Motivation for physical activity in young people: entity and incremental beliefs about athletic ability

Three studies are reported of children and youth aged 11–19 years (n?=?3478) examining the nature of beliefs about athletic ability. Drawing on related research in academic, moral and stereotyping domains, development of a psychometric instrument assessing athletic ability beliefs is detailed. Support was found for a multidimensional hierarchical structure that is invariant across age and gender. Confirmatory factor analysis revealed a structure comprising two higher-order factors of entity and incremental beliefs underpinned by beliefs that athletic ability is stable and a gift (entity), and is open to improvement and can be developed through learning (incremental). Incremental beliefs, indirectly through a task goal orientation, and entity beliefs directly, predicted self-reported amotivation towards physical education and sport. On the other hand, enjoyment of physical activity in youth was predicted directly by task orientation and incremental beliefs. Predictions concerning the moderating role of perceived competence were not supported. Our findings highlight the importance of ability beliefs and goals in understanding the determinants of physical activity in children and youth.     

Secure chaotic communication based on extreme multistability

Extreme multistability is the coexistence of a large number of attractors which can be reached by varying initial conditions. In this paper we show how this fascinating phenomenon can be used for secure communication. The main advantage of the communication system based on extreme multistability over a conventional chaos-based communication system is its exceptionally high security. The proposed system consists of two identical six-order oscillators; one in the transmitter and another one in the receiver, each exhibiting the coexistence of a large number of chaotic attractors. The oscillators are synchronized using a private channel through one of the system variables, while the information is transmitted via a public channel through another variable. The information is encrypted by varying the initial condition of one of the state variables in the transmitter using a chaotic map, adhering message packages in a staggered form to the coexisting attractors within the same time series of another state variable, which leads to switching among the coexisting chaotic attractors. To ensure communication security, the duration of the packages is shorter than synchronization time, so that synchronization attacks are ineffective.     

Young Children's Understanding of Forgetting over Time

2 studies investigated young children's understanding that as the retention interval increases, so do the chances that one will forget. In Study 1 (24 3-year-olds and 24 4-year-olds), 4-year-olds but not 3-year-olds understood that of 2 characters who simultaneously saw an object, the character who waited longer before attempting to find it would not remember where it was. In study 2 (24 3-year-olds and 24 4-year-olds), 4-year-olds but not 3-year-olds understood that of 2 objects seen by a character, the object that was seen a "long long time ago" would be forgotten and the object seen "a little while ago" would be remembered. The findings are discussed in relation to research on young children's understanding of the acquisition, retention, and retrieval of knowledge over time.     

Seeing and believing: children's understanding of the distinction between appearance and reality

When young children are asked questions about objects with misleading appearances, they make two kinds of errors: (1) phenomenism--they report appearance when asked to report reality; and (2) intellectual realism--they report reality when asked to report appearance. Two studies with 3-year-old children tested the hypothesis that phenomenism errors predominate when children are asked about objects' real and apparent properties, whereas intellectual realism errors predominate when children are asked about objects' real and apparent identities. The results of these studies provided some support for the property-identity hypothesis; children's appearance-reality judgments about properties tended to differ from those about identities. More phenomenism errors were elicited when the stimuli were described to the children in terms of their properties than when the very same stimulus objects were described in terms of their identities. Identity tasks were not found to elicit predominantly intellectual realism errors, although the data showed trends in this direction. The implications of these results for theories about young children's tendency to accept things in terms of their perceptual characteristics were briefly discussed.     

Young Children''s Understanding of Different Types of Beliefs

The purpose of this investigation was to see whether children's understandings of different types of beliefs develop concurrently. Children of 3, 4, and 5 years of age were told or shown that child story characters held beliefs different from their own or from one another, not only concerning matters of physical fact ("false beliefs"), but also concerning morality, social convention, value, and ownership of property. In contrast to the older subjects, most 3-year-olds had difficulty in attributing to others deviant beliefs of all types, except perhaps ownership, sometimes even after having been told repeatedly what the other child believed. In addition, intercorrelations among different belief tasks were positive and substantial. It was suggested that an emerging representational conception of the mind is what enables older preschoolers to understand the possibility of belief differences of all these types.     

Preschoolers' Understanding of the Link between Thinking and Feeling: Congnitive Cuing and Emotional Change

In 3 studies we investigated 3- through 6-year-olds' knowledge of thinking and feeling by examining their understanding of how emotions can change when memories of past sad events are cued by objects in the current environment. In Study 1, 48 4-, 5-, and 6-year-olds were presented with 4 illustrated stories in which tocal characters experience minor sad events. Later, each story character encounters a visual cue that is related to one of his or her previous sad experiences. Children were told that the character felt sad and they were asked ot explain why. Study 1 suggested considerable competence as well as substantial development in the years between 4 and 6 in the understandings of the influence of mental activity on emotions. Studies 2 and 3 more systematically explored preschoolers' understanding of cognitive cuing and emotional change with difterent types of situations and cues. Across these 2 studies, 108 3-, 4-, and 5-year-olds listened to illustrated stories that featured story characters who each experienced a sad event and swho were later exposed to a related cue. Children were not only asked to explain why the characters suddenly felt sad, but in some stories, they were also asked to predict and explain how another character, who was never at the past sad event, would feel. Results of studies 2 and 3 showed an initial understanding of cognitive cuing and emotion in some children as young as 3, replicated and extended the evidence for significant developmental changes in that understanding during the preschool years, and revealed that the strenght and consistency of preschoolers' knowledge of cognitive cuing and emotion was affected by whether cues were the sme, or only similar to, parts of the earlier events.