There has been ongoing research at an accelerated pace on negative priming since Dalrymple-Alford and Budayr (1966) examined this phenomenon. Negative priming is of interest to cognitive psychologists because it can help answer questions about the mechanisms of selective attention that allow us to prioritize some perceptual inputs while ignoring others. In a typical negative priming task, the stimuli are believed to leave a processing trace that can either facilitate or impair the processing of later identical or related stimuli over time. These priming effects are successfully obtained when the stimuli immediately follow the initial display. But can we obtain any priming effects when the stimuli are repeated with a protracted multi-minute interval? If yes, then are there any differences in the priming effects obtained at lagged interval compared to the ones obtained in the immediate condition? To answer these questions, the dissertation presents three pairs of experiments that examined identity priming with and without lag using a large pool of non-recycled words as stimuli. The results are argued to increase our understanding of the underlying mechanisms of selective attention which govern target and distractor processing. These experiments can also test some of the key predictions of the distractor inhibition hypothesis and episodic retrieval account concerning long-lag priming effects.

The task involved a pair of consecutive displays in which target and distractor words were presented. Participants were required to name the lowercase target word and later make a word/non-word judgment to the lowercase target item while ignoring the uppercase distractor words in both displays. The priming conditions were created by repeating the distractor word as a target in the ‘ignored repetition’ condition. Further priming conditions were created by repeating the target word as a target in the ‘attended repetition’ condition; by repeating the distractor word as a distractor in the ‘distractor repetition’ condition; and by repeating both target and distractor words as is in the ‘target and distractor repetition’ condition. The unrepeated items in the control condition provide a baseline against which to examine the possibility of obtaining any priming effects. In each experiment, the ignored repetition and control conditions were examined along with either one of the attended repetition, distractor repetition, or target and distractor repetition conditions; giving a total of three conditions per experiment. Those conditions were examined in one short-lag and one corresponding long-lag experiment. The stimuli were repeated successively without intervening stimuli in the short-lag experiments and 151 trials (about 10 minutes) later in the long-lag experiments.

Across the experiments, the most consistent finding was that negative priming was reliably observed in the ignored repetition condition evidenced by response delays at both short and long lags; indeed, without any diminishment over time. By contrast, response facilitation was observed in both short-lag and long-lag target repeat (e.g., attended repetition, target and distractor repetition) conditions. However, these response facilitatory effects diminished over time with lag compared to without lag condition. Taken together, these findings shed light on how we use attention to focus our processing resources on some information while minimizing others. During selective attention, the target was processed at the explicit level and the distractor was processed at the implicit level. When the ignored distractor appeared 151 trials (about 10 minutes) later, the effect of prime distractor implicit processing remained intact to obtain response time delays like the short-lag ignored repetition condition. However, when the explicitly attended target appeared 151 trials (about 10 minutes) later, a reduction in response facilitation was observed in both target repeat (e.g., attended repetition, target and distractor repetition) conditions with lag due to possible cluttering owing to intervening stimuli. Lastly, the response facilitation observed in the short-lag distractor repetition condition eliminated over time as no priming effects were obtained in the long-lag distractor repetition condition. It seems likely that the processing mechanisms applied to the distractor in the distractor repetition condition are less durable than the processing mechanisms applied to the distractor in the ignored repetition condition; as no facilitation emerged with lag. In short, current experiments systematically addressed the various ways our previous interactions with information influence our subsequent processing. The set results can be more easily accommodated by distractor inhibitory hypothesis than episodic retrieval account.