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Explore the early controversies, methods, and capabilities of infant sensory development, including vision, hearing, taste, smell, and touch.
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Chapter 6 Early Cognitive Foundations: Sensation, Perception, and Learning Dr. Pelaez
Sensation and Perception • Sensation - the process by which sensory receptor neurons detect information and transmit it to the brain. • Perception - the interpretation of the sensory input; cognitive awareness of what you sense. Ex. You sense a particular smell and have the ability to identify what you are smelling.
Early Controversies About Sensory and Perceptual Development • Nature versus Nurture- Empiricist philosophers believed that an infant was a tabula rasa (blank slate) who must learn to interpret sensations. By contrast, nativist philosophers took the nature side of the nature/nurture issue, arguing that many basic perceptual abilities are innate. • Enrichment versus Differentiation- Both these theories argue that there is an objective reality out there to which we respond.
Early Controversies cont… Enrichment vs. Differentiation • Enrichment Theory - Theory specifying that we must add to sensory stimulation by drawing on stored knowledge in order to perceive a meaningful world. -Sensory information is often fragmented and confusing, therefore we must pull on prior knowledge in order to construct meaning.
Early Controversies cont… • Differentiation Theory - Argues that sensory stimulation provides all we need to interpret our experiences. This implies that our main task is to simply to detect distinctive features in our environment. • distinctive features - characteristics of a stimulus that remain constant; dimensions on which two or more objects differ and can be discriminated.
Making Sense of the infant’s sensory and perceptual experiences • The Preference Method- is a simple procedure in which at least two stimuli are presented simultaneously to see whether infants will attend more to one of them than the other(s). • The Habituation Method- is the process whereby a repetitive stimulus becomes so familiar that responses initially associated with it no longer occur.
Cont………. • Evoked Potentials- another way of determining what infants can sense is to present them with a stimulus and record their brain waves. • High-Amplitude Sucking- provides infants with a special pacifier containing electrical circuitry that enables them to exert some control over the sensory environment.
Infant Sensory Capabilities • Vision- it may be the least mature of the newborn’s sensory capabilities. Changes in brightness will elicit a subcortical pupillary reflex, which indicates that the neonate is sensitive to light. Babies can also detect movement in the visual field and are likely to track a visual stimulus with their eyes as long as the target moves slowly. Newborn infants are likely to track faces than other patterns. • Visual acuity- a person’s ability to see small objects and fine detail. Neonates’ distance vision is about 20/600 (very blurry). Improves rapidly during the first few months
Vision cont… Color perception • By 2-3 months babies can discriminate all basic colors. • By 4 months they can group colors of slightly different shades into the same basic categories.
Infant Sensory Cont… • Hearing- using the evoked potential method, researchers have found that soft sounds that adults hear must be made noticeably louder before a neonate can detect them. In the first few hours of life infants may hear about as well as an adult with a head cold.
Hearing cont…. • Reactions to Voices-Research by Anthony DeCasper and his associates reveals that newborns suck faster on a nipple to hear a recording of their mother’s voice than a recording of another woman. • Reactions to Language- Not only do babies attend closely to voices, but they are also able to discriminate basic speech sounds, called phonemes, very early in life.
Hearing cont… • Consequences of Hearing Loss- Otitis media, a bacterial infection of the middle ear, is the most frequently diagnosed disease among infants and preschool children. As a result, developmentalists have feared that youngsters with recurring infections may have difficulties understanding others’ speech, which could hamper their language development and other cognitive and social skills that normally emerge early in childhood.
Infant Sensory Cont… • Taste and Smell- Infants are born with some very definite taste preferences. For example, they apparently come equipped with something of a sweet tooth because both full-term and premature babies suck faster and longer for sweet liquids than for bitter, sour, salty, or neutral solutions. Newborns are also capable of detecting a variety of odors, and they react vigorously by turning away and displaying expressions of disgust in response to unpleasant smells.
Infant Sensory Cont… • Touch, Temperature, and Pain- Receptors in the skin are sensitive to touch, temperature, and pain. Sensitivity to touch clearly enhances infants’ responsiveness to their environments. Newborns are also quite sensitive to warmth, cold, and changes in temperature. Do babies experience much pain? Apparently so, for even 1 day old infants cry lustily when pricked by a needle for a blood test.
Perception of Three Dimensional Space: • Steropsis - a convergence of visual images of the two eyes to produce a singular nonoverlapping image that has depth. (3 month olds do not exhibit this ability) • Pictorial cues - depth and distance cues including linear perceptive, texture gradients, sizing, interposition, and shading, that are monocular.
Perception of Three Dimensional Space cont… • Visual looming - the expansion of the image of an object to take up the entire visual field as it draws very close to the face. *One month olds may respond to a looming object by blinking defensively. • Size constancy - the tendency to perceive an object as the same size from different distance despite changes in the size of it’s retinal image.
Perception of Three Dimensional Space cont… • Kinetic cues - created by movements of objects or movements of the body; provide important information for the perception of forms and spatial relations. *Inferences about real size among 4 month olds are likely to be accurate if the infants can watch the object approach and recede. • Visual cliff - an elevated platform that creates an illusion of depth; used to test depth perception in infants.
Perception of Three Dimensional cont... • Development of Depth Perception- Eleanor Gibson and Richard Walk developed an apparatus they called the visual cliff to determine whether infants can perceive depth. The visual cliff consists of an elevated glass platform divided into two sections by a center board. On the “shallow” side, a checkerboard pattern is placed directly under the glass. On the “deep” side, the pattern is placed several feet below the glass, creating the illusion of a sharp drop-off, or a “visual cliff.”
Visual Perception in Infancy • Perception of Patterns and Forms- Recall Robert Fantz’s observations of infants in his looking chamber: Babies only 2 days old could easily discriminate visual patterns. • Early Pattern Perception (0 to 2 Months)- babies prefer to look at whatever they see well, and the things they see best are moderately complex, high-contrast targets, particularly those that capture their attention by moving.
Perception of Patterns cont… • Later Form Perception (2 months to 1 year)- Between 2 and 12 months, the infant’s visual system is rapidly maturing. He or she now sees better and is capable of making increasingly complex visual discriminations. He or she is also organizing what he or she sees to perceive visual forms. The most basic task in perceiving a form is to discriminate that object from its surrounding context (i.e., other objects and the general background).
Intermodal Perception -The ability to use one sensory modality to identify a stimulus or pattern of stimuli that is already familiar through another modality. - Are the Senses Integrated at Birth?- The senses are apparently integrated early in life. -Not confirmed to be present at birth but becomes more accurate over time possibly due to the maturation of the senses.
Intermodal Perception cont… • Explaining Intermodal Perception- The findings that the senses are integrated at birth and that at least some intermodal matching is possible in the first few months seems most consistent with the differentiation theory of perception. Differentiation theorists propose that the distinctive features that characterize sensory input are detectable by more than one sensory channel.
Basic Learning Process • Learning - a relatively permanent change in behavior that results from one’s experiences or practice. • Once the individual learns they now think, perceive or reacts to their environment in a new way. • The change is clearly the result of a person’s experiences - that is, attributable to repetition, study, practice or observations the person has made, rather than to hereditary or maturational processes or to physiological damage resulting from injury.
Learning cont…3.The change is relatively permanent. Facts, thoughts, and behaviors that are acquired and immediately forgotten have not really been learned; and temporary changes caused by fatigue, illness or drugs do not qualify as learned responses.
Basic Learning Processes • Learning is one of those deceptively simple terms that are actually quite complex. • Habituation: Early Evidence of Learning and Memory- the process by which we stop attending or responding to a stimulus that is repeated.
Classical Conditioning (Ivan Pavlov) - a type of learning where an initially neutral stimulus is repeatedly paired with a meaningful nonneutral stimulus so that the neutral stimulus come to elicit the response originally made only to the nonneutral stimulus. Process: a neutral conditioned stimulus is repeatedly paired with an unconditioned stimulus that always produces an unconditioned response. After several parings the CS alone will elicit the response which is now called a conditioned response. *
Operant Conditioning (B.F. Skinner) -a form of learning where freely emitted acts become either more or less probable depending on the consequences they produce.
Key Concepts • Reinforcer - any consequence that strengthens a response by making it more likely to occur in the future. • Positive reinforcer - an event that, when introduced following a behavior,makes that behavior more probable in the future. • Negative reinforcer - also strengthen behaviors, but the behavior is strengthened because something unpleasant is removed after the behavior occurs. • Punisher - any consequences of a behavior that suppresses the responses and decreases the chance that it will reoccur.
Key Concepts cont… • Positive punishment - occurs when an unpleasant consequence is added to a situation following behavior. • Negative punishment - occurs when something pleasant is taken away from a situation following a behavior.
Observational Learning -results from observing the behavior of other people. Almost anything can be learned by watching or listening to others. • Encoding - the process by which external stimulation is converted to a mental representation. • Deferred imitation - the ability to reproduce the actions of a model at some point in the future. Develops rapidly during the second year. *
