| Title & Author | Abstract | |
|---|---|---|
| 12(017) | THE PUZZLE OF MIRROR REVERSAL: A VIEW FROM CLOCKLAND
Target Article by Navon on Mirror-Reversal David Navon dnavon@psy.haifa.ac.il |
Abstract:
Why is it that when we view an image in a mirror parallel
to the object's front, we are aware of a left-right reversal but
not of a top-bottom reversal, though the mirror does not optically
discriminate between the two axes? An elaborate exposition of ideas
formerly proposed by Navon (1987) is presented. It notes that the
real source of the perception of reversal is not the one suggested
by naive cause attribution: Whereas the mirror does not
discriminate between frontal axes, frontal encounters do. Mirror
images thus appear to be reversed along a planar axis - the
horizontal one, in our ecology - because they suggest a
prototypical frontal encounter, yet deviate from it in a lawful
manner. The deviation is due to the fact that, unlike in mirror
viewing, in any frontal encounter, homologue intrinsic sides are
opposite to each other only along one planar axis. The
distinguished axis, namely that particular axis whose homologue
poles ARE opposite to each other in a prototypical frontal
encounter within a given ecology, would constitute there the
mirror-invariant axis. A generalization to other coordinate
systems, other encounters and other ecologies follows. Finally,
other accounts of the issue are critically reviewed.
Keywords: spatial cognition, mirror vision, mirror reversal, left-right reversal, perceptual frame of reference, object perception, frontal encounter. |
| 12(031) | THE EFFECT OF MIRROR-REFLECTION ON CHIRALITY AND HANDEDNESS CAN
BE EXPLAINED WITHOUT SOCIAL PSYCHOLOGY Commentary on Navon on Mirror-Reversal Dr Neil Burgess Inst. of Cognitive Neuroscience & Dept. of Anatomy University College London 17 Queen Square, London WC1N 3AR, U.K. n.burgess@ucl.ac.uk |
Abstract:
The intrinsic handedness of an object depends on its
physical organisation along all axes, and is reversed by reversal of
its organisation along any one axis. The attribution of top and
bottom or front and back depends solely on the object's organisation
along the axes to which they refer. Mirror reflection reverses
organisation along the axis perpendicular to the mirror, and so also
reverses intrinsic handedness, but does not affect locations along
the axes parallel to it. Attempting to label one of the axes as
'left-> right' in terms of the intrinsic handedness of the object is
mistake in that these labels are reversed by mirror reflection,
producing an apparent reversal along this axis.
Keywords: spatial cognition, mirror vision, mirror reversal, left-right reversal, perceptual frame of reference, object perception, frontal encounter. |
| 12(032) | WHY MIRRORS REVERSE LEFT AND RIGHT
Commentary on Navon on Mirror Reversal Michael C. Corballis Department of Psychology University of Auckland Private Bag 92019 Auckland New Zealand m.corballis@auckland.ac.nz |
Abstract:
Navon (2001) suggests that we interpret our reflection in
a mirror as a left-right reversal because it suggests a frontal
encounter, yet the image deviates from how we would look if in the
same position. I argue that this interpretation involves an
arbitrary act of mental rotation, and is overly restrictive. I
suggest that the more general reason why we interpret enantiomorphs
of objects as the left-right reversal of the original objects has
to do with the fact that left and right sides can only be defined
once the other canonical axes (top-bottom, back-front) have been
established.
Keywords: spatial cognition, mirror vision, mirror reversal, left-right reversal, enantiomorphs, perceptual frame of reference, object perception, frontal encounter |
| 13(005) | FROM PIAGET'S ASSIMILATING MIND TO NAVON'S CLOCKLAND: TOWARDS A
CATEGORICAL ACCOUNT OF MIRROR VISION. Commentary on Navon on Mirror-Reversal Eric Laurent Laboratoire "Sport et Adaptation", IFR Marey Université de La Méditerranée 163 Avenue de Luminy 13009 Marseille France El@nomade.fr |
Abstract:
In this commentary I discuss Navon's interpretation
(2001) of mirror reversal in "perception". In his framework, Navon
emphasizes the notion of prototypicality for explaining left-right
reversal awareness. I argue that in any domain of life, it is a
common phenomenon to process information with respect to background
knowledge. From Piaget's assimilation view to Navon's left-right
reversal of mirror perception, the evidence of prototypicality
effects on reversal awareness is reviewed. It is concluded that
Navon's view is plausible but subject to some object-related
constraints.
Keywords: Prototypicality, categorical perception, assimilation, mirror vision, left-right reversal, frontal encounter, symmetry, critical perceptual features. |
| 13(011) | IT TAKES TWO FOR AN INVERSE RELATIONSHIP
Reply to Burgess on Navon on Mirror-Reversal David Navon dnavon@psy.haifa.ac.il |
Abstract:
Burgess (2001) discusses, in his words, "the effect of
mirror reflection on chirality and handedness". In my view, the
known effect of mirror optics on what it shows is part of the
question addressed in the target article, not the answer to it. The
phenomenon in question is the cognition of mirror viewers that
what they see in it in a frontal view reverses position along the
horizontal axis of the facet facing the mirror plane. The puzzle is
why that is true only of that planar axis GIVEN what we know about
mirror optics. Both the account of the phenomenon and the solution
of the puzzle are argued to transcend the optics of the mirror.
Following that, Burgess' claim that the puzzle is
notation-dependent is shown to be false.
Keywords: spatial cognition, mirror vision, mirror reversal, left-right reversal, perceptual frame of reference, object perception, frontal encounter, enantiomorphs, chirality, handedness |
| 13(012) | IT IS NOT ALL IN OUR MIND
Reply to Corballis on Navon on Mirror-Reversal David Navon dnavon@psy.haifa.ac.il |
Abstract:
That people see left-right reversal in various mirror
positions suggests to Corballis (2001) that the reversal is not due
to any geometric relationship but rather to some cognitive
disposition. It is argued here that though the spatial
relationship between real-world enantiomorphs greatly vary, a
viewer and her mirror counterpart are bound in a specific spatial
relationship determined uniquely by mirror position. When that
position optically reverses the transversal axis, the perception of
left-right reversal has a straightforward, physical account. Thus,
the locus of the puzzle is in the case in which that condition is
not met, namely in a frontal view. In that view a viewer judges her
image in the mirror not by its relationship with her facet which
faces the mirror but rather with the putative image of the latter
in a frontal encounter. That entails left-right reversal. The
cognitive disposition account is argued to be incomplete and
doubtfully more parsimonious.
Keywords: spatial cognition, mirror vision, mirror reversal, left-right reversal, perceptual frame of reference, object perception, frontal encounter, enantiomorphs, handedness |
| 13(013) | RECOGNIZING LEFT-RIGHT REVERSAL FOR WHAT IT IS
Reply to Laurent on Navon on Mirror-Reversal David Navon dnavon@psy.haifa.ac.il |
Abstract:
Detecting a deviation from a schema is most often
perceptual. The process of accounting for the deviation, on the
other hand, is not mandatory and might require post-perceptual
processing. I agree with Laurent (2002) that recognizing as
left-right inversion the deviation of a mirror view from the schema
of frontal encounter might sometimes require post-perceptual
processing, especially when it concerns the viewer's own body, let
alone when it is done for the first time.
Keywords: spatial cognition, mirror vision, mirror reversal, left-right reversal, perceptual frame of reference, object perception, frontal encounter, prototypicality, schema |