Object identification: The mental representation of physical and conceptual attributes

In two experiments, subjects indicated whether two pictures of famih’ar objects were equiv-alent. The picture pairs were identical, showed the same object in various perspectives and states, or showed different objects with varying degrees of conceptual relatedness. In Experi-ment 1, the equivalence criterion for judging the picture pairs was varied between subjects (identity of pictures; conceptual equivalence of objects at subordinate, basic, or superordinate level}. The reaction times of the four subject groups suggest that a pictorial stimulus is not al-ways mentally represented in the same way, and that the instructions given determine which attributes of the stimulus are represented. In Experiment 2, the visual similarity of the picture pairs was varied. The results indicate, at least with a basic-level equivalence instruction, that not only perceptual, but also non-perceptual, functional attributes are represented--namely, those that, according to Rosch et al. {1976}, are common to the members of a superordinate category. Object identification is a quasi-automatic, virtually instantaneous process that is fairly inaccessible to intro-spection. It is one of the most ubiquitous, if not basic, processes of cognition and a component process of any more complex action. Object identification may not, however, be a unitary process. Presumably, object identification comprises several subprocesses of informa-tion transformation, reduction, and elaboration inter-relating different mental codes representative of differ-ent forms of identification. In recent years, a number of investigators have made use of picture-matching tasks to study the process of object identification. The experimental paradigm used originated from Posner and Mitchell’s (1967)influential study of letter matching. Drawing from this research