James Laird and his colleagues (1974, 1984, 1989) subtly induced students to make a frowning expression by asking them to "contract these muscles" and "pull your brows together" (supposedly to help the researchers attach facial electrodes). They found that subjects reported feeling .

subjects reported being a little angry

Explanation:

Researchers found subjects reported being a little angry, as these expressions to contract muscles and pull your brows together, these meant frowning expressions in which brows come together and wrinkles appeared in forehead to express the feeling of displeasure and sadness or extreme angry.

the historians cited in the article all agree with one another about the cause of the civil war. despite coming from different backgrounds and cultures, the historians agree that slavery was the root cause of the civil war. the fact that all these historiansgenerally agree with one another makes their shared viewpoints more reliable and valid, especially because the historians have different backgrounds and all work for the well-respected institutions of howard university, clemson university, and the university of colorado.