Question: It is perhaps too easy to think of mathematical truths as objective entities existing in the universe, simply waiting to be "discovered" by brilliant minds such as Pythagoras, Newton, and Descartes. Indeed, such a mentality may be cemented in Western minds raised in the Platonic tradition of a world of ideals that exists outside of the material world we reside in.
But new research in the fields of cognitive science and developmental psychology may be challenging this long-held belief in mathematics as a truth outside of human experience, and recasting mathematics as a product of the brain, an entity that is not discovered by man but rather created by him.
Such a radical paradigm shift has predictably met with stiff resistance, but the evidence in favor of a created mathematics rather than a discovered mathematics is compelling. Study after study has shown that all people possess an innate arithmetic. Babies as young as three or four days old can differentiate between groups of two and three items. And by the age of four months or so, an infant can see that one plus one is two and two minus one is one. Researchers discovered this startling fact by means of a simple experiment, following what is known as the violation of expectation model in developmental psychology. An infant was presented with a scenario in which a researcher held a puppet before the baby's eyes. Then a screen was moved in front of the puppet and another researcher placed a second puppet behind it. The screen was removed and if there were two puppets now visible, the infant registered no surprise (as measured by both the direction of the child's gaze and the duration of her stare). But if the screen was removed and only one puppet appeared, the infant registered perplexity at the situation. This experiment and others like it strongly suggest that all individuals are born with certain mathematical concepts hardwired into their brains. The ability to quickly and accurately count a small number of items, called subitizing by psychologists, is also found in animals. Researchers using experiments similar to the violation of expectation setup described previously have found an innate mathematical ability not just in primates, our closest evolutionary cousins, but in raccoons, rats, parrots, and pigeons. These findings are consistent with the belief that mathematical thinking is a function of the structures in the brain and not a product of the outside world.
Anomalous cases involving brain injuries and disorders also support the idea that mathematical thinking arises from the organization of the brain. There is a documented case of a subject with a $\mathrm{PhD}$ in chemistry who suffers from acalculia, the inability to perform basic arithmetic functions. Strangely, this patient is unable to perform simple calculations such as five plus three or eight minus two, but has no problem manipulating abstract algebraic operations. This curious fact has led psychologists to conclude that the part of the brain that handles abstract algebraic operations must be different from the part of the brain that works with more concrete arithmetic functions.
In the discussion of the violation of expectation experiment, the author assumes that:

Options:
A. Certain observable behaviors accurately indicate inner mental states.
B. The infants in the study did not know what happened to the puppets behind the screen.
C. Researchers used the same types of puppets in all of the experiments.
D. Animals and infants performed at similar levels of competency in the experiments.
Answer: In order to answer this question, you must be able to judge credibility. The author cites the violation of expectation experiment as support for the author's claim that mathematics is an innate part of human cognition. In order for these experiments to be credible, the author is assuming that the researchers can accurately determine that the infants are in fact surprised when the number of puppets changes. The only evidence for this is the direction and duration of the stares of the subjects. Accepting these results as evidence indicates the author believes outward signs accurately indicate inner emotional states; otherwise, the evidence would not support the argument. The correct answer is A.