Problem 36 - Biological Psychology

Question

A monkey that loses sensation from one arm stops using it, but a monkey that loses sensation from both arms does use them. Why?

Step-by-Step Solution

Answer

With one numb arm, the monkey lacks usable feedback; with both numb, it adapts to use them.

Step 1: Understanding Sensation Loss in One Arm

When a monkey loses sensation in one arm, it stops using that arm because it cannot feel or receive feedback from that limb. This lack of sensory feedback makes the arm feel ineffective or non-functional from the monkey's perspective.

Step 2: Evaluating Behavior with Loss of Sensation in Both Arms

When both arms lose sensation, the monkey compensates for the lack of feedback by using both arms. The need for exploring, maintaining balance, and interacting with its environment drives it to use whatever resources it has, despite the numbness in both arms.

Step 3: Examining Behavioral Adaptation

The monkey's behavior adaptation reflects the survival instinct. With sensation gone in both limbs, the monkey learns to rely on visual and proprioceptive cues instead of tactile feedback to utilize both arms effectively in its environment.

Step 4: Conclusion on Dual Arm Usage

Ultimately, the monkey uses both numb arms to meet its intrinsic and external needs—such as acquiring food and climbing—despite the lack of direct sensory feedback.

Key Concepts

Sensory Feedback

Sensory feedback is crucial for how organisms interact with their environment. It refers to the information that the senses, such as touch, send to the brain about the body's interactions and positions. For a monkey, or any primate, sensory feedback from the limbs helps in:

• Detecting touch or pressure, which indicates the environment's texture or form.
• Signaling pain, which prevents harm and guides safe actions.
• Providing information about limb movement and positioning, known as proprioception.

When a monkey loses sensation in one arm, it lacks this feedback. The arm may appear to be detached from body control or useless. This is primarily because the brain no longer receives updates about the arm's activities, making it hard for the monkey to judge its effectiveness. Hence, the monkey tends to ignore that arm in favor of the one with intact sensation that can still effectively interact with its surroundings.

Behavioral Adaptation

Behavioral adaptation in animals refers to changes in behavior that allow an organism to survive in changing environments. For a monkey that loses sensation in both arms, this concept is perfectly illustrated. Despite the loss of feeling, monkeys adapt by developing new ways to sustain basic activities:

• They use visual cues—since touching and feeling is not possible, eyesight guides them in manipulating objects.
• Relying on proprioceptive feedback, which provides an understanding of limb positioning even without touch.
• Continuing activities vital for survival—the pressure of needing to feed or move effectively compels a monkey to engage both arms.

This adaptability showcases an essential survival mechanism, where reliance on other sensory inputs or strategies compensates for the lack of one. It's this ability to adapt that ensures a creature can continue interacting with its environment even with a significant sensory deficit.

Primate Behavior

Primate behavior is a rich field for observing cognitive and physical adaptability. When sensation is lost, as in the case of the monkey with numb arms, we see fundamental principles of primate behavior in action:

• Survival instincts prompt exploration and interaction even when conditions change drastically.
• Monkeys demonstrate problem-solving skills by switching strategies—from reliance on tactile feedback to other sensory modalities.
• Even under physical impairment, the need for social interaction and engagement in their environment drives them to persistently use both arms.

Such behaviors reflect the resilience and complexity of primates. Their actions under duress illustrate how important behavioral flexibility is for thriving in complex and sometimes harsh environments. This ability to adapt ensures that even when a significant sensory tool is lost, life goes on through other means.