Infancy Task 3 Development of haptic and visual perception
Learning goals:
1. Development of haptic perception
2. Development of context integration
3. Methods to measure visual context integration
1. Development of haptic perception
Hands are a complex system that involves two functions: a perceptual function (knowing) and
an instrumental function (doing). Infants can know the physical world and surfaces or object
properties with their hands, almost as they do with their eyes. Hands can transform the
environment but visual events may be much more complex and much more numerous, but
their appearance is independent of the perceiver. This discrepancy between vision and touch
limits the study of the haptic system because it is not possible to adapt all the visual
experimental techniques to the haptic mode. Haptic abilities were underestimated and seen as
reflexes, the mouth was seen as an important part of the haptic system and manual exploration
was very limited, and babies often practice manual exploration under visual control so that the
hands were not considered as exploratory tools.
Beyond the hand’s refelexes
Perception of object shape
The haptic modality is the first modality to appear in the foetus. In newborns, the grasping
reflex is seen, followed by the avoiding reflex a few days later. Thse reflexes prelude more
voluntary actions, like handling objects, which allows gathering information about them.
There are two kinds of object properties: material properties (texture, substance, temperature)
and geometric properties (size and shape). The procedure necessary to detect the global shape
is exhibited by the baby from birth, because it is important for object identification. It is also a
prerequisite for observing cross-modal transfer between touch and vision in infants. The
habituation/dishabituation procedure is effective for revealing babies’ manual perceptive
abilities: a baby cannot see his/her hands but receives an object in it -> wait for holding time
to decrease. Then a new object is presented to the baby. The increase in holding times means
that the baby has differentiated between the two objects. Newborns are able to detect
differences in the contour of two small objects (a prism and a cylinder), with either hand. In
the first six months after birth, the baby can detect changes between shapes quite well.
Geometrical shapes are well differentiated from the age of two months. However, these
performances do not mean that the baby has a clear representation of what is being held in the
hand. At 4 months, the baby can explore with both hands at the same time. When putting an
object with a ring at each end into the infant’s hands (connected by either a rigid or a flexible
device) babies discriminate between the objects manipulated according to their rigid or their
flexible properties. At the same age, babies are capable of detecting differences in the weight
of two objects held in each hand.
Haptic memory
Haptic memory is present from birth (habituation). Babies show good texture memory and
recognition of the shapes of familiar objects after a break, but not after an interference (30s at
2months and 2min/LTM at 4months). Nevertheless, recognition can remain fragile after
haptic interference.
Learning goals:
1. Development of haptic perception
2. Development of context integration
3. Methods to measure visual context integration
1. Development of haptic perception
Hands are a complex system that involves two functions: a perceptual function (knowing) and
an instrumental function (doing). Infants can know the physical world and surfaces or object
properties with their hands, almost as they do with their eyes. Hands can transform the
environment but visual events may be much more complex and much more numerous, but
their appearance is independent of the perceiver. This discrepancy between vision and touch
limits the study of the haptic system because it is not possible to adapt all the visual
experimental techniques to the haptic mode. Haptic abilities were underestimated and seen as
reflexes, the mouth was seen as an important part of the haptic system and manual exploration
was very limited, and babies often practice manual exploration under visual control so that the
hands were not considered as exploratory tools.
Beyond the hand’s refelexes
Perception of object shape
The haptic modality is the first modality to appear in the foetus. In newborns, the grasping
reflex is seen, followed by the avoiding reflex a few days later. Thse reflexes prelude more
voluntary actions, like handling objects, which allows gathering information about them.
There are two kinds of object properties: material properties (texture, substance, temperature)
and geometric properties (size and shape). The procedure necessary to detect the global shape
is exhibited by the baby from birth, because it is important for object identification. It is also a
prerequisite for observing cross-modal transfer between touch and vision in infants. The
habituation/dishabituation procedure is effective for revealing babies’ manual perceptive
abilities: a baby cannot see his/her hands but receives an object in it -> wait for holding time
to decrease. Then a new object is presented to the baby. The increase in holding times means
that the baby has differentiated between the two objects. Newborns are able to detect
differences in the contour of two small objects (a prism and a cylinder), with either hand. In
the first six months after birth, the baby can detect changes between shapes quite well.
Geometrical shapes are well differentiated from the age of two months. However, these
performances do not mean that the baby has a clear representation of what is being held in the
hand. At 4 months, the baby can explore with both hands at the same time. When putting an
object with a ring at each end into the infant’s hands (connected by either a rigid or a flexible
device) babies discriminate between the objects manipulated according to their rigid or their
flexible properties. At the same age, babies are capable of detecting differences in the weight
of two objects held in each hand.
Haptic memory
Haptic memory is present from birth (habituation). Babies show good texture memory and
recognition of the shapes of familiar objects after a break, but not after an interference (30s at
2months and 2min/LTM at 4months). Nevertheless, recognition can remain fragile after
haptic interference.
