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Dear murugappan,

Study of the unconscious after freud is even more worthwhile when we try to understand it. As my letters to you tries to focus on the Freudian contexts in the siddhantha texts, I felt it is better to dwell  some thing about the subsequent trends in unconscious. This is to make sure that  both Freudian and siddhanthic similarities are only to a limited extent to the actual knowledge of the unconscious!

I am giving you the systematic exposition of current trends in the theory of unconscious by Prof.John F. Kihlstrom:University of California, Berkeley

Developments in unconscious studies:

Unfortunately, just when the concept of the psychological unconscious was getting up steam, the behaviorist revolution hit. Interest in consciousness disappeared virtually overnight, and interest in the psychological unconscious went with it briefly.

But  revival of interest in unconscious mental life followed shortly thereafter. The seeds for this revival had been planted at the very beginnings of the cognitive revolution, when the linguist Noam Chomsky argued that human language was mediated by "deep" grammatical structures which are inaccessible to conscious introspection, and can be known only by inference. Along the same lines, the philosopher Jerry Fodor argued that many mental functions, such as visual perception, were mediated by dedicated structures which were impenetrable by conscious awareness and voluntary control. Cognitive approaches to perception, as exemplified by the work of Irvin Rock on visual illusions, entailed a version of Helmholtz’s notion of unconscious inference. Finally, the classic multistore model of memory invoked a concept of pre-attentive, or preconscious, information processing.

We're now at a point, however, where interest in the psychological unconscious runs wide and deep within psychology.This happy state of affairs is the end product of at least four quite independent strands of investigation, which together converge on our modern conception of the psychological unconscious: automaticity, cognitive neuropsychology, subliminal perception, and hypnosis.

1.Automaticity:

One research tradition contributing to the modern interest in the psychological unconscious is the distinction commonly drawn between "automatic" and "strategic" cognitive processes. Skilled reading provides one example of automaticity: we recognize certain patterns of marks on the printed page as letters, and certain patterns of letters as words, and decode the meanings of words in light of the words around them, but we rarely have any conscious awareness of the rules by which we do so. It just happens, as an automatic consequence of having learned to read.

According to traditional formulations, automatic processes are inevitably engaged by the appearance of specific environmental stimuli, independent of the person’s conscious intentions. Once invoked, their execution is incorrigible, so that they proceed inevitably to their conclusion.  Because automatic processes consume no attentional resources, they leave no traces of themselves in conscious memory: their products may be conscious, but the processes are not. Some automatic processes are innate, or nearly so, while others are automatized only after extensive practice with a task -- a process sometimes called proceduralization.

More recently, some of these properties have been called into question by revisionist, memory-based views of automaticity. It’s no longer clear that ostensibly automatic processes are really executed involuntarily and really consume no attentional resources. But even these revisionist views agree that some mental processes, represented in procedural memory, are unconscious in the strict sense of the term: they are inaccessible to phenomenal awareness under any circumstances, and can be known only by inference from task performance.

Both traditional and revisionist approaches to automaticity assume, at least tacitly, that the mental contents upon which these processes operate are accessible to conscious awareness. However, it is now clear that our experiences, thoughts, and actions can be influenced by mental contents – percepts, memories, thoughts, feelings, and desires, of which we are unaware. Compelling evidence for this proposition began to accumulate about 30 years ago, as cognitive psychology turned into cognitive neuropsychology, and researchers began to see evidence of the psychological unconscious in the behavior of brain-damaged patients.

Pride of place in this history goes to studies of the amnesic syndrome resulting from bilateral damage to the hippocampus and related structures in the medial temporal lobe, or, alternatively, to the diencephalon and mammillary bodies. On clinical observation, such patients show a dense anterograde amnesia: after only a few moments of distraction, they cannot consciously remember events that have occurred just recently. But as the study of these patients shifted from clinical description to controlled laboratory investigation, it became apparent that the events apparently covered by the amnesia nonetheless influenced the patients’ ongoing experience, thought, and action.

For example, Warrington and Weiskrantz showed that amnesic patients, who could not remember having studied a list of words, were nonetheless biased to complete ambiguous word stems or fragments with items from the previously studied list. Past experience influenced their subsequent task performance, even though they had no conscious recollection of the experience itself.

2. cognitive neuro psychology -Implicit and explicit memory:

Based on effects such as these, Schacter and others drew a distinction between two expressions of memory, explicit and implicit. Explicit memory refers to one's conscious recollection of the past, as manifested on tasks like recall and recognition. Implicit memory, by contrast, refers to any change in experience, thought, or action that is attributable to a past event, regardless of whether that event is consciously remembered.

Priming effects, in which prior exposure to a word like ‘assassin’ makes it easier to complete a fragment like” a__a__i_” than one like” t_p__r_y”, are good examples of implicit memory, because the priming effect obviously depends on memory, but the task does not, logically, require conscious recollection of any past event. All the subject has to do is to generate an acceptable word that fits in the spaces provided. The sparing of implicit memory in amnesia shows that some representation of a prior event has been encoded and stored in memory, and influences ongoing experience, thought and action, even though that event cannot be consciously remembered. Implicit memories are unconscious memories.

3.Subliminal perception:

Neuropsychological research has also revealed unconscious influences in the perceptual domain.

Perhaps the most dramatic example is the phenomenon of blindsight documented in some patients with damage to the striate cortex of the occipital lobe. Such patients experience a scotoma – a portion of the visual field where they have no visual experience. When a stimulus is presented their scotoma, they see nothing at all. Yet when encouraged to make guesses about the properties of the stimulus, their conjectures about presence, location, form, movement, velocity, orientation, and size prove to be more accurate than would be expected by chance alone.

Something similar occurs in at least some cases of visual neglect arising from lesions in the temporoparietal region of one hemisphere (usually the right) that do not affect primary sensory or motor cortices. These patients appear to neglect the corresponding portion of the contralateral sensory field (usually the left). Thus, a patient asked to bisect a set of horizontal lines may ignore the ones on the left side of the page; and for the remainder, the pencil strokes tend to be located about one-quarter of the way in from the right. It is as if the left half of the page, and the left half of each line, isn't seen at all. But in at least some cases, it can be shown that these patients respond to information available only the neglected field. For example, McGlinchey-Berroth and her colleagues found that pictures presented in the neglected portion of the visual field primed lexical decisions concerning semantically related words presented in the intact portion. Preserved visual functioning in blindsight and in neglect is unconscious perception.

Perception without awareness can also be observed in neurologically intact subjects, in the form of "subliminal" perception. In the early 1980s Anthony Marcel presented solid evidence of subliminal semantic priming effects on lexical decision: presentation of a word like doctor primed lexical decisions of a semantically related word like nurse, even though an intervening mask prevented subjects from consciously perceiving the prime itself.

In any event, things are vastly different now. Even in these days of signal detection theory, when we don’t take the concept of the limen too seriously, a wealth of evidence supports the validity of subliminal perception, defined broadly as the influence of stimuli that are too degraded by their conditions of presentation to be accessible to conscious perception. The debate now is not so much over whether subliminal perception occurs, as over the extent of subliminal processing.

4.Hypnosis:

The fourth line of research contributing to the rediscovery of the unconscious was hypnosis, a social interaction in which the subject acts on suggestions for experiences involving alterations in perception, memory, and the voluntary control of action. As William James recognized more than a century ago, many of these phenomena involve a division in consciousness such that memories, percepts, and the like influence experience, thought, and action outside of phenomenal awareness.

1.Consider, for example, posthypnotic amnesia – the phenomenon which gave hypnosis its very name. After receiving appropriate suggestions, many highly hypnotizable subjects come out of hypnosis unable to remember the events and experiences which transpired while they were hypnotized.

For example, subjects who have studied a list of animal names while hypnotized will be unable to remember them afterward. However, these unremembered items will also give rise to priming effects: if asked to generate names of animals, subjects will be more likely to give the names they studied, compared to instances that they did not encounter in hypnosis. Moreover, after the amnesia suggestion has been canceled by a prearranged reversibility cue, the subject will regain perfect conscious memory for the studied list. The reversibility of amnesia indicates that, in contrast to the organic amnesias associated with hippocampal damage, posthypnotic amnesia reflects a deficit in retrieval rather than encoding. But the preserved priming effects show that the retrieval deficit affects explicit, but spares implicit, expressions of memory.

2.Hypnotic suggestion can also affect perceptual functions. When given hypnotic suggestions for blindness, many hypnotizable subjects have the subjectively compelling experience that they no longer can see. However, Bryant and McConkey presented subjects with cards on which were printed a homophone (i.e., words which have the same sound but two different spellings, such as pain and pane) together with a disambuguating word (e.g., body or window).The hypnotically blind subjects did not see the cards, but on a subsequent test they spelled the homophones in accordance with the disambiguating associates with which the words had been paired. This is another kind of priming effect, and it indicates clearly that the words in question were perceptually processed outside of awareness.

3.Yet a third example of unconscious processing in hypnosis is provided by posthypnotic suggestion -- the phenomenon that, so our mythology tells us, gave Freud his first good insight into the psychological unconscious. In some sense, posthypnotic suggestion is a special case of implicit memory, because subjects act on a suggestion given during hypnosis, despite the fact that they cannot remember the suggestion itself. But posthypnotic suggestion is interesting in another way, because it is typically experienced as an involuntary, quasi-automatic response to the cue. In a doctoral dissertation by Irene Hoyt, hypnotized subjects were given a posthypnotic suggestion to press a key whenever a particular number appeared on a computer screen. After hypnosis was terminated, they were also instructed to press the key in response to a different number. On some test trials, the posthypnotic suggestion and the waking instruction were put into conflict. The posthypnotic suggestion did not always win out, once again shattering the myth of the coercive power of hypnosis.

But the most important finding was that even when the two did not conflict, response to the posthypnotic suggestion interfered with response to the waking instruction, and vice-versa. In other words, despite the experience and appearance of automaticity, processing the posthypnotic suggestion consumed a lot of cognitive resources. Posthypnotic response is unconscious, in the sense that subjects are unaware of why they behave as they do, or even that they are behaving as they are; but it has had no opportunity to be automatized by extensive practice.