Lecture 10: sensation: sensation , transduction converting the physical world stimuli into a mental representation, conduction relaying that info to the brain, perception , select/organize/interpret these mental representations. The study of the relationships between physical characteristics of stimuli (energy) and our experience of them. Absolute threshold smallest magnitude of a stimulus that can be reliably detected from no stimulus at least 50% of the time: detecting something from nothing. Difference threshold minimum difference between 2 stimuli that a person can detect at least. Signal detection theory predicts how/when we will detect the presence of absolute and difference thresholds: complex decision mechanisms are involved to determine if a stimulus exists, based on both. Factors that influence absolute/difference thresholds: chance variation noise in the system influences sensitivity, stimulus intensity, weber"s law greater the intensity of the stimulus, the larger the difference must be to detect a difference.