Looming studies

Seeing it Coming: Infant's brain responses to looming danger

by Van der Weel & Van der Meer

A fundamental property of most animals is the ability to see whether an object is approaching on a direct collision course and, if so, when it will collide. Using high-density electroencephalography in 6- to 11-month-old infants and a looming stimulus approaching under three different accelerations, we investigated how the young human nervous system extracts and processes information for impending collision. Here we show that visual evoked potentials are precisely timed to when the looming stimulus makes virtual contact. Source analyses reveal localised activity in the visual cortex. Analysing the rate of change of the source waveform, we provide evidence that crucial temporal characteristics of our looming stimulus are maintained during processing in the infant brain, providing important time-to-collision information about looming danger.

Seeing it coming: infant's brain responsen to looming danger

Timing strategies used in defensive blinking to optical collisions in 5- to 7- month-old infants 

by Kayed & Van der Meer

When objects approach on a collision course, young babies will blink to protect their eyes. The timing of the blink is crucial, since it serves to protect the eyes from being injured. The image of a looming virtual object approached infants under different constant velocities and constant accelerations. The youngest infants (5–6 months) blinked when the image of the virtual object reached a threshold visual angle, while older infants (6–7 months) geared their blinks to the image’s time-to-collision. Infants using a strategy based on time coped successfully with all approach conditions, while infants using a strategy based on visual angle had difficulty with the fastest accelerative approach condition. The findings indicate that infants around 6 months of age shift to a more sophisticated strategy based on time, allowing them to deal with more demanding perceptual tasks.

Read article: Infant Behavior & Development

Infants' timing strategies to optical collisions: A longitudinal study

by Kayed & Van der Meer

Blinking is a good indication of awareness to optical collisions in early infancy. In the current longitudinal study, infants were
presented with the image of a looming virtual object approaching on a collision course under different constant velocities and constant accelerations. The aim was to investigate which timing strategies the infants used to determine when to make the defensive blink. Blinking when the virtual object reaches a threshold visual angle (angle-strategy) or angular velocity would result in difficulties with accelerating approaches, while blinking when the object is a certain time away (time-strategy) would enable successful responses to all approaches. Eleven infants were tested longitudinally at 22, 26, and 30 weeks. Five infants switched from an angle- to a time-strategy, while one infant switched from using angular velocity to a time-strategy. Five infants used a timestrategy already at 22 weeks. These findings show that with age there is an attunement in the perceptual systems of infants which makes them switch to better specifying variables, enabling them to successfully time their defensive blinking to impending optical collisions.Looming is a Naturally Occuring Phenomenon

Arm Waving

The Functional Significance of Arm Movements in Neonates

by Van der Meer, Van der Week & Lee

Arm movements made by newborn babies are usually dismissed as unintentional, purposeless, or reflexive. Spontaneous arm-waving movements were recorded while newborns lay supine facing to one side. They were allowed to see only the arm they were facing, only the opposite arm on a video monitor, or neither arm. Small forces pulled on their wrists in the direction of the toes. The babies opposed the perturbing force so as to keep an arm up and moving normally, but only when they could see the arm, either directly or on the video monitor. The findings indicate that newborns can purposely control their arm movements in the face of external forces and that development of visual control of arm movement is underway soon after birth.

Feeding

Coordination of Sucking, Swallowing, and Breathing in Healthy Newborns

by Van der Meer, Holden & Van der Weel

Successful feeding requires precise coordination of sucking, swallowing, and breathing. We aimed to describe the normal organization of bottle feeding in healthy newborn infants (10 full-term and 3 near-term). Sucking pressure and breathing movements were recorded by specialized pressure transducers. Swallowing sounds were recorded on a professional DAT sound recorder with a miniature microphone attached to the infant’s throat. A well-coordinated feeding pattern showed flexibility and good control, and was characterized by a 1:1:1 coordination of sucking, swallowing, and breathing, where maximum sucking pressure was coordinated with breathing out, and swallowing took place just before the onset of the next suck and between breathing out and breathing in. An efficient sucking pattern was characterised by a relatively lower sucking pressure and longer duration of each suck. When the coordination broke down, breathing was typically the bottleneck, with infants being unable to maintain adequate ventilation while sucking and swallowing during nutritive feeding. In order to be able to positively identify abnormal feeding patterns that may be indicative of brain damage in infants who are neurologically at risk, detailed knowledge about what characterizes a normal feeding pattern is first required. The results of this study are promising as they provide us with norm data on the temporal organization between sucking, swallowing, and breathing. However, in order to be able to use feeding successfully to identify neurological problems in infants early on in life, more data on premature infants are warranted.

Locomotion

The Fetus and Newborn Considered as Water-Babies

by Van der Meer

We have all seen pictures of an unborn fetus sucking its thumb in the womb. So why does it take the average newborn baby about eight weeks before it can do the same again? The human newborn, compared to other primate babies, is born with very unfortunate body proportions which make the production of movements difficult. First of all, in order to accommodate the large human brain, babies are born with a head a quarter of their total body size. Imagine having to go around your daily business with a head the size of a large watermelon on your shoulders! Secondly, our newborns are born relatively fat to make up for the fact that we do not have any fur to keep us warm. Add to this that the human newborn has been floating around in a watery environment for the past nine months which made it impossible for the baby to build up muscles strong enough to cope with gravity, and you end up with a recipe for disaster when it comes to the control and coordination of early movements.