Difficulty: Introductory | Prerequisites: None, though familiarity with basic biology vocabulary helps.
This activity introduces the scientific method by walking through a real published study: Braun et al. (2009) on animal-assisted therapy (AAT) for children's pain relief. It is one of the first exercises in BIO 311C and sets the foundation for how you will read, evaluate, and design experiments throughout the course. You are expected to identify the hypothesis, experimental design (treatments and controls), results, conclusions, and limitations of a study. If you can do that here, you can do it for any paper the course throws at you.
The scientific method is a structured process for testing ideas: form a hypothesis, design a controlled experiment, collect data, and draw conclusions. In this activity, you practise each step using a study that tested whether therapy dogs reduce pain in hospitalised children aged 3 to 7. The study found that AAT lowered pain and blood pressure, but had notable limitations including a very small sample size.
Hypothesis
A testable, falsifiable statement predicting the outcome of an experiment. In simple terms, it is your educated guess about what will happen, stated in a way that can be proven wrong.
Independent variable
The factor the researcher deliberately changes between groups (here, exposure vs. no exposure to a therapy dog). Think of it as the thing you are testing.
Dependent variable
The factor the researcher measures to see the effect of the treatment (here, pain score, blood pressure, respiratory rate). In simple terms, this is the outcome you are watching.
Control group
The group that does not receive the experimental treatment, used as a baseline for comparison. In this study, the control group sat in a quiet, calm environment for 15 minutes with no dog present.
Treatment group
The group that receives the experimental intervention. Here, children who interacted with an AAT dog for 15 to 20 minutes.
Animal-assisted therapy (AAT)
A goal-directed intervention in which an animal meeting specific criteria is an integral part of the treatment process. In plain terms, using trained animals (commonly dogs) as part of a patient's care plan.
Wong-Baker FACES Pain Assessment Scale
A self-report tool using a series of faces (from smiling to crying) that lets young children rate their own pain intensity. Widely used in paediatric settings because it does not require the child to describe pain in words.
In vivo
Research conducted in or on a living organism, in its natural biological context. Contrast with in vitro (in a dish or test tube). This study is in vivo because it observed living children in a hospital setting.
Holistic approach
Studying the organism as a whole system rather than isolating individual molecules or pathways. This study looked at the child's overall pain experience and vital signs, not a single cellular mechanism.
Reductionist approach
Breaking a system down into its smallest parts to study each in isolation (e.g., examining a single protein's function). This study is not reductionist.
Statistical significance
A result is statistically significant when the observed difference between groups is unlikely to have occurred by chance alone. When the study says pain was "significantly" lower, it means the difference passed a statistical test, not just that the number looked different.
Observation: Researchers noticed that animal interactions seemed to comfort hospitalised children.
Question: Can a structured AAT intervention measurably reduce pain and improve vital signs in young patients?
Hypothesis: AAT animals (dogs) can alleviate pain and improve vital signs in sick children aged 3 to 7.
Experiment: Designed a controlled study with a treatment group and a control group (details below).
Data collection: Measured blood pressure, respiratory rate, and pain (Wong-Baker FACES) before and after the intervention.
Analysis: Compared measurements between groups and before/after within each group.
Conclusion: Drew conclusions about AAT's effectiveness and acknowledged limitations.
Organisms studied: Sick children between 3 and 7 years old in a hospital setting.
Treatment group: Children exposed to an AAT dog for 15 to 20 minutes.
Control group: Children placed in a quiet, calm environment for 15 minutes with no dog.
Variables measured (dependent variables):
Blood pressure
Respiratory rate
Pain, measured on the Wong-Baker FACES Pain Assessment Scale
Independent variable: Presence or absence of the therapy dog.
Children in the AAT group had statistically significantly lower pain scores compared to the control group.
Blood pressure was also lower in the AAT group.
Respiratory rate increased in the AAT group (possibly due to excitement or physical activity with the dog).
Even brief exposure (15 to 20 minutes) to a therapy dog can reduce children's subjective experience of pain.
AAT may help reduce the need for pharmaceutical pain relief in paediatric patients.
Small sample size, limiting the generalisability of the findings.
Only one AAT dog was used, which was elderly and died during the course of the experiment. This means the results may not generalise to other dogs, breeds, or younger animals.
The study cannot separate the effect of the dog specifically from the effect of any novel, positive distraction.
This study is holistic: it examines the child's overall pain and vital-sign response, not a single molecular pathway.
This study is in vivo: it takes place in living organisms (children in a hospital), not in a laboratory dish.
AAT programmes now operate in hospitals, nursing homes, and rehabilitation centres worldwide. The principle tested here, that positive animal interaction can modulate pain perception, is part of a broader shift toward integrative medicine that combines conventional treatments with complementary therapies. Understanding how to evaluate such studies with the scientific method is a skill you will use whenever you read health claims in the news or assess clinical evidence.
Students often confuse the dependent and independent variables. The independent variable is what the researcher changes (dog vs. no dog). The dependent variable is what gets measured (pain, blood pressure, respiratory rate).
Students sometimes list the measurement tools (e.g., the Wong-Baker scale) as the treatment. The scale is how you measure the dependent variable; the treatment is the dog interaction itself.
"Significant" in science does not mean "large" or "important" in the everyday sense. It means the result is unlikely to be due to chance, based on a statistical test.
A control group is not a group that receives nothing. In this study, the control group still had a defined experience (quiet, calm environment for 15 minutes). The point is that they did not receive the specific intervention being tested.
Identifying hypothesis, independent variable, dependent variable, control group, and treatment group is one of the most commonly tested skills in introductory biology.
Know the difference between holistic and reductionist approaches. Be able to classify a study as one or the other and explain why.
Know the difference between in vivo and in vitro. A study on living organisms in their normal environment is in vivo. A study on cells or molecules in a lab dish is in vitro.
Be prepared to identify limitations of a study. Small sample size and lack of replication are classic answers, but go further: think about confounding variables, generalisability, and whether the control truly isolates the variable being tested.
"Statistically significant" will come up repeatedly. Understand that it refers to a formal test, not a subjective judgement.
True or False: The independent variable in this study was the children's pain level.
False. Pain level is the dependent variable. The independent variable is exposure to the therapy dog.
Fill in the blank: A study conducted on living organisms in their natural setting is called an ______ study.
In vivo.
True or False: The control group in this experiment received no experience at all.
False. The control group spent 15 minutes in a quiet, calm environment.
Fill in the blank: A ______ approach studies the organism as a whole, rather than breaking it into isolated parts.
Holistic.
True or False: "Statistically significant" means the result was very large.
False. It means the result is unlikely to have occurred by chance.
Q: What is the hypothesis tested in the Braun et al. (2009) study?
A: That animal-assisted therapy (specifically dogs) can alleviate pain and improve vital signs in sick children aged 3 to 7.
Q: Identify the independent and dependent variables in this experiment.
A: The independent variable is the presence or absence of the AAT dog. The dependent variables are pain (measured by the Wong-Baker FACES scale), blood pressure, and respiratory rate.
Q: What did the control group experience, and why is a control group necessary?
A: The control group spent 15 minutes in a quiet, calm environment without a dog. A control group is necessary to provide a baseline, so researchers can attribute any differences in outcomes to the treatment rather than to other factors.
Q: Describe two limitations of this study and explain how each weakens the conclusions.
A: First, the sample size was small, which limits statistical power and makes it harder to generalise results to a larger population. Second, only one elderly dog was used (and it died during the study), so the results may reflect something unique to that particular animal rather than AAT in general.
Q: Is this study holistic or reductionist? In vivo or in vitro? Justify each answer.
A: Holistic, because it examines the child's overall pain and vital-sign response rather than isolating a single molecular mechanism. In vivo, because it studies living children in a hospital setting, not cells or tissues in a laboratory.
Q: The AAT group showed increased respiratory rate. Does this contradict the hypothesis? Why or why not?
A: Not necessarily. The hypothesis focused on pain and vital signs broadly. An increase in respiratory rate could reflect excitement or physical activity with the dog rather than distress. It does, however, show that AAT effects are not uniformly in one direction and highlights the importance of measuring multiple variables.
The scientific method framework you practise here applies to every experiment you will encounter in BIO 311C, from cellular respiration to ecology. The distinction between holistic and reductionist thinking will resurface when you study systems biology versus molecular biology. Understanding experimental controls and variables is also foundational for interpreting data in genetics and evolution units later in the course.
Scientific method, hypothesis, independent variable, dependent variable, control group, treatment group, animal-assisted therapy, AAT, therapy dog, Wong-Baker FACES pain scale, in vivo, in vitro, holistic, reductionist, experimental design, BIO 311C, introductory biology, UT Austin, Braun et al. 2009, complementary therapy, paediatric pain, vital signs, blood pressure, respiratory rate, statistical significance, sample size, study limitations