The psychologist would need to make sure the advice was based on sound research.
Explanation:
Psychologists are the people who deal with the patients who are affected by any kind of mental illness. These illness can arise due to difficult life situations and stress factors. There are many branches in psychology such as behavioral, communal and social psychology and the specialists differ varied based on their skills and expertise.
When a psychologist is asked to write a column in a newspaper regarding mental health issues and it treatment, he has to advise based on the proved and scientifically tested research findings rather than hypothetical statements.
<span>Native American tribes competed for resources and were independent of each other.</span>
I believe the answer is: Her perceptual set that the house was haunted
Perceptual set refers to human tendency to process the information that we see based on one particular aspect of data while ignoring the others. In the example above, the aspect of data that Jackie used to make her perception is that the house of haunted. So every new information that she receive at that place would be automatically perceived as an extension of her pre-exisitng belief.
The answer is less and more (respectively).
To complete the sentence and to get the idea of the phrase:
They became less likely to under-perform on aptitude tests and more likely to become aggressive toward those who had insulted them.
