a traumatic event, he or she might have difficulty processing the experience and integrating it into memory. As a result, stimuli that are similar to the trauma can trigger unwanted memories, emotions, or sensations. For example, a child who is attacked by a dog might have flashbacks about the attack when he hears a dog bark. Supporters of EMDR assert that flashbacks and other symptoms can be reduced by helping clients process and integrate traumatic experiences into their long-term memory (Shapiro & Laliotis, 2015).
To integrate traumatic memories, EMDR therapists ask clients to remember and describe aspects of their traumatic experience. This procedure is a form of exposure therapy in which the client deliberately thinks about the traumatic event. Then, the client performs a series of bilateral eye movements by following the therapist’s finger or another moving target back and forth across the visual field for several seconds. The eye movements resemble spectators at a fast-paced tennis match, following the ball back and forth with their eyes. The procedure repeats several times until the client’s anxiety dissipates.
There is some evidence that EMDR is effective in reducing posttraumatic stress in adolescents and adults. However, scientists do not agree on how it works. EMDR practitioners have offered several explanations. Some have suggested that the rapid eye movements used in EMDR mimic the eye movements during sleep. Others have suggested that the back-and-forth movement of the eyes increases interaction between the left and right hemispheres of the brain. Still others have posited that eye movements boost a person’s memory (Shapiro & Laliotis, 2015).
However, some scientists wondered whether the rapid eye movements—the hallmark of EMDR—are necessary for treatment. To test their importance, researchers examined children who experienced anxiety and mood problems following a traumatic event, such as a fire or explosion. Some children received traditional EMDR, whereas others received exposure therapy alone, without the rapid eye movements. Results showed that children in both groups had similarly good outcomes. However, adding rapid eye movements to exposure therapy led to only small improvements beyond exposure therapy alone (Rodenburg, Benjamin, de Roos, Meijer, & Stams, 2009).
Several researchers have concluded that EMDR works simply by exposing clients to memories of the trauma until their anxiety decreases. Occam’s razor directs us to select this more parsimonious explanation over more complex alternatives (Jeffries & Davis, 2014). Indeed, exposure therapy is considered a first-line treatment for children with trauma-related disorders and anxiety (Higa-McMillan, Francis, Rith-Najarian, & Chorpita, 2017).
Principle 4: Precision
The principle of precision means that scientists are careful in the way they collect data and the conclusions that they draw from their observations. In everyday life, humans often perceive relationships between events when none actually exist. We also assume that if two events occur together in time, then one event caused the other. These false or illusory correlations lead us to believe that our favorite sports team will win if we wear its jersey on game day, that we should avoid going out on nights with a full moon, and that feeding children sugary snacks will make them hyperactive.
The antivaccine movement illustrates the dangers of imprecise thinking and inferring a causal relationship from correlational data (Miller, 2015). In 1998, physician Andrew Wakefield published a paper in the prestigious medical journal, The Lancet, suggesting a link between infants’ exposure to the measles, mumps, and rubella (MMR) vaccine and the emergence of neurological problems. The paper described 12 children who developed symptoms of autism shortly after vaccination. In several press conferences, Wakefield suggested that the vaccine might cause autism and that certain forms of the vaccine should be discontinued to prevent the disorder. As a result, vaccination rates plummeted from a high of 95% to a low of 80%. The prevalence of measles rose from 56 cases prior to the publication of Wakefield’s paper to more than 1,300 cases 1 decade later (Centers for Disease Control and Prevention, 2019b).
It is clear that the prevalence of autism has increased dramatically in recent years. For example, approximately 1 in 150 children were diagnosed with autism in 2007, whereas 1 in 59 children are diagnosed with the disorder today. It is also true that some children experience signs of autism shortly after vaccination. Indeed, the first signs of autism typically emerge between 6 and 24 months of age—about the same time that the MMR vaccine is administered to most children (Howard & Reiss, 2019).
Although vaccinations and autism co-occur, this does not mean that vaccines cause autism. Given the high rate of vaccination and the high prevalence of autism, a certain number of children will begin to show signs of autism shortly after vaccination simply by chance (Table 3.1).
Researchers have spent the past 20 years looking for a causal relationship between vaccines and autism. A recent analysis involving more than 1,200,000 children showed no relationship between autism and vaccines (Taylor, Swerdfeger, & Eslick, 2015). Wakefield’s original paper was retracted from The Lancet because his data were fraudulent and he was banned from practicing medicine. Nevertheless, he continues to warn parents against vaccines. In the meantime, outbreaks of measles have occurred throughout the United States, Great Britain, and other countries where parents refuse to vaccinate their children because of these unsubstantiated fears (Hopkins, 2019).
Principle 5: Reproducibility
Reproducibility is the scientific principle that the results of research studies must be replicated before they are accepted. The need for reproducibility is based on the notion that if a result is real, then another researcher should be able to obtain it using similar methods. Reproducibility is important because children and families are entitled to information that is trustworthy and accurate (Simons, 2015).
There are two types of replication studies: direct and conceptual. Direct replication involves repeating the exact procedures used in a research study to determine if the same results are found. Direct replication allows us to have confidence that the findings of the original study are accurate and robust. Conceptual replication involves using different methods to test the same hypothesis examined in the original study. Conceptual replication helps us confirm whether the theoretical ideas behind the original findings are true (Tackett, Brandes, King, & Markon, 2019).
Table 3.1
Note: Children who receive the measles, mumps, and rubella (MMR) vaccine get shots on at least 2 days between 6 and 24 months of age. Therefore, just by chance, we would expect 92 children in the United States each year to show the first signs of autism immediately after vaccination. Based on Howard and Reiss (2019).
For example, researchers might find that a phonics program improves the reading skills of children with dyslexia. The researchers might perform a direct replication by repeating the original study with a new sample of children with dyslexia using the same methods. Alternatively, they might perform a conceptual replication by using a different phonics-based reading program to see if it is also effective in helping children with dyslexia learn to read.
The Drug Abuse Resistance Education (D.A.R.E.) program illustrates the importance of reproducibility. D.A.R.E. was the most widely used alcohol and drug prevention program in the United States. Created in the 1980s, D.A.R.E. was designed to provide children with information about the dangers of drug use, teach decision-making skills, and build self-esteem. Weekly lessons were taught by police offers to students at school.
Early evaluations of D.A.R.E., conducted by researchers associated with the program, indicated that it was extremely successful (Faine & Bohlander, 1989). These results fueled the popularity of the program, which was eventually adopted by 80% of school districts and cost almost
