Question

The hippocampus is a region of the brain whose size is positively correlated with navigation and spatial mapping ability in birds and mammals. Which one of the following observations would NOT be consistent with this statement?

• A. When the size of the hippocampus is surgically reduced in laboratory rats, their ability to find food is reduced in a radial arm maze.
• B. Bird species that hoard food in different parts of their territory have a larger hippocampus than similarly-sized bird species that do not hoard food.
• C. In domestic pigeons, non-homing varieties have a larger hippocampus than homing varieties.
• D. In voles, males have larger home ranges than females, and the hippocampus of males is larger than that of females.

Hint:

The hippocampus is positively correlated with spatial memory and navigation skills. Species that rely more on navigation typically have larger hippocampi.

Answer 1

The Correct Option is C

Step 1: Understand the correlation between hippocampus size and spatial ability.
The hippocampus plays a key role in spatial navigation and memory. Generally, a larger hippocampus is associated with enhanced spatial abilities such as locating food caches or navigating long distances.

Step 2: Analyze the options.

• Option (A): Consistent – Reduced hippocampus size in rats impairs spatial memory, which aligns with the expected role of the hippocampus.
• Option (B): Consistent – Birds that cache food need to remember cache locations, hence they have larger hippocampi.
• Option (C): Inconsistent – Non-homing pigeons having larger hippocampi than homing pigeons contradicts the expected pattern. Homing pigeons, which navigate over long distances, should have a larger hippocampus.
• Option (D): Consistent – Animals with larger home ranges typically need better spatial navigation, which is supported by larger hippocampal volume.

Conclusion: The correct answer is Option (C), as it contradicts the known correlation between hippocampus size and spatial ability.