Question

The article "Doctor Dogs Diagnose Cancer by Sniffing It Out" (Knight Ridder Newspapers, January 9, 2006 ) reports the results of an experiment described in the journal Integrative Cancer Therapies. In this experiment, dogs were trained to distinguish between people with breast and lung cancer and people without cancer by sniffing exhaled breath. Dogs were trained to lay down if they detected cancer in a breath sample. After training, dogs' ability to detect cancer was tested using breath samples from people whose breath had not been used in training the dogs. The paper states "The researchers blinded both the dog handlers and the experimental observers to the identity of the breath samples." Explain why this blinding is an important aspect of the design of this experiment.

Short answer

Blinding in this experiment is crucial as it prevents bias from both the dog handlers and experimental observers. If they knew the identities of the breath samples, they could unintentionally cue the dogs, leading to inaccurate results about the dogs' real ability to detect cancer through scent.

Step-by-step solution

Understand the experiment

The first step to understand why blinding is important in this study is to comprehend how the experiment was carried out. Dogs were trained to detect cancer in people by sniffing exhaled breath samples. After training, their ability was tested using new breath samples from individuals not used during training.

Importance of blinding in experiments

Blinding in experiments is a procedure where the identities or certain information are withheld from participants, experimenters, or both to prevent bias. It is a crucial part of any experiment to ensure the results are solely based on the experiment variables without the influence of external, potentially biased factors.

Analyze the Impact of blinding in this specific case

In this case, the researchers blinded the dog handlers and the experimental observers about the identities of the breath samples. This prevents them from consciously or unconsciously influencing the outcome of the experiment based on their knowledge about the sample. For instance, if a dog handler knew which samples were from cancer patients, it might subconsciously cue the dog to the correct answer, which would skew the results and not accurately reflect the dogs' ability to detect cancer.