Orientation priming of grasping decision for drawings of objects and blocks, and words
Hanna Chainay
Lucie Naouri
Alice Pavec
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) Laboratoire d'Etude des Mcanismes Cognitifs, Universit Lumire Lyon 2
, 5 avenue Pierre Mendes France, 69676, Bron cedex,
France
This study tested the influence of orientation priming on grasping decisions. Two groups of 20 healthy participants had to select a preferred grasping orientation (horizontal, vertical) based on drawings of everyday objects, geometric blocks or object names. Three priming conditions were used: congruent, incongruent and neutral. The facilitating effects of priming were observed in the grasping decision task for drawings of objects and blocks but not object names. The visual information about congruent orientation in the prime quickened participants' responses but had no effect on response accuracy. The results are discussed in the context of the hypothesis that an object automatically potentiates grasping associated with it, and that the on-line visual information is necessary for grasping potentiation to occur. The possibility that the most frequent orientation of familiar objects might be included in object-action representation is also discussed.
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Performance of an object-directed action can be seen to
be based on two different types of processing: one using
conceptual knowledge about the object, the other using
visual information independent of the conceptual
knowledge. Some cognitive models have proposed that action
may be evoked without access to the conceptual
knowledge (e.g., Riddoch, Humphreys, & Price, 1989),
insofar as perceptual information contained in a visually
presented object is sufficient for action selection (Rumiati
& Humphreys, 1998; Humphreys & Riddoch, 2003).
However, more and more evidence suggests that
conceptual information and visual information are combined to
ensure correct use of an object (Chainay & Humphreys,
2002; for a review see Borghi, 2005). Tucker and Ellis
(1998) have proposed that observing an object, even when
it is not a target for action, could automatically activate
motor representations appropriate for reaching, grasping
and manipulating it. Furthermore, they proposed that
visual object representation includes motor patterns
associated with action it affords (Ellis & Tucker, 2000).
Numerous behavioural studies involving visuo-motor
priming (e.g., Craighero, Fadiga, Rizzolatti, & Umilta,
1998) and a stimulus-response compatibility paradigm
have supported the idea that seeing an object re-activates
action knowledge associated with it and results in the
generation of affordance effects (Tucker & Ellis, 1998,
2001; Phillips & Ward, 2002; Hommel, 2002; Derbyshire,
Ellis, & Tucker, 2006).
On the other hand, neuroimaging studies have provided
evidence that cortical representation of tools and
manipulable objects activates motor-related areas (e.g.,
CreemRegehr, 2009; Gerlach, Law, & Paulson, 2002; Grafton,
Fadiga, Arbib, & Rizzolatti, 1997). Creem-Regehr & Lee
(2005) pointed out that objects can have multiple
affordances that define how they can be grasped. However, familiar
objects such as tools have one specific use associated with
their identity and that may constrain action representation.
In their fMRI study, participants viewed images of 3D tools
and 3D graspable shapes (cone, cylinder) presented in
different orientations, or imagined grasping them. For
imagined grasping, the region of activation observed in
the left posterior parietal cortex was larger for tools than for
graspable shapes. Activation for tools was also observed in
the middle temporal gyrus and fusiform gyrus. It is thought
that these regions have a special role to play in the
generation of actions based on internal representations
related to the functional identity of objects.
Of particular interest for the re-activation of action
knowledge associated with an object is the influence of
its orientation with respect to grasping decisions. The
orientation of an object, along with its location, is a
viewpoint-dependent object property that varies
continuously as the object or the observer moves. This kind of
information is particularly important for real-time
processing when actual grasping is required and a precise
parameterisation of the particular grasp is crucial. When
grasping is not required, however, the information about
object orientation does not seem to be particularly
relevant for action potentiation of a certain type of grasp.
Tucker and Ellis (2004) proposed that intrinsic properties
such as object size and shape are especially important for
re-activating an appropriate type of grasp. However, they
did not rule out the possibility that our knowledge of
familiar objects and their usual orientation may also
provide information about the type of grasp required.
More recently, Derbyshir, Ellis, and Tucker (2006), failed
to find the compatibility effect between object orientation
and hand used to respond, and questioned this possibility.
One of the aims of the present study is to investigate
whether the orientation of (...truncated)