Interceptive Actions in Adults and Children

Interceptive actions refer to goal directed movements in which people attempt to make a controlled collision with a moving object (e.g. catching a ball). Because interceptive actions often take place under severe temporal constraints, movements need to be executed with exquisite temporal accuracy and precision. To achieve this the sensorimotor system needs to: (i) accurately predict the motion of the target object, and (ii) move the intercepting effector (e.g. hand, bat) to a location through which the object will pass at just the right time. This presents the sensorimotor system with numerous computational challenges. Examining interceptive timing in adults provides insights into how these challenges are overcome in the developed sensorimotor system, while studying children can reveal how these abilities are acquired and how they are related to the development of other sensorimotor and cognitive processes. The first part of this thesis investigates the control of interceptive timing behaviours in adults. Chapter 3 provides evidence that online sensory information is combined with a-priori knowledge, using Bayesian integration, to optimise movement timing. Chapter 4 demonstrates that adults optimally time their movements to exploit a physical relationship between the speed and temporal precision of their movements. The second part of this thesis then examines interceptive timing abilities in children. Chapter 5 documents the developmental trajectory of interceptive timing abilities over childhood, revealing that performance is still far from adult levels by the time children finish primary school (age 11 years). Chapter 6 tests a common taxonomy of motor skills, revealing that interceptive timing tasks measure a somewhat distinct ‘motor construct’ from that measured by ‘fine’ and ‘gross’ motor tasks. Finally, chapter 7 reveals a relationship between interceptive timing abilities and academic attainment in mathematics, even after controlling for motor skills in other taxonomic domains. Together these experiments shed light on how humans are able to exquisitely time interceptive actions, and provide key insights into the ontogeny of this fundamental motor ability.