Minds and Computers : An Introduction to the Philosophy of Artificial Intelligence

stimulus–response times.
The groundbreaking work of Fechner and Helmholtz lay the foun-
dation on which others would build an independent science of the
mind. Fechner demonstrated the possibility of employing empirical
methods to investigate mentality and identified psychophysics as a
fruitful domain for further experimentation. Helmholtz was the first
to demonstrate that the measurement of stimulus–response times
could be a fertile methodology for the fledgling psychology.
It is of significant interest that the pioneering work of these early
physiological psychologists was only possible as a result of the broad
academic interests and interdisciplinary training of both researchers.
This is to be taken as a cautionary note to those who would specialise
too narrowly, as well as a clear endorsement of the value of cross-
disciplinary analysis and interdisciplinary cooperation.
3.3 INTROSPECTIONIST PSYCHOLOGY
It is Wilhelm Wundt (1832–1920) who clearly deserves the appellation
‘founder of psychology’. Wundt established the first psychologi-
cal laboratory, inaugurated the first journal of psychology –
Philosophische Studien – in 1881, and founded an Institute for
Experimental Psychology at Leipzig in 1894. He also wrote the first
textbook in psychology and supervised legions of graduate students
from around the world who would become the first generation of psy-
chological practitioners.
Wundt’s programme of psychological structuralism placed central
importance on introspection as a methodological technique. The
aim of the programme was to analyse consciousness in order to iden-
tify its basic elements and the laws which connect them. This was
pursued through the use of carefully designed experiments in which
trained observers introspected their mental states and reported their
observations.
One methodological facet of crucial importance here is the training
of observers. Wundt believed that only properly qualified observers
could introspect with the appropriate care and attentiveness and
report their observations in a pertinent fashion, suitable for analysis.
A further point of interest lies in the rigour with which experiments
were designed and conducted. Wundt and his students and colleagues
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were instrumental in developing many of the now standard criteria
for experimentation, such as the publicity of the experimental situ-
ation, the repeatability of results and the ability to hold certain vari-
ables constant while modifying others.
Another important researcher in the introspectionist tradition was
Hermann Ebbinghaus (1850–1909). Ebbinghaus established a rival
journal to Wundt’s – Zeitschrift für Psychologie und Physiologie der
Sinersorgane – in 1890, and established laboratories for psychological
research in Berlin and Breslau. Like Wundt, he also published an
influential textbook on psychology.
Whereas Wundt and his followers thought that the scope of psy-
chology should be properly restricted to what we might call ‘lower-
order’ mental functions, concentrating their empirical programme
solely on the investigation of mental imagery, Ebbinghaus was inter-
ested in formulating experiments with which to study memory.
In order to gain some insight into the mechanisms underpinning
human memory in a fashion isolated from the potentially contami-
nating e
ffects of what was already known, Ebbinghaus devised a very
large number of lists of nonsense syllables – consonant-vowel-
consonant segments which had no meaning in the language. He then
proceeded to memorise these lists and measure, with painstaking pro-
cedures, his ability to recall these syllables.
This research delivered further quantitative psychological princi-
ples, central among them being the exponential decay of memory.
Ebbinghaus discovered that his ability to recall the nonsense lists
would decay very quickly at first, but increasingly more slowly
through time. One consequence of this exponential decay of memory
for students is the crucial importance of early reinforcement.
Ebbinghaus also demonstrated that while the initial memorisation of
the lists was subject to rapid decay, the rate of decay of the ability to
recall the lists slowed in proportion to the number of repetitions.
Again, this finding has obvious implications for study techniques.
Putting these two results together, we see that if one wants to be able
to recall material with a high rate of accuracy, one should revisit the
material very soon after first presentation, then reinforce the material
after increasingly longer intervals. For instance, to recall the material
presented in a lecture, it is advisable to revise the material later that
day, then again a couple of days later, then again a week later, then a
month later, and so on. The most cursory examination of modern
advice on study techniques will yield just such recommendations.
The final figure of note in the introspectionist tradition is Oswald
Külpe (1862–1915). Külpe was a student of Wundt’s at Leipzig and
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later established a rival school of psychology at Würzburg. There
were two key points of dispute between the Leipzig school and the
Würzburg school. The two schools disagreed on the appropriate
purview of psychology and this disagreement brought with it an asso-
ciated dispute concerning experimental methodology.
Where as Wundt and his students believed that the legitimate scope
of psychology was properly restricted to the investigation of mental
imagery alone, Külpe and his followers thought – as did Ebbinghaus –
that the empirical examination of ‘higher-order’ cognitive functions,
such as reasoning, had an important role to play in psychology. So the
Leipzig school and the Würzburg school were essentially investigat-
ing distinct aspects of mentality.
The other point of contention between the Wundtians and the
Külperians concerned the role of observers in introspectionist experi-
mentation. Wundt, as we emphasised earlier, placed significant
importance in the training of observers, in order that they be qualified
introspectors. Külpe, on the other hand, used exclusively untrained
observers. History has borne Külpe out in this respect: modern-day
psychological experiments typically require that the subject be not
only untrained in psychology, but also ignorant of (and often deceived
about) the aims of the particular experiment in which they participate.
The introspectionist tradition in early psychology was unified by
the belief that introspection – whether it be by trained observers
(Wundt), untrained observers (Külpe) or oneself (Ebbinghaus) – was
the key to investigating mentality. Although self-reporting is still used
to some extent in modern psychology (typically in combination with
various other methodologies), the introspectionist tradition died out
in the early twentieth century. The reasons for this are several.
Firstly, it became increasingly apparent that much of mental life is
simply opaque to introspection. I can’t, for instance, investigate the
mechanisms governing language production and comprehension
purely through introspection.
Secondly, introspection is fairly unreliable, regardless of who is
doing the introspecting. People are notoriously poor at identifying
their own mental states; untrained observers particularly so. Trained
observers, on the other hand, have a tendency to manufacture
observations in accordance with their perceived expectations.
Furthermore, introspection is itself a mental process and therefore
has an e
ffect on the mental processes which are being introspected. If,
for example, you reflect on your anger, you’re likely to become either
resolved and thereby less angry, or increasingly heated and thereby
more angry.
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Finally, only the introspecting agent is privy to the direct results of
their introspection. Where introspecting subjects disagree, there is no
way for a third party to adjudicate observational disputes. So while
the experimental situation in which the introspection occurs can
satisfy the requirement for publicity, the introspective process itself
cannot.
3.4 PSYCHOLOGICAL BEHAVIOURISM
Aside from the foundational work of the physiological and introspec-
tionist psychologists, there are two further important historical pre-
conditions which led to the emergence of psychological behaviourism.
One of these historical antecedents was the influential nineteenth-
century doctrine of positivism. Positivism, as championed by
Auguste Comte (1798–1857) and Ernst Mach (1838–1916), was a
reaction to the speculative metaphysics and theological conjecture
which was held to have infected philosophy. Proponents of positivism
held that legitimate intellectual inquiry, or ‘positive science’, should
treat exclusively of the observable. Any doctrine which posited enti-
ties or processes beyond what could be observed was labelled with the
pejorative ‘pseudoscience’.
The other significant influence on psychological behaviourism was
the work of Ivan Pavlov (1849–1936). Pavlov was a Russian physiol-
ogist and the originator of the theory of reflex arcs. Pavlov held that
the connection between environmental stimulus and behavioural
response was to be explained in terms of these reflex arcs. No doubt
you have heard of Pavlov’s dog. Pavlov first showed that the environ-
mental presence of food stimulus would cause a dog’s digestive juices
to flow in its stomach, even if the food never reached the stomach. He
postulated the existence of an innate reflex arc to account for this
connection.
Most famously, however, Pavlov demonstrated that reflex arcs
could be conditioned as well as innate. In the case of Pavlov’s dog, a
bell was sounded whenever food was brought into the presence of the
animal. Eventually, the dog would salivate upon hearing the sound of
the bell alone. This behaviour, according to Pavlov, demonstrated a