Question 51: Gut Microbiome and Depression

Recent evidence by neurobiologist Anne-Lise Goddard suggests that gut bacteria play a critical role in mood regulation. In a clinical trial, subjects consuming probiotics daily for eight weeks reported lower depressive symptoms than placebo groups. Surprisingly, the probiotic group initially experienced worsened mood during the first two weeks. Goddard hypothesized this initial deterioration could result from changes in microbiota composition disrupting serotonin synthesis before a beneficial balance was restored.

Which conclusion aligns best with Goddard’s findings regarding gut microbiota and depression?

A. The gut microbiome influences mood indirectly by altering serotonin production after initial imbalance.

B. Gut bacteria immediately improve serotonin levels upon probiotic consumption.

C. Probiotics consistently worsen depressive symptoms during long-term use.

D. Placebo effects explain short-term mood deterioration in probiotic users.

Sociologist Daniel Edwards conducted research indicating AI hiring tools initially decreased unconscious human bias in candidate selection. However, over time, biases embedded in historical hiring data amplified existing inequalities. Edwards suggests algorithms reflect human biases unless periodically retrained using diverse, updated datasets.

What deeper implication arises from Edwards’s research on AI hiring?

A. AI systems inherently eliminate all hiring biases permanently.

B. AI is incapable of reflecting biases if initially designed correctly.

C. Regular data updates are crucial to prevent AI from perpetuating human bias.

D. Historical data inevitably improve AI fairness in hiring practices.

Psychologist Irene Vázquez found sustained exposure to urban noise led to subtle but significant cognitive decline, primarily due to disrupted sleep and increased cortisol. Interestingly, brief exposure to loud urban sounds temporarily increased alertness and cognitive performance in some individuals. Vázquez concluded chronic noise exposure fundamentally differs from acute noise events regarding cognitive impact.

What key inference about noise exposure and cognition does Vázquez’s study support?

A. Both short-term and long-term urban noise exposure equally harm cognition.

B. Acute noise exposure can paradoxically boost short-term cognitive functions.

C. Sustained urban noise exposure universally improves cognitive alertness.

D. Cortisol increases from noise have minimal impact on cognitive performance.

Sports nutritionist Erika Müller demonstrated that vegetarian athletes showed improved cardiovascular health initially but struggled with muscle recovery after intense training sessions compared to omnivorous athletes. Müller attributes this to lower protein bioavailability from plant-based sources, suggesting supplementation or dietary adjustments are necessary for sustained