Aging, Neuropsychology, and Cognition, 15: 281–301, 2008 http://www.psypress.com/anc ISSN: 1382-5585/05 print; 1744-4128 online DOI: 10.1080/13825580701336874 © 2007 Psychology Press, an imprint of the Taylor & Francis Group, an Informa business NANC 1382-5585/05 1744-4128 Aging, Neuropsychology, and Cognition, Vol. 00, No. 0, April 2007: pp. 1–25 Aging, Neuropsychology, and Cognition Identity and Location Priming Effects and their Temporal Stability in Young and Older Adults Identity and Location Priming Effects s. j. troche et al. S. J. TROCHE, H. GIBBONS, AND T. H. RAMMSAYER Georg Elias Müller Institute for Psychology, University of Göttingen, Göttingen, Germany ABSTRACT Unlike previous studies, the present experiment was designed to directly compare negative (NP) and positive priming (PP) in 37 young (mean age: 21.5 years) and 37 older adults (mean age: 69.4 years) by means of two independent identity- and loca- tion-based priming tasks. While identity PP was shown to be reduced in older adults, no age-related differences were found for location PP. This pattern of results supports the notion that mechanisms involved in identity- and location-based PP are largely independent of each other. Both age groups exhibited reliable identity and location NP although location NP was decreased in older adults. Extremely low temporal test–retest coefficients indicated that mechanisms underlying identity and location NP represent situational states rather than stable traits. This lack of tempo- ral stability may also account for highly ambiguous results obtained in previous studies. INTRODUCTION In priming tasks, two stimuli are presented on each display and participants are required to respond to one of these stimuli (target) and to ignore the other (distractor). In so-called ignored-repetition (IR) conditions a stimulus becomes target that was ignored on a preceding prime display. It was fre- quently reported that response latencies are delayed and error rates enhanced in those conditions. This effect is called negative priming (NP). Positive priming (PP), on the other hand, refers to the phenomenon that response latencies are shortened and error rates diminished when the target stimulus on a probe display was the same stimulus on an immediately preceding prime display. Several theories offer different explanations of priming Address correspondence to: Stefan Troche, Georg Elias Müller Institute for Psychology, University of Göttingen, Gosslerstr. 14, D-37073 Göttingen, Germany. E-mail: stroche@uni-goettingen.de