Perceptual awareness

Sakai, K., Sastre, J. P Kanamori, N. Jouvet, M. (1981). State-specific neurones in the ponto-medullary reticular formation with special reference to the postural atonia during paradoxical sleep in the cat. In Brain Mechanisms of Perceptual Awareness and Purposeful Behavior, ed. O. Pompeiano C. Aimone Marsan. New York, NY Raven Press. 

Contrary to the effects associated with the therapeutic use of dextromethorphan, those who abuse the drug report a variety of mind-altering effects such as visual hallucinations, changes in time perception, and an increased sense of perceptual awareness. It has been determined that a small amount of Robitussin can produce intoxication in most persons. Abusers have been found to use anywhere from one-half bottle to three or four bottles of Robitussin every day. Drinking large amounts of Robitussin or other cough syrups tends to cause vomiting. 

Now I m feeling like a newborn baby very small and soft, with very thin skin, through which everything can pass without any possibility of defense or resistance. My whole body consists of perceptual awareness, a very clear perception, with a mixture of amazement and terror about everything that is going on around me. 

Heidegger located the tntentionality, or meaning, of experience not in its cognitive structure, but in the totality of man s perceptual awareness and practical involvement with the world. Heidegger s phenomenology was hermeneutical... 

I turn now briefly to adverbial theories of experiential awareness. According to these theories, it will be remembered, qualia exist only as forms of perceptual awareness — ways of being perceptually aware of nonqualitative phenomena. 

The main disturbance in inhalant intoxication delirium is a reversible decrease in the level of consciousness and awareness of the environment, which includes an inability to focus, sustain, or shift attention. The intoxicated person is confused and easily distracted by irrelevant stimuli and difficult to engage in a meaningful conversation. He or she may also exhibit prominent disorientation, short- and long-term memory deficits, language disturbances, and perceptual disturbances that may include illusions and hallucinations. Other prominent features associated with inhalant intoxication delirium are... 

The posterior multimodal association area is located at the junction of the parietal, temporal, and occipital lobes. It pools and integrates somatic, auditory, and visual stimuli for complex perceptual processing. As such, this area is involved primarily with visuospatial localization, language, and attention. Lesions here interfere with awareness of one s body position and of the space in which it moves as well as the ability to integrate and make sense of elements of a visual scene. In other words, these patients have normal visual acuity but cannot focus on an object of interest. 

A stimulus-filter model of nicotine reinforcement has been proposed that suggests that it helps screen irrelevant stimuli from awareness (Kassel 1997). An alternative explanation asserts that nicotine induces attentional narrowing and facilitates perceptual processing. Human nonsmokers given an acute dose of nicotine (administered in gum) showed dose-related trends toward decreased accuracy and increased response time (Heishman et al. 1993). 

Attention and the related phenomenon of arousal are clearly crucial to the generation of consciousness. Both processes contribute to the (everyday) experience of the focus and level of awareness. Many reviews of attention begin with the following quotation from William James Everyone knows what attention is. It is the taking possession of the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. (James, 1890). The enduring resonance of this dehnition is due to its encapsulation of the essence of the subjective experience of attention. James emphasises the fact that attention selects stimuli from a surplus of environmental information ( simultaneously possible objects ), and maybe focussed perceptually or inwardly as a train of thought. Of particular relevance to the present chapter,... 

Were the subjects asleep, and were their experiences actually dreams When occasionally questioned specifically by the experimenter, A and B felt sure they had not been asleep when the reported phenomena occurred. They referred to the continuity of the vase and the table percept throughout most of the experiences in question. The vivid phenomena seemed to be superimposed on that continuity. On some occasions, the subjects specifically mentioned that they had fallen asleep for a brief time, as they had become "suddenly" aware that their heads had fallen forward and that there had been a break in the continuity of the concentration. Nevertheless, the subjects could have had brief periods of sleep of which they were not aware. The perceptual continuity they experienced would argue against a dream state, as does the fact that their experiences did not have the complex structures normally associated with dreaming. 

If, as evidence indicates, our passage from infancy to adulthood is accompanied by an organization of the perceptual and cognitive world that has as its price the selection of some stimuli to the exclusion of others, it is quite possible that a technique could be found to reverse or undo, temporarily, the automatization that has restricted our communication with reality to the active perception of only a small segment of it, Such a process of de-automatization might then be followed by an awareness of aspects of reality that were formerly unavailable to us. 

After an initial reaction of "tightness," not unlike the involuntary muscle contraction one experiences on plunging into cold water, I became aware of how acute my perception was. In fact, it appeared that I was freed completely from a partial deafness of my left ear as well as from my acute astigmatism. Briefly, the perceptual highlights of my first LSD experience were ... 

Psychologists are well aware of the phenomenon known as perceptual defense, of the selectivity of perception, of the fact that we more readily see what we want to see, tend not to see what we do not want to see, and/or distort what we do perceive into what we would to perceive, what we would "like to" perceive may often seem unpleasant, yet it has secondary advantages insofar as it is supportive of the ego structure. 

The reality of unconscious processes, mental or emotional processes that affect us and yet lie outside conscious awareness, is widely accepted in modern psychology. A specific form of unconscious processes, known as perceptual defense, has not been generally accepted, in spite of good experimental evidence for it. The haggling over the reality of perceptual defense has been so intense that I have suspected the idea is being actively resisted. It is too clear a reminder of how mechanical we are. 

Mackintosh I m aware that it is unfair to cite unpublishable data, but we have done a study ourselves in which we give various marker IQ tests for verbal ability, fluid intelligence and perceptual speed, and inspection time correlates with perceptual speed but not with the other two characteristics. When you do the partial correlations, the correlation of inspection time with Raven s is entirely attributable to its correlation with measures of perceptual speed and nothing else. Much the same conclusion is also suggested by the recent study of Burns et al (1999). 

If one of the fundamental questions in cognitive science has been whether perceptual data for which there is no conscious awareness can influence behavior, then from the above it can be seen that not only is this possible, but sensory input is used primarily (almost select habit routine complexes in thinkingl,... 

---