A. D. Rd and P. Armerina, Sicily, 4 th century A.D.) and have an echo in the mosaics of Ravenna, These are mainly documented in Roman mosaics Mausoleo di Galla Placidia

B. Vivarini, In two different panels the stick possesses and lacks a shadow, respectively. 33 Anonymous, Triumph of Love, Polittico di Conversano, pp.1432-1499, 1475.

R. Van-der-weiden, The Crucifixion (c. 1460), Philadelphia. 35 Vittore Carpaccio (1473-1526, Presentazione della Vergine al Tempio, pp.1400-1464

S. Crivelli and . Giacomo-della-marca, is the only case I am aware of an object that has both a neat cast imitating shadow and a small enhancing shadow; the two shadows are inconsistent. transparent films. However, the ecological phenomenology does not seem to support this description: shadows do not appear normally as being superposed to surfaces. 42 Anonymus, Adoration of the Magi

. Witz, Madonna col Bambino e Santi; Urbino. 47 Some of these shadows heavily blacken the area they are cast upon shadow from a character inverts the baseline luminosity of steps, Adoration of the Magi Gaudenzio Ferrari Presentazione di Maria Flagellation (c. 1455), pp.1400-1446

. Tarsie and U. Studiolo, In recent art, painters have made a deliberate use of an even more extreme device, that of orphan shadows with no object to cast them (not only an object in the painting, but most likely an object tout court). I can think here of Filippo de Pisis (1896-1956), Natura morta marina con la penna, shadows have no object casting them. Obviously, in order to categorize them as shadows we take stock of the fact that some objects do cast a shadow in the painting and that the latter are quite similar to the orphans, 1953.

G. Bellini, Pietà (c. 1465), Milan, Brera; the shadow of Christ " s left hand indicates a light on our side of the painting, Presentation of the Virgin at the Temple (1486-1490), pp.1430-1516

D. Biagio and . Antonio, Getty Museum, Los Angeles, which also provides an example of the two preceding categories Getty Museum, Los Angeles, has many reflections on water, clearly distinct from shadows: even the reflection of a shadow is present. 53 Violated (much later) e.g Adoration of the Magi, Galleria Nazionale dell " Umbria Perugia, where the shadow of right foot climbs right foot. This is also an example of a shadow that climbs a step, The Story of Joseph Convito in Casa di Simeone, Venezia, Accademia. 54 Violated e.g. by Eustachio di Jacopo di Cristoforo References A large bibliography on shadow cognition, as well as images of some of the items in the sample, can be found at www.shadowmill.com, pp.1445-15101581, 1485.

R. Arnheim, Art and Visual Perception, 1974.

M. Baxandall, Shadows and Enlightenment, 1995.

I. Biederman, Visual Image Understanding: Recent Research and a Theory, Computer vision, Graphics, and image Processing, pp.29-73, 1985.

W. L. Braje, G. E. Legge, and D. Kersten, Invariant Recognition of Natural Objects in the Presence of Shadows, Perception, vol.7, issue.4, pp.383-98, 2000.
DOI : 10.1068/p3051

K. Bühler, Die Erscheinungsweisen der Farben, 1922.

R. Casati, La scoperta dell'ombra, Milan: Mondadori. English trans The Shadow Club, 2000.

R. Casati, The Unity of the Kind Work of Art " " , on www.interdsciplines.org, a discussion devoted to Art and Cognition, Origgi and N. Arhika, 2002.

P. Cavanagh, Pictorial Art and Vision, MIT Encyclopedia of the Cognitive Sciences, pp.648-650, 1999.

K. Von-fieandt, Über Sehen von Tiefengebilden bei wechslender Beleuchtungsrichtung, 1938.

E. Hering, 1878, Zur Lehre vom Lichtsinne: Sechs Mittheilungen an die Kaiserl Akademie der Wissenschaften in Wien

J. M. Kennedy, A Psychology of Picture Perception, 1974.

D. Kersten, P. Mamassian, and D. C. Knill, Moving Cast Shadows Induce Apparent Motion in Depth, Perception, vol.7, issue.2, pp.171-192
DOI : 10.1068/p260171

E. W. Kirsch, The Visconti Hours, 1972.

P. Mamassian, Impossible shadows, IOVS, vol.40, p.414, 1999.

F. Quiviger, Postural sense and human figure in Renaissance art " , on www.interdsciplines.org, a discussion devoted to Art and Cognition, Origgi and N. Arhika, 2002.

E. Panofsky, Iconography and iconology, Studies in Iconology, 1939.

V. Ramachandran, Perceiving Shape from Shading, Scientific American, vol.259, issue.2, pp.76-83, 1988.
DOI : 10.1038/scientificamerican0888-76

L. Talmy, Fictive motion in language and " ception Language and Space, pp.211-276, 1997.

K. Toyama, La Fuga in Egitto " di Giovanni di Paolo riesaminata: luce, ombre portate, pp.477-482, 1997.

B. Tversky, Where partonomies and taxonomies meet, Meanings and Prototypes: Studies in Linguistic Categorization, pp.334-344, 1990.