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.
External validity
Sigmund freud's psychoanalytic theory was based primarily on descriptive data from a few case studies. Critics question how well the experiences of these unusual individuals represent others. The concern referred to is that this type of research may lack external validity.
External validity is the extent to which the information and theories of a study can be generalized to other conditions or to other people. People, places and times are the three major threats ( factors that could be wrong) to external validity
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Answer:
a. proved essential for the success of Grant’s attrition strategy.
Explanation:
The Union is known as the "North" and the Confederacy is known as the "South".
At the event of the American Civil War, the Union also know as the "United States of America" under the presidentship of Abraham Lincoln was opposed by 11 southern states known as the "Confederate States of America" under the presidentship of Jefferson Davis.
Abraham Lincoln believed that he could win over the Confederacy states until and unless he have control over the border states, mainly Maryland.
Union's man power was more as they had nearly 20 states associated with them.
The Union in order to win over the Confederacy States made strategies to gradually reduced the power of the Confederacy States.
Thus the advantage that the Union's soldier or manpower have over the Confederacy has proved to be essential for the success of Grant’s attrition strategy.
Hence the answer is
a. proved essential for the success of Grant’s attrition strategy.