● Sensation: the processing of basic information from the external world by the sensory receptors in the sense organs (eyes, ears, skin, and so forth) and the brain
● Perception: the processing of organizing and interpreting sensory information about the objects events and spatial layout of the world around us
● Example of sensation and perception: sensation involved light in and sound waves activating receptors in Benjamin’s eye, ears and brain and an instance involving perception was Benjamin experiencing the visual and auditory stimulation provided by the crashing goblet as a single coherent event
● Recent studies have revealed that despite their immature visual systems, even the youngest infants have some surprisingly sophisticated visual abilities
● Preferential-looking technique: a method for studying visual attention in infants that involves showing infants two patterns or two objects at a time to see if the infants have a preference for one over the other ○ Established by Fantz -- infants would rather look at something than nothing -- when a pattern of any sort (striped, newsprint, schematic face) was paired with a plain surface, infants chose to look at the pattern. If you want to learn more check out How common is fetal alcohol syndrome?
● Habituation: repeatedly presenting an infant with particular stimulus until the infant’s response to it declines -- essentially the more you get used to something, the less you notice it
○ Novel stimulus is presented → if the infant’s response increases, the researcher infers that the baby can discriminate between the old and new stimulus
● Preferential-looking method enables researchers to access an infant’s visual acuity
● Visual acuity: the sharpness of visual discrimination -- how clearly they can see
○ This method builds on the research showing that infants who can see the difference between a simple pattern and a solid background prefer to look at the pattern
● Contrast sensitivity: the ability to detect differences in light and dark areas in a visual pattern ○ Infants have poor contrast sensitivity and can only detect a pattern when it is composed of HIGHLY contrasting elements and therefore will prefer to look at black and white patterns ● A reason for poor contrast sensitivity in infants is the immaturity of infant’s cones (the light sensitive neurons that are highly concentrated in the fovea and are involved in seeing fine detail and color Visual Scanning
● Infants are attracted to moving stimuli -- but have difficulty tracking these stimuli because their eye movements are jerky and often do not stay with whatever they are trying to visually follow ● Not until 2 or 3 months of age are infants able to track objects smoothly -- visual scanning gets better with maturation If you want to learn more check out What is written in the dead sea scrolls?
● Infant’s visual scanning is restricted -- infants younger than 2 months old scan the outer edges of complex shapes (ex. Faces -- tend to fixate on the perimeter - hairline, chin where it is in relatively high contrast with the background) at about 2 months, infants scan much more broadly, allowing them to pay attention to overall shape and inner details
● Accurate visual perception of the world requires acquity, systematic scanning and analyzing and integrating the separate elements of a visual display into a coherent pattern
● Figure 5.3 Subjective contour: seeing a square in the 4 pacman circles -- infants see this as well showing that they integrate separate element to perceive the whole
● Bertenthal study: infants watched a film of moving points of light. Adults who watch the film immediately identify what they see as a person walking; the moving lights to be (and are) attached to the major joints of
the head of an adult -- infants see the same thing: they look longer at the point light displays suggest human movement than at ones that do not
○ Infants prefer moving lights that depict biological motion over non biological motion Object Perception We also discuss several other topics like How do we determine if something is nominal, ordinal or interval?
Don't forget about the age old question of What is moral skepticism in ethics?
● Perceptual constancy: the perception of objects as being of constant size, shape, color, etc., in spite of physical differences in the retinal image of the object We also discuss several other topics like What is linguistic anthropology?
● Slater study: newborns were repeatedly shown either a large or small cube at varying distances. While the cube’s size remained the same, the size of the retinal image projected by the cube changed from one trial to the next. The question was whether newborns would perceive these events as multiple presentations of the same object or presentations of similar objects of different sizes. If the infant looks longer at the larger but farther-away cube, researchers will conclude that the child has size consistency
● Object segregation: the perception of boundaries between objects
○ Kellman and Spelke experiment: (presented the importance of motion as a cue of indicating boundaries between objects) - Infants who see the combination f elements in (a) perceive two seperate objects, a rod moving behind a block. After habituating to the display, they look longer at two rod segments than a single rod (b), indicating that they find the single rod familiar but the two segments novel. If they first see a display with no movement, they look equally long at the two test displays. (babies looked longer at the broken rod because it was novel -- making object We also discuss several other topics like What is globalization?
■ Common movement (segments that always move together in the same direction and speed) allowed the infants to perceive the two rod segments as one unit
● Optical expansion: a depth cue in which an object occludes increasingly more of the background, indicating that the object is approaching (object increases size as it comes towards us, occluding more and more of the background)
○ Infants use optical expansion to know when to blink if an object is coming towards them because they cannot duck and this is the only way they can protect their open eye
● Binocular disparity: the difference between the retinal image of an object in each eye that results in two slightly different signals being sent to the brain
○ The closer we are looking at an object, the greater the disparity between the two images; the further away the object, the less the disparity
● Stereopsis: the process by which the visual cortex combines the differing neural signals caused by binocular disparity, resulting in the perception of depth
● Monocular depth cues (pictorial depth cues): the perceptual cues of depth (such as relative size and interposition) that can be perceived by one eye alone
○ Sometimes called pictorial depth cues because they can be used to perceive depth in pictures ● Yonas’s Monocular depth cue study: infants will reach toward whichever object is nearer. Puts a patch over the eye of 5-7 month olds and presented them with a trapezoidal window with one side considerably longer than the other. The 7 month olds but not the younger babies reached towards the longer side, indicating that they perceived it as being nearer, providing evidence that they used relative size as a depth cue
● Auditory localization: the perception of the spatial location of a sound source
○ When they hear a sound, newborns tend to turn towards it -- to localize sound, listeners rely on differences in the sounds that arrive at both of their ears: a sound played to their right will arrive at their right ear before reaching their left and vice versa -- young infants have more difficulty using this information because their heads are small, and thus the differences in timing and loudness in information arriving at each ear are smaller for infants
● The development of an auditory spatial map requires multimodal experiences, which infants become able to integrate information from what they hear with the information from what they see and touch -- the development of an auditory spatial map must therefore await the improvements in visual and motor skills that emerge later in infancy
● Hochberg and Brooks study: tested at 18 months, children readily identified people and objects in photographs and line drawings. Later research established that infants as young as 5 months can recognize people and objects in photographs and drawings, and even newborns can recognize two dimensional versions of 3d objects. However, children will often treat the drawings and pictures as if they are the real thing, not understanding the concept of 2-D
● Infant-directed singing trumps infant-directed speech as a preferred stimulus, as suggested by a study in which 6 month olds were more attentive to videos of their own mother singing than to videos of her speaking
● Infants are able to remember what they hear, recognizing musical excerpts for several weeks after being first exposed to them -- will remember aspects of pitch, timbre, and tempo
● Studies have shown that infants pay more attention to a consonant version of a piece of music (songs with octaves) than a dissonant one (songs like abc)
○ Masataka study -- it was conducted with hearing infants whose mothers were deaf, making it unlikely that the infants would have had prenatal exposure to singing. These results suggest that preferences for consonant music as opposed to dissonant music are not due to musical experience.
● Study: 8 month old infants and adults listened to a brief repeating melody that was consistent with the harmonic conventions of western music. Then, in a series of test trials, they heard the melody again - but with one note changed. On some trials, the changed note was in the same key as the melody; on others, it fell outside the key. Both infants and adults noticed changes that violated the key of the melody, but only the infants noticed the changes that stayed within the key of the melody
○ Suggests that with experience, there is a process of perceptual narrowing. Across all these examples in other doimas, experience leads the young learned to begin to lose the ability to make distinctions that he or she could make at an earlier point in development. Perceptual narrowing permits the developing child to become especially attuned to patterns in biological and social stimuli that are important in their environment
Taste and Smell
● Studies in which infants choose the scent of their own mother opposed to another woman: A pad that an infant’s mother had worn next to her breast was placed on one side of the infant’s head and a pad worn by a different woman was placed on the other side. Two-week-old infants turned more often and spent more time orientated to their mother’s pad
● Another important way infants learn about their environment -- First through the mouth and then with their hands
● Intermodal perception: the combining of information from two or more sensory systems ○ Allows you to perceive an auditory and visual stimulation as a unitary, coherent event ● According to Piaget, info from different sensory modalities is initially separate, and only after some months do infants become capable of forming associations between how things look and how things sound, taste, feel and so on. -- but this is not the case
● Research has shown that very young infants link oral and visual experiences -- infants sucked on a pacifier without seeing it, and were then shown their pacifier and a novel pacifier -- looked longer at the pacifier they sucked on -- infants could visually recognize an object they had only experienced through oral exploration
● Infants possess a variety of forms of auditory-visual intermodal perception: infants simultaneously viewed two different videos, side by side, while listening to a soundtrack that is synchronized with one of the videos and noth the other. If an infant responds more to the video that goes with the soundtrack, it is taken as evidence that the infant detects the common structure in the auditory and visual information
● Spelke Study: showed 4 month olds two videos, one of a person playing peekaboo and another of a hand beating a drum-stick against a block. The infants responded more to the film that matched the sound they were hearing.
● Infants are sensitive to the relation between human faces and voices and between 5-7 months infants notice the relation between emotional expression in faces and voices -- when infants hear a happy voice they look longer at the happy face and when infants hear an angry voice they look longer at the angry face -- when viewing two separate videos of people talking infants are able to figure out which video matches the audio by lip movements and synchronized speech
● Perceptual narrowing -- young infants can detect correspondences between speech sounds and facial movements for nonnative speech sounds that older infants cannot. Similarly, young infants can detect correspondence between monkey facial movements and monkey vocalizations, but older infants are unable to do so
● Study: 7 month olds listened to a musical rhythm that was ambiguous and could be interpreted in either duple or triple time. While infants were listening, they were bounced up and down at a rate either matching duple or triple time interpretation of the ambiguous rhythm. When tested, infants prefer to listen to the version of the rhythm that fit the pattern they were bouncing at -- indicates that infants readily integrate vestibular information with auditory information: how infants were bounced altered how infants interpreted what they were hearing
● Reflexes: innate, fixed patterns of action that occur in response to particular stimulation ○ Grasping reflex: newborns close their fingers around anything that presses against their palm ○ Rooting reflex: when stroked on cheek near their mouth, infant will turn their head in the direction of the touch and open their mouth
○ Sucking reflex/swallowing reflex: both of which increase the baby’s chance of survival ○ These reflexes are not fully automatic: ex. A rooting reflex is more likely to occur w/ hunger ● Tonic neck reflex: when an infant’s head turns or is turned to one side, the arm on that side of the body extends, while the arm and knee on the other side flex -- no benefit is associated with this relex ● The presence of strong reflexes at birth is a sign that the newborn’s central nervous system is good Motor Milestones
● 0-1 month: prone, lifts head
● 2-5 month: Prone, chest up, uses arms for support, rolls over
● 3-6 months: supports some weight with legs
● 5-8 months: sits without support
● 5-10 months: stands with support
● 6-10 months: pulls self to stand
● 7-13 months: walks using furniture for support
● 10-14 months: stands alone easy
● 11-14 months: walks alone easy
● Widely varying cultural practices can affect infant’s development. Researchers have documented somewhat slower motor development in Ache and Chinese infants compared with the norms; Kipsigis babies and the infants who undergo exercise regimes are advanced in motor skills compared to North American infants
● Diapers have an impact on walking behavior? - researchers found that the same infants exhibited more mature walking behavior when tested naked than when wearing diapers
Current Views of Motor Development
● Gesell and Mcgraw -- concluded that infants’ motor development is governed by brain maturation ● Contrast, current theorist believe that early motor development results from a confluence of numerous factors that include developing neural mechanisms, increases in infant’s strength, posture control, balance, and perceptual skills
● Every milestone in this transition is fueled by what infants can perceive of the external world and their motivation to experience more of it
The case of the Disappearing Reflex
● Stepping reflex: holding a newborn so their feet touch the surface; baby will reflexively perform stepping motions -- disappears at about 2 months of age -- Thelen concluded it was because babies gain more weight in their legs and stop this reflex -- disappearance of the stepping reflex is not caused by cortical maturation but the movement is masked by the changing ratio of leg weight to strength
Expanding the World of the Infant
● Prereaching movements: clumsy swiping toward the general vicinity of the objects they see ● at around 3-4 months, they begin successfully reaching for objects
● Study: prereaching infants given velcro patches mittens and velcro patches toys that allowed them to pick up objects. The manual exploration of objects made possibly by the velcro mittens led to the infants’ increased interest in objects and the earlier emergence of their ability to reach independently for them
● At around 7 months, as infants gain the ability to sit independently, their reaching becomes quite stable, and the trajectory of their reaches is consistently smooth and straight to the target
● Great deal of interaction between visual development and motor development
○ But also infants can perform quite well on some motor tasks without auditory of vestibular cues ■ Infants in a completely dark room can successfully grab an invisible object that is making a sound
● Self Locomotion: the ability to move oneself around in the environment
● First by crawling, then by walking
● Gibson found that infants adjust their mode of locomotion according to their perception of the properties of the surface they want to traverse -- would revert back to crawling for more stability
● Scale errors: the attempt by a young child to perform an action on a miniature object that is impossible due to the discrepancy in relative size of the child and the object
○ The child momentarily fails to take into account the relation between his or her own body and the size of the target object
○ These errors are hypothesized to result from a failure to integrate visual information represented in two different areas of the brain in the service of action
Box 5.5: A Closer Look
● Can children perceive depth?
● Gibson and Walk used the visual cliff (a thick sheet of plexiglass that can support the weight of a toddler. A platform across the middle divides the apparatus into two sides. A checked pattern right under the glass on one side makes it look as if it is a solid sade surface. On the other side, the same pattern is far beneath the
glas, and the contrast in the apparent size of the checks make it look as though there is a cliff between the two sides)
○ 6-14 month olds would readily cross the shallow side of the cliff but would not cross the deep side even when a parent was telling them to come -- strong evidence that they perceived and understood the significance of the depth cue of relative size
● Adolph: parents enticed infants to crawl or walk down sloping walkways that varied in steepness. Some tasks were impossible for an infant -- experienced crawlers distinguished between which slopes were safe to traverse and which weren't but new walkers overestimated which slopes they could safely travel down -- used social referencing (child's use of another person’s emotional response to an uncertain situation to decide how to behave) to decide which slope to travel down
● Habituation: recognizing something that has been experienced before
● Habituation is highly adaptive: diminished attention to what is familiar enables us to pay attention to, and learn about, what is new
● The speed with which an infant habituates is believed to reflect the general efficiency of the infant’s processing of information
● Infants who habituate relatively rapidly, who take relatively short looks at visual stimuli, and/or who show a greater preference for novelty tend to have higher IQs
● Differentiation: extracting from the events in the environment the relation between those elements that are constant
○ ex) infants learn the association between tone of voice and facial expression because, in their experience, a pleasant, happy or eagerly excited tone of voice occurs with a smiling face - not a frowning one - and a harsh, angry tone of voice occurs with a frowning face - not a smiling one. ● Affordances: the possibilities for action offered by objects and stimulations
○ They discover, for example, that small objects - but not large ones - afford the possibility of being picked up, that liquid affords the possibility of being poured and spilled, and chairs of certain size affords the possibility of being sat on
○ Infants learn that solid, flat surfaces afford stable walking, whereas squishy, slick or steeply sloping surfaces do not
● Learning is not required to detect an event involving sight and sound as a unitary; however, one does have to learn what particular sights and sounds go together (shattering is glass being broken)
● Predictability in the environment: ex) hearing mom’s voice then seeing her face shortly after ● Study showing that infants are sensitive to the regularity of one event following the next: 2-8 month olds were habituated with 6 visual shapes that were presented one after another w/ specified levels of probability ○ ex) three pairs of colored shapes always occur together in the same order -- in a test the order of appearance of one or more of the shapes was changed and the infants looked longer when the order was violated
● Goldilocks effect - avoiding patterns that are too simple or too hard while continuing to focus on those abilities that are just right, given the infants learning abilities suggests that infants allocate attention differently to different learning problems, preferentially attending to those patterns that are the most informative
● Classical conditioning: a form of learning that consists of associating an initially neutral stimulus with a stimulus that always evokes a particular reflexive response
● First discovered by Ivan Pavlov with his famous dog experiment
● Unconditioned stimulus (UCS): in classical conditioning, a stimulus that evokes a reflexive response ● Unconditioned response (UCR): In classical conditioning, a reflexive response that is elicited by the unconditioned stimulus
● Conditioned stimulus (CS): in classical conditioning, the neutral stimulus that is repeatedly paired with the unconditioned stimulus
● Conditioned response (CR): in classical conditioning, the originally reflexive response that comes to be elicited by the conditioned stimulus
● ex) the nipple in the infants mouth is an USC that reliably elicits an UCR (sucking reflex), breast or bottle is an CS repeatedly occurs just before the unconditioned stimulus (baby ses the breast or bottle before receiving the nipple). Gradually, the originally reflexive response becomes a learned behavior (CR), triggered by the exposure to the CS (anticipatory sucking movements now begin whenever the baby sees the breast or bottle)
● Instrumental conditioning (operant conditioning): learning the relation between one’s own behavior and the consequences that result from it (relationship between one’s own behavior and the reward or punishment it results in)
○ ex) shaking a rattle produces sound, exploring the dirt in a potted plant leads to parental reprimand ● Positive reinforcement: a reward that reliably follows a behavior and increases the likelihood that the behavior will be repeated
○ Contingency relation between the infant’s behavior and the reward: if the infant makes the target response, then he or she receives the reinforcement
○ ex) learned response: push a lever; reinforcement: cause a toy train to move along a track ● Rovee-Collier procedure: experimenters tie a ribbon around a baby’s ankle and connect it to a mobile hanging above infant’s crib. Babies will then realize the relation between kicking their legs and moving the mobile. They then kick their legs deliberately to enjoy the mobile. Mobile movement serves as reinforcement for kicking
○ Intensity of reward (amount of mobile movement) depends on intensity of baby’s behavior ○ Findings: 3 month olds remember the kicking response for 1 week; 6 months old for 2 weeks; and infants younger than 6 months old remember the kicking response only when the mobile is identical to the training mobile, whereas older infants remember it with novel mobiles
● Infants with depressed mothers smile less maybe because their smiling is rarely rewarded by the preoccupied parent
● infants work hard at learning to predict and control their experience, and once control has been established, they dislike losing it -- babies cry when they turn their head and do not receive the sweet liquid like they were conditioned to
● Potent source of infant’s learning is their observation of other people’s behaviors
● Meltzoff and Moore found that after newborns watch an adult model slowly and repeatedly stick out their tongue, they often stick out their own tongue. At 6 months, infants will even try to stick out their tongue to the same side adults do.
● Infants imitate novel, strange behaviors: experimenter would lean over and touch his head to a box, causing it to light up. Infants did the same even a day after the experimenter first did it.
● Infants seem to analyze the reason for the person’s behavior -- if the experimenter remarks that they are cold and clutches a blanket around herself as she leans over and touches the box with her head, the baby will touch the box with their hand instead of their head. Infants reason that the experimenter would have touched the box with their hand if their hands were free. -- their imitation is based on the analysis of the person’s intentions
● Dumbbell toy experiment: the adult pulled two ends, but his hand then slipped off and the dumbbell remained in one piece. When the infants were given the toy, they pulled the two ends apart, imitating what the adult had intended to do, not what they actually did. When they watched a machine try to pull the two ends apart, they rarely attempted to pull apart the dumbbell themselves. Thus, infants attempt to reproduce the behavior and intentions of other people, but not inanimate objects.
● Infants also observe and learn from other peers or adults in videos
● Mirror neuron system: this system becomes activated when monkeys engages in action and is also activate when the monkey merely observes another monkey or human engage in action as though the monkey is doing it himself
● Rational learning: the ability to use prior experiences to predict what will occur in the future ○ ex) going to your favorite chinese food restaurant and expecting them to serve chinese food -- this is violated if you come back and they are serving mexican food
● Xu & Garcia Study: infants were shown a box containing 75 ping pong balls: 70 red, 5 white. The infants observed an experimenter close her eyes and draw 5 balls from the box - either 4 red and 1 white or 4 white and one red - and put them on display. The infants looked longer at the display with the four white balls, indicating that they were surprised that the experimenter drew mostly white balls from a mostly red ball set -- violation of expectation
● Nativist believe that babies possess innate knowledge in a few domains of particular importance while empiricists believe that babies do not. According to empiricists, infants’ mental representations of the physical world are gradually acquired and strengthened through the general learning mechanisms that function across multiple domains.
● Piaget believed that young infants’ understanding of the world is severely limited by and inability to mentally represent and think about anything that they cannot currently see, hear, touch, so on. His test of object permanence led him to believe that once an infant can no longer see an object, they believe it ceases to exist.
● Simplest evidence for young infants’ ability to represent an object that has vanished out of sight is the fact that tthey will reach for an object in the dark, that is, they reach for an object they cannot see. When infants see an attractive object then the lights are turned off, infants will grab towards the direction where they last saw the object proving that even though they cannot see it, it does not cease to exist.
● Violation of expectancy: a procedure used to study infant cognition in which infants are shown an event that should evoke a surprise or interest if it violates something the infant knows or assumes to be true ○ An event that is impossible or inconsistent with respect to the infants knowledge should evoke a greater response (looking at it longer) than does a possible or consistent event
● Baillargeon study: (sought to see if infants too young to search for an invisible object might nevertheless have a mental representation of its existence) In some of these studies infants were first habituated to the sight of a solid screen rotating back and forth on an 180 arc. Then a box was placed in the screen’s path, and the infants saw two test events. In one possible event, the screen rotated upward, occluding the box as it did so, and stopped when it contacted the box. In the impossible event, the screen continued to rotate the full 180 degrees, appearing to pass through the space occupied by the box. -- infants looked longer at the impossible event because they would’ve thought the box was still going to be present (mentally representing an object they could no longer see)
● Ball slope study: infants observed a ball being released on a slope, 7 month olds (but not 5 month olds) looked longer when the ball moved up the slope than when it moved down, indicating that they expected the ball to go down
● At 3 months of age, infants are surprised if a box that is released in midair remains suspended but as long as there is any contact between the box and the platform the young infants do not react when the box remains stationary. At 5 months, they appreciate the relevance of the type of contact involved in support, they now know that the box will only be stable if it is released on top of the platform. At one, they can take into account asymmetrical objects being balanced on top of the box
● Important aspect: understanding that behavior is purposive and goal directed
● Woodward study: 6 month old infants saw a hand repeatedly reach towards one of two objects sitting side by side. Then the position of the two objects was reversed and the hand reached again. The question was if the infants saw the behavior as directed towards a specific object -- they did! Shown by their looking longer when the hand went to a new object (in the old place) than when it went for the object consistently reached for
○ Shown the same training event, slightly older infants were able to correctly predict what the human hand would do next, moving their eyes to the goal object in the test display before the hand actually moved to the goal object
● Sommerville, Woodward and Needham study: established that infants’ understanding of the goal-directed nature of another’s actions is related to their own experience achieving a goal
○ 3 month olds were fitted with velcro mittens that enabled them to pick up velcro toys. Their brief experience of picking up toys enabled them to interpret the goal directed reaching of other in the Woodward’s previous procedure.
● Johnson study: 12-15 month olds were introduced to a faceless, eyeless blob that vocalized and moved in response to what the infant or experimenter did, thus stimulating a normal human interaction. When the blob turned in one direction, the infant looked in that direction -- they seemed to follow the blobs gaze like they'd do with a human partner BUT they did not behave this way if the blob’s initial behavior was not contingently related to their own
● Infants exhibit preferences for particular individuals and objects based on the individuals’ and objects’ actions
● Infants are more likely to accept an object offered by someone who speaks their native language ● If an object is moved to a new location while an infant - but not the adult - is looking, the infant expects the adult to search for the object in its original location. That is, the infant expects the adult to search where he or she should believe the toy to be, rather than in the location where the infant knows it actually is. The interpretation is based on the fact that the infants looked longer when the adult searched the object's current location than they did when the adult searched its original location. -- indicates that infants assume that a person’s behavior will be based on what the person believes to be true, even if the infant knows that belief is false.