Answer Key

For questions that had several possible options, the answer key T contains the most likely answers (things discussed in lecture and/or book). Other answers may also have been acceptable.


1) Longitudinal and cross-sectional studies are two designs that developmentalist use to study children. Give an example of each design and then provide one advantage and one disadvantage of each one. (6 points)

Longitudinal: Main point - same kids across time comparison

Advantage: fewer subjects, less variability (subject acts as own control), can look at change over time

Disadvantage: expensive timewise, subject dropout, practice effects (familiarity with the test)

Cross-Sectional: Main point - comparison between different subjects at different ages.

Advantage: fast to do, do practice effects, less drop out

Disadvantage: more subjects, more variability (betwwen subjects), can't investigate/indirect evidence for change.

2) Psychologists from the different theoretical frameworks offer contrasting answers to the key developmental questions. List one (1) strong proponent of each of the following positions. Feel free to list a specific psychologist’s name OR the name of the theory (Framework). You may use the same name or theory more than once if it applies. (5 points)

Gradual and continuous developmental change: Learning-Environmental (Watson, Skinner)/Social-learning

Genetic programming: Biological-maturational

Reciprocal relationship of nature and nurture in development: Constructivist (Piaget)

The source of developmental change is endogenous: Biological-Maturational

Development is actively co-constructed by the child and caretaker. Cultural-Context (Vygotsky)

3) Sickle Cell anemia is a recessive gene disorder . If the mother seriously suffers from sickle cell anemia and the father is heterozygous, answer the following (6 points)

A. What are the possible Genotypes of the offspring:

Recessive-recessive (rr), Dominant-recessive(Dr) They may list two of each of them.

B. What is the chance that an offspring will have Sickle Cell Anemia? 50%

C. Does offspring's genotype determine it's phenotype? Why/ Why not?

Yes No (circle one) NO

Explanation: Phenotype is the characteristic that the person will display based on the interaction of the genotype and the environment. (Different people display different levels of severity/symptoms, different treatiment, different prognosis, etc.)

4) Describe two types of studies that researchers use to try to determine the genetic influence of a characteristic. What are two possible problems with the conclusions of these types of studies? (4 points)

Twin Studies - comparing identical & fraternal twins (& other kinship relations) where the degree of genetic similarity is known

Adoption Studies - comparing adopted children to their biological and adopted parents and/or siblings, (Or comparing twins raised apart by adoption to twins raised together)

Problems (they need 2)

1: Identical twins may have more similar environments than other types of siblings.

2: Even children raised in the same home do not share all aspects of the environment (parents react differently to different children, parents change child-rearing practices, etc)

3: Adopted studies - children may have very similar environments anyway because Adoption agencies usually select similar types of homes (2 - parent, financially stable, emotionally stable, same race, religion, etc)

5) Describe 1 (one) study that suggests that learning occurs prenatally and briefly state why this is an important finding. (5 points)

Research Question: Can babies discriminate sounds prenatally

Method: Mothers read a story to babies during the last 6 weeks of pregnancy and after birth babies rate of sucking activated either the same or a different story. (or for half increasing sucking activated the old story and for the other half decreasing sucking rate activated old story).

Result: Babies adjusted their sucking rate to activate the old story

Conclusion/Interpretation: Fetuses can discriminate sounds in the womb


(see page 91-92 or lecture notes on prenatal development for other examples)

Why is this important? It shows the importance of the prenatal period in terms of growth and learning or it shows that babies come into the world with certain perceptual abilities (innateness of certain capabilities)

6) Define "teratogen", list two (2) specific examples, and indicate one (1) reason that the effects of teratogens are difficult to predict. (4 points)

Definition: Environmental agents that can cause deviations or changes in the normal course of prenatal development and can result in abnormalities or death

Examples (Need 2) 1) Drugs (cocaine, Heroin, caffeine, tobacco, some antibiotics, valium) & Alcohol, 2) Infections (Rubella, AIDS, gonorrhea - see page 100 for list) 3) Pollutants (mercury, air pollution), 4) Other: Rh factor incompatibility.

Reason for prediction difficulty: (Need 1) 1) Timing (will cause different symptoms depending on the period of fetal development - e.g. when arms are forming vs when auditory system is forming. 2) Interaction with Mother's genetics/health - different mothers will react differently to different teratogens, metabolize them differently 3) Babies genes may protect in varying degrees from the effects of the teratogen, 4) concentration of the teratogen affects outcome 5) length of exposure affects outcomes.

7) List three (3) maternal factors that can negatively influence prenatal development and indicate one (1) possible effect of each factor (6 points)

1) Negative Attitudes: : Low birth weight, more medical problems

2) Stress: Low birth weight, prematurity

3) Extreme Malnutrition: Miscarriage, Stillbirths, Malformations, Infant Mortality

4) Age: Older - chromosomal abnormalities (e.g. Down syndrome risk increases) prematurity, infant mortality, labor difficulties. Younger - low birth weight, less healthy overall

5) Low SES: Lack of nutrition, prenatal care, stress - any outcomes associated with these factors

6) Lack of Prenatal Care - failure to detect problems can lead to prematurity, outcomes associated with poor nutrition, stress,e tc

7) Undernourishment: Low birth weight, Miscarriage, (Delayed Effects -Heart disease, Stroke)

8) Give 2 examples of how changes in one domain (e.g., biological, perceptual, cognitive, social) can contribute to developments in another, seemingly unrelated domain. (2 points)

1: Cortical development (parietal, occipital lobes) increase visual acuity - necessary for social smiling

2: Self locomotion - emotional development (wariness of heights), depth perception, spatial relations

3: Maturation of the digestive system - sleep through the night

4: development of the prefrontal cortex (motor inhibition, active memory) - success in search tasks

5: Memory Development - fear of strangers

*There may be others.

9) Give one (1) example from prenatal or postnatal development of each of the following developmental principles: 1) There are periods of apparent regression, 2) Timing is important, 3) Development occurs unevenly (6 points)

Regressions: 1) reaching behavior when sitting vs crawling - know how far can reach over a precipice when sitting but when first learn to crawl it's as if they forgot & will try to reach across a too wide gap.

2) Going down slopes - experienced crawlers know when slope is too steep and go down on bottom or backwards but when they start to walk they "forget" and try to walk down too steep slopes.

3) Stepping - babies step early but then it seems to go away before it returns again .

4) Lots of prenatal activity then it slows down with quiet periods (when higher cortical areas are starting to become active)

5) Language - correct use of irregular verbs & plurals then overgeneralization of rules (ran then will say runned or feet then foots)

*There may be others

Timing: 1) Onset of growth spurt in puberty - late vs early, affects social interactions, self-esteem,e tc 2) Early vs late walkers - affects development of wariness of heights, depth perception, performance on search tasks, social relation with caregiver, 3) Ovum moves to fast or too slow down fallopian tube pregnancy will be terminated 4) When during prenatal period teratogen exposure occurs will influence the effect of it

*There may be others.

Uneven: 1) Cephalocaudal development - from head down (neck muscles before back, before hip, etc) 2) Proximodistal development - from center to periphery - control over arms before hands, development of inner organs before skin 3) Brain development - old brain before cortex, frontal cortex later than rest of cortex 4) Walking - stepping before balance 5) Vision - differences in acuity, color, face perception abilities. 5) Cell division & differentiation at differnet rates & times

*There may be others

10) Who is most likely to suffer from an X-linked recessive disorder, males or females and why? (3 points)

Males Females (Circle one) Ans = Males (1 point)

Explanation: Males only have one X chromosome so if they inherit the recessive from the mother they don't have another X that could have the dominate allele and override the disorder (carry the dominant gene). Females have 2 X's so even if they inherit the recessive from one X they have a chance of inheriting a dominant gene from the other X. (2 points)

11) Describe operant conditioning in general and then describe a particular research study in memory that used the paradigm. In your research description briefly describe the research question (what were they trying to find out), method, and the finding (4 points)

Operant Conditioning: A behavior is performed and as a result a reinforcer is presented that serves to increase the likelihood that the behavior will reoccur. (e.g. baby hits a lever and music plays)

Research Question: Do young babies have memory capacities or Is there a difference in the memory capacity of younger vs older infants (something along those lines)

Research Method: Babies put in crib with mobile, record baseline kicking rate. Then attach ankle to mobile so when kick the mobile moves. Collect kicking rate. Then have some time passage, put baby back in crib (not tied to mobile) and look at kicking rate. (if reminder/reactivation study - after a delay & before test they put baby back in crib or show piece of mobile)

Research Finding: Younger babies can remember but shorter time period than older babies (3 mo to 12 month range)

(if you discuss the reactivation or reminder study - reminder has to be given sooner to younger babies than older babies in order to extend period of memory)

12) Describe Piaget's Object Permanence task and his interpretation for why babies fail the task. Provide an alternative explanation and a study that contradicts Piaget and supports the alternative. (4 points)

Piaget's Object Permanence Task( just need 1): 1) baby sees object being hidden under a cover and then has to find it OR 2) Visible displacements : Multiple covers and baby watches E/ hide it under one, remove, hide it under another, etc and then has to find it, 3) A not B error - Does task with at least 2 covers, finds it, then hide in other location, baby has to find it. 4) Train task - baby watches train on track go into a tunnel - where does baby (look for train )

Piaget's Explanation: At various ages babies fail the task because they lack a strong notion of an object and when object is hidden they fail to search or search incorrectly because the object to them no longer exists or if fail to look in correct place - object is associated with location, not an object in itself. Just saying "they lack object permanence" is not enough for full points)

Alternative Explanation & study to support: (just need 1)

1) babies have bad memories - Use same task but you wait longer before they can search - correct performance decreases

2) Lack ability to inhibit motor movement - A not B error task set up - baby reaches to old, now incorrect location but looks at new correct location. Or even with transparent covers where baby can see the object they continue to make A not B error.

3) Piaget tested more than just object knowledge - coordination of knowledge and reaching - Baillergeon Studies: habituation paradigm with screen moving in 180 degree arc then show either it stopping when a block is put behind it or moving through the object. Look longer at the impossible event. OR pushing block off the support - baby looks longer at impossible

13) Define canalization and provide an example of a characteristic that illustrates it. (2 points)

Canalization: behavior or characteristic is restricted to a narrow range of variation & show strong tendency to self-correct.

Example: Language seems to develop across a wide range of verbal input environments

Crawling/walking - McGraw video with the enriched treatment of one twin but both had same development of walking, crawling (or cross cultural differences in walking experience but still develop it, lack of nourishment - you see catch up in physical growth once nutrition is restored

*There may be others

14) Give one (1) example of how developmental researchers can encourage application of their findings by professionals or the public in each of the following ways. Feel free to refer to one finding that could be applied in both cases OR to use two different findings. Be sure to specify both the research finding to be applied AND the impact of its application on child development. (4 points)


1)Maternal influences on prenatal development.- eg, effects of stress - can educate public about dangers, have Dr. discuss with patient, etc,

2)teratogens on prenatal development: various effects can be given, reduce risk behavior - no drinking, drugs, etc

3) Importance of visual experience - Held & Hein study with cats (p. ),

4)Rosensweig study with rats & importance of motor activity

*There may be others.

Treatment: 1)PKU - leads to mental retardation but can be treated & symptoms reduced with diet. 2)Down Syndrome - enrichment programs

3) Premature infants - sleeping teddybear to stimulate breathing

*There may be others

15) List two processes that contribute to genetic diversity. (2 points)

Processes: meiosis,crossover, mutations

16. Give one advantage and disadvantage of experimental methods over naturalistic observations. (2 points)

Advantage: Causal inference, control the event, generalization (if proper selection and controls)

Disadvantage: lack ecological validity