What are the two independent factors involved in a subject's detection of a stimulus?

The concept of stimulus detection is rooted in signal detection theory, which posits that two independent factors influence a subject's ability to detect a stimulus: the actual sensitivity of the sensory system and the response bias.

The actual sensitivity refers to how well a sensory system can perceive a stimulus, which is influenced by the inherent properties of the sensory organs and the neurological processing involved. This factor determines the true threshold at which a stimulus can be detected.

Response bias, on the other hand, reflects the individual's predisposition to respond in a certain way when uncertain about whether a stimulus is present. This could be influenced by factors such as previous experiences, expectations, or the context in which the stimulus is presented. Response bias can lead someone to either be more conservative in their responses (only indicating they detect a stimulus when they are very sure) or more liberal (indicating detection more readily).

The interplay between actual sensitivity and response bias is crucial in understanding how and why subjects may report different levels of detection even when exposed to the same stimulus. This dual-factor framework provides a comprehensive understanding of the complexities involved in perceptual processes.