Interference From Multi-dimensional Objects During Feature and Conjunction Discriminations Lisa R. Fournier, Christopher Bowd, and Rhonda J. Herbert Washington State University, Pullman, Washington, U.S.A. Feature discrimination performance within an attended object and interference from irrele- vant, multi-dimensional objects (distractors) were examined in a two-choice, response com- patibility paradigm. Results showed that the amount of interference by multi-dimensional distractors was dependent on three factors: (1) the discriminability of the incompatible, task- relevant distractor features; (2) the number of incompatible, task-relevant distractor features; and (3) whether the task-relevant, incompatible features matched the task goals. The most interesting ®nding was that additive priming effects were found for multiple, task-relevant features that matched the task goals, whether these features were present in the attended object or in the ignored object. Models that assume that each task-relevant feature primes its corresponding decision/response asynchronously and that this priming is combined to meet a decision/response criterion (at least when attended) can account for distractor interference during conjunction discriminations. Implications of these ®ndings for feature integration models, template models, and a response selection model are discussed. It is generally assumed that task complexity increases when two or more features must be determined to match a particular stimulus category relative to one feature (Wickens, 1984). Also, common sense suggests that comparing more information should require more time or may be time limited by the most dif®cult comparison. However, Fournier, Eriksen, and Bowd (1998) provide evidence that is inconsistent with such predictions. They had observers judge the presence or absence of one or two target features within an object. The object was a letter that varied in colour (red or green) and shape (H or K), and colour was easier to discriminate than shape. They found that judging the presence of the colour-shape conjunction was faster and more accurate than judging the presence of the less discriminable target feature of shape alone. Faster present responses for conjunctions relative to the less discriminable feature are referred to as ``conjunction bene®ts’’. Also, absent responses, required when one or both target features were not present within an object, showed similar response patterns for single and conjunction feature judgements, THE QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY, 2000, 53A (1), 191±209 Request for reprints should be sent to Lisa R. Fournier, Department of Psychology, Washington State University, Pullman, WA 99164±4820, U.S.A. Email: fournier@wsunix.wsu.edu We thank Brian Dyre, Bernhard Hommel, Kyle Cave, and Bob Patterson for their comments and suggestions concerning this manuscript. q 2000 The Experimental Psychology Society