Referential expressions often contain more information than what is strictly necessary for unique identification of the entity the expression refers to. If this extra information slows down the identification process, then this would suggest a violation of one of the Gricean maxims in the category quantity. A perception experiment was conducted in which overspecification was defined exophorically as the elements of referential expressions that denote non-uniquely identifying information of entities in a particular task environment. In the experiment, identifying information either related to object characteristics (size, color, shape) or location (on vertical or horizontal axis). The results of the experiment provide information about the effect of overspecification on the identification time. Overspecified expressions lead to faster identification when they allowed the reader (i) to fully complete a mental image of the entity and (ii) to delimit search behavior to a specific part of the task context. Extra information about vertical location (top, bottom) proved more efficient than extra information about horizontal location (left, right).