Daskagianni, Evangelie.

A total of 96 adults (mean age 23.5 years) solved simple arithmetic problems in digit and verbal format, using Siegler's choice, no-choice method. In the choice condition, they produced the answer and gave a self report of how they solved it. In the no-choice condition, they were asked to use only retrieval. Naming latencies of numerals in both formats were assessed. Verbal problems were solved more slowly than digit problems in all conditions but format did not interact with problem size effect for reaction times. This latter result does not support an effect of presentation format on calculation processes. Participants also named faster digits than verbal numerals. Smaller reaction times and three times as many errors were associated with the no-choice compared to the choice condition. Mathematical aptitude also had an effect. High arithmetic skill was related to smaller reaction times, more retrieval use and fewer errors.

Recent research in visual object recognition has shown that context can facilitate object recognition. This study assessed the effect of self-relevant familiarity of context in object recognition. Participants performed a task in which they had to recognize degraded objects shown under varying levels of contextual information. The level of degradation at which they could successfully recognize the target object was used as a measure of performance. There were five contextual conditions: (1) no context, (2) context, (3) context and size, (4) context and location, (5) context, size and location. Within each contextual condition, we compared the performance of "Expert" participants who viewed objects in the context of their own house and "Novice" participants who viewed those particular settings for the first time. Ratings were performed to assess each object's consistency, frequency, position consistency, typicality and shape distinctiveness. Object's size was the only contextual info rmation that did not affect performance. Contextual information significantly reduced the amount of bottom-up visual information needed for object identification for both experts and novices. An interaction (Contextual Information x Level of Familiarity) was observed. Expert participants' performance improved significantly more than novice participants' performance by the presence of contextual information. Location information affected the performance of expert participants, only when objects that occupied stable positions were considered. Both expert and novice participants performed better with objects that rated high in typicality and shape distinctiveness. Object's consistency, frequency and position consistency did not seem to affect expert participants' performance but did affect novice participants' performance.