This is an example of negative reinforcement. Her mother scolded her every time Jane bit her nails - so Jane learned that every time she bites her nails, she is going to be scolded sternly by her mother. In order to avoid that, she stopped biting her nails, and thus the reinforcement was successful.
The but-for test is a test commonly used in both tort law and criminal law to determine actual causation. The test asks, "but for the existence of P, would Q have occurred?" If the answer is yes, then factor P is an actual cause of result Q.
The British people, or Britons, are the citizens of the United Kingdom of Great Britain and Northern Ireland, the British Overseas Territories, and the Crown dependencies.
