Text Explanation

Elaboration likelihood model.: This answer choice is incorrect, because the elaboration likelihood model explains two pathways by which people may change their minds about something, one based on the power of the message, and the other based on how the message is delivered. The elaboration likelihood model does not address objective and subjective perceptions of reality.

Gestalt principle.: This answer choice is correct. Gestalt principles are extensive, but for the MCAT, they can usually be boiled down to the sentence "the whole is greater than the sum of its parts." Typically, the MCAT tests gestalt principles with questions about perceiving entire objects rather than just the edges, shadows, and contours that comprise them.

This question, however, is juxtaposing gestalt principles with the objectivist point of view. Objectivism states that there is one true "objective" reality, and our senses allow us unfettered access to that reality. Subjectivism (gestalt principles) maintain that perception is limited by our senses, and that people have their own "reality" that is limited by their sensory abilities.

Heuristics.: This answer choice is incorrect, because heuristics are completely irrelevant to human perception being limited by senses. Heuristics are "rules of thumb", or mental shortcuts that are used to speed up a mental process or an experimental investigation. A classic example of a heuristic that comes up on the MCAT is trial and error.

Weber's law.: This answer choice is incorrect, because Weber's law, while related to sensation in general, is not applicable to the statement about how we perceive reality. Weber's law states that the just noticeable difference of a particular stimulus is proportional to the magnitude of that stimulus. For example, if there is a tiny bit of ambient noise, then you would notice a whisper, because the whisper is, say, 10% louder than the ambient noise. If you were at a rock concert, however, then you would only notice an increase in sound volume that is 10% louder than the ambient noise at the concert, which is a large amount. According to Weber's law, it is the 10% that remains constant.