Discuss how classical conditioning research has been applied to advance our understanding and treatment of fear and anxiety related disorders in humans. Use experimental evidence to support your arguments.

For each reference in your reference list, include a brief description (e.g. up to 100 words) that explains why you have selected the specific source. For example, this might be because it explains a specific theory or concept, or because it provides experimental evidence that supports your thesis/argument. You need to be concise and specific.