I see dependent and independent variables all day long. Years of study both at the undergraduate and graduate level combined with many more years teaching experimental psychology and research methods have worked their effect on me.
The other day, I was driving to Texarkana and saw cattle egrets along the way. In one field with cattle, there were many more egrets than in other fields. That observation started me wondering why that one field had so many more egrets than the others.
Were I to follow up on my observation, then the number of cattle egrets in each field would become a dependent variable in my research.
A few days later, I was walking around campus and I noticed that some parked cars had one current campus parking permit affixed to their rear windows. However, other cars had two or more parking stickers affixed. Now, an independent variable came to mind: the number of parking stickers on each window. In other words, I could now use those two groups to divide drivers into two naturally-occurring groups.
Very quickly, hypotheses began to form in my mind. Were the drivers with more stickers students who were illustrating their tenure on campus? Or, were they simply unable to easily remove the old stickers?
After being exposed to research methods classes and after designing and conducting research projects, the world takes on a new look. Dependent and independent variables pop out everywhere.
Confused about the difference between dependent and independent variables? I like to find the dependent variables in a study first. The dependent variables are the measurements in research. Also, all of the participants will be measured.
On the other hand, independent variables divide the research into groups. The groups can occur naturally or be operationally defined by the researcher. The levels of the independent variable will not be the same for all participants. In the example above, some drivers have one parking sticker while others have two or more. See?
Monday, September 29, 2008
Sunday, September 14, 2008
Care and Feeding of Editors
A recent column by Lynn Worsham in the Chronicle of Higher Education (September 8, 2008) discusses what academic journal editors look for in submissions to their journals.
She identifies several oft-made mistakes by authors:
In our chapter 12, we cover some of the steps necessary to take a research project to completion. Finishing a research project can mean more than one thing. It could mean presenting your results orally in class or in public. Ultimately, it could mean publishing your research in a peer reviewed journal. If that's your goal, pay attention to Worsham's suggestions.
She identifies several oft-made mistakes by authors:
- submitting the wrong type of article to a journal
- failing to proofread the submission for grammatical and careless errors
- citing sources incorrectly
- being unaware of previous similar research in the same journal and not citing it
- not following specific submission requirements (e.g., # of copies or no return envelope)
- submitting a conference presentation without rewriting it as a paper
- arguing with editor over rejected submissions
In our chapter 12, we cover some of the steps necessary to take a research project to completion. Finishing a research project can mean more than one thing. It could mean presenting your results orally in class or in public. Ultimately, it could mean publishing your research in a peer reviewed journal. If that's your goal, pay attention to Worsham's suggestions.
Thursday, September 4, 2008
Crows Recognize People? Dogs Recognize Cars?
I have a fondness for field research. John Marzluff of the University of Washington and his colleagues observed that the crows they had trapped previously in order to band them for identification seemed to be harder to catch later.
So, they decided to test that hypothesis by conducting a field experiment. Three researchers, Marzluff and two students, then wore a caveman mask and trapped and released seven crows. Later, whenever one of the three wore the map on campus, the crows scolded them severely.
However, whenever they walked on campus wearing another mask (a Dick Cheney mask), the crows ignored the wearers. This, of course, was the control condition.
It seems, thus, that crows recognize people who catch and handle them and remember them later. Other researchers, too, have seen similar behaviors in crows and related birds. See a New York Times article for more information.
Informally, I have conducted similar exercises. I like to watch my dogs when I pull up in a rental car. Invariably, they bark at me viciously from behind the living room windows. They stop barking after I exit the rental car and start to walk toward the front door. Also, I have often sat outside in the afternoon while the dogs walk around in the front yard. I watch carefully for cars while I wait. I don't want to explain to my children why their dogs were run over. Interestingly, when I see my wife a block away and go to protect the dogs, they hear her van approaching and start to run in its direction (something they do not do for other vehicles).
So, it seems that dogs and birds can recognize and remember things about us.
So, they decided to test that hypothesis by conducting a field experiment. Three researchers, Marzluff and two students, then wore a caveman mask and trapped and released seven crows. Later, whenever one of the three wore the map on campus, the crows scolded them severely.
However, whenever they walked on campus wearing another mask (a Dick Cheney mask), the crows ignored the wearers. This, of course, was the control condition.
It seems, thus, that crows recognize people who catch and handle them and remember them later. Other researchers, too, have seen similar behaviors in crows and related birds. See a New York Times article for more information.
Informally, I have conducted similar exercises. I like to watch my dogs when I pull up in a rental car. Invariably, they bark at me viciously from behind the living room windows. They stop barking after I exit the rental car and start to walk toward the front door. Also, I have often sat outside in the afternoon while the dogs walk around in the front yard. I watch carefully for cars while I wait. I don't want to explain to my children why their dogs were run over. Interestingly, when I see my wife a block away and go to protect the dogs, they hear her van approaching and start to run in its direction (something they do not do for other vehicles).
So, it seems that dogs and birds can recognize and remember things about us.
Monday, August 25, 2008
Genes and Child Development
Newsweek recently published an article featuring some of the latest research in developmental psychology. Interestingly, specific gene loci may be responsible for many of the behavioral differences seen in children.
Temperament, for example, has a strong genetic link with associated behavioral consequences. Children with easy temperaments are less likely to pay attention to their parents and to listen to them. Fussy children, on the other hand, are more likely to pay close attention to their environment (including their parents) and are, thus, more likely to learn from experience.
The article discusses genetic variations other than the mellow/fussy baby. The gene FADS2, for example, raises IQ scores for babies who have been breast fed. However, the "C" variant of the gene, possessed by about 10% of babies, does not lead to a similar rise in IQ scores. Another gene, MAOA, comes in "sluggish" and "active" forms. The sluggish version of that gene seemingly protects victims of abuse from later risky behavior because memories of the trauma are damped by that version of the gene. The active version, unfortunately, rekindles the traumatic memories and may lead the victim into alcohol or drug abuse as a coping mechanism. Another gene, DRD4, has been linked to a variety of behaviors from increasing coping behavior in children and increased sexuality.
The implications this line of research are varied. For one thing, it multiplies the amount of individual variation previously suspected. For another, it causes researchers and practitioners to look more closely for genetic causes for behavior. Finally, it makes the entire behavioral picture much more complicated than previously thought.
Temperament, for example, has a strong genetic link with associated behavioral consequences. Children with easy temperaments are less likely to pay attention to their parents and to listen to them. Fussy children, on the other hand, are more likely to pay close attention to their environment (including their parents) and are, thus, more likely to learn from experience.
The article discusses genetic variations other than the mellow/fussy baby. The gene FADS2, for example, raises IQ scores for babies who have been breast fed. However, the "C" variant of the gene, possessed by about 10% of babies, does not lead to a similar rise in IQ scores. Another gene, MAOA, comes in "sluggish" and "active" forms. The sluggish version of that gene seemingly protects victims of abuse from later risky behavior because memories of the trauma are damped by that version of the gene. The active version, unfortunately, rekindles the traumatic memories and may lead the victim into alcohol or drug abuse as a coping mechanism. Another gene, DRD4, has been linked to a variety of behaviors from increasing coping behavior in children and increased sexuality.
The implications this line of research are varied. For one thing, it multiplies the amount of individual variation previously suspected. For another, it causes researchers and practitioners to look more closely for genetic causes for behavior. Finally, it makes the entire behavioral picture much more complicated than previously thought.
Friday, August 15, 2008
Coffee Research
I never drank much coffee before entering graduate school at LSU in Baton Rouge. Early in my first year I noticed two coffee urns at the end of the cafeteria line marked "Light" and "Dark." I turned to Pete Spiliotis, my predecessor in Don Hoffeld's lab, and asked the difference. He explained that dark was short for dark roasted or french roasted coffee, and that I should try a cup. I did and I was hooked.
By the time I left LSU for Milwaukee five years later, I was a Community Dark Roast coffee addict. So much of an addict that I had to order coffee by the case from Baton Rouge. In Milwaukee, I created a few coffee addicts including David Blackwelder, one of the grad students. One day he came into work complaining that he'd been awake all night. Seems he'd been drinking strong brewed dark roast into the wee hours. When I moved to Magnolia, Arkansas in 1980, I noticed that the local groceries stocked Community Dark Roast. I guess because we were only twenty miles from the Louisiana line. Since then, I have switched to Community's New Orleans blend. It adds chickory to the grounds.
Every year, the local schools hold their Red Ribbon week urging students not to do drugs. Alas, I cannot wear that red ribbon. I drink coffee for the kick. I tried going cold turkey a couple of years ago. That lasted about a week or less. It was my students who insisted that I start drinking again. They could not stand my coffee-free self, it seemed.
So, it was not passing interest that called me to read a recent New York Times article about coffee research titled, "Sorting out coffee's contradictions" by Jane E. Brody. She nicely summarizes coffee's myths and health benefits.
Among the myths are: coffee is not a diuretic, does not cause heart disease, hypertension, cancer, bone loss, or weight loss. Among the health benefits are: enhanced mood, performance, alertness, decreased reaction time, fat burning (instead of carbohydrates), lowered risk of Parkinson's and Type 2 Diabetes.
Whew, I guess I'll have another cup.
By the time I left LSU for Milwaukee five years later, I was a Community Dark Roast coffee addict. So much of an addict that I had to order coffee by the case from Baton Rouge. In Milwaukee, I created a few coffee addicts including David Blackwelder, one of the grad students. One day he came into work complaining that he'd been awake all night. Seems he'd been drinking strong brewed dark roast into the wee hours. When I moved to Magnolia, Arkansas in 1980, I noticed that the local groceries stocked Community Dark Roast. I guess because we were only twenty miles from the Louisiana line. Since then, I have switched to Community's New Orleans blend. It adds chickory to the grounds.
Every year, the local schools hold their Red Ribbon week urging students not to do drugs. Alas, I cannot wear that red ribbon. I drink coffee for the kick. I tried going cold turkey a couple of years ago. That lasted about a week or less. It was my students who insisted that I start drinking again. They could not stand my coffee-free self, it seemed.
So, it was not passing interest that called me to read a recent New York Times article about coffee research titled, "Sorting out coffee's contradictions" by Jane E. Brody. She nicely summarizes coffee's myths and health benefits.
Among the myths are: coffee is not a diuretic, does not cause heart disease, hypertension, cancer, bone loss, or weight loss. Among the health benefits are: enhanced mood, performance, alertness, decreased reaction time, fat burning (instead of carbohydrates), lowered risk of Parkinson's and Type 2 Diabetes.
Whew, I guess I'll have another cup.
Friday, August 8, 2008
Summer Research Ideas
Another research method class has come and gone. I thought I'd share their research ideas:
- Is shyness more common in males or females?
- An interpretation of Rap: What we see is what you get
- Wet vs. Dry: Opinions about liquor in Conway, Arkansas
- PTSD: More common after combat or peace keeping missions
- What makes a woman stay with her abuser?
- Reasons why Facebook users accept friend's requests from strangers
- Sports drinks and physical endurance
- Noise effects on concentration and response time of college students
- Teenage female marijuana use as a gateway to other drugs
- Parenting: Do you parent differently from how you were parented?
- Postpartum depression in married vs. single mothers
- Witnessing domestic abuse as a child: Are such men more abusive to their spouses
- Links between childhood abuse and adult domestic violence
Sunday, June 22, 2008
Elizabeth Loftus
This is additional material from the "cutting room floor." Originally, we thought of including examples of extremely successful scientists as a way of wrapping up chapter 1, Science. Here is our short biography of one such successful psychologist, Elizabeth Loftus.
Elizabeth Loftus currently holds joint faculty appointments. She is distinguished professor of psychology and social behavior at the University of California-Irvine and is affiliate professor of psychology and law at the University of Washington. Loftus received her BA from UCLA in 1966 and her PhD from Stanford in 1970. She began her academic career at New School University in 1970. From 1973 till the present she has worked at the psychology department at the University of Washington. In 1984, she began to serve as a law professor there too. In 2002, she was named distinguished professor at the University of California- Irvine as well (where she spends most of her time). Loftus is the author of 18 books and more than 250 articles. She has served on many editorial boards and as officer of several professional associations including the presidency of the American Psychological Society. She has also served as an expert witness on human memory in hundreds of legal cases.
At age 14, Loftus lost her mother to a drowning accident. To this day she believes that event marks a profound division in her life. Ever since that day, Loftus has seen herself as an agent for helping others. As an undergraduate at UCLA, she excelled at both math and psychology. Like Robert Sternberg, she attended Stanford and studied psychology. She married Geoffrey Loftus in graduate school. After graduating, he went to work at the University of Washington and she followed a year later (turning down an assistant professorship at Harvard to do so). Their marriage lasted 23 years, “...an accomplishment...” according to Loftus, given her work ethic. They are still friendly. Loftus fell into her first major research topic, eyewitness memory, because she wanted her research to have practical applications, and it has.
Early in her academic career (around 1972), Loftus was studying memory using pictures as stimuli. After a conversation with a man who had been convicted of killing someone in self–defense she began to use films of accidents as experimental stimuli. What she found surprised her. The participants who viewed the films gave her different answers depending on how she phrased the questions she asked them. The relationship between leading questions and eyewitness memory became her first major research project. She found that leading questions influenced eyewitness memory and that a large percentage of eyewitnesses (in her lab) insisted they had seen something that, in fact, they had never seen. They had, however, heard that thing mentioned while being questioned in an intentionally leading manner. For example, nearly 20% of participants claimed to have seen a barn in one of her films. In reality, there was no barn and only those who had been earlier asked a leading question about the non-existent barn claimed to have seen it. In 1999, the United States Department of Justice published guidelines on gathering eyewitness testimony in criminal investigations that stemmed directly from Loftus’ research. Those recommendations call for law–enforcement personnel to avoid the use of leading questions and to place only one suspect in a line-up. Loftus’ eyewitness reliability research has been called one of the best examples of how psychological research can affect public policy (Foxhall, 2000).
Later, Loftus began to study the difference between repressed memories and false memories. Repressed memories are true memories that have become unconscious for a time and then re-appear. Repressed memories of child abuse are a common example. However, some memories that appear to be repressed are not true, they are false memories. Although false memories are not true, the person believes them to be true. After observing a link between some therapists and the subsequent revelation of incriminating memories by their patients, Loftus demonstrated that false memories could be induced in a small percentage of individuals (See Chapter 3 for a more complete discussion of this research.). Her research ignited a legal and psychological controversy. Because of the large number of criminal cases based upon repressed memories, Loftus began to testify as an expert witness on human memory at hundreds of trials including those of the Hillside Strangler, O. J. Simpson, Rodney King, the Menendez brothers, and the Oklahoma City bombing. Her success in defending people accused of crimes like murder and child–molestation has created enmity from prosecutors, their witnesses, and even the public. Because of her research, her public appearances often require security personnel to be present. Her work has caused her hardship and grief while also bringing her fame and prestige. Recently, she was named as one of the top 100 most eminent psychologists of the 20th century (and the top ranked woman) putting her in the company of Freud, Skinner, and Piaget.
Reference
Foxhall, K. (2000). Suddenly, a big impact on criminal justice. Monitor on Psychology, 31 Retrived September 8, 2006 from http://www.apa.org/monitor/jan00/pi4.html
Elizabeth Loftus currently holds joint faculty appointments. She is distinguished professor of psychology and social behavior at the University of California-Irvine and is affiliate professor of psychology and law at the University of Washington. Loftus received her BA from UCLA in 1966 and her PhD from Stanford in 1970. She began her academic career at New School University in 1970. From 1973 till the present she has worked at the psychology department at the University of Washington. In 1984, she began to serve as a law professor there too. In 2002, she was named distinguished professor at the University of California- Irvine as well (where she spends most of her time). Loftus is the author of 18 books and more than 250 articles. She has served on many editorial boards and as officer of several professional associations including the presidency of the American Psychological Society. She has also served as an expert witness on human memory in hundreds of legal cases.
At age 14, Loftus lost her mother to a drowning accident. To this day she believes that event marks a profound division in her life. Ever since that day, Loftus has seen herself as an agent for helping others. As an undergraduate at UCLA, she excelled at both math and psychology. Like Robert Sternberg, she attended Stanford and studied psychology. She married Geoffrey Loftus in graduate school. After graduating, he went to work at the University of Washington and she followed a year later (turning down an assistant professorship at Harvard to do so). Their marriage lasted 23 years, “...an accomplishment...” according to Loftus, given her work ethic. They are still friendly. Loftus fell into her first major research topic, eyewitness memory, because she wanted her research to have practical applications, and it has.
Early in her academic career (around 1972), Loftus was studying memory using pictures as stimuli. After a conversation with a man who had been convicted of killing someone in self–defense she began to use films of accidents as experimental stimuli. What she found surprised her. The participants who viewed the films gave her different answers depending on how she phrased the questions she asked them. The relationship between leading questions and eyewitness memory became her first major research project. She found that leading questions influenced eyewitness memory and that a large percentage of eyewitnesses (in her lab) insisted they had seen something that, in fact, they had never seen. They had, however, heard that thing mentioned while being questioned in an intentionally leading manner. For example, nearly 20% of participants claimed to have seen a barn in one of her films. In reality, there was no barn and only those who had been earlier asked a leading question about the non-existent barn claimed to have seen it. In 1999, the United States Department of Justice published guidelines on gathering eyewitness testimony in criminal investigations that stemmed directly from Loftus’ research. Those recommendations call for law–enforcement personnel to avoid the use of leading questions and to place only one suspect in a line-up. Loftus’ eyewitness reliability research has been called one of the best examples of how psychological research can affect public policy (Foxhall, 2000).
Later, Loftus began to study the difference between repressed memories and false memories. Repressed memories are true memories that have become unconscious for a time and then re-appear. Repressed memories of child abuse are a common example. However, some memories that appear to be repressed are not true, they are false memories. Although false memories are not true, the person believes them to be true. After observing a link between some therapists and the subsequent revelation of incriminating memories by their patients, Loftus demonstrated that false memories could be induced in a small percentage of individuals (See Chapter 3 for a more complete discussion of this research.). Her research ignited a legal and psychological controversy. Because of the large number of criminal cases based upon repressed memories, Loftus began to testify as an expert witness on human memory at hundreds of trials including those of the Hillside Strangler, O. J. Simpson, Rodney King, the Menendez brothers, and the Oklahoma City bombing. Her success in defending people accused of crimes like murder and child–molestation has created enmity from prosecutors, their witnesses, and even the public. Because of her research, her public appearances often require security personnel to be present. Her work has caused her hardship and grief while also bringing her fame and prestige. Recently, she was named as one of the top 100 most eminent psychologists of the 20th century (and the top ranked woman) putting her in the company of Freud, Skinner, and Piaget.
Reference
Foxhall, K. (2000). Suddenly, a big impact on criminal justice. Monitor on Psychology, 31 Retrived September 8, 2006 from http://www.apa.org/monitor/jan00/pi4.html
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