Sensorimotor Development: Hands-On Activities for Infants and Toddlers

f e a t u r e by Louise Parks Sensorimotor development: Hands-on activities for infants and toddlers

laire clings to Ms. Rocca. from his balanced bottom in order Why is early CRay sits up, watching and lis- to follow the ball. sensorimotor tening as the musical ball rolls Jessica practices holding on to development away from him. the sturdy shelf with one hand, important? Jessica pulls herself up to stand- while she reaches for the block Infants and toddlers, like the ing in order to reach a red block. with the other. babies above, use their senses to José makes “mmmmmm” José anticipates the taste of his take in stimuli from the environ- sounds when he smells the roast- favorite lunch food with its sweet, ment and respond through reflexes ed sweet potatoes—his favorite. roasted aroma. and motor activity. Although much And Kashera is ready to lick the And Kashera, always eager to development follows genetically finger paint off her finger, but Mr. explore with her mouth, accepts determined patterns, a great part Hay redirects her to the paper: Mr. Hay’s words and presses her comes from the environment. As “Paint goes on paper. Only food finger to the paper. babies respond to the environment,

goes in the mouth.” z t

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n common, these babies, 2 o

Imonths to 32 months old, are phto by susan gae fine tuning their sensorimotor skills. They are learning about their world through tasting, touching, seeing, hearing, and smelling. For each child, the senses initiate, propel, and refine fine and gross muscles into practiced balance, precision, coordination, agility, and stability. Through sensory and motor stimulation, each child is building strong cognitive connections.

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laire receives reassurance of Cher worth through her attach- ment to Ms. Rocca. Ray prepares to risk a topple

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com they build neural connections in ism is especially susceptible to opment (1952) described the first the brain. Actually, the degree to environmental influences. The sen- four months of life as part of the which the brain responds to envi- sitive periods suggest that without sensorimotor stage—that is, ronmental events—its plasticity—is environmental stimulation an infants get information through greatest during the first few years infant may fail to develop capabili- cycles of sensory and motor activi- of life. ties that cannot be remediated. ty. Beyond the theory, however, it’s An infant’s or toddler’s sensory Brain development, especially in apparent that the senses, coupled experiences affect both the size of these youngest learners, depends with the movements the senses individual neurons and their inter- upon responsive care in which stimulate, are the foundation for connections. Research has shown adults recognize and respond to much of the learning that takes that the brains of infants with rich the needs of a particular child. place during the first three years. sensory experiences are physically Responsive caregivers build on Skilled and responsive caregiv- larger and heavier and have more three basic concepts: attention, ers incorporate their background neuron activity than the brains of approval, and attunement—con- knowledge of children’s sensory infants born in severely deprived cepts that are founded on under- capabilities into planning devel- circumstances. That research indi- standing children’s needs, respect- opmentally appropriate activities, cates that the day-to-day interac- ing children as individual and the environment, and their own tions with people and the environ- unique learners, and being aware expectations and interactions with ment influence the brain’s physi- and reflective of interactions that babies. cal structure and thus the func- lead to security, autonomy, and Vision. Researchers have tions the brain directs. competence (Swimm 2013). explored three aspects of vision: Further, researchers point to an acuity, color, and depth percep- infant’s sensitive periods—specific The senses tion. Visual acuity—the ability to but limited times when an organ- Piaget’s theory of cognitive devel- see fine detail—is limited in new-

z borns and develops over the first t year from 20/150 to 20/20 (the distance it takes a person with typical vision to read a letter 20

feet away). Color discrimination o

phto by susan gae seems to be relatively mature in a 6-month-old infant. And depth perception seems to be intact by the time infants begin to crawl. Each of these vision milestones guides teachers and caregivers in the selection of materials, equipment, and décor for environments in which infants spend time. When “…development proceeds normally, infant vision seems per- fectly adequate for the things that infants need to do” (Hainline 1998). Hearing. What we know about infant and toddler hearing is simi- larly informed by clinical research. Even before birth, a fetus responds to loud sounds and, some research suggests, the

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com rhythm of the mother’s conversa- developmental milestones closely their first hearing test shortly after tions (De Casper and Spence align with communication skills birth, caregivers, parents, and 1986). At birth, infants typically and language development. teachers need to monitor chil- respond to loud sounds and the Because language is a medium of dren’s hearing and communication human voice, and by 6 months thought, children’s ability to hear skills throughout the preschool they respond to music and the and speak is critical to the devel- years. The chart below, from the sound of their own name. opment of their thinking skills. American Speech, Hearing, and Hearing and its associated Although babies generally get Language Association (2013), lays

Developmental milestones in hearing and speech

Hearing and Understanding Talking

Birth – 3 months Birth – 3 months ■ Startles to loud sounds ■ Makes pleasure sounds (cooing, gooing) ■ Quiets or smiles when spoken to ■ Cries differently for different needs ■ Seems to recognize your voice and quiets if crying ■ Smiles when sees you ■ Increases or decreases sucking behavior in response to sound 4 – 6 months ■ Babbling sounds more speech-like with many different 4 – 6 months sounds, including /p/, /b/, and /m/ ■ Moves eyes in direction of sounds ■ Chuckles and laughs ■ Responds to changes in tone of your voice ■ Vocalizes excitement and displeasure ■ Notices toys that make sounds ■ Makes gurgling sounds when left alone and when ■ Pays attention to music playing with you

7 months – 1 year 7 months – 1 year ■ Enjoys games like peek-a-boo and pat-a-cake ■ Babbling has both long and short groups of sounds ■ Turns and looks in direction of sounds such as “tata upup bibibibi” ■ Listens when spoken to ■ Uses speech or noncrying sounds to get and keep ■ Recognizes words for common items like cup, shoe, attention book, or juice ■ Uses gestures to communicate (waving, lifting arms to ■ Begins to respond to requests (e.g. “Come here” or be picked up) “Want more?”) ■ Imitates different speech sounds ■ H as one or two words (“Hi,” “dog,” “Dada,” “Mama”) 1 year – 2 years around first birthday, although sounds may not be clear ■ Points to a few body parts when asked ■ Follows simple commands and understands simple 1 year – 2 years questions (“Roll the ball,” “Kiss the baby,” “Where’s ■ Says more words every month your shoe?”) ■ U ses some one- or two-word questions (“Where kitty?” ■ Listens to simple stories, songs, and rhymes “Go bye-bye?” “What’s that?”) ■ Points to pictures in a book when named ■ Puts two words together (“more cookie,” “no juice,” “mommy book”) 2 years – 3 years ■ Uses many different consonant sounds at the ■ Understands differences in meaning (go/stop, beginning of words up/down, big/little, in/on) ■ Follows two requests (“Get the book and put it on 2 years – 3 years the table”) ■ Has a word for almost everything ■ Listens to and enjoys hearing stories for longer ■ U ses two or three words to talk about and ask for things periods of time ■ Uses /k/, /g/, /f/, /t/, /d/, and /n/ sounds ■ Is understood by familiar listeners most of the time ■ Often asks for or directs attention to objects by naming them

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com a framework for what to expect as —a dry and a wet sponge, for their family members. typical hearing and language example. Enclosing play dough Learning centers best reflect the skills—both receptive (interpreting and other gooey materials in a ages, developmental skills, inter- sounds) and expressive (producing zip-close bag gives toddlers the ests, and needs of the babies sounds). opportunity to poke and prod using them. Ideally their location Smell and taste. Newborn without getting their fingers and props are kept stable, because infants express their reaction to sticky. frequent and capricious changes certain odors and tastes just as Reflexes and intermodal in the environment are disturbing adults do—with pursed lips, perception. Reflexes—the invol- to babies. When alterations are wrinkled noses, and turned untary movements made in essential, it’s important to main- heads. The research of Marlier response to environmental stimu- tain the look and location of the and Schall (2005) describes infants li—are well integrated into a environment’s most important 3 or 4 days old who indicate a baby’s sense of touch. When elements. preference for the smell of their someone touches an infant’s Infants and toddlers need safe mother’s breast milk to that of cheek, the child turns the head in spaces filled with opportunities to formula, even if the baby is fed the direction of that touch (root- explore, discover, and learn with a bottle. Further, sweetness ing reflex). If something touches through the sensory experiences is favored over sour by neonates the lips, the infant sucks (sucking that reinforce developing motor who indicate their pleasure by reflex). And if an object touches skills. Sensorimotor development sucking sweet solutions longer an infant’s palm, the baby will is built on this premise of looping than less sweet ones (Crook 1987). grasp, wrapping fingers around it and spiraling discovery, reinforce- Infants and toddlers typically (grasping reflex). ment, and new discovery. It’s the explore with their mouths more As their brains and nervous fundamental tool for infant and thoroughly than with their eyes, systems continue to develop, toddler learning. ears, or noses. In providing learn- babies begin to coordinate, com- Use or modify the following ing activities, caregivers need to bine, and integrate sensory input activities and materials to build be ready to redirect infants to toys in what researchers call intermod- sensorimotor skills in infants and they can safely mouth, and follow al perception. Voluntary move- toddlers. Adapt the activity sanitary procedures for cleaning ments gradually replace reflexes, according to the sequence of them. and coupled with increasing mus- developmental milestones the Touch. Tactile activities abound cle strength and sensory percep- babies seek to achieve. Tweak the in infant and toddler classrooms. tion capacity, a baby’s hard-wired activity to offer new challenges The sensory table—sometimes need to explore and learn is ready gently, and tweak again to avoid just a small dish tub—invites to be satisfied. boredom or frustration. exploration of water, snow, sand, play dough, confetti, shaving Activities for infants Swat it, grab it, hold it cream, and even leaves, bells, and and toddlers (visual acuity and motor skills) small plastic animals. Responsive caregiving—meeting Some children are cautious infants and toddlers where they Infants often see something they about tactile experiences. Some are developmentally and without would like to touch and hold but seem to prefer not to be messy, a preplanned agenda—requires are thwarted by unrefined mus- and others may have true sensi- some environmental basics. Safety cles in the arms and hands. tivities to light, sound, and touch. considerations are paramount in Expect the youngest babies to With these children, caregivers all parts of the environment, swipe and swat; grasping what can introduce tactile activities including equipment, tools, and they see happens only accidently. slowly, inviting children to move play materials. Consistent places With improving hand-eye coor- at their preferred paces. for diapering, sleeping, preparing dination the baby may grab an Caregivers can also share famil- food, and feeding instill trust and object but still lacks the skills to iar objects with different textures confidence in both babies and hold on to it. With even more

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com practice the baby will be able to Shake the bottle to focus attention ■ scarves or translucent fabric grab and hold on to an object. A and watch as the baby swats at squares milestone for toddlers is to hold the bottle with the feet, sometimes an object in one hand and transfer making contact. 1. If desired, decorate the paper it to the other. Sitting infants: Place the bot- towel tube. For a longer lasting Your careful observations will tle within the baby’s arm reach. prop, use as 12-inch length of help you decide how to modify Notice whether the child swats at plastic pipe or bamboo. this activity to accommodate the the bottle or grabs it. Does the 2. Collect a variety of scarves or baby in your care. baby try to follow the bottle when 12-inch squares of lightweight it tips over and rolls out of reach? fabric. Here’s what you need: Variations: The classroom is 3. Adapt the activity to the chil- ■ clear plastic bottle with lid filled with materials that encour- dren’s developmental needs ■ colored tape age this kind of sensorimotor and interests. ■ large metallic confetti or cut-up learning. For example, thread Newborns: Simply brush an colored paper bits sturdy cord through the holes in a edge of the scarf over the baby’s ■ glue Wiffle® ball. Hold one end of the head, face, arms, and legs. Talk cord for tracking, swatting, and with the baby about the sensation 1. Wash the bottle thoroughly and grabbing exercises, remembering and use words like tickle, breeze, let it dry. Use lengths of boldly to remove the cord from the chil- feel, soft, and brush. colored tape to decorate the dren’s play area after use. Sitting infants: Play peek-a- outside surface of the bottle. Put boo with the scarf. Cover your about ¼ cup of large metallic Scarf play face and encourage the baby to confetti into the bottle. Replace (object permanence, visual acuity, pull the scarf away. Cover the the lid and seal it with glue. cause and effect, and motor skills) baby’s face and cheer when the Newborns: With the baby on scarf is removed. your lap or on a flat floor mat, At around 8 or 9 months of age, Young toddlers: Stuff a scarf hold the bottle about 12 inches babies become aware that an object into the tube, leaving one corner from the baby’s face. Move it can exist even when they cannot protruding. Encourage fine motor slowly across the baby’s field of see it. This awareness is referred to skills by helping the toddler grab vision, shaking the bottle occa- as object permanence. It explains the edge of the scarf and pulling sionally to hold the baby’s inter- a younger infant’s delight and sur- it out of the tube. est. Notice how the baby tracks prise in playing peek-a-boo. Older toddlers: Tie the cor- the bottle with the eyes and later ners of several scarves together by moving the whole head. Here’s what you need: and stuff them into the tube. Infants: Place the baby on a ■ paper towel tube Watch for the toddler to use alter- flat floor mat and hold the bottle ■ markers, crayons, colored tape nating hands to pull the scarves in the air above the baby’s feet. (optional) out of the tube. Share the toddlers’ z t s o phto by susan gae

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com delight and surprise when the col- ■ squares of differently textured Older toddlers: Introduce ors and textures of the fabric materials more of the folders to small change. ■ glue groups of children. Encourage the ■ scissors children to describe the materials T ouch, sense, and know and how they might be used. (tactile sensation and fine motor skills) 1. Cut each file folder in half from When the children are familiar the fold to the open end. with each of the texture folders, During the first year of life, babies 2. Gather 3-inch squares of tex- show them in pairs. Invite the in cultures around the world are tured materials, such as satin children to explore the textures fed, carried, cleaned, and comfort- fabric, fake fur, aluminum foil, with both hands at the same time, ed through touch. Tactile sensa- corrugated cardboard, sandpa- one on each folder. Extend this tion provided by parents and per, and carpet. into a matching game (with fold- caregivers not only helps satisfy 3. Glue matching squares of each ers open) and later into a game of an infant’s physical needs but also material in the two halves of concentration matching the two affects emotional development. each folder to make pairs. textures. Research suggests that severe tac- Young toddlers: Introduce Variation: Newborns and tile deprivation can result in the texture folders to one or two infants won’t be able to gain learning delays and cognitive children at a time. Choose one much information from the tex- impairment. Gentle tactile activi- material, open the folder, and tures that they touch. However, ties can enhance exploration and invite the children to touch the you can stimulate the sense of learning. material. Offer descriptive vocab- touch in babies with simple mate- ulary for the material including rials like a large pom-pom. With Here’s what you need: color, texture, and other appropri- the baby in your lap or on a flat ■ colored file folders ate features. floor mat, show the pom-pom and

z describe its color, size, and tex- t ture. Tell the baby that you’re going to rub the texture on the arms, legs, and face. Watch for the

baby’s accepting responses o

phto by susan gae (smiles, waving arms, and kicking feet) as an invitation to continue the activity. If the baby turns away or squirms uncomfortably, acknowledge (and label) the emo- tion and discontinue the activity.

Sticky play (large and small motor skills, memory, and visual acuity)

During the first year of life, babies are busily developing large motor skills: learning to sit up, stand, crawl, and walk. Alongside these skills, babies are developing small, or fine, motor skills by using their hands and fingers to grasp and manipulate objects. By building on these skills, children

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com gradually learn to do such things for them to understand and dis- 3. Pour about ¼ cup of dry noise- as eat, dress, and clean them- tinguish sounds and to respond makers—pebbles, bolts, spools, selves as well as to turn pages of appropriately. Playing with noise- sand, bells, or seeds, for exam- a book, use writing implements, makers helps babies develop ple—into the different contain- and work a puzzle. auditory discrimination, and talk- ers. Leave one container empty. ing, doing finger plays, singing, 4. Cover the containers and use Here’s what you need: and reading help them develop permanent glue to secure the ■ cardboard box with lids, no language. lids in place. larger than 8 inches on a side 5. Introduce the shakers, one at a ■ clear, adhesive-backed vinyl Here’s what you need: time. ■ colored, adhesive-backed vinyl ■ matching plastic or metal con- Sitting infants: While the ■ scissors tainers with lids baby is sitting on the floor or at a ■ photos ■ permanent glue, such as Super table, show a container and give it Glue a shake. Position the container 1. Seal the box closed and cover ■ small, dry noisemakers, such as within the baby’s reach and with patterned vinyl or paint as pebbles or seeds watch. Is there an effort to reach desired. ■ patterned adhesive-backed vinyl the container? Does the baby use 2. Cover the outside of the box both hands to reach and grasp? with clear, adhesive-backed 1. Collect several containers. You Can the baby repeat your shaking vinyl, sticky side out. might use, for example, peanut motion? 3. Gather pictures—for example, butter jars, 16-oz. soda bottles, Young toddlers: Share two family photos or food, pet, or spice jars, or coffee tins. containers with distinctly differ- face pictures from old maga- 2. Cover the outside of the con- ent sounds—bells and bolts, for zines. To make the pictures tainer with patterned vinyl. example. Talk with the child

more durable, encase them in z t clear, adhesive-backed vinyl or laminate. 4. Invite the toddlers to hang the

pictures on the box. The babies o

will position and reposition the phto by susan gae photos being engaged with both the stickiness and the image in the photo. Be sure to talk with the toddlers about the pictures they choose. Variation: Instead of photos, invite toddlers to use collage materials (string, paper scraps, foil, gift wrap, cotton balls, straws, craft sticks, leaves, and twigs, for example) to decorate the box.

Shakers and movers (auditory discrimination, hand-eye coordination, and motor skills)

Typically babies have good hearing at birth. But it takes a while

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com about the sounds and encourage vertical surface like the back of engages with these materials rhythmic shaking with simultane- a heavy bookshelf or a wall so spontaneously or if you need to ous full-body movement. that the objects are about 6 to 8 introduce the activity. Does the Older toddlers: Introduce the inches from the floor. child find more pleasure in fill- shakers and place all the contain- 4. Position a baby on the tummy ing rather than dumping? Does ers on a low shelf. Encourage chil- and point to the toys. the child use the materials in dren to explore them indepen- Encourage the baby to balance other ways? Does the child pick dently, listening to the different and reach the object. Watch how up the manipulatives with one sounds and sensing the different the baby uses the hands— hand or both? Is the movement weights. Help the toddlers notice sweeping, making contact, fluid? that one of the containers is grasping and pulling? empty—there is no sound or Note: As always, attend to safe- Musical wall weight. ty. Make sure the objects don’t (auditory discrimination, motor pose a choking hazard and that skills, and cause and effect) Find it and reach there is no chance the baby could (visual acuity, auditory discrimina- topple a shelf or get caught in the As children develop motor skills, tion, and gross and fine motor skills) elastic. they learn the important principle of cause and effect. Hitting an Because we put babies to sleep on Fill and dump object with a mallet, splashing their backs to prevent Sudden (motor skills, hand-eye coordination, water, pushing a toy truck, and Infant Death Syndrome (SIDS), and tactile stimulation) similar movements help them infants need to spend some of understand that they can change their play time on their stomachs At first, infants don’t connect their environment. It gives them a for healthy development. Tummy looking at objects with touching sense of delight and power. time strengthens neck and upper them. Around 6 months, however, back muscles, which allow infants they begin to put looking and Here’s what you need: to hold up and turn their heads. touching together. With practice, ■ variety of objects that make Tummy time also gives infants a they refine this hand-eye coordi- interesting sounds when hit different view of the world. nation and gain dexterity in with a mallet exploring objects and the environ- ■ heavy cord Here’s what you need: ment. ■ small wooden mallets or dowels ■ ½-inch wide sewing elastic ■ secure area of playground ■ collection of attractive and Here’s what you need: fencing unbreakable objects, such as ■ large manipulatives such as measuring spoons or toy ani- plastic clothespins 1. Gather an array of objects that mals ■ empty containers with handles, can be hung on the fence. ■ construction-strength stapler like milk jugs and plastic buckets Include objects like a toy xylo- and staples phone, a metal triangle, a hub- ■ sturdy vertical surface 1. Gather large (too big to be a cap, a metal pot lid, wind choking hazard) manipulatives chimes, a metal trash can lid, 1. Cut the elastic into 18-inch like plastic clothespins, Duplo® metal pipes, large metal food lengths. bricks, or plastic linking rings. containers, and a bike tire with 2. Securely tie one end of the elas- 2. Make available empty contain- metal spokes. tic to one of the collected ers. Make sure the opening in 2. Determine a section of the play- objects. Rattles, plastic measur- the container will easily accom- ground fence on which to ing tools, toy animals, and mir- modate the manipulative. mount the musical wall. rors are good examples of 3. Watch toddlers engage in the Because this will be a semi-per- appropriate objects. favorite game of fill and dump. manent installation, consider an 3. Staple the end of the elastic to a Note whether the toddler area in the shade and away

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com from wheel toy traffic. Here’s what you need: Many sensorimotor activities 3. Attach all the objects to the ■ sheets of various paper types require common materials often fence, including the mallets, at in minimal amounts. Parents may toddler height. Infants: Crunch a sheet of be happy to donate materials 4. Introduce the musical wall by paper near the baby and note the from their homes and offices, and beating out a rhythm on one of response. it gives them a chance to practice the objects. Hand a mallet to a Sitting infants: Provide sheets recycling. Make sure that all child and encourage continued of paper for the baby to grasp, materials are clean and free of music and movement. crunch, and tear. potential hazards, such as loose Young toddlers: Place a vari- parts, sharp points, and toxic Crunch, crackle, and ety of paper types in the art cen- chemicals. pop ter. Include heavy construction (auditory discrimination and motor paper, printer paper, tissue paper, Here’s what you need: skills) paper towels, toilet tissue, and ■ variety of flooring materials foil. Encourage tactile exploration ■ heavy tape Listening is a critical skill that with questions. ■ scissors humans use in communication Older toddlers: Introduce and learning. As babies listen, bubble wrap and the opportunity 1. Gather a variety of textured they begin to distinguish sounds, to stomp or hammer the bubbles flooring materials. Ask for sense rhythms, and process what to pop them. donations such as a tufted bath- they hear. By listening to sounds room mat, low-pile carpet and voices, they lay the founda- It’s on the floor squares, a rubber bathmat with tion for language. (tactile stimulation and suction cups, outdoor (fake discrimination) grass) carpet, a door mat, fake

z fur, adhesive-backed vinyl, and t bubble wrap. 2. Plan a texture path through the classroom or in a hall.

3. Tape all edges of the flooring o

phto by susan gae materials to the floor. Make sure the edges are smooth to prevent tripping. 4. Invite children to experience the path. Newborns: Choose a section of textured flooring that can be easily laundered—the tufted bath- room mat, for example. Place infants on the tummy and encourage grasping and brushing the texture. Sitting infants: Choose different sections of the textured flooring for unique sensory experiences throughout the day. Notice each infant’s preferences of materials. What did the infant seem to notice in each? Toddlers: Scooters, crawlers,

© Texas Child Care quarterly / spring 2014 / VOLUME 37, NO. 4 / childcarequarterly.com toddlers, and beginning walkers will notice the differences in each texture along the path. Notice toddler preferences. Compare the reactions to the sticky vinyl with the bubble wrap, for example. Did toddlers avoid some of the textures?

References American Speech-Language- Hearing Association. Typical Speech and Language Development. Retrieved on 4 Nov. 2013 at www.asha.org/ public/speech/development/01.htm. Crook, C. K. 1987. Taste and olfac- tion. In P. Salapatek and L. B. Cohen (Eds.), Handbook of Infant Perception, Vol. 1. New York: Academic Press. Hainline, L. 1998. The development of basic visual abilities. In S. Slater (Ed.), Perceptual Development: Visual, Auditory, and Speech Perception in Infancy. East Sussex, U.K.: Psychology Press. Marlier, L. and B. Schall. 2005. Human newborns prefer human milk: Conspecific milk odor is attractive without post- natal exposure. Child Development, 76. Piaget, J. 1952. The Origins of Intelligence in Children. New York: International University Press. Swimm, Terri Jo. 2014. Infants and Toddlers: Curriculum and Teaching, 8th Ed. Belmont, Calif.: Wadsworth/Cengage Learning. n