Research Paper on:
Signal Theory and Hallucination

Unformatted Sample Text from the Research Paper:
if this perception is real and do not act on it unless the perception is proven to be legitimate. What causes such momentary hallucinations? What are the cognitive or physiological  processes involved? In the early 1960s, a psycho-physical technique, signal detection theory, was developed as a means for isolating perceptual components from non-sensory or attitudinal factors (Gardner, 1996). Research in  this area shows that people who hallucinate easily, such as schizophrenics, are more likely to "hear" a signal in pure-noise trials. As this suggests, signal detection theory and its resulting  methodology provides researchers with one possible means of exploring the topic of hallucinations and its relationship to human cognition. Signals (i.e. sensory information or stimuli) are constantly being detected,  whether by electronic instruments or by human begins, against a competing background of activity. The level of this background activity is referred to as "noise," and may be either external  to the detecting device or caused by internal sources (Gardner, 1996). In other words, in a human being, noise can be generated by the spontaneous activity of the nervous system  itself. In a detection situation, the observer must make an observation (x) and then make a decision as to whether x is due to signal that is added to noise  background or to the noise itself (Gardner, 1996). As this suggests, the perception of sensation is not solely on stimulus, as the individual also influences the perception of sensation  through use of judgement and motivation (Holme, et al, 1972). The formulation of signal detection theory called into question the traditional ways of conceptualizing threshold (Holme, et al, 1972). "Threshold"  refers to the "energy level at which a stimulus is detected a certain percentage of the time" (Holme, et al, 1972, p. 222). In a yes-no experiment, wherein the observer