Chapter Two: - PowerPoint PPT Presentation

Loading...

PPT – Chapter Two: PowerPoint presentation | free to view - id: 8363ee-OWI2O



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Chapter Two:

Description:

Chapter Two: Theories of Development What Theories Do, cont. Theories form basis for hypotheses that can be tested by research studies formulating right question is ... – PowerPoint PPT presentation

Number of Views:90
Avg rating:3.0/5.0
Slides: 120
Provided by: Grossm2
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Chapter Two:


1
Chapter Two
  • Theories of Development

2
What Theories Do
  • Developmental theorysystematic statement of
    principles and generalizations that provides a
    coherent framework for studying development

3
What Theories Do, cont.
  • Theories
  • form basis for hypotheses that can be tested by
    research studies
  • formulating right question is more difficult that
    finding right answers
  • generate discoveries
  • offer insight and guidance by providing coherent
    view

4
What Theories Do, cont.
  • Different Types
  • grand theoriescomprehensive, traditional
    theories
  • originated in psychology
  • minitheoriestheories that focus on specific area
    of development
  • originated more in sociology through study of
    social groups and family structures
  • emergent theoriesnew, comprehensive groupings of
    minitheories
  • multidisciplinary approach includes historic
    events and genetic discoveries

5
Grand Theories
  • Grand Theoriespowerful framework for
    interpreting and understanding change and
    development that applies to all individuals in
    all contexts, across all contents

6
(No Transcript)
7
Psychoanalytic Theory
  • Psychoanalytic theory interprets human
    development in terms of motives and drives

8
Freuds Ideas
  • Sigmund Freud
  • Three stages of development in first six years
  • oral, anal, phallic
  • in early childhood, latency and then adolescence,
    genital
  • each stage includes potential conflicts
  • how a person experiences and resolves conflicts
    determines personality and patterns of behavior

9
Eriksons Ideas
  • Erik Erikson, a follower of Freud, proposed 8
    developmental stages, each characterized by a
    developmental crisis
  • trust vs. mistrust
  • autonomy vs. shame
  • initiative vs. guilt
  • industry vs. inferiority
  • identity vs. role diffusion
  • intimacy vs. isolation
  • generativity vs. stagnation
  • integrity vs. despair

10
(No Transcript)
11
Behaviorism
  • Behaviorism is built on laws of behavior and
    processes by which behavior is learned
  • focus ways we learn specific behaviors that can
    be described, analyzed, and predicted with
    scientific accuracy

12
Laws of Behavior
  • Conditioningany process in which behavior is
    learned
  • Classical conditioningIvan Pavlov
  • process by which a neutral stimulus become
    associated with a meaningful stimulus
  • stimulus and response (respondent conditioning)
  • Operant conditioningB. F. Skinner
  • process by which a response is gradually learned
    via reinforcement or punishment
  • also called instrumental conditioning

13
(No Transcript)
14
Social Learning
  • Extension of learning theory that includes
    modeling which involves people observing behavior
    and patterning their own after it
  • Modeling
  • process in which people observe, then copy
    behavior
  • Alfred Banduramost likely to occur if model is
    admired or observer is inexperienced
  • self-efficacy motivates people to change
    themselves and their contexts

15
Cognitive Theory
  • Focuses on the structure and development of
    thought processes, which shape perceptions,
    attitudes, and actions.
  • Jean Piagets 4 Stages
  • sensorimotor
  • pre-operational
  • concrete operational
  • formal operational

16
Cognitive Theory, cont.
  • Cognitive equilibriumstate of mental balance
  • Cognitive adaptationassimilation, accommodation
    of ideas

17
(No Transcript)
18
Emergent Theories
  • Emergent theories arise from several accumulated
    minitheories and may be the new systematic and
    comprehensive theories of the future

19
Sociocultural Theory
  • Seeks to explain growth of individual knowledge,
    development, and competencies in terms of
    guidance, support, and structure supplied by the
    society
  • human development is the result of dynamic
    interaction of the developing persons and their
    surrounding culture

20
Guided Participation
  • Guided participationtutor engages learner in
    joint activities, providing instruction and
    direct involvement in learning
  • Apprenticeship in thinkingmentor provides
    instruction and support needed by novice

21
The Zone of Proximal Development
  • Zone of proximal developmentrange of skills
    learner can perform with assistance but not
    independently
  • learner is drawn into learning by teacher
  • Cultural variations Basic principles are
    universal, but skills, challenges, and
    opportunities vary from culture to culture,
    depending on the values and structures of the
    cultures society

22
(No Transcript)
23
Epigenetic Theory
  • Emphasizes the interaction between genes and the
    environmentthe newest developmental theory
  • stresses that we have powerful instincts and
    abilities that arise from our biological
    heritage. Timing and pace of certain
    developmental changes are genetically guided
  • performismeverything is set in advance by genes
    and then is gradually manifested in the course of
    maturation

24
With, On, and Around the Genes
  • Genetic refers to the entire genome that makes up
    the particular genes that cause each person to be
    unique
  • each human has a genetic foundation that is
    unique
  • epigenetic theory acknowledges the powerful
    instincts and abilities that arise from our
    biological heritage

25
With, On, and Around the Genes, cont.
  • Epi with, around, before, after, on, or near
    surrounding factors
  • epigeneticsurrounding factors that affect
    expression of genetic instructions
  • some surrounding factors may be stress factors
    others may be facilitating factors
  • Genetic-environmental Interactions
  • genes never function alone

26
Genetic Adaptation
  • Adaptation of the Genes
  • selective adaptation means that genes for the
    traits that are most useful will become more
    frequent, thus making survival of species more
    likely

27
What Theories Can Contribute
  • Psychoanalytic theory has made us aware of
    importance of early childhood experiences
  • Behaviorism has shown effect of immediate
    environment on learning
  • Cognitive theory helps us understand how
    intellectual process and thinking affect actions

28
What Theories Can Contribute, cont.
  • Sociocultural theory has reminded us that
    development is embedded in a rich and
    multifaceted context
  • Epigenetic theory emphasizes interactions between
    inherited forces and immediate contexts

29
(No Transcript)
30
Other Theories
  • Brief Solution Focused
  • Narrative
  • Art
  • Play
  • PsychoDrama
  • Object-Relations
  • Jungian
  • Transactional Analysis
  • 12 - step
  • Social Learning
  • Biblio-therapy

31
What Theories Can Contribute, cont.
  • Eclectic perspective
  • approach taken by most developmentalists in which
    they apply aspects of each of the various
    theories rather than staying with just one
  • Integrated is better

32
Eclectic verses Integrated
  • Eclectic picks from multiple sources without
    common thread

33
Integration
  • Integration picks from theories with purpose and
    with commonality

34
Level of Concepts
35
The Nature-Nurture Controversy
  • Is it heredity or environment that shapes us?
  • How much is a result of any given
    characteristics, behavior or pattern of
    development is a result of genes and how much is
    a result of experiences
  • Policy and practice nature/nurture theories are
    implicit in many public policies

36
Theoretical Perspectives on Hyperactivity and
Homosexuality
  • AD/HD and homosexualityHow and to what extent
    are nature and nurture involved in each case?
  • Evidence from AD/HD research that it can come
    from either

37
Theoretical Perspectives on Hyperactivity and
Homosexuality, cont.
  • Earlier assumptions about homosexuality more
    nurture than nature. As hypotheses tested,
    nurture was revealed as less crucial
  • sexual orientation may be a matter of nature
  • sexual expression may be a matter of cultural
    attitude (nurture) but not sexual orientation
  • evidence supporting nature as main factor (e.g.,
    affect of genetic linkage, prenatal hormones)

38
Theoretical Perspectives on Hyperactivity and
Homosexuality, cont.
  • Ideology often adds to complexity and
    polarization of opinions on many subjects when
    nature and nurture are considered
  • Important to separate assumptions from facts
  • done via research and testing of hypotheses

39
Chapter Three
  • Heredity and Environment

40
The Genetic Code
  • Development that is dynamic, ongoing,
    interactional, and unique just four chemicals
    are the basic building blocks of the genetic code

41
What Genes Are
  • Genes are made up of DNAthe complex protein code
    of genetic information
  • DNA directs the form and function of each body
    cell as it develops

42
What Genes Are, cont.
  • Each molecule of DNA is called a chromosome
  • Chromosomes contain instructions to make all the
    proteins a living being needs
  • The complete packet of instructions is called a
    genome
  • Each person has 23 sets of chromosomes, or 46
    chromosomes
  • The human genome contains 30,000 genes

43
The Beginnings of Human Life
  • Gametereproductive cell that directs process by
    which genetic information combined and
    transmitted
  • Father gametessperm
  • Mother gametesovum

44
Zygote and Genotype
  • Male and female gametes fuse and become a zygote
  • Zygote begins process of duplication and division
  • two reproductive cells
  • Genotypethe genetic information from the 46
    chromosomes
  • set at human conception and endures through life

45
Sex Determination and Sex Ratio
  • Of 22 out of 23 pairs of human chromosome, the
    matching chromosomes are very closely matched
  • but not identical
  • some genes come in slight, normal variations
    called alleles
  • The 23rd pair is different
  • in females, it is designated XX
  • in males, it is designated XY

46
Sex Determination and Sex Ratio, cont.
  • Females always contribute one X
  • Males will have 1/2 of the sperm contributing an
    X and the other half contributing a Y
  • Critical factor in determining the sex of a
    zygote is which sperm reaches the ovum first

47
Sex Determination and Sex Ratio, cont.
  • Other factors include
  • rarely, male sperm may only carry either X or Y
  • sometimes a womans uterus either unusually
    alkaline or acid, giving either an X or Y sperm
    an advantage
  • in a stressful pregnancy XY embryos are more
    likely to be expelled than are XX embryos in a
    spontaneous abortion, or miscarriage
  • current sex ratio in United States is 52 males to
    48 females

48
Multiple Zygotes
  • Monozygotic twinsidentical twins (or
    quadruplets) originate from one zygote
  • share identical instructions
  • possibility of cloning
  • 1/3 of twins monozygotic

49
Multiple Zygotes, cont.
  • Dizygotic twinsfrom two separate zygotes
  • Dizygotic births occur once in every 60 births,
    and occur as frequently as 1 in 6 pregnancies,
    but usually only 1 twin develops past embryo
    stage

50
Multiple Zygotes, cont.
  • Dizygotic twins
  • women in late 30s are three times more likely to
    have dizygotic twins
  • as menopause approaches, ovulation becomes
    irregular with some cycles producing no ovas and
    others producing multiple ovas
  • share no more genes than other offspring (about
    50 percent)
  • 50 percent of the time one twin is male

51
Duplication, Division, and Differentiation
  • The zygote contains a complete set of
    instructions to create a person
  • Complex instructions on duplication, cell
    division, and differentiation

52
Duplication and Division
  • Zygote begins duplication and division within
    hours after conception
  • the 23 pairs of chromosomes duplicate, forming
    two complete sets of the genetic code for that
    person (zygote)
  • these two pair sets move toward the opposite
    sides of the zygote and the single cell in the
    zygote splits down the middle
  • the zygotes outer membrane surrounds two cells,
    each containing a complete set of the original
    genetic code
  • these two cells then duplicate and divide to
    become four, then eight, and so on

53
Duplication and Division, cont.
  • by birth, your original zygote has duplicated and
    divided into 10 trillion cells . . . by
    adulthood, its 100 trillion cells
  • Every cell carries an exact copy of the complete
    genetic instructions inherited by the one-celled
    zygote

54
Differentiation
  • Not just any cell found in the zygote can become
    a person
  • At the 8-cell stage a third process,
    differentiation, occurs
  • Cells begin to specialize
  • they take different forms
  • they reproduce at different rates, depending on
    where in the growing mass they are located

55
Differentiation, cont.
  • Certain genes affect differentiation by switching
    other genes on and others off so that the other
    genes produce the right proteins at the right
    timeson-off switching mechanisms
  • Genotypethe genetic potential

56
Gene - Gene Interactions
  • Multifactoral traitsinherited traits produced by
    interaction of genes and environment
  • Polygenetic traitsinherited traits produced by
    gene interaction
  • These are affected by on-off switching
    mechanisms, additive genes, and
    dominant-recessive genes

57
Additive Genes
  • Additive genesone of a number of genes affecting
    a specific trait
  • each additive gene contributes to the trait
  • skin color and height are determined by them
  • every additive gene has some impact on a persons
    phenotype
  • when genes interact this way, all the involved
    genes contribute fairly equally

58
Dominant and Recessive Genes
  • Nonadditive genesphenotype shows one gene more
    influential than other genes
  • This is also referred to as the
    dominant-recessive pattern
  • gene showing the most influence is referred to as
    dominant
  • gene showing the least influence is referred to
    as recessive

59
Dominant and Recessive Genes, cont.
  • X-linked geneslocated on X chromosome
  • if recessive gene is X-linked, that it is on the
    X chromosome is critical
  • males have only one X chromosome females have 2
    X chromosomes
  • Whatever recessive genes a male inherits on his X
    chromosome cannot be counterbalanced or dominated
    by alleles on a second X, so any recessive genes
    on X will be expressed
  • Explains why males have more X-linked disorders
    (ex. color blindness, many allergies, several
    diseases, some learning disabilities)

60
More Complications
  • Genes direct the creation of 20 amino acids that
    produce thousands of proteins forming the bodys
    structure and directing biochemical functions
  • proteins of each body cell are continually
    affected by other proteins, nutrients, and toxins
    that influence the cell functioning

61
More Complications, cont.
  • genetic imprintingtendency of certain genes to
    be expressed differently when inherited from
    mother than from father (tagging)
  • some of the genes which influence height, insulin
    production, and several forms of mental
    retardation affect a child differently depending
    on which parent they came from

62
Genetic Diversity
  • Every person is unique

63
Mechanisms of Genetic Diversity
  • Since each gamete contains only 23 chromosomes,
    why is every conception genetically unique?
  • 8 million chromosomally different ova x 8 million
    of the same 64 trillion different possibilities
    of children from each couple

64
Health Benefits of Genetic Diversity
  • Genetic diversity safeguards human health
  • Minute differences can affect the ability to
    stave off certain diseases
  • Genetic diversity maintains the species

65
From Genotype to Phenotype
  • Every psychological characteristic is genetically
    influenced
  • Every psychological characteristic and personal
    trait is affected by the environment

66
From Genotype to Phenotype, cont.
  • Genotypegenetic potential
  • Phenotypethe actual appearance of an
    indivudal--combination of genetic potential and
    expression
  • we are all carriers of the unexpressed genes
  • we can pass them along through the sperm or ova

67
Behavior Genetics
  • Behavior geneticsstudy of effects of genes on
    behavior
  • personality patterns, psychological disorders,
    and intellectual abilities

68
Senility Caused by Alzheimers Disease
  • Most common and feared type of senility is
    Alzheimers disease
  • amyloid B protein accumulates in the brain,
    leading to dysfunction and destruction of brain
    cells and disruption of the mind
  • Can be geneticbut only when early-onset

69
Senility Caused by Alzheimers Disease, cont.
  • If late-onset, may be a combination of genes
    and environment
  • other predictors may include hypertension,
    diabetes, high cholesterol, diet, exercise, not
    smoking, weight control, mental alertness, and
    physical health

70
Alcoholism
  • Inherited biochemistry makes some people highly
    susceptible to alcohol addiction
  • addictive pull can be overpowering, or weak, or
    something in the middle
  • may explain ethnic variations

71
Alcoholism, cont.
  • Not simply a biochemical reactionit is
    psychological and physical, and biological thus
    alcoholism is polygenetic, with alcoholics
    inheriting a combination of biochemistry-affecting
    and temperament-affecting genes
  • Culture counts too(whether alcohol is present in
    environment)

72
Chromosomal and Genetic Abnormalities
  • We now give attention to these because we can
    recognize
  • disruptions of normal development
  • origins of genetic and chromosomal abnormalities
  • misinformation and prejudice add to problems of
    people with these abnormalities

73
Chromosomal Abnormalities
  • A gamete with more than or less than 23
    chromosomes creates a zygote with chromosomal
    abnormalities
  • most likely variable that creates chromosomal
    abnormalities is mothers age (over 35)
  • fathers age (over 40) also a variable

74
Chromosomal Abnormalities, cont.
  • Most zygotes with chromosomal abnormalities never
    come to term
  • spontaneous abortion occurs in about one-half of
    all fetus with chromosomal abnormalities

75
Down Syndrome
  • Three chromosomes at gene 21 (trisomy-21)
  • Syndromea cluster of distinct characteristics
    that occur together in a given disorder

76
Abnormalities of the 23rd Pair
  • Location of sex chromosome
  • Kleinfelters syndromeXXY
  • seemingly normal child has delayed puberty
  • Fragile X syndrome
  • hanging on by a thread (mutated gene)
  • intensifies from generation to generation
  • Page 78

77
Genetic Testing and Genetic Counseling
  • Individuals with a parent, sibling, or child with
    a serious genetic condition known to be dominant
    or recessive
  • Couples with history of early spontaneous
    abortions, stillbirths, or infertility
  • Couples from the same ethnic group or
    subgroupespecially if closely related
  • Women over 35 and men over 40

78
The Process of Genetic Counseling
  • Counselor constructs couples family history
  • charts patterns of health and illness over
    generations
  • Some tests provide information before conception

79
The Process of Genetic Counseling, cont.
  • Other tests are prenatal- page 83
  • alpha-fetoprotein assay
  • ultrasound (AKA sonogram)
  • amniocentesis
  • chorionic villi sampling
  • pre-implantation testing (used in in vitro
    fertilization)
  • gamete selection ova/and or sperm are screened
    to select ones free of particular problems

80
A Basis for Decision
  • Many want to know ahead of time
  • Some do not
  • There is a more knowledge of what is to comeor
    not

81
Alternatives
  • If both partners are carriers of a serious
    condition or are at high risk because of age or
    family characteristics, they may turn to
  • in-vitro fertilization (IVF)
  • gamete intrafallopian transfer (GIFT)
  • zygote intrafallopian transfer (ZIF)
  • artificial insemination donor (AID)
  • postponement of pregnancy until promising
    treatments are further developed

82
Chapter Four
  • Prenatal Development and Birth

83
(No Transcript)
84
From Zygote to Newborn
  • Germinal periodfirst 14 days
  • Embryonic period3rd through 8th weeks
  • Fetal period9th week through birth

85
Process of Conception
86
Germinal The First 14 Days
  • Zygote divides and keep dividing (at least though
    3rd doubling they are the same)
  • At this stage (8 cells) differentiation begins
  • early stem cells take on distinct
    characteristics
  • they gravitate to locations, foreshadowing the
    type of cells they will become

87
Germinal The First 14 Days, cont.
  • At about a week after conception the multiplying
    cells separate into two masses
  • outer layer forms a shell (later the placenta)
    and the inner cells from a nucleus (later the
    embryo)
  • first task of out cells to achieve implantation
    embed themselves into the nuturant environment of
    the uterus
  • 60 of all natural conceptions fail to implant
    70 of in vitro procedures fail to implant

88
Embryo From the Third to the Eighth Week
  • First sign of human structure thin line down the
    middle (22 days) that becomes the neural tube,
    which eventually forms the central nervous
    system, including brain and spinal column
  • fourth week
  • head begins to take shape
  • heart begins with a miniscule blood vessel that
    begins to pulsate

89
Embryo From the Third to the Eighth Week, cont.
  • fifth week
  • arm and leg buds appear
  • tail-like appendage extends from the spine
  • eighth week
  • embryo weighs 1 gram and is 1 inch long
  • head more rounded face formed
  • all basic organs and body parts (but for sex)
    present
  • 20 of all embryos spontaneously abort now

90
Fetus From the Ninth Week Until Birth
  • Called a fetus from 9th week on

91
Third Month
  • Sex organs take shape (Y cell sends signal to
    male sex organs for females, no signal occurs)
  • genital organs fully shaped by 12th week
  • All body parts present
  • Fetus can move every part of body
  • Fetus weighs 3 ounces and is 3 inches long

92
Middle Three Months Preparing to Survive
  • Heartbeat stronger
  • Digestive and excretory systems develop more
    fully
  • Impressive brain growth (6X in size and
    responsive)
  • new neurons develop (neurogenesis)
  • synapsesconnections between neurons
    (synaptogenesis)

93
Middle Three Months Preparing to Survive, cont.
  • Age of viabilityage at which preterm baby can
    possibly survive (22 weeks)
  • 26 weeks survival rate about 50
  • brain maturation critical to viability
  • weight critical to viability
  • 28 weeks survival rate about 95

94
Fetal Brain Maturation
95
Final Three Months Viability to Full Term
  • Maturation of the respiratory and cardiovascular
    systems
  • critical difference
  • Gains weight4.5 lbs. in last 10 weeks

96
Risk Reduction
  • Despite complexity, most babies are born healthy
  • Most hazards are avoidable
  • Teratologystudy of birth defects
  • Teratogens (ter-at-o-gens)broad range of
    substances that can cause environmental insults
    that may cause prenatal abnormalities or later
    learning abilities

97
Determining Risk
  • Risk analysisweighing of factors that affect
    likelihood of teratogen causing harm

98
Timing of Exposure
  • Critical periodin prenatal development, the time
    when a particular organ or other body part is
    most susceptible to teratogenic damage
  • entire embryonic period is critical

99
Amount of Exposure
  • Dose and/or frequency
  • Threshold effectteratogen relatively harmless
    until exposure reaches a certain level

100
Amount of Exposure, cont.
  • Interaction effectrisk of harm increases if
    exposure to teratogen occurs at the same time as
    exposure to another teratogen or risk

101
Genetic Vulnerability
  • Genetic susceptibilities product of genes
    combined with stress
  • Folic-acid deficiency may cause neural- tube
    defects
  • occurs most commonly in certain ethnic groups and
    less often in others
  • Males are more genetically vulnerable

102
(No Transcript)
103
Specific Teratogens
  • No way to predict risk on an individual basis
  • Research has shown possible effects of most
    common and damaging teratogens
  • AIDS and alcohol extremely damaging
  • pregnant women with AIDS transmit it to their
    newborns high doses of alcohol cause FAS
    alcohol drug use increase risk to developing
    organism

104
(No Transcript)
105
(No Transcript)
106
(No Transcript)
107
(No Transcript)
108
Low Birthweight
  • Low Birthweight (LBW)
  • less than 5 1/2 lbs.
  • grows too slowly or weighs less than normal
  • more common than 10 years ago
  • second most common cause of neonatal death
  • Preterm
  • birth occurs 3 or more weeks before standard 38
    weeks

109
Low Birthweight, cont.
  • Small for Gestational Age (SGA)
  • maternal illness
  • maternal behavior
  • cigarette smoking (25 of SGA births)
  • maternal malnutrition
  • poorly nourished before and during pregnancy
  • underweight, undereating, and smoking tend to
    occur together

110
Low Birthweight, cont.
  • Factors that affect normal prenatal growth
  • quality of medical care, education, social
    support, and cultural practices

111
(No Transcript)
112
The Birth Process
  • Hormones in mothers brain signals process
  • Contractions begin strong and regular at 10
    minutes apart
  • average labor for first births is 8 hours

113
The Newborns First Minutes
  • AssessmentApgar scale
  • five factors, 2 points each
  • heart rate
  • breathing
  • color
  • muscle tone
  • reflexes
  • score of 7 or better normal
  • score under 7 needs help breathing
  • score under 4 needs urgent critical care

114
(No Transcript)
115
Variations
  • Parents Reaction
  • preparation for birth, physical and emotional
    support, position and size of fetus, and
    practices of mothers culture
  • Medical Attention
  • birth in every developed nation has medical
    attention
  • 22 of births in U.S. are cesarean section
  • removal of fetus via incisions in mothers
    abdomen and uterus
  • is medical intervention always necessary?

116
Birth Complications
  • Cerebral Palsybrain damage causing difficulties
    in muscle control, possibly affecting speech or
    other body movements
  • Anoxialack of oxygen that, if prolonged, can
    cause brain damage or death

117
First Intensive Care . . . Then Home
  • At the Hospital
  • many hospitals provide regular massage and
    soothing stimulation ideally, parents share in
    caregiving
  • At Home
  • complications, e.g., minor medical crises
  • cognitive difficulties may emerge, but high-risk
    infants can develop normally

118
Mothers, Fathers and a Good Start
  • Strong family support (familia)
  • Fathers play a crucial role
  • may help wives abstain from drugs or alcohol
  • can reduce maternal stress
  • Parental alliancecommitment by both parents to
    cooperate in raising child
  • helps alleviate postpartum depression

119
Mothers, Fathers and a Good Start, cont.
  • Parent-infant bondstrong, loving connection that
    forms as parents hold, examine, and feed their
    newborn
  • immediate contact not needed for this to occur
About PowerShow.com