Subjects exposed to lists of semantically related words falsely remember nonstudied words that are associated with the list items (e.g., Deese, 1959; Roediger & McDermott, 1995). To determine if subjects would demonstrate this false memory effect if they were unable to recognize the list items, we presented lists of semantically related words with or without a concurrent memory load at rates of 2 s, 250 ms, or 20 ms per word (Experiment 1, between-subjects design) and 2 s or 20 ms per word (Experiment 2, within-subjects design). We found that the subjects falsely recognized semantically related nonstudied words in all conditions, even when they were unable to discriminate studied words from unrelated nonstudied words. Recognition of list items was unnecessary for the occurrence of the false memory effect. This finding suggests that this memory illusion can be based on the nonconscious activation of semantic concepts during list presentation.

Repetition blindness (RB) refers to the reduced performance in reporting a repeated as opposed to a nonrepeated item in rapid serial visual presentation. In Experiment 1, we found RB for two-item stimuli in uncertain locations. The magnitude of RB decreased significantly with increases in interstimulus interval, but not with increases in spatial separation, indicating that RB is determined primarily by temporal factors. In Experiment 2, we found RB when subjects were required to report only the second of two successively presented items. The magnitude of RB increased with the duration of the first item, indicating that RB is determined by the encoding effectiveness of the first item. The results of this study collectively indicate that RB is not a memory or a sensory phenomenon, but rather a perceptual phenomenon occurring at the stage of identity encoding. The findings also undermine the arguments (Kanwisher, 1987) that have been offered in favor of the type-token binding failure hypothesis and indicate instead that type-node refractoriness may be the cause of RB.

A color-word matching task was used to investigate the basis of Stroop interference. Subjects were shown a pair of stimuli: an ink color (e.g., a red bar) and a colored word (e.g., RED printed in red or blue) and decided whether the two items had the same meaning (meaning decisions) or whether they had the same surface color (visual decisions). In Experiment 1, the two stimuli were shown simultaneously, and conflicting visual information of the word (e.g., RED printed in blue, against a red bar) led to interference in meaning decisions, whereas conflicting verbal information (e.g., BLUE printed in red, against a red bar) produced no interference in visual decisions. In Experiment 2, as an increasing time interval was imposed between presentation of the color bar and the colored word, interference in meaning decisions diminished, whereas interference in visual decisions was established. These results suggest that semantic competition, not response competition, is the major source of Stroop and Stroop-like interference.One of the most popular tasks for studying the relationship of word reading, object naming, and selective attention is the Stroop colorword task (Stroop, 1935). In the Stroop task, subjects are asked to name the color of a color patch or the color of a colored word. Relative to naming a color patch, subjects often show a large delay in naming the color in which a color word is printed (e.g., blue in red ink). The Stroop effect is highly robust and has been demonstrated for a variety of stimulus materials and experimental tasks (see MacLeod, 1991, for a comprehensive review). The mechanism underlying the Stroop effect is, however, far from clear, despite more than six decades of intensive investigation.There are two classic accounts of the Stroop phenomenon (MacLeod, 1991). The relative-speed-of-processing hypothesis (e.g., Morton & Chambers, 1973;Posner & Snyder, 1975) attributes Stroop interference to the fact that word reading is faster than color naming (e.g., Cattell, 1886;Theios & Amrhein, 1989). According to this account, when two potential responses, one from reading a word and one from naming an ink color, compete to be the response to be selected for output, the consequence is a delay in response production, especially when the response from the more rapid process is the one to be ignored. Note that the relative-speed-of-processing hypothesis places the locus of interference at the stage of response output.The second account, the automaticity hypothesis (e.g., LaBerge & Samuels, 1974;Shiffrin & Schneider, 1977), attributes Stroop interference to the fact that word reading is more automatic than color naming (e.g., Cattell, 1886;Posner & Snyder, 1975

What is the effect of retention interval on accurate and false recollection in the Deese, Roediger, and McDermott (DRM) procedure? Previous researchhas suggestedthat false recall is more persistent than accurate recall, but the recognition results have been inconsistent. In two parametric studies, we tested recall and recognition for the same DRM lists, over retention intervals that ranged from no delay to a 2-month delay. We found that accurate and false memory were diminished by increases in retention interval, false memory persistence was present for recall and recognition, greater persistence for false memory than for accurate memory was more readily observed for recall than recognition, and the highthreshold (P r ), signal detection (d9), and nonparametric (A9) recognition measures differed in their sensitivity for detecting change. The effect of retention interval on accurate and false memory is consistent with expectations from fuzzy trace theory. In the DRM procedure, truth is not more memorable than fiction.

This study showed that regardless of its actual status, a test item was more likely to be judged as old if, before making an old-new judgment, subjects attempted to (a) identify a test word or a test picture's name (Experiments 1 and 2), or (b) to work on a normally presented test word, such as reversing the letter order of the word or constructing a word that rhymed with the test word (Experiment 3). Experiment 1 replicated the enhanced feeling of recognition effect reported by M. Watkins and Z. F. Peynircioglu (1990). Experiment 2 extended the effect to a cross-modality priming situation. Experiment 3 further extended the finding by showing that the effect could occur for reasons having nothing to do with the perception of test items. Finally, Experiment 4 showed that increased exposure to test items alone cannot produce the enhanced feeling of recognition.

In this study, participants were asked to identify briefly presented 5-letter (Experiments 1-3) or 2-letter (Experiment 4) strings. Identical items in a repeated trial were identified worse than their counterparts in a nonrepeated trial, indicating repetition blindness (RB; N. G. Kanwisher, 1987). In Experiment 1, RB occurred regardless of whether items were presented successively or simultaneously. In Experiments 2-4, RB occurred regardless of whether 2 simultaneously presented items were spatially close or far apart. The magnitude of RB, however, varied with presentation mode and repetition lag: RB was smaller in simultaneous than successive presentation, and RB increased and then decreased with the number of items separating 2 identical ones. These results provide important constraints in the interpretation of RB. A model that attributes RB to the refractoriness of perceptual recognition units is proposed.

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