Re: [escepticos] algún psicólogode guardia

[Carlos Dominguez]

Hola JM:

En realidad el término "subconsciente" ni siquiera es de Freud. Es del
lenguaje popular y alude a la entidad  psíquica que (según Freud,
claro) existe entre el inconsciente y lo conscientedenominada
"preconsciente" .

El Inconsciente freudiano es una especie de reservorio energético que
determinaría la vida psíquica por diversas razones que no vienen al
caso.  Eso no es aceptable. Sí, es aceptable en cambio, utilizar el
ADJETIVO inconciente para referirse a  la recuperación de información
mnémica de  manera no intencional , que influye en el comportamiento.
A eso se lo llama "memoria implícita". De seguro que en el libro de
autoayuda hacen un uso del término que no es éste ;-)

Por si te interesa un poco más el asunto, te hago un copy & paste de
parte de un  artículo de la Enciclopedia del cerebro humano de  2002,
dirigida por V.S.  Ramachandran desgraciadamente no está on line :-(
------------------------------------------
Memory, Explicit and Implicit

KATHLEEN B. MCDERMOTT
Washington University, St. Louis

I. Explicit Memory
II. Implicit Memory
III.Implications
IV.Terminological Considerations


I. EXPLICIT MEMORY

A. Definition
Explicit memory can be thought of as intentional retrieval. That is,
explicit memory is the willful process of thinking back in time for
the purpose of retrieving previously encountered events. It is also
sometimes referred to as episodic memory because explicit memory
involves memory for prior episodes in one's life (as opposed to memory
for general knowledge of the world, e.g., who served as the first U.S.
president, which is called semantic memory). In psychology
experiments, explicit memory is usually defined operationally in terms
of test instructions. That is, if participants are asked to retrieve a
previous event, then the experiment is one that taps explicit memory.
(siguen varias páginas que no voy a reproducir)

II. IMPLICIT MEMORY

A. Definition
As mentioned previously, explicit memory refers to intentional
retrieval. In contrast, implicit memory can be thought of as
unintentional or incidental retrieval.
Implicit memory refers to the change in performance as a result of
prior experience without intentionally trying to remember the prior,
facilitating event. For example, if you were to read this entry a
second time, you would read it faster than the first. This would
happen even if you are not conscious of this difference or trying to
produce it. What is important is that you
are not attempting to draw on previous experience to aid you in the
current task; instead, it manifests itself in the absence of your
intent to use that information. As will be seen, implicit and explicit
memory differ in many important ways.

B. Measures
Implicit memory is measured in terms of priming, or the amount of
change (often facilitation) observed on an implicit memory test. In
order to better understand how implicit memory works, psychologists
have devised three main classes of implicit memory tests:
perceptual implicit memory tests, conceptual implicit memory tests,
and procedural learning.
Perceptual implicit memory tests require people to resolve a
perceptually degraded object or word. For example, a word might be
flashed very briefly (e.g., 30 msec) on a computer screen, and the
task of the person is to try to guess the word. Accuracy in guessing
the word is better if the word was recently read. Other types of tests
involve completing word puzzles, such as
those seen on game shows (e.g., ''a _ r _ _ a r _'' will be more
readily recognized as ''aardvark'' if the intact word was recently
read). Another popular test is to have people fill in the blanks to
form the first word that comes to mind that begins with specified
letters (e.g., ''app_____''). If ''apple'' were previously seen, it
would be primed; it would be used by subjects more often
than if they had not previously seen this word.
However, if ''appendix'' were previously seen, it would be the primed
word. These tests are called word identification, word fragment
completion, and word stem completion, respectively.
Similar tests can be employed with pictures, unfamiliar objects,
visual patterns, or sounds. For example in picture fragment
identification, people are given line drawings of common objects
(e.g., a lamp), but parts of the lines have been erased. Their task is
to guess the name of the
picture from its fragmented form.

The second type of implicit memory test, conceptual implicit memory
tests, have received much less attention.
They, too, use priming as the measure of memory, but they do so by
observing how performance on a conceptual, or meaning-based task is
influenced by the recent past. For example, if someone asked ''What is
the name of an airplane without an engine?'' a person
would be more likely to answer correctly with ''glider'' if he or she
recently encountered that word. Similarly, if a person were asked to
say the first word to come to mind when given ''aviation'', he or she
would be more likely to say ''glider'' than he or she otherwise would
if
it had not recently been encountered. Peoples' thinking processes in
the present are influenced by the recent past, even when there is no
attempt to use that recent past to perform the task at hand.
Notice that unlike explicit memory tests, there are sometimes no
correct or incorrect answers on an implicit memory test. For example,
saying the first word that comes to mind when given another word
(i.e., word association) or saying the first word that comes to mind
that begins with ''app____'' have many ''right'' answers; priming,
however, is measured in the enhancement of saying a word prespecified
by the experimenter and recently studied. Specifically,  researchers
search for enhanced probabilities of producing whatever word was
recently encountered (usually called the target word or the primed
word) relative to the condition in which that word was not recently
encountered.
Another example of a conceptual implicit memory test is a ''liking''
judgment. That is, the answer to ''How much do you like this?'' can be
affected by recent experience. A song heard several times will
sometimes tend to ''grow on'' a person, and this, too, is a form of
conceptual implicit memory.

Procedural learning is a third index of implicit memory. The previous
example of reading a passage of text faster the second time than the
first is an example of procedural learning. Other examples include
relearning mazes and recompleting jigsaw puzzles.
People can perform complex procedural tasks more quickly and
efficiently if they have had recent prior experience with the same
materials.

C. Typical Patterns of Results

As mentioned previously, implicit memory tests tend to show different
patterns of results from those of explicit memory tests. Perhaps the
most dramatic difference is that patients with amnesia (e.g., patient
H.M. described previously) perform normally on these tests, despite
profound impairments on explicit memory tests (Fig. 2). Indeed, this
finding was the spark
that produced such great interest in these tests.
With respect to independent variables, perceptual implicit memory
tests show patterns markedly different from those exhibited by most
explicit memory tests.
Conceptual implicit tests, however, tend to exhibit patterns similar
(although not always identical) to many explicit tests. The following
sections discuss the three patterns of effect of encoding tasks
discussed previously with respect to explicit memory (the level of
processing effect, the generation effect, and the picture superiority
effect), as they relate to perceptual and
conceptual implicit memory.
Sigue una parrafada que lo hartía muy largo...

D. Neural Correlates

As alluded to previously, damage to regions in the medial temporal
lobes does not produce a general impairment on perceptual implicit
memory tests.
Whether general impairments occur on conceptual implicit memory tests
is more controversial. The finding of intact perceptual priming in
patients with damage to the hippocampus and surrounding structures
within the medial temporal lobe was reported by Elizabeth Warrington
and Lawrence Weiskrantz in the late 1960s. This finding spurred
interest in the phenomenon of priming. Prior to this finding, it had
been thought that the medial temporal lobes were globally important in
memory; however, this finding demonstrated that this was not the case.

If the medial temporal lobes are not critical for producing perceptual
priming, then what brain regions are? The brain mechanisms that
underlie priming effects differ as a function of the type of implicit
memory test. In general terms, brain regions that are critical for
performing a task in the unprimed state are less active in the primed
state. This makes sense if one thinks about priming as facilitation;
the brain regions critical to performing the task have to put forth
less
effort in the primed (facilitated) state.

Consider first perceptual implicit memory tests.

Reading a visually presented word taxes the visual system. However,
regions in extrastriate visual cortex (Fig. 1) show less activity in
the primed state relative to the unprimed state, consistent with the
idea that less neural effort is required to performthe task; the
neural
pathways necessary to accomplish the goal are facilitated.
Although less well studied, on the basis of this logic we would expect
auditory implicit memory tests (e.g., identifying an auditory word
stem) to show less activation in regions of the brain responsible for
auditory processing (relative to the unprimed state).
Conceptual implicit memory tests, however, are not sensitive to the
match or mismatch in perceptual features between the study and test
phases; hence, the neural manifestation is not at the perceptual
level.

Rather, facilitation is observed at higher level regions of the brain,
which are concerned with the task at hand. Consider the case of
generating an associate to a presented word (e.g., given the word
''elephant,'' the person would respond with a related word, such as
''tusk''). This task calls on many brain regions, and two critically
important regions lie within the left inferior frontal cortex (Fig. 1,
anterior and posterior inferior frontal gyri). These regions show
diminished
activation in the primed condition. Again, it can be seen that regions
that are important for performing the task have to put forth less
effort to accomplish the task at hand in the primed condition. The
brain is more efficient in the primed case.

III. IMPLICATIONS
As previously reviewed, implicit and explicit memory differ as a function of:

1. Subject populations: The finding that amnesic patients exhibit
intact implicit memory despite grossly impaired explicit memory
spawned a great deal of interest in characterizing implicit memory
tests.

2. Independent variables: Many standard findings in explicit memory do
not hold up (and often are reversed) for perceptual implicit memory
tests. Explicit and implicit memory seem to be fundamentally different
types of memory.

3. Neural substrates: Explicit memory tests show increased activity in
a network of brain regions, including regions within anterior
prefrontal cortex and lateral and medial parietal cortex. Implicit
memory tests showdecreased activity in regions critical for performing
that task (e.g., in visual cortex as seen for word stem completion).
In the late 1980s, there was a debate over the question of whether
different memory ''systems'' were responsible for performance on
implicit and explicit memory. This hotly contested  question was
argued before the tools to observe localized brain activity relatively
directly (via PET and fMRI) had become widely available. The
availability of these techniques has allowed researchers to go beyond
debating whether there is a system or network of regions in the brain
responsible for implicit memory (or explicit memory) and instead to
focus on the precise role of various specific brain regions to
specific memory tasks. The general conclusion is that no single brain
region is solely responsible for implicit (or explicit) memory.We do
now have an emerging understanding of the network of brain regions
underlying implicit memory and explicit memory tests, and there are
marked differences between the two. However, differences also
exist among various explicit tasks as well as among different implicit
tasks. Whether one wants to refer to the networks underlying
performance as brain systems is largely a matter of taste.

One suggestion advocated here (in collaboration with Henry Roediger
and Randy Buckner) is that it makes sense to put the question of
systems aside until the individual components
of the systems (i.e., individual brain regions) are better understood,
with the eventual goal being to understand the entire network of brain
regions contributing to implicit and explicit memory in their multiple
instantiations.

IV. TERMINOLOGICAL CONSIDERATIONS

I consider here a few difficult issues involving terminology.

First, implicit and explicit memory tests have been defined here
according to instructions. However, consider the case in which the
instructions given to subjects are for an implicit test, but people
choose to ignore the instructions and decide to think back to the past
in an effort to enhance performance on the test. Is the test still
implicit? Conversely, what if people decide
that an explicit memory test is too difficult and therefore begin
responding with whatever first comes to mind? Is the test explicit
simply because the instructions asked people to think back in time?
The approach advocated here is that safeguards can (and in some
situations should) be built into experiments to ensure that subjects
do indeed follow instructions; this is as true of explicit memory
experiments as of implicit memory experiments, however. Thus,
instructions to
subjects define the test type to a first approximation, but it is
desirable to have some behavioral evidence documenting that people did
follow those instructions.

A second issue that researchers have wrestled with is the concept John
Gardiner termed involuntary conscious recollection. This term refers
to the situation in which a person vividly recollects some aspect of
the past even though he or she is not trying to do so.

Consider the case in which, for example, you are walking down the
street when seemingly out of
nowhere you recall going to the circus as a child.
You did not intentionally recall that memory; it simply ''popped to
mind,'' perhaps sparked by the unconscious association to some cue in
the environment.
Does such an experience tend to happen on implicit memory testsFa
subject recognizes a word as studied after it has been retrievedFand,
if so, does it contaminate the results? Although such phenomena
sometimes do occur on implicit tests, research indicates that it need
not affect the implicit test results. As long as people do not alter
their strategy on the implicit
test (i.e., as long as they do not adopt a strategy of attemp ing to
recollect the recent past to aid performance on the test and instead
continue to follow instructions), such involuntary conscious
recollection does not contaminate the results.

A third difficult issue is that implicit and explicit have been
referred to here as representing test types as defined by instructions
and have also been referred to as representing different
manifestations of memory, which underlie performance on the two types
of test.
This confounding of terms is pervasive in the field but can lead to
confusion. One approach (advocated here) is to apply the terms to the
type of test (implicit or explicit memory test) because test type can
be defined (at least approximately) by instructions, whereas
''implicit memory'' and ''explicit memory'' cannot be observed
directly. However, the title of this article referred to implicit and
explicit ''memory,'' and these concepts are widely discussed in the
literature; therefore, implicit and explicit are used in both senses
throughout this article.

Suggested Reading

Gardiner, J. M., and Java, R. I. (1993). Recognising and remembering.
In Theories of Memory (A. Collins, M. A. Conway and P. E.
Morris, Eds.), pp. 163–188. Erlbaum, Hillsdale, NJ.
McDermott, K. B. (2000). Implicit memory. In The Encyclopedia of
Psychology (A. E. Kazdin, Ed.), pp. 231–234. Oxford Univ.
Press, Oxford.
Richardson-Klavehn, A., and Bjork, R. A. (1988). Measures of
memory. Annu. Rev. Psychol. 39, 475–543.
Roediger, H. L. (1990). Implicit memory: Retention without
remembering. Am. Psychol. 45, 1043–1056.
Roediger, H. L., and McDermott, K. B. (1993). Implicit memory in
normal human subjects. In Handbook of Neuropsychology (F.
Boller and J. Grafman, Eds.), Vol. 8, pp. 63–131. Elsevier,
Amsterdam.
Roediger, H. L., Buckner, R. L., and McDermott, K. B. (1999).
Components of processing. In Memory: Systems, Process, or
Function? (J. K. Foster and M. Jelicic, Eds.), pp. 31–65. Oxford
Univ. Press, Oxford.
Schacter, D. L. (1987). Implicit memory: History and current status.
J. Exp. Psychol. Learning Memory Cognition 13, 501–518.
Schacter, D. L., and Buckner, R. L. (1998). Priming and the brain.
Neuron 20, 185–195.
Tulving, E., and Schacter,D. L. (1990). Priming and human memory
systems. Science 247, 301–306.