Ss classified visually presented verbal units into the categories "in your vocabulary" or "not in your vocabulary." The primary concern 01' the experiment was to determine if making a prior decision on a given item affects the latency 01' a subsequent lexical decision for the same item. Words 01' both high and low frequency showed a systematic reduction in the latency 01' a lexical decision as a consequence 01' prior decisions (priming) but did not show any reduction due to nonspecific practice effects. Nonwords showed no priming effect but did show shorter latencies due to nonspecific practice. The results also indicated that many (at least 36) words can be in the primed state simultaneously and that the effect persists for at least 10 min. The general interpretation was that priming produces an alteration in the representation 01' a word in memory and can facilitate the terminal portion 01' the memory search process which is assumed to be random.Some recent experiments Meyer, Schvaneveldt, & Ruddy, 1972) have demonstrated semantic priming effects in memory using a word-nonword classification task. The results indicate that Ss can make faster lexical decisions for primed, as cornpaired to unprimed, words. One such priming technique (Meyer et al, 1972) consists of sequentially presenting a pair of semantically related words, e.g., BREAD-BUTTER, and requiring a lexical decision for each. A positive decision for BUTTER is faster if preceded by BREAD than if preceded by an unassociated word such as NURSE. The priming technique in a word-nonword classification task appears to offer a very general and useful method for identifying an d measuring characteristics of the functional organization of memory.Another kind of priming effect was suggested in a tachistoscopic recognition experiment by Morton (1964) in which Ss often mistakenly responded with words which had occurred on some earlier trial. This result suggests the possibility of a temporary alteration in the status of a memory representation which makes the item more accessible. The concern of the present experiment was to investigate priming which might result from making a lexical decision about the same letter string more than once during aseries of trials. A priming effect based on repetition would indicate that a memory representation may be altered, at least temporarily, simply by its activation. The repetition technique would also have the advantage of allowing for the comparison of priming effects for words and nonwords as a means of investigating possible differences in memory representations for these types of items. Two further objectives of the present study were to determine if *The present experiment was partially supported by funds from the Oklahoma State University Research Foundation.tRequests for reprints should be sent to Gary B. Forbach, who is now at the Department 01' Psychology, Washburn University, Topeka, Kansas 66621. several items would be in the primed state simultaneously and to investigate nonspecific practice effects, the effect on...

Repetition blindness (RB) may reveal a new limitation on human perceptual processing. Recently, however, researchers have attributed RB to postperceptual processes. The standard rapid serial visual presentation (RSVP) paradigm used in most RB studies is open to such objections. The "single-frame" paradigm introduced by J. C. Johnston and B. L. Hale (1984) allowed investigation of RB with minimal memory demands. Participants made a judgment about whether 1 masked target word was the same or different than a posttarget probe. Confidence ratings permitted use of signal detection methods. In the critical condition for RB, a precue of the posttarget word was provided prior to the target stimulus so that the required judgment amounted to whether the target did or did not repeat the precue word. In control treatments, the precue was an unrelated word or a dummy. Results showed that perceptual sensitivity was significantly reduced in the RB condition relative to baseline control conditions. The data showed that RB can be obtained under conditions in which memory problems are minimal and perceptual sensitivity is assessed independently of biases. RB therefore can be a perceptual phenomenon.

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A visual prime succeeded by a brief target produces a paradox. Namely, target repetition yields poorer identification accuracy and shorter duration judgments than unrelated prime-target pairs. Experiment 1 manipulated stimulus onset asynchrony to learn when repetition blindness is maximized. Experiments 2 and 3 manipulated expectancy of repetitions through changes in the proportion of repeated trials and instructions, respectively. Results indicate that repetition blindness is influenced by subject strategies and that the change is not mediated by response bias. Experiment 4 showed that increasing the spatial distance between prime and target reduced but did not eliminate repetition blindness. The current data support joint explanation of repetition blindness in terms of perceptual capture (prime-target fusion) and token individuation failure (problems in encoding episodic reoccurrences of an event).

Four experiments tested whether repetition blindness (RB; reduced accuracy reporting repetitions of briefly displayed items) is a perceptual or a memory-recall phenomenon. RB was measured in rapid serial visual presentation (RSVP) streams, with the task altered to reduce memory demands. In Experiment 1 only the number of targets (1 vs. 2) was reported, eliminating the need to remember target identities. Experiment 2 segregated repeated and nonrepeated targets into separate blocks to reduce bias against repeated targets. Experiments 3 and 4 required immediate "online" buttonpress responses to targets as they occurred. All 4 experiments showed very strong RB. Furthermore, the online response data showed clearly that the 2nd of the repeated targets is the one missed. The present results show that in the RSVP paradigm, RB occurs online during initial stimulus encoding and decision making. The authors argue that RB is indeed a perceptual phenomenon.