In the first years of life there is a dramatic development of cognitive abilities supporting cognitive control of behavior. This development allows the child to make future-oriented predictions and to increasingly act in a goal-directed manner. The early development of cognitive control is presumably closely tied to the maturation of the attention systems. Further, attentional control processes have been suggested to be the unifying construct underlying cognitive control in both children and adults. The general aim of the present thesis was to further our understanding of the early development of cognitive control. This aim was approached by examining the attention processes underlying cognitive control in infancy and toddlerhood, with a particular focus on age-related improvements in attentional control. This thesis consists of three studies that have used the A-not-B paradigm to investigated infants’ and toddlers’ ability to search for a hidden object or to correctly anticipate the reappearance of a hidden object. The A-not-B paradigm is one of few well-studied paradigms for research on the early development of cognitive control and this paradigm involves conflict resolution and requires a flexible shift of response set to achieve a goal. Study I of this thesis examined individual differences in 10-month-olds’ ability to search for a hidden object in a manual A-not-B task. We investigated the infants’ search behavior, both in terms looking and reaching responses, the relation between individual differences in performance on A and B trials, and also the relation between the two response modalities. Study II used eye tracking and focused on the role of attentional demand on 10- and 12-month-olds’ ability to anticipate the reappearance of a hidden object. This study intended to clarify age-related improvements, particularly in relation to the ability to resist visually distracting information that interfered with the task at hand. Study III also employed an eye tracker to measure 18-month-olds’ predictive eye movements in anticipation of a hidden object under conditions marked by different attention demands. This study not only investigated the toddlers’ ability to overcome a visual distractor, but also their ability to keep a representation in actively in mind over different delays. In addition, the 18-month-olds’ performance was compared to that of an adult group to shed further light on the development of attentional control in children. In conclusion, this thesis demonstrated that important age-related improvements in cognitive control take place by the end of the first year of life and between 12 and 18 months of age. More specifically, with increasing age, the children were able to resolve higher levels of conflict thereby demonstrating improvements in attentional control. In interpreting the present data, we argue that this development is gradual, developing from variable to stable and also that the attentional control process is best described as continuous rather dichotomous in infancy and toddlerhood. Based on our findings, future research should be motivated to examine changes in attentional control processes in relation to the early development of cognitive development.

The current study revisits the causal link between finite cognitive capacity and infant perseveration originally put forth by Berger (2004) wherein perseverative errors resulted from a limited amount of cognitive resources. A dynamic systems perspective was used to test the interaction of a limited cognitive capacity and task difficulty by manipulating the contextual layout of Berger’s stair A-not-B paradigm (i.e. from 90-degrees to 180-degrees). Two groups of infants, differing in walking experience but not in biological age, were presented the task of descending A-side 5 consecutive times and to B-side on the 6th trial. Perseveration was not seen in either experience group; however, inexperienced walkers exhibited slower decision-making and stair descent on B-trial than their experienced counterparts. Results suggest that task difficulty alone is not enough to elicit perseveration but is a considerable factor when investigating the error.

Two studies investigated the effects of various motor constraints of reaching on infants’ search performance on the A-not-B task. These studies were motivated by the idea that motor memories for reaching lead to A-not-B errors. The 2 motor constraints that were evaluated included barriers that blocked the path of the hand and hand-use preferences. Each of these motor constraints was examined separately. In Experiment 1, infants (N = 40, 20 8-month olds, 20 16-month olds) were given the A-not-B task twice. One condition was analogous to the traditional A-not-B task (i.e., using 2 hiding locations) and the other was modified such that a barrier (i.e., an opaque screen) blocked the infants’ reaching path of location A on A trials only. On A trials, all infants searched correctly less often when a barrier was present, and younger infants searched correctly less often than older infants. On B trials, younger infants made more errors in the no barrier condition, whereas older infants did not show any significant difference in B trial performance across conditions. In Experiment 2, infants (N = 51) completed an adapted handedness test (Michel, Ovrut, & Harkins, 1985) followed by a modified A-not-B task. The test assessed infants’ hand-use preferences for reaching, which was used to group infants into their respective preference group (i.e., consistent or inconsistent). Infants with a consistent preference were randomly assigned to a hiding side group (i.e., A on preferred side or A on non-preferred side). Infants searched correctly more often when hiding side was congruent with their preferred reaching hand, and older infants searched correctly more often than younger infants. On the B trial, neither age nor hiding side affected the production of the A-not-B error. Collectively, these studies present data that address the theory that motor memories for reaching are the cause for the production of A-not-B error. These studies provide novel evidence that motor memories for reaching are present in infants aged 8- and 16-months, and that motor memories can influence the production of such errors in certain A-not-B contexts. Implications and directions for future research are also discussed.

Two studies investigated the effects of various motor constraints of reaching on infants’ search performance on the A-not-B task. These studies were motivated by the idea that motor memories for reaching lead to A-not-B errors. The 2 motor constraints that were evaluated included barriers that blocked the path of the hand and hand-use preferences. Each of these motor constraints was examined separately. In Experiment 1, infants (N = 40, 20 8-month olds, 20 16-month olds) were given the A-not-B task twice. One condition was analogous to the traditional A-not-B task (i.e., using 2 hiding locations) and the other was modified such that a barrier (i.e., an opaque screen) blocked the infants’ reaching path of location A on A trials only. On A trials, all infants searched correctly less often when a barrier was present, and younger infants searched correctly less often than older infants. On B trials, younger infants made more errors in the no barrier condition, whereas older infants did not show any significant difference in B trial performance across conditions. In Experiment 2, infants (N = 51) completed an adapted handedness test (Michel, Ovrut, & Harkins, 1985) followed by a modified A-not-B task. The test assessed infants’ hand-use preferences for reaching, which was used to group infants into their respective preference group (i.e., consistent or inconsistent). Infants with a consistent preference were randomly assigned to a hiding side group (i.e., A on preferred side or A on non-preferred side). Infants searched correctly more often when hiding side was congruent with their preferred reaching hand, and older infants searched correctly more often than younger infants. On the B trial, neither age nor hiding side affected the production of the A-not-B error. Collectively, these studies present data that address the theory that motor memories for reaching are the cause for the production of A-not-B error. These studies provide novel evidence that motor memories for reaching are present in infants aged 8- and 16-months, and that motor memories can influence the production of such errors in certain A-not-B contexts. Implications and directions for future research are also discussed.

Made available in DSpace on 2014-06-11T19:22:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-23Bitstream added on 2014-06-13T19:08:23Z : No. of bitstreams: 1 souza_jm_me_rcla.pdf: 420849 bytes, checksum: 96e572c023cf9e826bcf7705b8a27d24 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Durante o desenvolvimento da criança, a manipulação de objetos provoca no bebê o interesse por novas experiências. Estudos sobre alcançar e manipular objetos sugerem que o desenvolvimento destas habilidades depende de experiências prévias de ver e tocar. Porém o alcance não depende só de ver o alvo mas também de algumas características de controle motor, pois mesmo quando a criança olha para o objeto, ela pode cometer erros de direção de alcance. Um exemplo sobre errar qual objeto deve ser alcançado é o erro da perseveração. A perseveração motora no ato de alcançar mostra o envolvimento entre eventos de controle motor e percepção, planejamento, decisão e execução dentro da dinâmica corporal. Sendo assim, perseveração é definida como uma reposta repetitiva e inapropriada ao estímulo. Por exemplo: porque somos acostumados a dirigir um carro com câmbio manual quando dirigimos um carro com câmbio automático é comum pisarmos no freio pensando que é a embreagem. Para testar a perseveração em crianças vários estudos utilizam a tarefa “A não B” que originalmente foi utilizada por Piaget em para entender o desenvolvimento cognitivo infantil. Esta tarefa consiste em, após mostrar um objeto para um bebê, escondê-lo em um de dois locais (ex., um buraco numa caixa). Após 5 segundos de espera o experimentador permite a criança procurar pelo objeto escondido. O fato é que após alguns alcances no mesmo local, mesmo que a criança observe o experimentador esconder o objeto em outro local, a criança volta a procurar o objeto no local anterior. Existem várias linhas de pesquisas que estudam o porquê cometemos erros de perseveração... / During the development of the child, causing the manipulation of objects in the baby's interest for new experiences. Studies reach and manipulate objects suggest that the development of these skills depends on previous experience of seeing and touching. But the scope depends not only to see the target but also some characteristics of motor control, because even when the child looks at the subject, she may commit errors of direction of power. An example of mistakes which object to be achieved is the error of perseveration. The perseveration motor shows in the act of achieving the involvement of events between perception and motor control, planning, decision and implementation within the dynamic body. So perseveration is defined as a repetitive and inappropriate response to the stimulus. For example, because we are accustomed to driving a car with manual exchange rate when addressing a car with automatic exchange is common in oppress brake thinking that is the clutch. To test the perseveration children in several studies using the task A not B that was originally used by Piaget in order to understand the children's cognitive development. This is, after showing an object for a baby, hide it in one of two locations (eg, a hole in a box). After 5 seconds of waiting allows the investigator to search for the child hidden object...(Complete abstract, click electronic access below)

Orientador: Eliane Mauerberg de Castro / Banca: José Angelo Barela / Banca: Renato de Moraes / Resumo: Durante o desenvolvimento da criança, a manipulação de objetos provoca no bebê o interesse por novas experiências. Estudos sobre alcançar e manipular objetos sugerem que o desenvolvimento destas habilidades depende de experiências prévias de ver e tocar. Porém o alcance não depende só de ver o alvo mas também de algumas características de controle motor, pois mesmo quando a criança olha para o objeto, ela pode cometer erros de direção de alcance. Um exemplo sobre errar qual objeto deve ser alcançado é o erro da perseveração. A perseveração motora no ato de alcançar mostra o envolvimento entre eventos de controle motor e percepção, planejamento, decisão e execução dentro da dinâmica corporal. Sendo assim, perseveração é definida como uma reposta repetitiva e inapropriada ao estímulo. Por exemplo: porque somos acostumados a dirigir um carro com câmbio manual quando dirigimos um carro com câmbio automático é comum pisarmos no freio pensando que é a embreagem. Para testar a perseveração em crianças vários estudos utilizam a tarefa "A não B" que originalmente foi utilizada por Piaget em para entender o desenvolvimento cognitivo infantil. Esta tarefa consiste em, após mostrar um objeto para um bebê, escondê-lo em um de dois locais (ex., um buraco numa caixa). Após 5 segundos de espera o experimentador permite a criança procurar pelo objeto escondido. O fato é que após alguns alcances no mesmo local, mesmo que a criança observe o experimentador esconder o objeto em outro local, a criança volta a procurar o objeto no local anterior. Existem várias linhas de pesquisas que estudam o porquê cometemos erros de perseveração...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: During the development of the child, causing the manipulation of objects in the baby's interest for new experiences. Studies reach and manipulate objects suggest that the development of these skills depends on previous experience of seeing and touching. But the scope depends not only to see the target but also some characteristics of motor control, because even when the child looks at the subject, she may commit errors of direction of power. An example of mistakes which object to be achieved is the error of perseveration. The perseveration motor shows in the act of achieving the involvement of events between perception and motor control, planning, decision and implementation within the dynamic body. So perseveration is defined as a repetitive and inappropriate response to the stimulus. For example, because we are accustomed to driving a car with manual exchange rate when addressing a car with automatic exchange is common in oppress brake thinking that is the clutch. To test the perseveration children in several studies using the task "A not B" that was originally used by Piaget in order to understand the children's cognitive development. This is, after showing an object for a baby, hide it in one of two locations (eg, a hole in a box). After 5 seconds of waiting allows the investigator to search for the child hidden object...(Complete abstract, click electronic access below) / Mestre