Perception

• Sensation is the processing of basic info from the external world by receptors in the sense organs (eyes, ears, skin…) and the brain.

• Perception is the process of organizing and interpreting sensory info about the objects, events, & spatial layout of the world around us.

Vision

• Preferential-looking technique

  • This technique is a method for studying visual attention in infants.

  • Infants are shown 2 images simultaneously to see if the infants prefer one over the other.

• A method that is used to study sensory and perceptual development is habituation, where an infant is presented with a stimulus until it essentially gets used to it and acts accordingly, which lets the researcher know that the baby can discriminate between old and new stimuli.

Visual Acuity and Color Perception

• The preferential-looking method lets researchers assess visual acuity which is the sharpness and clarity of vision.

• Infants have poor contrast sensitivity, which is the ability to detect differences in light and dark areas in a visual pattern. So, using this method or a variation of it helps them learn about infant’s early visual abilities.

• A reason for this is the immatury of their cone cells which are light-sensitive neurons that are involved in seeing fine detail and colour.

• By 8 months, infants can see almost as well as adults, and by 2 months, they can see colour almost as well as adults, and at 5 months, they can categorize some colours without labels.

Visual Scanning

• By 4 months, infants develop the use of smooth pursuit eye movements which is when their gaze shifts at the same rate and angle as a moving object, which keeps it in view and is a way infants have active control over what they observe and learn.

• Infants younger than 2 months look at one corner, and 1 month olds fixate on the perimeter because of the high contrast.

  • Faces are the most prominent in infant’s visual environments.

• At 4 months, before infants babble, they look at the speaker’s eyes, but once they do, they look at the speaker’s mouth. This supports the view that attention to a talking mouth may be related to infant’s development of spoken language.

  • When they are learning two similar-sounding languages, they pay even more attention to the mouth than if they were learning two different-sounding languages.

Object Perception

• When a person moves to or away from us, they look to change shape and size, but we do not think they do in reality, which is perceptual constancy.

• Through an experiment with similar objects of different sizes, researchers found out that newborns percieved the multiple presentations of the same object as a single object of constant size, meaning newborns do have perceptual constancy.

• In another experiment, 4-month-olds were presented with a display of a block with what could either be two pieces of a rod moving on each end of a block of wood or a single rod moving behind the block.

  • The infants assumed there was a single intact rod moving behind it because they were moving together in the same direction and at the same speed, which highlights the importance of common movement.

  • Infants who saw the display without movement stared equally long at the two pieces of a rod and the intact rod, which means they were not sure which one was correct.

• Essentially, common movement is essential in perceiving disparate elements moving together as one, but it has to be learned and infants only learn to around 2 months of age.

• Experience with specific objects helps infants understand their physical properties to decide whether a certain image is possible or not.

• The culture in which infants develop also influences their attention to the visual world (for example, viewing eyes instead of mouths, and viewing objects instead of actions, and background contexts depending on where in the world they are raised and the customs).

Object Knowledge

• Piaget based his theory in part on his tests on object permanence, but it has been proven that infants do have object permanence as they reach for objects they had before in the dark.

• The violation-of-expectancy procedure is used to study infant cognition in which infants are supposed to be shocked or intrigued if the event they are shown goes against something they know.

  • This was used to investigate infant’s representations of non-visible objects.

Depth Perception

• Optical expansion is a depth cue where an object increases in size as it comes towards us, and we know if the object expands symmetrically as well, it is headed for us.

• Infants blink if they see something approaching them from as young as 1 month.

• Preterm infants show a delayed developmental pattern of blinks to approaching objects showing that brain maturation is crucial for depth perception.

• Binocular disparity (the difference between the retinal image of an object in each eye that results in 2 slightly different signals being sent to the brain) helps us percieve depth due to the process of stereopsis, where the visual cortex combines the differing neural signals caused by binocular disparity.

  • Stereopsis is an example of experience-expectant plasticity. If infants are deprived of normal visual input, they may fail to develop normal binocular vision and have difficulty making sense of binocular depth cues.

• At about 6-7 months of age, infants become sensitive to a variety of monocular depth cues which are the perceptual cues of depth that can be percieved with only one eye.

Auditory Perception

• Auditory localization is the perception of the location in space of a sound source, and newborns have difficulty with this because their heads are small which impacts timing and loudness of incoming information.

Music Perception

• Infants enjoy listening to infant-directed singing more than infant-directed speech.

• Infant music perception is adult-like, as they have preferences for consonant intervals (pleasant tones) over dissonant intervals (unpleasant tones).

• Infants can make peceptual discriminations in melody that adults cannot, and are more sensitive to aspects of musical rhythm than adults.

  • These examples suggest that experience fine-tunes the perceptual system which is called perceptual narrowing.

    • Infants become more attuned to patterns in important biological and social stimuli in their environment, making them less sensitive to distinctions they could make before.

• Experience plays a key role in supporting the development of musical abilities and suggests potential relationships between early musical experience & development of language and literacy.

Taste and Smell

• Sensitivity to taste and smell develops before birth.

• Smell plays an important role in how various infant mammals learn to recognize their mothers.

• Food neophobia is when children avoid unfamiliar foods, and is strongly influenced by smell instead of taste.

Touch

• Infants learn about their environment through active touch.

• They gain greater control over their hand and arm movements by 4 months, and relate the sensation of being touched to the locations on their bodies that are being touched (mental maps of their own bodies are being formed).

Intermodal Perception

• Intermodal perception - the combining of information from 2 or more sensory systems

• Infants integrate information from different sense from as early as 1 month (recognizing a pacifier the infant had only sucked before).

• Young infants can detect the correspondences between monkey facial movements and vocalizations, but older infants cannot. Therefore, experience fine-tunes the types of intermodal correspondences that infants detect.

Motor Development

Reflexes

• Fixed patterns of action that occur in response to particular stimulation.

• Examples are rooting, sucking and swallowing, tonic neck, startle, grasping, and stepping.

  • These are not fully automatic as some occur when an infant is feeling something (ex. rooting is more likely when an infant is hungry).

  • Some neo-natal reflexes disappear, but some - coughing, sneezing, blinking, and withdrawing from pain - remain throughout life.

Motor Milestones

• Infants acquire basic movement patterns quickly, and this gives them new ways to think about the world and new things to learn.

• The major milestones of motor development in infancy are:

  • prone, lifts head

  • prone, chest up, uses arms for support

  • rolls over

  • supports some weight with legs

  • sits without support

  • stands with support

  • pulls self to stand

  • walks using furniture for support

  • stands alone easily

  • walks alone easily

• There are tremendous individual and cultural differences in the ages in which these milestones are achieved due to cultural norms & practices and how much motor skills are encouraged, if at all.

• Cultural practices undertaken in one domain can have unforeseen consequences in another domain.

Modern Views of Motor Development

• Arnold Gesell and Myrtle McGraw concluded that infants’ motor development is governed by brain maturation, but current theorists emphasize that early motor development results from the joining of numerous factors including developing neural mechanisms, increases in infants’ strength, posture control, balance, perceptual skills and so on.

• An important aspect of motor development is the infant’s discovery of affordances (the possibilities for action offered, or afforded, by objects and situations).

  • Small objects afford the possibility of being picked up but large objects do not…

  • By figuring this out, they understand the relations between their own bodies, abilities, and the things around them.

• Infants’ increasing ability to explore and manipulate the world around them facilitates learning about the world.

• Infants who are better able to interact with their environment may have an advantage in perceptual and cognitive development by being better able to seek out new opportunities for learning.

The Expanding World of the Infant

Reaching

• Reaching involves a complex interaction of muscle development, postural control, and development of various perceptual and motor skills.

• Infants are limited to pre-reaching movements (clumsy swiping in the general vicinity of objects).

• Reaching behaviour interacts with infants’ growing understanding of the world around them, and has a social component as infants perceive adults as able to help them accomplish goals they can’t on their own, so they reach more often when an adult is present.

Self-Locomotion

• The ability to move oneself around in the environment.

• At about 8 months of age, infants can do this.

• It alters other aspects of infant’s perceptual experience as babies who are lying down can see their caregiver’s face, but when they are crawling they cannot.

• Infants move themselves around in many ways, through crawling before they start to walk by themselves at about 11-12 months.

  • At first, its shaky but as they get stronger, their steps are more consistent and their proficiency at motor tasks improves.

• Scale errors are the attempts by a young child to perform an action on a miniature object that is impossible due to the large difference in the sizes of the child and the object.

  • Scale errors occur because of challenges in integrating perceptual information with motor behaviour.

Learning and Memory

Habituation

• Habituation is a decrease in response after repeated simulation, and it revelas that learning has taken place as the infant has formed a memory of the repeated and now familiar stimulus.

• Habituation is adaptive as lessened attention to what is familiar lets infants pay attention to and learn about what is new.

• How fast an infant habituates is believed to reflect the general efficiency of its processing of information.

  • Infants who habituate relatively rapidly tend to have higher IQs when tested as many as 18 years later.

Statistical Learning

• Infants are highly sensistive to the regularity with which one event follows another, meaning they learn order.

• In music, action, and speech, it has been shown that newborns track statistical regularities, suggesting that statistical learning mechanisms are available at birth, if not before.

  • Statistical learning has been proposed to play an important role in learning languages as well.

• Infants have preferences in statistical patterns, and they like ones that have some variability over ones that are very predictable or very complex.

Classical Conditioning

• Classical conditioning is a form of learning that consists of associating an initally neutral stimulus with a stimulus that always evokes a particular reflexive response.

• This plays a role in infants’ learning about the relations between significant environmental events.

  • Example: a bottle is given to a baby, and the baby starts sucking. The bottle’s suction top would be an unconditioned stimulus (UCS) (a stimulus that evokes a reflexive response), and the sucking reflex would be the unconditioned response (UCR) (a reflexive response that is elicited by the UCS). Conditioning (learning) happens when the bottle, which is the conditioned stimulus (CS) (the neutral stimulus that is repeatedly paired with the unconditioned stimulus) is repeatedly seen before the suction top. Eventually, the originally reflexive response (sucking) becomes a learned behaviour or a conditioned response (CR) (the originally reflexive response that comes to be elicited by the conditioned stimulus) trigged by exposure to the CS → anticipatory sucking movements begin as soon as the baby sees the bottle.

    • The infant may also begin to associate the pleasurable feelings of feeding with the caregiver.

Instrumental Conditioning

• A key form of learning is to discover consequences of one’s own behaviour.

• Instrumental conditioning is learning the relation between one’s own behaviour and the consequences that result from it.

• Most research on this involves positive reinforcement (a reward for correct behaviour in the situation that increases the likelihood the behaviour will be repeated).

• There is a contingency relation between the behaviour and the reward, because if the infant performs the behaviour, then and only then will they recieve the reward.

• Infants’ intense motivation to explore and master their environment shows up in instrumental-learning situations as infants work hard at learning to predict and control their experience and display positive emotions during peaks.

  • Infants also learn that there are situations where they have no control (they cannot change the mood or behaviour of someone else (ex. depressed mother).

• Instrumental learning helps infants learn about the relation between themselves, their environment, and the extent of impact they have on it.

Observational Learning/Imitation

• Imitation is a form of observational learning.

• Infants seem to analyze the reason for the person’s behaviour, and imitate intentions and act accordingly instead of just actions.

• Infants also learn about abstract concepts, like how hard to try at a task (by observing adults who work hard to accomplish their goals, infants may learn to persist at theirs).

Rational Learning

• Infants use prior experience to generate expecations about what will happen next.

• Rational learning is the ability to use prior experience to predict what will happen in the future.

• Infants generate inferences about the future based on prior data and use new experiences to adjust incorrect inferences.

Active Learning

• Active learnign is learning by engaging with the world, rather than passively observing objects and events.

• Infants learn actively instead of passively, and active engagement with the content facilitates learning.

  • Surprise is a driving factor in active learning as infants will be more likely to seek out explanations for what just occured when something unexpected happens.

• Infants use rational learning along with active learning to figure out how the world works.

Memory

• Infants retain information over weeks or months, and long-term memory strengthes with age.

• There are rapid changes in memory over the first year.

  • 6-month-olds can detect changes in only a single item’s colour or location but 12-month-olds can maintain up to 4 items in working memory.

• Infants can retain small numbers of objects in working memory.