Question

Leaming how to build a nest plays an important part in the breeding success of birds. For example, Dr. Snow has recorded the success of a number of blackbirds in several successive years. He finds that birds nesting for the first time are less successful in breeding than are older birds, and also less successful than they themselves are a year later. This cannot be a mere matter of size and strength, since blackbirds, like the great majority of birds, are fully grown when they leave the nest. It is difficult to avoid the conclusion that they benefit by their nesting experience. Which one of the following, if true, would most weaken the argument? (A) Blackbirds build better nests than other birds. (B) The capacity of blackbirds to lay viable eggs increases with each successive trial during the first few years of reproduction. (C) The breeding success of birds nesting for the second time is greater than that of birds nesting for the first time. (D) Smaller and weaker blackbirds breed just as suecessfully as bigger and stronger blackbirds. (E) Up to 25 percent of all birds are killed by predators before they start to nest.

Short answer

Option (B) weakens the argument by suggesting an alternative reason for improved breeding success.

Step-by-step solution

Identify the Argument

The argument claims that learning to build a nest is crucial to the breeding success because first-time nesters are less successful than those with experience, implying experience, not physical development, improves breeding success.

Look for the Weakening Evidence

You need evidence that suggests factors other than nesting experience could be responsible for improved breeding success in subsequent years and not merely the experience of building nests.

Analyze Each Option

- **(A)** states blackbirds build better nests than other birds, which doesn't directly address the reasoning of the argument. - **(B)** suggests the capacity to lay viable eggs increases with successive tries, providing an alternative reason for breeding success that isn't related to nesting experience. - **(C)** restates part of the argument, supporting not weakening it. - **(D)** supports the argument by showing size isn't affecting success, aligning with the argument. - **(E)** mentions predation rates not directly related to the argument's claims.

Identify the Most Weakening Option

Option (B) directly challenges the argument by providing a biological reason—improved egg viability—explaining the improved success rate not related to nesting experience.

Key concepts

Argument Analysis

Argument analysis involves dissecting a statement or a series of statements to understand the core conclusion and the evidence presented to support it. In this exercise, the argument is about the nesting success of blackbirds. The conclusion drawn is that birds improve their breeding success due to the learning or experience they gain from previous nesting attempts, not from physical changes. To analyze this argument, identify two main components:

• Conclusion: Experience in nesting leads to improved breeding success.
• Premises: First-time nesters are less successful than in subsequent attempts; birds are fully grown physically when leaving the nest.

The goal of argument analysis is to determine whether the conclusion logically follows from the premises provided. By doing so, one can evaluate the strength and validity of the argument. If you identify assumptions or notice missing information, these become crucial points in critical evaluation.

Critical Thinking

Critical thinking is essential when evaluating an argument, allowing you to discern between strong and flawed conclusions. It requires analyzing the argument beyond face value and asking whether the argument is logically sound. In this context, consider:

• The assumptions: The argument assumes that experience is the only factor affecting breeding success.
• Alternative explanations: Are there other factors, like egg viability or learning from trial and error, that might contribute to success?
• Evidence evaluation: Is the evidence provided adequate and relevant to support the conclusion?

Critical thinking involves questioning each piece of the argument and its evidential link. It's about not taking things at face value, checking biases, and ensuring every claim is backed by appropriate logic or evidence.

Logical Reasoning Questions

Logical reasoning questions test your ability to understand and evaluate arguments similar to those found in the LSAT. Such questions require you to identify, strengthen, weaken, or draw parallels from given statements to ensure a deep comprehension of logical principles at play. To tackle logical reasoning questions effectively:

• Identify conclusions and premises: Clarifying these helps locate the argument's foundation.
• Consider counterexamples or alternative scenarios: Examine options that might offer different explanations or contradict the argument's premises.
• Analyze options methodically: Understand each possible answer, asking how it fits or contests the argument structure.

Logical reasoning questions demand clear, concise thinking. Practice recognizing patterns, strengthening your comprehension, and questioning assumptions to excel in these types of queries.