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Abstract

There is plenty of evidence that object recognition is orientation-dependent, but there is still considerable debate why recognition performance depends on orientation. It was proposed that recognition relies on an adjustment of a perceptual reference frame [Graf, 2002 Form, Space and Object. Geometrical Transformations in Object Recognition and Categorization (Berlin: Wissenschaftlicher Verlag)]--so that the recognition of disoriented objects would be facilitated if it is preceded by a different object in the same orientation. These orientation congruency effects were demonstrated previously for letters (Jolicoeur, 1990 Journal of Experimental Psychology: Human Perception and Performance 16 351 - 364) and for novel objects (Gauthier and Tarr, 1997 Perception 26 51 - 73), but not yet for common objects. Two objects from different categories were presented in close temporal contiguity in brief masked displays, either in the same or in different picture plane orientations. Subjects were required to name the objects. The main dependent measure was the number of errors. Line-drawings of twenty-four common objects were employed. Presentation times for the second object were individually adjusted before the test phase such that accuracy was at 80, when using a different set of objects. Naming accuracy was significantly higher when the orientation of the second object was congruent with the orientation of the previously presented object. Thus, an orientation congruency effect could be demonstrated also with common objects from different basic-level categories. The results suggest that the recognition of disoriented objects involves an adjustment of an abstract frame of reference which facilitates the recognition of different objects in the same orientation. This finding provides further important constraints for any model of object recognition.