Control and development of time-based visual selection

Attention plays an integral role in healthy cognitive functioning, and failures of attention can lead to unfavourable and dangerous consequences. As such, comprehending the nature of attentional mechanisms is of fundamental theoretical and practical importance. One way in which humans can attentionally prioritise new information is through top-down inhibition of old distractors, known as the preview benefit (Watson & Humphreys, 1997). In the preview benefit, time is used to efficiently guide visual selection in space. Given that this ability is based on limited resources, its deployment in everyday life may be hindered by a multitude of factors. This thesis will explore the endogenous and exogenous factors that can facilitate or constrain the preview benefit, and determine its developmental trajectory. Understanding the nature of this mechanism (endogenous and exogenous factors) in adults can elucidate the contexts in which visual selection can efficiently filter old distractors. In turn, a developmental perspective can unravel the hidden aspects of this ability and inform when children are endowed to use temporal information for efficient attentional selection. Chapter 1 introduces the theoretical problems and topics of attentional research in adults and children. Chapter 2 addresses the question of endogenous control of top-down inhibition in time-based visual selection – when can top-down inhibition be controlled by the observer? Chapter 3 examines the exogenous influence of complex stimuli on time-based visual selection. Chapters 4 and 5 focus on the development of time-based visual selection for stationary and moving stimuli, respectively, in children aged 6 to 12 years. These chapters also examine the relative association of the efficiency of the preview benefit with the development of executive functions across different age-groups. Overall, the findings suggest that there exist remarkable endogenous and exogenous constraints in how time guides selection. This may account for why in certain contexts, attentional selection can fail to be efficient. Moreover, time-based visual selection shows striking quantitative and qualitative changes over developmental time, and most importantly, children have a long developmental trajectory in learning to ignore moving items. Unlike children, adults’ time-based visual selection is coupled with individual differences in executive functions, highlighting an acquired functional connection. The findings are discussed in terms of their theoretical implications for time-based visual selection, the development of children’s attentional control for distractors, and impact routes for educational and clinical practice, and policy makers.