Stephen Harris

David Longley David at
Sun Apr 19 15:43:09 EST 1998

In article <6hdmhg$1nq$1 at> cijadra at  writes:

> Stephen Harris <mulcyber at> wrote:
> >cijadra at wrote:
> >> 
> >> You do not perceive the thoughts because you do not know enough.
> >> 
> >> I believe there is a lot you'd not understand in Carlos Castaneda's
> >This sort of stuff appeals to the gullible fairly intelligent.
> >Astrology, Tarot, I Ching, Crystal Chakra healing, are all fake
> >and in the same category. All of it, including C Casteneda is
> >a pile of spiritual hubris. You will never find a fact or evidence.
> >This is what some grownups do instead of believing in Santa Claus.
> It seems there is a lot that you do not understand.
> And that you are proud of it.
> What Carlos Castaneda writes, is, as he says, a guide to real sorcery.
> But, as I said, he is leaving out key data, without which it is
> unlikely that you understand what he says.
> Sorcery is not meant for all  according to many people's opinions; and
> I heard that even for what he wrote he got complaints from many places
> of the world.  And I can see why.
> There is data in there which much have taken centuries if not
> thousands of years of research to get at it.
> That you are too ... to see the incredible value of it is not speaking
> for you.
> And I do not say that all he says is correct; some is b.s., some is
> dangerous b.s., and in his first books he is going forever after stuff
> that is not so interesting if one is alteady knowing a bit about it
> and is t=not paying attention to some of the stuff that is beyond
> nominal value, so that it is just mentioned shortly but never
> explained deeper. Argh.
> The point of Tarot is a mental counselling.
> Personally I do not like it, but for some people it is good if they
> stop once a week or more often and look at where they are in life,
> think about that, their past, their future.
> It helps them to go a more steady and content course through life.
> About Crystal Chakra healing  I cannot say anything.
> So far I do not have enough control over the Chakren in the body, nor
> know about all crystals and their effect upon those centers, so I am
> not able to judge.
> With Astrology I believe that the planets still have effects upon us,
> but not the stars, but that the time of the year y9u are born in plays
> a high role in some cultures.
> In my land in winter it is dark at five and in summer light till after
> eleven. A child born in winter and learning to walk one year later can
> not go out into the snowy land and has other melatonin levels than a
> summer child who one year later might take first steps through the
> garden and look at the flowers and insects...
> That is a very different input and I believe it makes changes.
> I-Ching I do not know.
> I believe that you judge things fast without understanding them.

> >This sort of stuff appeals to the gullible fairly intelligent.
> >Astrology, Tarot, I Ching, Crystal Chakra healing, are all fake
> >and in the same category. All of it, including C Casteneda is
> >a pile of spiritual hubris. You will never find a fact or evidence.
> >This is what some grownups do instead of believing in Santa Claus.

Yes - well put.

It will help if an idea of what we mean by 'clinical'  and  'actuarial' 
judgement  is provided. The following is taken from a an early  (Meehl 
1954),  and  a relatively recent review of the  status  'Clinical  vs. 
Actuarial Judgement' by Dawes, Faust and Meehl (1989):

    'One  of the major methodological problems  of  clinical 
    psychology concerns the relation between the  "clinical" 
    and   "statistical"   (or   "actuarial")   methods    of 
    prediction.  Without  prejudging  the  question  as   to 
    whether  these methods are fundamentally  different,  we 
    can at least set forth the main difference between  them 
    as  it appears superficially. The problem is to  predict 
    how  a person is going to behave. In what manner  should 
    we go about this prediction?

    We may order the individual to a class or set of classes 
    on  the  basis of objective facts  concerning  his  life 
    history,  his  scores on  psychometric  tests,  behavior 
    ratings or check lists, or subjective judgements  gained 
    from  interviews.  The  combination of  all  these  data 
    enables us to CLASSIFY the subject; and once having made 
    such  a  classification,  we  enter  a  statistical   or 
    actuarial table which gives the statistical  frequencies 
    of  behaviors of various sorts for persons belonging  to 
    the  class. The mechanical combining of information  for 
    classification  purposes, and the resultant  probability 
    figure  which  is  an  empirically  determined  relative 
    frequency,  are  the  characteristics  that  define  the 
    actuarial or statistical type of prediction.
    Alternatively,  we may proceed on what seems, at  least, 
    to  be a very different path. On the basis of  interview 
    impressions, other data from the history, and   possibly 
    also psychometric information of the same type as in the 
    first sort of prediction, we formulate, as a psychiatric 
    staff   conference,   some   psychological    hypothesis 
    regarding  the  structure  and  the  dynamics  of   this 
    particular  individual. On the basis of this  hypothesis 
    and certain reasonable expectations as to the course  of 
    other events, we arrive at a prediction of what is going 
    to  happen.  This  type of procedure  has  been  loosely 
    called the clinical or case-study method of prediction'.
    P. E. Meehl (1954)
    The Problem: Clinical vs. Statistical Prediction

    'In  the clinical method the decision-maker combines  or 
    processes  information  in  his  or  her  head.  In  the 
    actuarial  or  statistical  method the  human  judge  is 
    eliminated  and conclusions rest solely  on  empirically 
    established relations between data and the condition  or 
    event  of  interest.  A life insurance  agent  uses  the 
    clinical  method  if data on risk factors  are  combined 
    through personal judgement. The agent uses the actuarial 
    method if data are entered into a formula, or tables and 
    charts that contain empirical information relating these 
    background data to life expectancy.
    Clinical judgement should not be equated with a clinical 
    setting  or  a  clinical practitioner.  A  clinician  in 
    psychiatry or medicine may use the clinical or actuarial 
    method.  Conversely, the actuarial method should not  be 
    equated   with  automated  decision  rules  alone.   For 
    example, computers can automate clinical judgements. The 
    computer  can  be programmed to  yield  the  description 
    "dependency  traits", just as the clinical judge  would, 
    whenever  a certain response appears on a  psychological 
    test.  To  be truly actuarial, interpretations  must  be 
    both automatic (that is, prespecified or routinized) and 
    based on empirically established relations.'
    R. Dawes, D. Faust & P. Meehl (1989)
    Clinical  Versus  Actuarial Judgement Science  v243,  pp 
    1668-1674 (1989)
As long ago as 1941, Lundberg made it clear that any argument  between 
those committed to the 'clinical' (intuitive) stance and those arguing 
for the 'actuarial' (statistical) was a pseudo-argument, since all the 
clinician  could possibly be making his or her decision on was his  or 
her limited experience (database) of past cases and outcomes.
    'I  have no objection to Stouffer's statement  that  "if 
    the  case-method  were  not  effective,  life  insurance 
    companies   hardly   would  use  it  as   they   do   in 
    supplementing  their  actuarial  tables  by  a   medical 
    examination  of the applicant in order to  narrow  their 
    risks."  I do not see, however, that this constitutes  a 
    "supplementing"  of actuarial tables. It is  rather  the 
    essential task of creating specific actuarial tables. To 
    be  sure, we usually think of actuarial tables as  being 
    based  on  age alone. But on the basis  of  what  except 
    actuarial  study has it been decided to charge a  higher 
    premium  (and  how  much) for  a  "case"  twenty  pounds 
    overweight,  alcoholic, with a certain  family  history, 
    etc.?  These case-studies have been classified  and  the 
    experience for each class noted until we have arrived at 
    a  body of actuarial knowledge on the basis of which  we 
    "predict" for each new case. The examination of the  new 
    case  is for the purpose of classifying him as one of  a 
    certain class for which prediction is possible.'
    G. Lundberg (1941)
    Case  Studies vs. Statistical Methods -  An Issue  Based 
    on Misunderstanding. Sociometry v4 pp379-83 (1941)

A  few  years  later, Meehl (1954), drawing on the  work  of  Lundberg 
(1941) and Sarbin (1941) in reviewing the relative merits of  clinical 
vs.  statistical prediction (judgement) reiterated the point that  all 
judgements about an individual are always referenced to a class,  they 
are always therefore, probability judgements.
    'No  predictions  made about a single case  in  clinical 
    work  are  ever certain, but are  always  probable.  The 
    notion of probability is inherently a frequency  notion, 
    hence statements about the probability of a given  event 
    are statements about frequencies, although they may  not 
    seem  to be so. Frequencies refer to the  occurrence  of 
    events in a class; therefore all predictions; even those 
    that from their appearance seem to be predictions  about 
    individual concrete events or persons, have actually  an 
    implicit reference to a is only if we have a 
    reference  class to which the event in question  can  be 
    ordered   that   the  possibility  of   determining   or 
    estimating a relative frequency exists.. the  clinician, 
    if he is doing anything that is empirically  meaningful, 
    is  doing  a second-rate job  of  actuarial  prediction. 
    There is fundamentally no logical difference between the 
    clinical or case-study method and the actuarial  method. 
    The  only  difference is on two  quantitative  continua, 
    namely  that the actuarial method is more  EXPLICIT  and 
    more PRECISE.' 
    P. Meehl (1954)  
    Clinical vs. Statistical Prediction:  
    A Theoretical Analysis and a Review of the Evidence

There  has,  unfortunately, over the years, been a  strong  degree  of 
resistance to the actuarial approach. It must be appreciated  however, 
that  the technology to support comprehensive actuarial  analysis  and 
judgment  has only been physically available since the 1940s with  the 
invention  of  the computer. Practically speaking, it  has  only  been 
available on the scale we are now discussing since the late 1970s with 
the   development  of  sophisticated  DBMS's  (databases  with   query 
languages  based  on  the Predicate Calculus; Codd  1970;  Gray  1984; 
Gardarin and Valduriez 1989, Date 1992), and the development and  mass 
production  of  powerful and cheap microcomputers. Minsky  and  Papert 
(1988)  in  their  expanded edition of  'Perceptrons'  (basic  pattern 
recognition systems) in fact wrote:

    'The   goal  of  this  study  is  to  reach   a   deeper 
    understanding of some concepts we believe are crucial to 
    the  general  theory of computation. We  will  study  in 
    great detail a class of computations that make decisions 
    by  weighting  evidence.....The people we want  most  to 
    speak  to  are  interested in  that  general  theory  of 

    M. L. Minsky & S. A. Papert (1969,1990)
    Perceptrons p.1

The  'general  theory  of computation' is,  as  elaborated  elsewhere, 
'Recursive  Function Theory' (Church 1936, Kleene 1936, Turing  1937), 
and  is  essentially the approach being advocated here  as  evidential 
behaviourism,  or eliminative materialism which  eschews  psychologism 
and  intensionalism. Nevertheless, as late as 1972, Meehl still  found 
he had to say:
    'I  think  it is time for those who resist  drawing  any 
    generalisation   from   the   published   research,   by 
    fantasising  about  what WOULD happen if  studies  of  a 
    different sort WERE conducted, to do them. I claim  that 
    this  crude, pragmatic box score IS important, and  that 
    those  who deny its importance do so because  they  just 
    don't like the way it comes out. There are few issues in 
    clinical,  personality,  or social psychology  (or,  for 
    that matter, even in such fields as animal learning)  in 
    which  the research trends are as uniform as  this  one. 
    Amazingly,  this strong trend seems to exert  almost  no 
    influence  upon  clinical  practice, even,  you  may  be 
    surprised to learn, in Minnesota!...
    It  would  be  ironic  indeed  (but  not  in  the  least 
    surprising  to one acquainted with the sociology of  our 
    profession)  if  physicians in  nonpsychiatric  medicine 
    should learn the actuarial lesson from biometricians and 
    engineers,  whilst the psychiatrist continues to  muddle 
    through  with  inefficient  combinations  of  unreliable 
    judgements  because he has not been properly  instructed 
    by his colleagues in clinical psychology, who might have 
    been expected to take the lead in this development.
    I  understand  (anecdotally) that there  are  two  other 
    domains,  unrelated to either personality assessment  or 
    the  healing  arts, in which actuarial methods  of  data 
    combination  seem  to do at least as good a job  as  the 
    traditional impressionistic methods: namely, meteorology 
    and the forecasting of security prices. From my  limited 
    experience  I have the impression that in  these  fields 
    also   there  is  a  strong  emotional   resistance   to 
    substituting formalised techniques for human judgement. 

    Personally,  I look upon the  "formal-versus-judgmental" 
    issue  as one of great generality, not confined  to  the 
    clinical   context.   I   do  not   see   why   clinical 
    psychologists should persist in using inefficient  means 
    of  combining  data  just  because  investment  brokers, 
    physicians,  and  weathermen do so.  Meanwhile,  I  urge 
    those  who  find  the box score  "35:0"  distasteful  to 
    publish  empirical  studies filling in the  score  board 
    with numbers more to their liking.'
    P. E. Meehl (1972)
    When  Shall  We Use Our Heads Instead  of  the  Formula? 
    PSYCHODIAGNOSIS: Collected Papers (1971)

In  1982, Kahneman, Slovic and Tversky, in their collection of  papers 
on (clinical) judgement under conditions of uncertainty, prefaced  the 
book with the following: 
    'Meehl's  classic  book, published in  1954,  summarised 
    evidence   for   the  conclusion  that   simple   linear 
    combinations  of cues outdo the intuitive judgements  of 
    experts in predicting significant behavioural  criteria. 
    The lasting intellectual legacy of this work, and of the 
    furious  controversy that followed it, was probably  not 
    the  demonstration that clinicians performed  poorly  in 
    tasks  that,  as  Meehl  noted,  they  should  not  have 
    undertaken.  Rather,  it  was  the  demonstration  of  a 
    substantial discrepancy between the objective record  of 
    people's  success  in prediction tasks and  the  sincere 
    beliefs  of  these  people about the  quality  of  their 
    performance.  This  conclusion  was  not  restricted  to 
    clinicians or to clinical prediction: 

    People's  impressions of how they reason, and  how  well 
    they reason, could not be taken at face value.'  
    D. Kahneman, P. Slovic & A. Tversky (1982)
    Judgment Under Conditions of Uncertainty: Heuristics and 

Earlier in 1977, reviewing the Attribution Theory literature  evidence 
on  individuals' access to the reasons for their  behaviours,  Nisbett 
and Wilson (1977) summarised the work as follows:
    '................................... there may be little 
    or  no  direct  introspective  access  to  higher  order 
    cognitive processes. Ss are sometimes (a) unaware of the 
    existence  of a stimulus that importantly  influenced  a 
    response, (b) unaware of the existence of the  response, 
    and  (c)   unaware that the stimulus  has  affected  the 
    response.  It  is proposed that when people  attempt  to 
    report  on  their cognitive processes, that is,  on  the 
    processes  mediating  the  effects of a  stimulus  on  a 
    response,  they  do not do so on the basis of  any  true 
    introspection.  Instead,  their reports are based  on  a 
    priori, implicit causal theories, or judgments about the 
    extent  to  which a particular stimulus is  a  plausible 
    cause  of  a given response. This suggests  that  though 
    people  may  not  be  able  to  observe  directly  their 
    cognitive  processes,  they will sometimes  be  able  to 
    report  accurately  about them.  Accurate  reports  will 
    occur  when  influential  stimuli are  salient  and  are 
    plausible causes of the responses they produce, and will 
    not  occur  when  stimuli are not  salient  or  are  not 
    plausible causes.' 
    R. Nisbett & T. Wilson (1977)
    Telling More Than We Can Know: Public Reports on Private 

Such  rules  of thumb or attributions, are of course  the  intensional 
heuristics  studied by Tversky and Kahneman (1973), or  the  'function 
approximations'  computed by neural network systems discussed  earlier 
as  connection weights (both in artificial and real neural  nets,  cf. 
Kandel's work with Aplysia).

Mathematical  logicians  such as Putnam (1975,1988);  Elgin  1990  and 
Devitt  (1990)  have  long been arguing  that  psychologists  may,  as 
Skinner (1971,1974) argued consistently, be looking for their data  in 
the  wrong  place.  Despite the empirical evidence  from  research  in 
psychology on the problems of self report, and a good deal more  drawn 
from  decision  making  in medical diagnosis, the  standard  means  of 
obtaining information for 'reports' on inmates for purposes of review, 
and the standard means of assessing inmates for counselling is on  the 
basis  of clinical interview. In the Prison Service this makes  little 
sense,  since  it  is possible to  directly  observe  behaviour  under 
relatively  natural  conditions of everyday activities.  The  clinical 
interview,  is  still  the basis of much of the  work  of  the  Prison 
Psychologist  despite the literature on fallibility  of  self-reports, 
and  the  fallibility  and  unwitting  distortions  of  those   making 
judgments  in  such contexts has been consistently  documented  within 

    'The  previous review of this field (Slovic, Fischoff  & 
    Lichtenstein  1977)  described  a  long  list  of  human 
    judgmental    biases,   deficiencies,   and    cognitive 
    illusions. In the intervening period this list has  both 
    increased   in  size  and  influenced  other  areas   of 
    psychology  (Bettman 1979, Mischel 1979, Nisbett &  Ross 

    H. Einhorn and R. Hogarth (1981)

The following are also taken from the text:

    'If  one  considers  the rather  typical  findings  that 
    clinical judgments tend to be (a) rather unreliable  (in 
    at least two of the three senses of that term), (b) only 
    minimally  related  to  the  confidence  and  amount  of 
    experience  of the judge, (c) relatively  unaffected  by 
    the  amount of information available to the  judge,  and 
    (d)  rather  low in validity on an  absolute  basis,  it 
    should come as no great surprise that such judgments are 
    increasingly   under  attack  by  those  who   wish   to 
    substitute  actuarial prediction systems for  the  human 
    judge  in many applied settings....I can summarize  this 
    ever-growing  body  of literature by pointing  out  that 
    over  a  very  large array of  clinical  judgment  tasks 
    (including by now some which were specifically  selected 
    to show the clinician at his best and the actuary at his 
    worst),  rather simple actuarial formulae typically  can 
    be constructed to perform at a level no lower than  that 
    of the clinical expert.'

    L. R. Goldberg (1968)
    Simple models or simple processes?
    Some research on clinical judgments
    American Psychologist, 1968, 23(7) p.483-496

    'The  various  studies can thus be  viewed  as  repeated 
    sampling  from  a uniform universe  of  judgement  tasks 
    involving   the  diagnosis  and  predication  of   human 
    behavior.  Lacking  complete knowledge of  the  elements 
    that constitute this universe, representativeness cannot 
    be determined precisely. However, with a sample of about 
    100  studies  and the same outcome  obtained  in  almost 
    every  case,  it  is reasonable  to  conclude  that  the 
    actuarial  advantage is not exceptional but general  and 
    likely  to  encompass many of  the  unstudied  judgement 
    tasks.  Stated  differently,  if one  poses  the  query:  
    Would an actuarial procedure developed for  a particular 
    judgement  task (say, predicting academic success at  my 
    institution) equal or exceed the clinical method?",  the 
    available research places the odds solidly in favour  of 
    an affirmative reply. "There is no controversy in social 
    science  that shows such a large body  of  qualitatively 
    diverse studies coming out  so this  one 
    (Meehl J. Person. Assess, 50,370 (1986)".' 
The distinction between collecting observations and integrating it  is 
further brought out vividly by Meehl (1989):

    'Surely  we  all know that the human brain  is  poor  at 
    weighting  and  computing.  When  you  check  out  at  a 
    supermarket you don't eyeball the heap of purchases  and 
    say to the clerk, "well it looks to me as if it's  about 
    $17.00 worth; what do you think?" The clerk adds it  up. 
    There   are   no  strong   arguments....from   empirical 
    studies.....for  believing that human beings can  assign 
    optimal  weight in equations subjectively or  that  they 
    apply their own weights consistently.'

    P. Meehl (1986)
    Causes and effects of my disturbing little book  
    J Person. Assess. 50,370-5,1986
    'Distributional information, or base-rate data,  consist 
    of  knowledge  about  the distribution  of  outcomes  in 
    similar  situations.  In predicting the sales of  a  new 
    novel, for example, what one knows about the author, the 
    style,  and  the plot is singular  information,  whereas 
    what   one   knows  about  the  sales   of   novels   is 
    distributional information. Similarly, in predicting the 
    longevity   of  a  patient,  the  singular   information 
    includes  his  age, state of health,  and  past  medical 
    history, whereas the distributional information consists 
    of  the  relevant population  statistics.  The  singular 
    information  consists  of the relevant features  of  the 
    problem  that  distinguish  it from  others,  while  the 
    distributional  information characterises  the  outcomes 
    that  have  been observed in cases of the  same  general 
    class.  The present concept of distributional data  does 
    not  coincide  with  the Bayesian  concept  of  a  prior 
    probability  distribution. The former is defined by  the 
    nature  of  the data, whereas the latter is  defined  in 
    terms of the sequence of information acquisition.
    The  tendency to neglect distributional information  and 
    to  rely mainly on singular information is  enhanced  by 
    any  factor that increases the perceived  uniqueness  of 
    the problem. The relevance of distributional data can be 
    masked  by detailed acquaintance with the specific  case 
    or by intense involvement with it........

    The   prevalent   tendency  to  underweigh   or   ignore 
    distributional information is perhaps the major error of 
    intuitive     prediction.    The    consideration     of 
    distributional   information,   of  course,   does   not 
    guarantee  the accuracy of forecasts. It does,  however, 
    provide  some protection against completely  unrealistic 
    predictions.  The  analyst should therefore  make  every 
    effort  to  frame  the  forecasting  problem  so  as  to 
    facilitate utilising all the distributional  information 
    that is available to the expert.'

    A. Tversky & D. Kahneman (1983)
    Extensional Versus Intuitive Reasoning: The  Conjunction 
    Fallacy  in  Probability Judgment  Psychological  Review 
    v90(4) 1983

    'The  possession  of  unique  observational   capacities 
    clearly implies that human input or interaction is often 
    needed  to  achieve maximal predictive accuracy  (or  to 
    uncover  potentially useful variables) but tempts us  to 
    draw an additional, dubious inference. A unique capacity 
    to  observe  is  not the same as a  unique  capacity  to 
    predict on the basis of integration of observations.  As 
    noted  earlier, virtually any observation can  be  coded 
    quantitatively and thus subjected to actuarial analysis. 
    As Einhorn's study with pathologists and other  research 
    shows,  greater accuracy may be achieved if the  skilled 
    observer  performs this function and then  steps  aside, 
    leaving  the interpretation of observational  and  other 
    data to the actuarial method.'
    R. Dawes, D. Faust and P. Meehl (1989)

see for elaboration.

David Longley (check end reply line #)

Longley Consulting                                                  London, UK
Behaviour Assessment & Profiling Technology,
Research, Data Analysis and Training Services,
Small IT Systems                      

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