On the time course of negative priming: Another look

In two experiments, the pattern of persistence of negative priming effects across delay intervals of 500 and 2,500 msec was assessed using a within-subjects, random sequencing of delays. Neill and Valdes (1992; Neill, Valdes, Terry, & Gorfein, 1992) have argued that a within-subject experimental design is required for decay of negative priming to be seen, in contrast to results reported elsewhere (e.g., Tipper, Weaver, Cameron, Brehaut, & Bastedo, 1991) showing stable negative priming effects across delays. In neither experiment was substantial evidence of decay detected, raising questions for the notion that suppression necessarily declines across brief temporal intervals and for the assertion that episodic retrieval is the sole source of negative priming.     

Negative priming from ignored distractors in visual selection: A review

Ignoring a distractor on a prime trial generally impairs responses to that object on a subsequent probe trial. This negative-priming (NP) effect supports the notion that distracting objects are actively inhibited during target selection (Tipper, 1985). Alternatively, NP may be caused either by amismatch between the features of items across prime and probe trials (Park & Kanwisher, 1994) or by the episodic retrieval of information from the prime trial which conflicts with the current, correct response (Neill & Valdes, 1992). These alternative accounts are called theselective inhibition,feature mismatching, andepisodic retrieval hypotheses, respectively. The present paper reviews the NP literature and considers the evidence for each of the three accounts. Feature mismatching does produce NP in a limited number of cases, but it is not a necessary condition for NP. In other cases, NP must be due to either selective inhibition or episodic retrieval of previously ignored distractors. Though results from critical tests designed to discriminate among these hypotheses have not yet been reported, such results are crucial for both theoretical and practical reasons.     

Long-term positive and negative identity priming: Evidence for episodic retrieval

An episodic retrieval account of negative priming (Neill, 1997; Neill & Valdes, 1992) was evaluated in three experiments. Duringpractice, regular word pairs were presented to subjects differing numbers of times. The subjects named specific target words while they ignored specific distractor words. Following a 5-min retention interval, memory for practice was revealed:Test responses for target words exhibited positive priming that increased with increases in the number of times that the words had been attended. Test responses for distractor words exhibited either positive priming (Experiment 1) or negative priming (Experiments 2–3) that also increased with increases in the number of times that the words had been ignored. The type of priming that abstractors exhibited was determined by several contextual similarities between the practice environment, in which distractors were ignored initially, and the test environments, in which they were processed subsequently. Negative priming that spanned a 5-min interval, increased with increases in the number of times that a distractor was ignored, and was sensitive to contextual changes indicated that the direction of the effect was temporally backward because the test probe cued memory for earlier processing of the priming stimulus when the distractor had been ignored.     

Negative identity priming is contingent on stimulus repetition

Five experiments demonstrate that negative identity priming is contingent on stimulus repetition. In ignored repetition conditions, priming was initially positive and became negative as the number of repetitions increased. Moreover, it was repetition as a target, not as a distractor, that was critical for negative priming. The effects of repetition were general: They were found with both naming and same-different paradigms, verbal and pictorial material, familiar and unfamiliar stimuli, and vocal and manual responses. Findings support an activation-based model of negative priming (G. B. Malley & D. L. Strayer, 1995) and are problematic for the episodic retrieval model of negative priming (W. T. Neill & L. A. Valdes, 1992). Finally, the experiments did not replicate B. DeSchepper and A. Treisman's (1996) reported negative priming with nonrepeated novel shapes.     

The cost of a voluntary task switch

Task-switching paradigms are widely used to study executive control. However, standard paradigms may not require active control to switch tasks. We examined voluntary task switching by having subjects choose which task to perform on a series of bivalent stimuli. Subjects performed parity or magnitude judgments on single digits. Instructions were to perform the two tasks equally often and in a random order. The response-to-stimulus interval (RSI) was either 100 or 1,000 ms, manipulated between blocks. Task alternations were slower than task repetitions, and this switch cost was greater at the short RSI than at the long RSI (310 and 94 ms, respectively). Additionally, subjects produced more task repetitions than expected if the tasks were performed in a random sequence. These results show costs associated with a voluntary task switch, when subjects must actively control the choice of the task to be performed.     

Sequence learning and sequential effects

In a serial reaction time (RT) task with a probabilistic stimulus sequence, the length of the response-to-stimulus interval (RSI) and the sequence complexity was manipulated to investigate the relationship between sequence learning and sequential effects in serial RT tasks. Sequential effects refer to the influence of previous stimulus presentations on the RT to the current stimulus. Sequence learning is stimulus-transition specific and is demonstrated as the difference between practiced and unpracticed sequences within an interpolated random block of trials. There is a clear parallel between sequence learning and specific changes in sequential effect in the short RSI conditions, suggesting that a common mechanism may lie at the basis of sequence learning and automatic facilitation, which is responsible for sequential effects at short RSI. Importantly, the changes in sequential effects accompanying sequence learning are the same as those observed with practice in random serial RT tasks, indicating that the learning process underlying sequence learning is the same as in random tasks.     

Conflicts between expected and actually performed behavior lead to verbal report of incidentally acquired sequential knowledge

According to the Unexpected-Event Hypothesis (UEH) (Frensch, Haider, Rünger, Neugebauer, Voigt & Werg, 2002), conflicts between expected and actually performed behaviors trigger attribution processes and ultimately lead to the ability to verbally report an incidentally experienced sequential regularity. In two experiments, we manipulated the likelihood that a specific conflict, a premature response, occurred in a sequential version of the Number Reduction Task (NRT). Experiment 1 demonstrated that a longer RSI leads to a larger number of premature responses and to more verbal report than a shorter RSI. However, this effect of the RSI on verbal report was removed when participants were discouraged from emitting premature responses. Experiment 2 revealed that artificially inducing premature responses leads to an increase in verbal report, but only when premature responses are introduced late in training. Overall, the findings strongly support the assumptions of the UEH.     

Response-to-stimulus interval does not affect implicit motor sequence learning, but does affect performance

Nissen and Bullemer (1987) reported that implicit motor sequence learning was disrupted by the addition of a secondary task. They suggested that this effect was due to the attentional load that the secondary task adds. Recently it has been suggested that the attentional load is not critical, but rather that the secondary task affects timing, either by lengthening or by making inconsistent the response-tostimulus interval (RSI)-that is, the delay between when a subject makes a response and when the next stimulus appears. In six experiments we manipulated the RSI and found no support for these two hypotheses. An inconsistent RSI did not adversely affect implicit motor sequence learning. A long RSI did not affect learning, although under some conditions subjects did not express learning if the RSI was long. These results are interpreted as reflecting the effects of attention.     

Influence of attended repetition trials on negative priming in younger and older adults

A lengthened response time when a distractor becomes a target, called negative priming, is an undisputed phenomenon in selective attention, yet just what the underlying mechanism responsible for negative priming is has not been resolved. In this study, the proportion of attended repetition trials was manipulated in order to test the predictions of three theories that have been proposed for explaining spatial negative priming: distractor suppression (e.g., Tipper, 1985), episodic memory retrieval (e.g., Neill, Valdes, &; Terry, 1995), and novelty bias (e.g., Milliken, Tipper, Houghton, &; Lupiáñez, 2000). The results supported the proposal that a novelty bias, which is flexible and can be overridden, is the primary mechanism responsible for priming in spatial tasks. Memory retrieval obscured the novelty bias for target processing, was more selective in older adults, and did not affect distractor processing. Novelty bias and distractor suppression may share the same inhibitory attentional mechanism.     

Prime display offset modulates negative priming only for easy-selection tasks

Responses to probe targets that have been distractors in a prime display are slower than responses to new targets, a finding called negative priming (NP). The selective attention model, which attributes NP to lingering inhibition of the prime distractor, predicts that NP should occur only when the prime display has disappeared before the probe display is processed. The present study tested this prediction both in easy- and in difficult selection tasks. In Experiments 1, 2, and 3A, target selection was easy, and NP was observed only after prime display offset, regardless of whether offset was manipulated between or within participants. In Experiment 3B, target selection was difficult, and NP was found with and without prime display offset. Experiment 4 replicated the finding of NP without prime display offset in a difficult-selection task. A modified version of the selective attention model can explain the results of the present study. However, we also discuss the results in light of episodic retrieval theory and temporal discrimination theory.     

Task-set reconfiguration and perceptual processing: behavioral and electrophysiological evidence

Oriet and Jolic?ur (2003) proposed that an endogenous task-set reconfiguration process acts as a hard bottleneck during which even early perceptual processing is impossible. We examined this assumption using a psychophysiological approach. Participants were required to switch between magnitude and parity judgment tasks within a predictable task sequence while event-related potentials (ERPs) were recorded. Stimulus contrast and response stimulus interval (RSI) were manipulated. Behavioral data demonstrated typical task switch costs that decreased as RSI increased. However, whereas ERP analysis of visual ERP component latencies sensitively revealed the contrast effect, a switch-specific postponement of perceptual processing during task-set reconfiguration at short RSIs was not observed. The present findings indicate that the process of task-set reconfiguration does not constitute a hard bottleneck that delays perceptual processing.     

Cost of mental set reconfiguration between digits and their photisms in synaesthesia

In this study we present an experiment investigating the reconfiguration process elicited by the task switching paradigm in synaesthesia. We study the time course of the operations involved in the activation of photisms. In the experimental Group, four digit-color synaesthetes alternated between an odd-even task and a color task (to indicate the photism elicited by each digit). In both tasks, the target stimuli were numbers between 1 and 9 written in white. One of the control groups ran the same tasks but this time with colored numbers (Naive Control Group). The results of these studies showed the expected pattern for the control group in the case of regular shift: a significant task switch cost with an abrupt offset and a cost reduction in long RSI. However for the experimental group, we found switch cost asymmetry in the short RSI and non-significant cost in the long RSI. A second control group performed exactly the same tasks as the experimental group (with white numbers as targets and a second imaginary color task) -Trained Control Group-. We found no cost for this second control group. This means that the cost of mental set reconfiguration between numbers (inducers) and their photisms (concurrent sensations) occurs, that there is a specific cost asymmetry (from photisms to inducers) and that this cost cannot be explained by associative learning. The results are discussed in terms of exogenous and endogenous components of mental set reconfiguration.     

Response monitoring and expectancy in random serial RT tasks

Two different sequential patterns have been reported in serial reaction-time (RT) tasks with random stimulus sequences, depending on the response-to-stimulus interval (RSI). When RSI is short a first-order repetition effect and a higher order benefit-only pattern are found, and when RSI is long a cost-benefit pattern is observed. In a series of three experiments, we found that the patterns are not unique for spatial dimensions, and that the benefit-only pattern does not appear for irrelevant stimulus features. The cost-benefit pattern, on the other hand, can shift to irrelevant locations, but not to irrelevant colour. Distributional analyses of the sequential effects demonstrate that the first-order repetition effect can be dissociated from the higher order effects. The results are interpreted as support for the role of response monitoring in the development of the benefit-only pattern at short RSI, while the first-order repetition effect is explained as repetition priming. With a long RSI, the cost-benefit pattern is confirmed as a low-level subjective expectancy process, which is primarily controlled by stimulus location. The data clearly strengthen the support for three different processes generating sequential effects in random serial RT tasks.     

Noun-phrase anaphors and focus: the informational load hypothesis

The processing of noun-phrase (NP) anaphors in discourse is argued to reflect constraints on the activation and processing of semantic information in working memory. The proposed theory views NP anaphor processing as an optimization process that is based on the principle that processing cost, defined in terms of activating semantic information, should serve some discourse function--identifying the antecedent, adding new information, or both. In a series of 5 self-paced reading experiments, anaphors' functionality was manipulated by changing the discourse focus, and their cost was manipulated by changing the semantic relation between the anaphors and their antecedents. The results show that reading times of NP anaphors reflect their functional justification: Anaphors were read faster when their cost had a better functional justification. These results are incompatible with any theory that treats NP anaphors as one homogeneous class regardless of discourse function and processing cost.     

A sequential analysis of relevant and irrelevant information in the Stroop task

The effect of repeating relevant (colour) and irrelevant (word) stimulus information is investigated in two Stroop tasks. Thomas (1977) observed that the Stroop effect is reduced when the irrelevant word is repeated from trial n -1 to trial n. A similar effect was observed in the Simon task (Notebaert, Soetens, & Melis, 2001; Notebaert & Soetens, 2003a). MacLeod (1991) interprets this effect as sustained suppression and relates it to negative priming. In this paper we investigate whether the reduced Stroop effect for word repetitions is indeed related to the negative priming effect. In Experiment 1 with a response-stimulus interval (RSI) of 50 ms, the Stroop effect is not influenced by the sequence of the word and there is no negative priming effect. In Experiment 2 with an RSI of 200 ms, the Stroop effect is reduced for word repetitions but there is still no negative priming effect. This does not support the sustained-suppression hypothesis. The reduced Stroop effect for word repetitions is explained in terms of response priming.     

Linking inhibition to activation in the control of task sequences

Inhibition of abandoned tasks in task switching can be inferred when a worse performance is found withn− 2 task repetitions (ABA sequences) than with nonrepetitions (CBA sequences). Recent evidence has shown that this inhibition effect decreases with long intertrial intervals (i.e., response-cue intervals, RCIs). Two alternatives have been proposed to account for this decrease. One alternative attributes the observed decrease to the decay of inhibition itself. The other alternative proposes that decay of the activation of competing tasks reduces the interference and leads to less inhibition. To decide between these alternatives, we manipulated RCI trialwise. The results favor the decay-of-activation account as an explanation for the decreased inhibition effect. This links the amount of inhibition to the activation level of the competing tasks, whereas evidence for the decay of inhibition remains weak.     

刺激同一性对错误后反应的影响

当错误发生后,人们往往会放慢错误后反应的速度,以避免错误的再次发生,许多研究者认为,这是自上而下的认知控制对错误后反应的影响.为了探讨刺激属性是否也在错误后的反应中起作用,本研究从刺激同一性角度出发,探讨错误反应刺激与错误后刺激的同一性以及反应-刺激间隔时间(RSI)对错误后反应的影响.结果发现,当错误后的刺激与错误反应的刺激一致时,可减小错误后反应时延长的程度,同时,RSI越大,PES越小.本研究得出结论,刺激同一性和RSI作为自下而上的刺激驱动在PES的产生过程中发挥了作用.     

Effects of animacy and noun-phrase relatedness on the processing of complex sentences

Previous work has suggested that syntactically complex object-extracted relative clauses are easier to process when the head noun phrase (NP1) is inanimate and the embedded noun phrase (NP2) is animate, as compared with the reverse animacy configuration, with differences in processing difficulty beginning as early as NP2 (e.g., The article that the senator . . . vs. The senator that the article . . .). Two eye-tracking-while-reading experiments were conducted to better understand the source of this effect. Experiment 1 showed that having an inanimate NP1 facilitated processing even when NP2 was held constant. Experiment 2 manipulated both animacy of NP1 and the degree of semantic relatedness between the critical NPs. When NP1 and NP2 were paired arbitrarily, the early animacy effect emerged at NP2. When NP1 and NP2 were semantically related, this effect disappeared, with effects of NP1 animacy emerging in later processing stages for both the related and arbitrary conditions. The results indicate that differences in the animacy of NP1 influence early processing of complex sentences only when the critical NPs share no meaningful relationship.     

Persistence of negative priming: II. Evidence for episodic trace retrieval.

Responses to recently ignored stimuli may be slower or less accurate than to new stimuli. This negative priming effect decays over time when delay is randomized within subjects, but not when delay varies between subjects. In Experiment 1, response-stimulus intervals (RSI) of 500 and 4,000 ms were randomized within subjects in a target localization task. Negative priming of ignored locations diminished with longer delay. However, no significant decay was obtained when RSI and the preceding RSI were equal. Similar results were obtained when RSI and preceding RSI were deliberately confounded by blocking (Experiment 2). Negative priming appears to depend on temporal discriminability of the priming episode.     

Sequential effects in two-choice reaction time: Subjective expectancy and automatic after- effect at short response-stimulus intervals

Between three serial two-choice reaction-time tasks, the response-stimulus interval (RSI), stimulus-response compatibility, and practice were varied in order to examine two determinants of sequential effects — subjective expectancy and automatic aftereffect. It appears that subjective expectancy is absent when the RSI is below a critical minimum. In an incompatible task, however, this minimum is greater. This is interpreted in support of the single-channel hypothesis: the subject only builds up expectancies when the “central processor” is unoccupied. The automatic aftereffect increases as the RSI decreases. The decay of the aftereffect seems to take place mainly during the RSI and only to a minor degree during the reaction process. Normally, a strong aftereffect operates in a general way, but after extensive practice it becomes stimulus specific. A model is presented, which assumes that only at the initial stages of practice is the unused “neural pathway” inhibited each time the stimulus is an alternation.