength-based report greater strengths use (especially when they have a growth mindset about their strengths) and greater subjective wellbeing.     

A complex dynamic systems approach to lasting positive change: The Synergistic Change Model

This paper argues that psychological and social functioning is fundamentally complex, and that this complexity is critical to understanding how lasting positive changes can be achieved. Principles from complex systems theory are integrated into an empirical positive psychological framework to propose a domain-based systems model of positive change called the Synergistic Change Model. This model proposes that enduring positive change depends on the formation of mutually supportive interactions across multiple domains of psychological and social functioning. The paper uses the model to explore three types of response to intervention – relapse, spill-over, and synergy – which have been supported in the existing positive psychology literature. Three practical intervention strategies arising from the model are outlined to inform the design of future positive interventions. The model challenges reductionistic approaches to positive change and offers several approaches to embrace the complexities of lasting positive change in future theory and research.     

The Development of Latent Dimensions of Psychopathology across Early Childhood: Stability of Dimensions and Moderators of Change

Recent research has described the structure of psychopathology as including one general and multiple specific factors, and this structure has been found in samples across development. However, little work has examined whether this structure is consistent across time, particularly in young children, within the same sample. Further, few studies have examined factors that influence the magnitude of the stability of latent dimensions of psychopathology. In the present study, we examine these issues in a community sample of 545 children assessed at ages 3 and 6. In addition, we explored child temperament, parental history of psychopathology, and parenting behaviors as potential moderators of the longitudinal stability of latent dimensions of psychopathology. We found that the same bifactor model structure identified at age 3 provided an adequate fit to the data at age 6. Further, our model revealed significant homotypic stability of the general, internalizing, and externalizing specific factors. We also found evidence of differentiation of psychopathology over time with the general factor at age 3 predicting the externalizing factor at age 6. However, we failed to identify moderators of the longitudinal associations between psychopathology latent factors. Overall, our results bolster support for the bifactor structure of psychopathology, particularly in early childhood.     

Incremental Bayesian Category Learning From Natural Language

Models of category learning have been extensively studied in cognitive science and primarily tested on perceptual abstractions or artificial stimuli. In this paper, we focus on categories acquired from natural language stimuli, that is, words (e.g., chair is a member of the furniture category). We present a Bayesian model that, unlike previous work, learns both categories and their features in a single process. We model category induction as two interrelated subproblems: (a) the acquisition of features that discriminate among categories, and (b) the grouping of concepts into categories based on those features. Our model learns categories incrementally using particle filters, a sequential Monte Carlo method commonly used for approximate probabilistic inference that sequentially integrates newly observed data and can be viewed as a plausible mechanism for human learning. Experimental results show that our incremental learner obtains meaningful categories which yield a closer fit to behavioral data compared to related models while at the same time acquiring features which characterize the learned categories. (An earlier version of this work was published in Frermann and Lapata 2014 .)