Brenda's Aunt Shelby got to the point where she just couldn't recall any more details. "Honestly, that's all I can remember about being in the same first-grade class as Bruce Springsteen. It was just too long ago," Shelby explained to her disappointed niece. That Shelby was unable to recall her other long-term memories about attending elementary school with Bruce Springsteen is most likely an example of:

Retrieval cue failure is the correct answer.

Explanation:

facts: the 14th amendment

the 14th amendment addresses citizenship rights and equal protection of the laws.

the 14th amendment was intended to protect the rights of former slaves after the american civil war.

the 14th amendment was approved by congress in june of 1866 and ratified by the states on july 9, 1868.

the 14th amendment establishes that all persons born in the united states are citizens and are guaranteed all the rights of citizenship.

the 14th amendment establishes that the law protects all citizens equally.

in this case the passage of the 14th amendment   that was violated was the last part in which it states that there is equal protection of the law.

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.