Interposition {Ans: monocular visual cue in which two objects are in the same line of vision and one patially conceals the other, indicating that the first object concealed is further away}Stage 2 {Ans: Lasts about 20 minutes and involves deeper relaxation and occasional bursts of rhythmic brainwaves called sleep spindles and K-complexes}Brainstem {Ans: The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions}Psychoactive Drugs {Ans: Chemicals that affect the nervous system and result in altered consciousness}Binocular Cues {Ans: depth cues, such as retinal disparity and convergence, that depend on the use of two eyes}Convergence {Ans: a binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object}Surveys {Ans: Questionnaires and interviews that ask people directly about their experiences, attitudes, or opinions.}Parietal Lobes {Ans: the portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position}Functionalists {Ans: studied the function of consciousness}Difference Threshold {Ans: also called the jnd; smallest distinction between two stimuli