CNS unit II full chapter

Reasoning and Problem Solving

Introduction

• Reasoning and problem solving are crucial components of human cognition, often associated with intelligence.

• René Descartes famously stated, "I think, therefore I am," highlighting the importance of the ability to reason.

• These abilities are not only human traits but also observed in other primates and some birds.

• Reasoning and problem solving share features such as:

  • Planning and sequencing actions

  • Use of foresight and logic

  • Goal-oriented focus.

Differentiating Reasoning and Problem Solving

• Reasoning: Involves logical inferences based on clear rules, such as syllogisms. Example:

  • "All men are mortal. Socrates is a man. Therefore, Socrates is mortal."

• Problem Solving: Starts with a problem and desired outcome without specifying steps required to achieve the outcome.

  • Example: Solution to hanging a light without a ladder involves creative thinking.

  • Often requires trying various approaches and can have multiple solutions.

Deductive Reasoning

• Definition: Drawing conclusions from premises known to be true.

• Syllogism Example:

  • Structure: Two premises leading to a conclusion, such as:

    • "If P, then Q. Not P. Therefore, not Q."

• Logical Errors:

  • Denying the antecedent: Ignoring the conclusion when the initial condition is false.

  • Affirming the consequent: Incorrectly assuming that if Q is true, P must also be true.

  • Modus tollens: A valid deduction form that states if Q is false, then P is also false.

Theories of Deductive Reasoning

• Various theories abound regarding how deductive reasoning is processed:

  • Mental Logic Theory: Indicates individuals have rules akin to formal logic that they apply.

    • Problems arise with syllogisms that contain false premises.

  • Mental Model Theory (Philip Johnson-Laird): Suggests that reasoning involves constructing models that assume premises are true to evaluate conclusions.

    • Predicts that people are better at confirming hypotheses than falsifying them.

Social Context Effects on Reasoning

• Studies like the Wason Card Sorting Task show that reasoning improves in social contexts. Subjects tend to perform better when tasked with identifying rule violations in social scenarios than in abstract logical contexts.

• Neural correlates show different brain areas are activated based on social content in reasoning tasks.

Neural Systems Supporting Deductive Reasoning

• Left frontal lobe is primarily involved:

  • Associated with symbolic processing.

  • Inferior frontal lobes activate during deductive tasks.

• Neuroimaging studies show brain systems overlap but differ based on content type in reasoning tasks.

Inductive Reasoning

• Definition: Inferring likely truths based on probabilistic premises, such as examples or analogies.

• More prevalent in everyday situations than deductive reasoning.

• Examples:

  • "Most birds can fly. A magpie is a bird. Therefore, a magpie can fly."

• Inductive reasoning involves more lenient logical frameworks compared to deductive reasoning.

Neural Systems Supporting Inductive Reasoning

• The left prefrontal cortex is crucial for inductive reasoning, with different activation patterns for reasoning types:

  • Dorsolateral prefrontal cortex activated during induction; ventrolateral for deduction.

• Damage to prefrontal areas impairs reasoning abilities.

Problem Solving

• Definition: Involves identifying goals and potential methods to reach these goals. Example: Archimedes' principle of water displacement to assess a gold crown's purity without damaging it.

• Problem Space: Represents all possible ways to approach a given problem.

• Heuristics: Simple strategies such as hill-climbing, which involves minimal steps towards the goal, though not optimal for complex problems.

• Common pitfalls include:

  • Functional Fixedness: Tendency to rigidly adhere to one method of problem-solving even when a simpler solution exists.

Insight in Problem Solving

• Representing a problem in a new way often leads to sudden insights ("Eureka" moments).

• Insight is linked to brain regions responsible for semantic association and cognitive reorganization, especially the right hemisphere.

Neural Systems for Problem Solving

• Involves executive functions including planning, evaluating, and reasoning. Insight is often tied to right hemisphere activation.

• Damage to prefrontal areas can complicate problem-solving processes, impacting a person's ability to adapt established rules to new situations.