Dear Ken and Terence,


   - The work of Manfredo Massironi to which I refer is a corpus of
   experimental investigations on the subject of *expressiveness*, in
   particular expressiveness of *causal**ity*. His paper (in Italian) can
   be downloaded at

   http://ephp.dpac.univr.it/ephp_db/javapages/util/get.jsp?bibliography=3825
   - Massironi specified that the term *expressiveness *is broader than *
   expression*: in fact it refers to a content we relate to an object, with
   no correspondance to a process of expression *stricto sensu*, for
   example:

a weeping willow conveys the expressiveness of sadness, even though there
is no actual feeling of sandness in the tree
 same thing happens in the succession of the colors of a sunset: the
objectitself (succession of colors) has
no emotions.

However there is a *structural isomorphism* with the "feeling of sadness"
pattern, and from this comes out our impression.

   - So not always there is a coincidence between the actual expression (and
   its communication purpose) and the expressiveness the observer receives
   (on a merely phenomenological level): indeed at times there is a real
   discrepancy.
   - The same is true for the *expressiveness of causality*. One thing is
   the causality in the physical world, another is the impression that the
   viewer receives (both of you have made this comment about my examples, it
   means that they are clear!). *Massironi states: for designers is
not interesting
   to learn how to control the physical causality, but to learn how to control
   the expressiveness of causality: to predict and control the causality
   experienced by the observer.*
   - Massironi is not satisfied neither with the simple, spontaneous or
   intuitive production of forms which express the causality, nor with
   their production on the basis of a wide range of empirical knowledge (the
   taxonomy of Terence?).
   - Massironi wonders: *how** can **we obtain and control, through a
   systematic research, the main variables that predict the expressiveness of
   causality in the observer?*
   - Earlier (in 1947), Michotte  had studied the expressiveness of
   causality. However, was limited to the physical variables that produce it
   , rather than focussing on the phenomenological ones.
   Twenty years after, Massironi develops the work of Michotte, shifting
   the focus on the phenomenological variables: thanks to those, merely on
   the perceptual level, you can find an immediate experience of
causalityin the observer.
   - Massironi has demonstrated that, together with variables relevant to
   specific situations (*hic et nunc*), there are more general variables of
   the form, present in different cultural contexts, which allow us to
   control the perception of causal relations in visual situations.
   Therefore, these variables must be identified and explained.
   - The paper above, and more modestly the visual examples of my
pinboard, explain
   *the** variables which cause the perception of causal relationships in
   the observer.*
   If you are interested in this approach, and you think it is useful to
   develop the discussion, I will be pleased to provide more explanation
   about this branch of studies.

Best regards
Paola Trapani