What distinguishes reliability from validity in psychological testing?

Reliability is primarily concerned with the consistency of a test and its results over time, across different situations, and among different populations. When a test is reliable, it produces stable and consistent outcomes, meaning that if the same individual takes the test under similar conditions multiple times, they would receive similar scores. This consistency is crucial for establishing confidence in the test results, allowing psychologists to make meaningful comparisons and decisions based on those outcomes.

The other options, while they touch on important aspects of psychological testing, do not accurately define the distinction between reliability and validity. For example, focusing on emotional responses does not encapsulate the broader concept of validity, which specifically pertains to whether a test measures what it claims to measure. Similarly, the assessment of external factors does not directly relate to reliability, and the age appropriateness of a test is more related to its validity than to its reliability. Thus, the correct understanding of reliability as a measure of consistency is what sets it apart from validity in the context of psychological testing.