Exam 3, Biology 301D, 14 November 2001 Printed name ________________

(2pts) Social security number and name. Bubble in the scantron with your name and your social security number (your SSN goes(in the first 9 bubbles of the scantron ID field). (For good measure, put your name on this hard copy too, in case your key code does not carry over.)

(2pts) Key Code: One of the exam questions will indicate a key code. Make sure you fill those in as indicated on the question indicated.

When finished, turn in both the Scantron and hard copy. You may write on this hard copy, but your grade will be determined by the Scantron form.

None, one, all, or any combination of individual answers may apply to a question unless stated otherwise.

1. (5 points) Which of the following constitutes an example of inferring causation from correlation (i.e., a correlation leads someone to infer the causal basis of the correlation)? Base your answer only on the information provided. Do not circle answers that merely describe a correlation or which infer correlation from causation (the reverse of what we want).

(A) You bring your “perfect partner” home to meet your parents for the first time, telling them of your engagement to get married. Your parents find out that the parents of your partner are divorced and object to your marrying this person because it has been shown that children whose parents are divorced also have high divorce rates, and your parents are thus worried that marrying this partner will end in divorce.

(B) In the 1970s it was noted that prison populations contained an unusually high incidence of men with two Y chromosomes (they also had an X), in contrast to their low incidence in the non-prison population. Thus, the XYY genotype was over-represented in criminals.

(C) A person is more apt to make mistakes when they are sleepy than when they have had adequate sleep because the lack of sleep impairs judgment. As a consequence, sleepy drivers are involved in auto accidents more often than are awake drivers.

(D) Studies have documented that people with high-fat diets have higher cancer rates than people with low-fat diets.

(E) Studies have documented that people who consume low amounts of alcohol have low levels of heart disease compared to people who do not drink at all. You thus encourage your parents (who have traditionally been non-drinkers) to start consuming 1-2 ounces of alcohol a day.

2. (5 pts) You observe a correlation between levels of tooth decay and the amount of junk food a person eats (more tooth decay with higher amounts of junk food). Which of the following models are consistent with this observation?

(A) Junk food causes higher levels of tooth decay.

(B) Bad teeth cause a person to eat more junk food.

(C) Junk food reduces tooth decay, but people who eat lots of junk food don’t take care of their teeth, and it is the poor hygiene that causes the tooth decay.

(D) Junk food reduces tooth decay, but people who eat lots of junk food have genes for bad teeth.

Electromagnetic Fields

3. (5 pts) Which statements about electromagnetic fields are true? (none, one, or many)

(A) This topic was used chiefly to illustrate the theme that interactions impede scientific progress.

(B) One of the main difficulties in interpreting the EMF-cancer data is a lack of controls from low-EMF households.

(C) Across most studies, the typical high-EMF homes with increased leukemia rates have a risk factor in the range of 1-2.

(D) EMFs have similar energy levels (frequencies) as visible light, which is why there is no obvious mechanism for their harmful effects.

(E) A variety of animal models have helped us understand specifically how EMFs cause cancer

(F) Alternating current generates EMFs, and electrical appliances such as TVs, electric hair dryers, and cordless phones are different sources of exposure to EMFs.

Videos

4. (4 pts) The Monty Python video on penguin intelligence compared the performance of humans and penguins on an IQ exam. Which of the following options pertain to that video and are true?

(A) Two different models of “intelligence” were considered (brain size, test performance)

(B) The tests shown in the videos exhibited a progression of increasingly better controls.

(C) The following factors were controlled for in at least one of the tests described: ability to speak English, inability to speak English, the test environment, the environment in which the test subjects were born and reared.

(D) None of the tests controlled for being covered by feathers.

5. (7 pts) Prisoners of Silence. In upcoming weeks, it will be shown that some parents and administrators had a strong, vested interest in believing that Facilitated Communication works, and they did not readily accept the test results shown in class which suggested that the facilitator was controlling the typing. One possible criticism these doubters raise is that the test environment did not accurately reflect the normal FC environment (it was "intimidating"), hence the children could not be expected to perform well during the test. Which of the following options are either legitimate criticisms of the test or are legitimate defenses of the test, taking into account the outcomes of the test? None, one, or many answers.

If any part of an option is incorrect, consider the option incorrect and do not mark it.

(A) Explicit protocol: the specification of a protocol in advance of the test allows the child and facilitator to prepare and thus overcomes the criticism that the test intimidates the facilitator or child.

(B) Replication: by asking the child/facilitator to identify more than one object/picture, any criticism of an intimidating test environment is overcome, because there is time for the child/facilitator to adjust to the test environment.

(C) Controls: As described (but not shown) in the video, one type of control was used in the "message passing" test: Betsy was shown a key out of sight of her facilitator, asked to type what she saw, and then asked again to type what she saw after being shown a key in the presence of her facilitator. The correct answer was typed only when the facilitator was shown the key. The fact that the correct answer was typed when the facilitator saw the same object Betsy did constitutes a control that demonstrates the testing environment was not preventing FC from working as expected.

(D) Controls: the controls for the parts of the study that used pictures were the cases in which the child and facilitator were shown the same photo; the fact that the correct response was typed in these cases demonstrates that the FC setting was operating as expected. If the wrong responses had been obtained with these controls, the criticism (of an intimidating testing environment) would have had merit.

(E) Blind: the ”picture” tests were double-blind, in that the facilitator did not know what the child saw, and the child did not know what the facilitator saw. “Blind” was an essential design feature in these tests to prevent the facilitator from knowing the expected/correct answer.

(F) Experiment: the tests did not constitute an experiment except when the facilitator was paired with an unfamiliar child.

6. (6 pts) Which statements about the palm reading study in the "Secrets of the Psychics" video (featuring James Randi and the palm reader Ray Hayman) are correct or valid?

(A) Design: The study consisted of reading a person’s right palm according to the book then reading that person’s left palm the opposite of the book and then comparing the subject’s responses to the reading of the right versus left palm.

(B) Progress through the scientific method: Ray's views on whether palm reading is valid changed at least twice in his life: (i) he initially doubted the validity of palm reading; (ii) then, after trying palm reading, he decided it was accurate; (iii) finally, after conducting his experiment, he decided that the patient's response had nothing to do with the reading's accuracy. These changes in his views illustrate progress through the scientific method, and include the features of models, data, evaluation, and revision.

(C) From the video segment shown, one can conclude that there are explicit protocols to use in reading palms (not necessarily the same as explicit protocols to use when testing the validity of palm reading).

(D) A test was conducted (but not shown) in which Ray obtained positive responses to palm reading, even though he told the client the opposite of what the books said about palms. This test is not considered an experiment because Ray did this test in response to a friend’s “bet” and thus it had no formal protocol.

(E) Control. A lack of an enthusiastic response to the palm reading is considered the baseline (control) for this study, and the accuracy of a palm reading is then judged by how enthusiastically the person responds to the reading.

Controls

7. (5 pts) Mark all of the following statements about controls that are correct (none, one, many)

(A) A control is a reference point (or group of points); controls are part of any correlation

(B) To establish a correlation between level of smoking and cancer rate, the control group must have a zero level of smoking.

(D) A control group must be chosen blindly to qualify as a true control

(E) To control for factor X, X may be fully present or completely absent in all study groups, but it cannot be present at an intermediate level.

(F) The choice of subjects randomly guarantees that a control is present.

(G) Controls are absent from correlational data because the data are gathered prior to any manipulation

8. (5 pts) A UT researcher decides to evaluate the effect of exam difficulty on teaching evaluations. Each instructor is to teach two sections of the same UT course (same course number and content but different lecture times to different students). Different instructors teach different course numbers, some instructors teaching upper division courses and other instructors teaching lower division numbers. For each instructor, the earlier section is given the harder exams. At the end of the semester, student evaluation scores are compared between the first and second sections by each instructor. What factors are explicitly controlled for (matched) in the design of this study? Do not infer more than is given. (none, one, many)

(A) Course number	(D)Upper division versus lower division course
(B) Order of lecture taught by a single instructor (earlier versus later section)	(E) Instructor
(C) University	(F) Course content and difficulty

9. (5 pts) Each of (A)-(E) are different treatments applied to farm fields and would provide data on crop yield under different conditions, as indicated by the 5 factors. Factor 1 is the use of irrigation; factor 2 is the use of fertilizer; factor 3 is the use of pesticide; factor 4 is the use of herbicide; factor 5 is the use of honey bees to pollinate the crop. Which two data sets would you want to compare to determine if factor 2 is correlated with differences in yield when the other factors are controlled? In evaluating possible answers, pick the comparison that controls for the most unwanted factors, and assume that these four data sets differ only in the ways stated. Mark exactly two options, or none if none apply. (A "+" indicates that a factor is present; a "-" indicates that it is absent.)

	factor
Option		1	2	3	4	5
	(A)	+	-	+	-	+
	(B)	-	-	-	+	+
	(C)	+	+	+	-	+
	(D)	+	+	-	+	-
	(E)	-	-	+	-	+

10. (4 pts) A psychologist does a survey to study correlates of criminal behavior, testing in particular whether family income level influences the propensity toward criminal behavior. Identical twins separated at birth and raised in different households (by different parents) are used, with the crime rates compared between the twin in the lower-income household and the twin in the higher-income household; the latter is treated as the control. What factors are controlled for in this study (which are matched between the control group and focal group)?

(A) gender/sex	(D) family economic level	(G) Birth date
(B) neighborhood	(E) parental favoritism toward different children
(C) performance in school	(F) household

Experiments

11. (8 pts). Which of the following studies describe experiments, regardless of whether the experiment was designed well or poorly. Some of these studies would be considered unethical, but the question is merely about which studies are experiments? (none, one, many)

(A) You wish to improve your grades. Instead of doing what you did last semester, which was wait until the last minute and study alone, you make a point of beginning your studies for exams early, and you study with other students in the class. But your grades don’t change.

(B) A scientist gives mice a diet that contains some alcohol to see if they live longer.

(C) In the summer of 1969, researchers at McDonald observatory were the first to measure the distance to the moon using lasers.

(D) A study is done to determine whether a drug increases the incidence of birth defects. The study design involves giving 50 pregnant mice food containing low levels of the drug. The control group is 50 pregnant mice with no drug in their food. The study finds that those receiving drug had a slightly higher incidence of birth defects than those who did not.

(E) You want to know if wild Indian paintbrush (a flowering plant) can only grow in the presence of bluebonnets (another plant). You stop at 50 locations along the road and record whether bluebonnets and (or) Indian paintbrush occur at each stop. You sometimes find bluebonnets alone, and you sometimes find Indian paintbrush alone. So you conclude that the paintbrush plants do not need bluebonnets.

(F) A study of 100,000 nurses records the diets, weight and height of each nurse, and then follows these nurses for five years, determining which die of heart disease. The study design does not involve asking the nurses to alter their diets. The study finds that overweight women die more frequently of heart disease.

12. (6 pts) Design an experiment to determine if mildly ill patients (who don’t need any treatment) complain less if given a useless pill by their physician than if given nothing. Which of the following options are correct? (We will leave aside ethical and “informed consent” issues.)

(A) Controls: Patients given no pill could serve as a control for patients given a useless pill.

(B) Controls: the best baseline for the study would be patients who aren’t ill at all, because if they complain, then we know that there is no basis for their complaints.

(C) Replication: the results of the study would be more general (be more widely applicable) if it included several physicians, each with several patients instead of several patients and a single physician.

(D) Random: the choice to give a patient a useless pill should be done at random, to avoid any unintentional bias whereby a physician might be inclined to give pills to the most-complaining patients.

(E) Blind: the patients should not be told the nature of the study.

(F) Manipulation. This study is not truly an experiment: since no patient is being given a medical treatment, there is no manipulation.

How our brains mislead us

13 (5pts). Which of the following points or examples were considered to be examples of how our brains (can) mislead us into making irrational decisions?

(A) Magic tricks and optical illusions

(B) We have multiple goals

(D) We learn by trial and error

(E) We unconsciously look for causation in correlations

(F) We respond to emotional factors in making many decisions (as in scams, chain letters, urban legends)

(G) Our educational system has taught us facts instead of problem-solving skills.

(H) We search for confirmation of our views rather than evidence to evaluate them

(I) We respond to perceived risks rather than actual risks

Intrinsic Difficulties

14-18 (3 pts each). These questions ask for the course theme(s) best illustrated by the given statement. Do not assume any more than what is explicitly given in the question (except that question 15 requires you to draw on information provided in class). That is, address only the difficulties specifically mentioned. One or more than one answers may apply. There are fewer options here than on some practice questions:

(A)

Rare events are difficult to quantify

(B)

Time lags slow progress

(C)

Pitfalls of complexity

(D)

Humans make difficult experimental subjects

(E)

None

14. Initial attempts to adjust a shower temperature are often met with mistakes (as per lecture).

(A) (B) (C) (D) (E)

15. The children of women who took DES during pregnancy acquired cancer more often than did the children of women who did not take this drug during pregnancy. However, these cancer cases generally did not appear until these offspring were twenty to thirty years old. Consequently, DES -- a harmful drug -- was used for several decades before the drug was banned.

(A) (B) (C) (D) (E)

16. Lifespan shows numerous correlations with diet and health, but it is difficult to identify cause and effect. First, it is difficult or impossible to do the necessary experiments with humans because of cost and compliance issues. Second, it may take decades to observe the effect of someone’s diet today. And there are potentially hundreds of problems caused by the fact that the effect of one item in a diet (e.g., fat content) depends on what else is in the diet. Thus, one should not hope for a speedy understanding of what kinds of foods provide the greatest longevity.

(A) (B) (C) (D) (E)

17. Small towns may be the victims of undiagnosed health hazards from various types of industrial pollution, because there are not enough people living in them to show statistically meaningful increases in disease rates.

(A) (B) (C) (D) (E)

18. Sometimes scientists are simply unable to directly observe and measure what interests them. For example, before spacecraft became available, nobody knew what the back side of the moon looked like. And even today, scientists have no rock samples from deep inside the earth; the deepest boreholes do not come anywhere near the center of the earth. In a similar vein, standard medical diagnostic procedures are generally ineffective for very obese patients, because their fatty tissue simply obscures the doctor from observing what they need to see.

(A) (B) (C) (D) (E)

19. (6 pts) Which of the following constitute an example of an interaction ("complexity")?

(A) Taking birth control pills at the same time as certain antibiotics lessens the effect of the birth control pills.

(B) Answering 20 questions on an exam gives you twice as many points as answering only 10 questions on the exam.

(C) Drinking alcohol and driving a car is hazardous to your health, whereas either of these activities alone is relatively safe

(D) Silver nitrate mixed with magnesium powder "flashes" when misted with water

(E) The old adage “Two wrongs make a right” describes an interaction.

(F) In one of the Batman movies, the villain had created a poison that was fatal only when a person used three products together.

(G) You dilute an alcoholic drink with water to lessen the intoxicating effect you would get from consuming all of it.

(H) Your car goes faster when you step down harder on the accelerator

Biological Correlates of Being Gay

20. (4 pts) What does the results of LeVay’s study allow one to conclude about the cause of sexual preference?

(A) Sexual preference is biologically determined

(B) The study does not address the causes of sexual preference, because the observations are correlations

(D) No conclusion is possible because sexual preference determines INAH3 volume.

21. (3pts). Which points apply to the material about the “Boy raised as a Girl”?. (None, one, or many)

(A) Gender identity appears to be culturally determined, not biologically determined

(B) Sexual preference appears to be culturally determined, not biologically determined

(D) Experiments provide the best controls

22. (2 pts). Key code. Fill in (A) and (B) on the scantron field for question 22 to indicate your key code.