NOTE: The text below is an excerpt from an unpublished manuscript. I introduce the idea that there are four periods in psychology, and I discuss the first period only in this excerpt. The other sections remain unposted at this time.
Wundt's ideas are somewhat at odds with the point of view expressed throughout these pages, i.e., that there are mental objects. However, we endorse Wundt's idea that introspection is a necessary and useful adjunct to empirical studies. I have included a version of Wundt's experiment with words and letters as an on-line experiment elsewhere on these pages. Please contact me if you would like more information about this text.
Portions of this text belong on the CONCEPTUAL SUBWAY MAP and will be moved there in the future.
Psychology and Mental Images
The Questions for Psychology
In the nineteenth century, new developments in neurology,
medicine, and physics laid the foundations for understanding
psychology as a science separate from philosophy. Part of this
new science was speculative, but it was also bound by a new
paradigm of science that demanded the use of experimental data
even in those matters that had traditionally been thought to be
strictly metaphysical or religious in nature. The rapid
development of the physical sciences during this period led many
philosophers and psychologists to hope that the nature of mental
processes could be illuminated by empirical, rather than
speculative or metaphysical, methods. It is therefore reasonable
to understand our guiding question about the nature of mental
images for psychology to be a variation on the original. We want
to know if psychology can answer this question:
Is there an empirical means for studying the nature and role
of mental images?
This question can not be answered by a simple "yes" or "no," for
it spawns innumerable other questions. Does the empirical method
include introspection or only the gross behavior of subjects?
Does the gross behavior of subjects include verbal reports of
their imagery experiences or only other sorts of bodily
movements? Finally, what is the scientific archetype for
psychology and how do mental images fit into this archetype? Is
psychology an offshoot of philosophy, a "soft" science
incorporating irretrievably metaphysical assumptions, or is it a
separate, "hard" empirical science like physics? How do these
scientific paradigms affect the way in which psychic phenomena
such as mental images are understood to be a part of empirical
psychology?
The answers given to these questions during the development
of psychology have been characterized by many sudden turns,
resulting in whole new experimental and theoretical perspectives
on psychology. In each case, the conception of mental imagery
has been of crucial importance to defining these various strains
of psychology. As several writers have observed, (Holt, 1964,
Yuille, 1983) one can almost identify the history of psychology
as a history of perspectives on mental images.
I have divided the history of psychology into eras that
roughly parallel a series of dominating positions on the study of
mental imagery. These are:
1. Foundational Period: 1860-1901
2. First Imagery Debate: 1901-1913
3. Behaviorism: 1913-1964
4. Reemergence of The Image: 1964-Present
Let us briefly review how these questions have been addressed
during the periods I have identified.
1. Foundational Period: 1860-1901
During this period introspection and the study of mental
images as conscious, psychical states were accepted as integral
parts of psychology. Wundt's Human and Animal Psychology, first
published in Germany in 1862, is considered to be one of the
foundational works of this period. While Wundt's work does not
completely define this period, it is indicative of a perspective
that finds psychology to be a self-consciously new science, aware
of its philosophical heritage and unsure, even skeptical, of its
destiny as an empirical science. Wundt's philosophy of
psychology is exceptionally interesting in light of the
contemporary issues we shall discuss in the following chapters,
so it will be useful to clarify some central themes of his
position.
Wundt is sometimes caricatured in the history of psychology
as a staunch defender of the infallibility of the introspective
method. This has the implication that Wundt was little more than
an arm-chair philosopher who accepted the Cartesian supposition
that the contents of the mind are infallibly given by
introspection. In fact, Wundt held that introspection
systematically fails to capture the complete contents of
consciousness. This is because introspection relies on memory.
Introspection is not instantaneous; the moment of conscious
awareness passes before introspection can be completed. When
attempting to introspect, one asks, "what was the content of
consciousness?" -- but the answer to this is already
contaminated by the contents of the present moment. We do not
know how much of the prior content may have been filled in,
extrapolated or deleted during the course of subsequent moments
(see Wundt, 1862/1912, p. 240).
Since introspection is not inherently reliable, Wundt
concluded that experiment would be a necessary adjunct to
psychology. Wundt illustrated this with an example. Suppose we
ask the general question, how many ideas are present in
consciousness at one time? Introspection or the collection of
data in the form of subject reports might suggest any number of
answers, from "one," to "several, perhaps, two or three," to "an
unspecified number, perhaps, dozens, or hundreds." Wundt
resolved to use an empirical test to assist in answering this
question. Wundt describes an experiment in which subjects are
exposed to random letters for a fraction of a second. Subjects
can recall 4 or 5 letters presented in this fashion. If the
letters are made into disyllabic words, two words of 6 letters
each may be recognized in the same amount of time (p. 243). If
more letters than can be retained are presented, Wundt found his
subjects were aware that these additional letters were present
even if the subjects could not recall what they were. The
experiment does not give a definitive answer to the number of
ideas that may be the momentary contents of consciousness, it
simply provides an indication of an answer that is more
definitive than idle speculation based solely on introspection.
On the other hand, Wundt did not hold introspection to be
permanently and irretrievably in error. He thought that
experimental conditions would, in many cases, allow the subjects
to focus their awareness, so that their introspective reports
would be a fair, if not 100 percent accurate, approximation of
mental events.
Here, as everywhere, psychological experiment does not
dispense with introspection, but, on the contrary, renders
introspection possible by furnishing the conditions which it
requires for exact observation. (p. 241)
This conviction derives (in part) from Wundt's philosophic view
that ideas are ever-changing processes, rather than permanent
objects stored in the mind. Wundt does not conclude that because
we have set up an experiment to measure experimental "things" we
call "ideas" that we have actually measured the properties of
these things or that these postulated entities actually exist in
precisely the manner that allows their precise experimental
measurement. On the contrary, Wundt concludes only that we can
measure something about conscious experience, but this
measurement is not definitive. To complete the account we also
have to rely on introspection. Thus, Wundt's philosophy of
psychology advocates a synthesis of experimental and
introspective evidence, in which neither is given absolute
preference.
This integrated view of the subject matter of psychology
places a limit on the precision of psychology, because it does
not allow for an absolute division between the psychic and the
physical events which constitute the entirety of the behavior
induced by an experimental situation. The context of the
experimental task always influences the subject. This holds for
even the simplest of all measurements of psycho-physical
phenomena: reaction times to sensory stimuli. In such
experiments, a visual, auditory, or other stimulus is presented
to the subject, and the subject responds by pressing a button.
Wundt claims that even here the mental realm, specifically the
impulse of the will and effect of subjective anticipation,
intrude into the explanation of what occurs within the subject.
Wundt describes the process of reacting to a stimulus as follows:
In the first place, physiological processes occupying a
certain period of time enter into the total movement-process
under consideration. The impression of the star upon the
meridian thread [the sense impression referred to in the
experiment under discussion] must be conducted to the brain,
must arouse an excitation there; and then, before the hand-
movement can take place, the impulse of will must be
conveyed to the muscles, and these stimulated to contract.
To these two purely physiological processes must be added
the psychological or psychophysical process of apperception
of the impression and impulse of the will. (p. 274)
Wundt discovered that the subject's anticipation of a stimulus
could be either concentrated on the muscular movement or on the
stimulus itself. As a result, the objective measurements may
vary significantly, even within the same subject. In Wundt's
view, there is no primitive, absolutely mechanical account for
reaction time that can be reflected in an external measurement.
It [reaction-time] is made up, as we have seen, of purely
physiological and of psychological processes; and we cannot
separate the two, or ascertain with even conjectural
probability the time-value of the mental component. (p. 275)
And the association of these constituents [physiological and
psychological] is so difficult of analysis that no
conclusion can be drawn regarding the duration of the mental
terms of the series.
This traditional view allows only a limited empirical means for
studying psychic phenomena. As we shall see, this view about the
nature of empirical measurements stands in sharp contrast to that
adopted by contemporary imagists.
Created on ... February 23, 2004