Unlearning a stimulus–response association

After a response has been associated with a particular stimulus, would this association be “unlearned” when the circumstances call for a new response to be made to that stimulus? This question was investigated in the present study with a negative priming (NP) paradigm developed by Shiu and Kornblum (1996). In the study, participants first practiced with a particular pairing of stimuli and responses in a four-choice reaction time (RT) task. Then, in the transfer phase, they switched to a different pairing of the same set of stimuli and responses. The results showed that a transfer response was slow if this response and the stimulus in the preceding trial had been paired in the training phase. Such NP effects persisted even after extended practice with the new pairing, suggesting that the “old” stimulus–response (SR) associations remain despite acquisition of some “new” associations.     

Influence of mapping complexity on negative priming for incompatible spatial mappings

For tasks with an incompatible stimulus-response mapping, whether the compatible response must be inhibited paradigm for four-choice tasks with three different incompatible spatial mappings. For a mapping that did not follow a simple rule, reaction time was lengthened when the corresponding response on the preceding trial became the required response on the current trial, as compared with when it did not, showing a negative priming effect. However, for mappings that followed a simple rule, negative priming was not evident. The present study extends this research to a more complex mapping. On the basis of a two-process model adopted from the negative priming literature, we hypothesized that high mapping complexity should also diminish the negative priming effect for incompatible mappings, because the balance of cognitive resources is allocated to identification of the correct response. Two experiments are reported in which mappings of different complexity were used in six-choice spatial tasks. Analyses of reaction times showed that negative priming diminished with increased mapping complexity, apparently due to increased dominance of response identification processes, rather than inhibition of the corresponding response.     

Influences of different combinations of conceptual, perceptual, and structural similarity on stimulus-response compatibility

This study evaluated the hypothesis that an increase in set-level stimulus-response compatibility produces facilitation for congruent mappings and interference for incongruent mappings. The degree of set-level compatibility was manipulated by varying combinations of conceptual, perceptual, and structural similarity. Experiment 1 varied perceptual similarity, by combining two stimulus codes (spatial, verbal) with two response modalities (manual, vocal) for orthogonal spatial dimensions, which have structural similarity. The element-level mapping effect did not vary as a function of the code-modality relation, in contrast to findings obtained with parallel spatial dimensions, which also have conceptual similarity. Experiment 2 manipulated combinations of conceptual and perceptual similarity by combining vertical and horizontal stimulus and response orientations, using verbal or spatial stimuli and vocal responses. The element-level mapping effect was larger for parallel than orthogonal orientations, with congruent mappings showing facilitation and incongruent mappings showing interference. The largest effect was facilitation for parallel orientations with the verbal-vocal set, consistent with the view that perceptual similarity contributes to performance primarily when responding with the identity of the stimulus. Our results indicate that conceptual similarity, but not perceptual similarity, produces the facilitation/interference pattern suggestive of automatic activation of the corresponding response regardless of mapping.     

Processing irrelevant location information: Practice and transfer effects in choice-reaction tasks

Left or right keypresses to a relevant stimulus dimension are faster when the stimulus location, although irrelevant, corresponds with that of the response than when it does not. This phenomenon, called the Simon effect, persisted across 1,800 trials of practice, although its magnitude was reduced. Practice with the relevant stimulus dimension presented at a centered location had little influence on the magnitude of the Simon effect when irrelevant location was varied subsequently, and practice with location irrelevant prior to performing with location relevant slowed responses. After practice responding to stimulus location with an incompatible spatial mapping, the Simon effect was reversed (i.e., responses were slower when stimulus location corresponded with response location) when location was made irrelevant. When the response keys were labeled according to the relevant stimulus dimension (the Hedge and Marsh [1975] task variation), this reversal from practice with a spatially incompatible mapping was found for both the congruent and the incongruent relevant stimulus-response mappings. Thus, task-defined associations between stimulus location and response location affect performance when location is changed from relevant to irrelevant, apparently through producing automatic activation of the previously associated response.     

Inhibition and decay of motor and nonmotor priming

Motor responses can be facilitated by congruent visual stimuli and prolonged by incongruent visual stimuli that are made invisible by masking (direct motor priming). Recent studies on direct motor priming showed a reversal of these priming effects when a three-stimulus paradigm was used in which a prime was followed by a mask and a target stimulus was presented after a delay. A similar three-stimulus paradigm on nonmotor priming, however, showed no reversal of priming effects when the mask was used as a cue for processing of the following target stimulus (cue priming). Experiment 1 showed that the time interval between mask and target is crucial for the reversal of priming. Therefore, the time interval between mask and target was varied in three experiments to see whether cue priming is also subject to inhibition at a certain time interval. Cues indicated (1) the stimulus modality of the target stimulus, (2) the task to be performed on a multidimensional auditory stimulus, or (3) part of the motor response. Whereas direct motor priming showed the reversal of priming about 100 msec after mask presentation, cue priming effects simply decayed during the 300 msec after mask presentation. These findings provide boundary conditions for accounts of inverse priming effects.     

An investigation of spatial representation of pitch in individuals with congenital amusia

Spatial representation of pitch plays a central role in auditory processing. However, it is unknown whether impaired auditory processing is associated with impaired pitch–space mapping. Experiment 1 examined spatial representation of pitch in individuals with congenital amusia using a stimulus–response compatibility (SRC) task. For amusic and non-amusic participants, pitch classification was faster and more accurate when correct responses involved a physical action that was spatially congruent with the pitch height of the stimulus than when it was incongruent. However, this spatial representation of pitch was not as stable in amusic individuals, revealed by slower response times when compared with control individuals. One explanation is that the SRC effect in amusics reflects a linguistic association, requiring additional time to link pitch height and spatial location. To test this possibility, Experiment 2 employed a colour-classification task. Participants judged colour while ignoring a concurrent pitch by pressing one of two response keys positioned vertically to be congruent or incongruent with the pitch. The association between pitch and space was found in both groups, with comparable response times in the two groups, suggesting that amusic individuals are only slower to respond to tasks involving explicit judgments of pitch.     

Attending, ignoring, and repetition: on the relation between negative priming and inhibition of return

A series of spatial localization experiments is reported that addresses the relation between negative priming and inhibition of return. The results of Experiment 1 demonstrate that slowed responses to repeated location stimuli can be obscured by repetition priming effects involving stimulus dimensions other than spatial location. The results of Experiments 2, 3A, and 3B demonstrate that these repetition priming effects may occur only when participants are required to respond to the prime display. Together, these results suggest that differences between attended and ignored repetition effects in selective attention studies of spatial localization do not provide a basis for distinguishing between spatial negative priming and inhibition of return.     

Mechanisms of Priming by Masked Stimuli: Inferences From Event-Related Brain Potentials

A metacontrast procedure was combined with the recording of event-related potentials (ERPs) to examine the mechanisms underlying the priming effect exerted by masked visual stimuli (primes) on target processing. Participants performed spatially arranged choice responses to stimulus locations. The relationship between prime and target locations (congruity) and the mapping between target and response locations (compatibility) were factorially manipulated. Although participants were unaware of prime locations, choice responses were faster for congruent than incongruent conditions irrespective of the mapping. Visual ERP components and the onset of the lateralized readiness potential (LRP), an index of specific motor activation, revealed that neither perceptual nor preselection processes contributed to the congruity effect. However, the LRP waveform indicated that primes activated responses that fit the stimulus-response mapping. These results support the view that sensorimotor processing of masked stimuli is functionally distinct from their conscious perception.     

PRP-paradigm provides evidence for a perceptual origin of the negative compatibility effect

Visual stimuli (primes) that are made invisible by masking can affect motor responses to a subsequent target stimulus. When a prime is followed by a mask which is followed by a target stimulus, an inverse priming effect (or negative compatibility effect) has been found: Responses are slow and frequently incorrect when prime and target stimuli are congruent, but fast and accurate when prime and target stimuli are incongruent. To functionally localize the origins of inverse priming effects, we applied the psychological refractory period (PRP-) paradigm which distinguishes a perceptual level, a central bottleneck, and a level of motor execution. Two dual-task experiments were run with the PRP-paradigm to localize the inverse priming effect relative to the central bottleneck. Together, results of the Effect-Absorption and the Effect-Propagation Procedure suggest that inverse priming effects are generated by perceptual mechanisms. We suggest two perceptual mechanisms as the source of inverse priming effects.     

Negative priming and stimulus-response compatibility

The subjects in this study made incongruent naming responses to words and pictures that were presented on alternate trials (e.g., say “car” toBIKE). Their response time was longer if the correct response for the current trial was the name of the stimulus presented on the preceding trial, as compared with a control condition. These results suggest that the tendency to produce the (congruent) name of the stimulus is automatically activated and then inhibited. The “negative priming” effects appeared stronger for words where pictures were primes than for pictures where words were primes. The implications of these results for negative priming and stimulus-response compatibility are discussed.     

On the difference between response inhibition and negative priming: Evidence from simple and selective stopping

Negative priming is a commonly observed after-effect in studies concerning inhibition. Effects of the preceding trial are also found in other paradigms, like the stop signal paradigm. In the present study, stop signals were introduced in a negative priming paradigm and the relation between stop signal inhibition and negative priming was investigated. In Experiment 1, we used a simple stop signal task. Stopping data clearly suggest that stopping performance was not influenced by negative priming. Interestingly, on no-signal probes the negative priming effect disappeared after successful inhibition of the response on the prime trial. On the contrary, when inhibition failed, the negative priming effect remained. In Experiment 2, we used the selective stop signal task. As in Experiment 1, inhibition of motor responses was not influenced by negative priming. The hypothesis that negative priming disappeared due to a general nonspecific stop was confirmed in this experiment, as a negative priming effect was found after both successful and unsuccessful behavioral inhibition. The results of both experiments show that response inhibition is not influenced by negative priming, and that negative priming is only affected after a successful general stop.     

Inverse cue priming is not limited to masks with relevant features

Apart from positive priming effects, masked prime stimuli can impair responses to a subsequent target stimulus which shares response-critical features in contrast to a target assigned to the opposite response. This counterintuitive phenomenon is called inverse priming (or negative compatibility effect). Here we examine the generality of this phenomenon beyond priming of motor responses. We used a non-motor cue-priming paradigm to study the underlying mechanism of inverse priming for relevant features masks which include task-relevant stimulus features and for irrelevant masks which omit task-relevant features. We found inverse cue-priming effects with both types of masks. With task-irrelevant masks inverse cue-priming was emphasized in those participants being unable to perceive the prime. The existence of inverse non-motor priming under conditions where simple perceptual interactions between the stimuli are ruled out as the source of inverse priming is at odds with the view that inverse priming reflects motor inhibition. Alternatives are discussed.     

On the locus of priming and inverse priming effects

Visual stimuli that are made invisible by a following mask can affect overt motor responses and nonmotor processing. Previous studies have compared the effects of primes that were perceptually similar to the subsequent stimulus with those of primes that were perceptually similar to an alternative stimulus. The present study examined the effect of congruent primes that are perceptually dissimilar to the target (or the cue) but are nonetheless associated with the same response (or the same task) as the later stimulus. Positive and inverse priming effects (negative compatibility effects) were studied in a target priming paradigm (Experiments 1 and 2) and in a cue priming paradigm (Experiments 3 and 4). The results showed stronger priming effects with similar primes than with dissimilar congruent primes. However, the effects of perceptually dissimilar congruent primes differed from those of dissimilar incongruent primes. These findings suggest that a substantial part of both positive target and cue priming effects is produced at levels of processing that are not affected by perceptual similarity. The version of inverse priming effects examined in this study, however, seems to arise from perceptual processing that is affected by the similarity between a prime and the stimulus that follows the mask.     

大小判断任务中正负号及其异同对SNARC效应的影响

SNARC效应(Spatial-Numerical Association of Response Codes)是指被试对数字做按键反应时,对于较小的数字,按左键的速度快于按右键;对于较大的数字,按右键的速度快于按左键。本研究以ERP作为测量手段,采用修正的大小判断任务,旨在探究数字正负号及其异同对SNARC效应的影响。行为结果发现,在反应时上,当目标数字与基线数字正负号相同且基线数字为+5时,一致条件显著快于不一致条件。ERP结果发现,当目标数字与基线数字正负号相同时,无论基线数字为+5还是–5,在反应选择阶段,不一致都比一致条件更负且均诱发了P3。当目标数字与基线数字正负号相异时,若基线数字为+5,一致比不一致条件在刺激呈现阶段诱发了波幅显著更小的N300;若基线数字为–5,一致比不一致条件在反应执行阶段诱发了更正的LPP。无论目标数字与基线数字正负号相同还是相异,在反应选择阶段,不一致都比一致条件更负且均诱发了P3,表明出现了SNARC效应。同时,SNARC效应的出现激活了额叶头皮位置,负数加工伴随左额叶的激活,而正数加工伴随右额叶的激活,溯源分析结果进一步表明SNARC效应定位于额叶与顶叶。这些结果说明负数按实际大小表征在心理数字线上,支持了负数空间表征的个体发展论假说;表明符号捷径机制会改变SNARC效应的发生时间;同时证明了负数与正数的空间表征具有不同的优势半球。     

Taking a bright view of negative priming in the light of dim stimuli: further evidence for memory confusion during episodic retrieval.

A same-different letter-matching task was used to examine the effects of stimulus intensity on negative priming, which is poorer performance when target letters have been presented as distractor letters on the immediately preceding trial. In Experiment 1, stimulus intensity was manipulated between-participants, whereas in Experiment 2, it varied randomly from trial-to-trial within-participants. In Experiment 1, negative priming was equivalent for both stimulus intensities. In Experiment 2, negative priming effects were larger for repeated intensity stimuli than for nonrepeated intensity stimuli, when stimulus intensity was dim. Furthermore, for repeated intensity stimuli, negative priming effects were enhanced when the overt response required to the stimulus was repeated from prime to probe trial. These results are consistent with the hypothesis that negative priming may be due to memory confusion, rather than to inhibition of the distractor stimuli.     

The role of stimulus-based and response-based spatial information in sequence learning

In 4 experiments, relational structures were independently varied in stimulus and response sequences in a serial reaction time task. Moreover, the use of spatial and symbolic stimuli and responses was varied between experiments. In Experiment 1, spatial stimuli (asterisk locations) triggered spatial responses (keystrokes); in Experiment 2, spatial stimuli triggered symbolic responses (verbal digit naming); in Experiment 3, symbolic stimuli (digits) triggered keystrokes; and in Experiment 4, digits triggered verbal responses. The results showed that there is a remarkably stronger effect of relational structures in spatial sequences than in symbolic sequences, irrespective of whether stimulus or response sequences are concerned. This suggests that learning is particularly effective for sequences of spatial locations. It is argued that spatial learning is a critical determinant for the debate on perceptual and motor learning.     

A PRP-study to determine the locus of target priming effects

Visual stimuli that are made invisible by a following mask can nonetheless affect motor responses. To localize the origin of these target priming effects we used the psychological refractory period paradigm. Participants classified tones as high or low, and responded to the position of a visual target that was preceded by a prime. The stimulus onset asynchrony (SOA) between both tasks varied. In Experiment 1 the tone task was followed by the position task and SOA dependent target priming effects were observed. When the visual position task preceded the tone task in Experiment 2, with short SOA the priming effect propagated entirely to the tone task yielding faster responses to tones on visually congruent trials and delayed responses to tones on visually incongruent trials. Together, results suggest that target priming effects arise from processing before and at the level of the central bottleneck such as sensory analysis and response selection.     

Tracking hand movements captures the response dynamics of the evaluative priming effect

We tested the response dynamics of the evaluative priming effect (i.e. facilitation of target responses following evaluatively congruent compared with evaluatively incongruent primes) using a mouse tracking procedure that records hand movements during the execution of categorisation tasks. In Experiment 1, when participants performed the evaluative categorisation task but not the non-evaluative semantic categorisation task, their mouse trajectories for evaluatively incongruent trials curved more toward the opposite response than those for evaluatively congruent trials, indicating the emergence of evaluative priming effects based on response competition. In Experiment 2, implementing a task-switching procedure in which evaluative and non-evaluative categorisation tasks were intermixed, we obtained reliable evaluative priming effects in the non-evaluative semantic categorisation task as well as in the evaluative categorisation task when participants assigned attention to the evaluative stimulus dimension. Analyses of hand movements revealed that the evaluative priming effects in the evaluative categorisation task were reflected in the mouse trajectories, while evaluative priming effects in the non-evaluative categorisation tasks were reflected in initiation times (i.e. the time elapsed between target onset and first mouse movement). Based on these findings, we discuss the methodological benefits of the mouse tracking procedure and the underlying processes of evaluative priming effects.     

Co-occurrence of sequential and practice effects in the Simon task: Evidence for two independent mechanisms affecting response selection

The Simon effect refers to the observation that responses to a relevant stimulus dimension are faster and more accurate when the stimulus and response spatially correspond than when they do not, even though stimulus position is irrelevant. Recent findings have suggested that the Simon effect can be strongly modulated by prior practice with a spatially incompatible mapping and by correspondence sequence. Although practice is thought to influence conditional stimulus —response (S-R) processing, leaving response priming through the unconditional route unaffected, sequential effects are thought to represent trial-by-trial adaptations that selectively involve unconditional S —R processing. In the present study, we tested this assumption by assessing the effects of correspondence sequence both when the Simon task alone was performed and when it was preceded by a spatial compatibility task with either incompatible (Experiments 1-2) or compatible (Experiment 2) instructions. The observation that practice and correspondence sequence co-occur and exert additive effects strongly demonstrates that the two factors affect different processing routes.     

金钱概念激活与金钱功能偏好对自我损耗后利他的影响

金钱启动能够提高自我损耗后个体的利他,而金钱功能也可能对损耗后个体利他产生不可忽视的影响。实验让处于自我损耗状态的被试数金钱或白纸,然后测量其利他水平及其对金钱功能的内隐偏好。结果证实了金钱启动的积极效应。此外,在数金钱和数白纸两种条件下,金钱象征性功能偏好对自我损耗后个体利他的效应是相反的。这表明,激活金钱概念与偏好金钱象征性功能都有可能补偿自我损耗后的消极影响,但两者的补偿作用是相互独立的。