Interactions between perceptual and numerical space

Interactions between numbers and space have become a major issue in numerical cognition. Neuropsychological studies suggest that the interactions occur, before response selection, at a spatially organized representation of numbers (the mental number line). Reaction time (RT) studies, on the other hand, usually point to associations between response codes that do not necessarily imply a number line. There is only one such study that has found a spationumerical interaction between perception and semantics (SNIPS) effect before response selection. Here, in Experiment 1, we isolated the SNIPS effect from other numerical effects and corroborated the prediction that it can be induced by both left and right spatial cues. In Experiment 2, we isolated the peak of the time course of the SNIPS effect and corroborated the prediction that it occurs when a cue follows a target, and not when both appear simultaneously. The results reconcile neuropsychological and RT studies and support the hypothesis that numbers are represented along a left-to-right spatially organized mental number line. [corrected]     

Automatic activation of spatial-numerical association in a primed parity judgement task: Evidence from the number-line congruency effect

Using a forward masked priming paradigm, the present parity judgement experiment examines how the automatic activation of spatial-numerical associations of single-digit primes and targets has an effect on the primed Spatial-Numerical Association Response Code (SNARC) effect. Both the parity priming effect (i.e., faster and more accurate responses when the prime and target are matched in parity) and the repetition-primed SNARC effect (i.e., responses to large numbers are faster when made by right hand than when made by left hand and the reverse is true for small numbers) are replicated. The nonrepetition-primed SNARC effect is stronger when the response (e.g., made by the left hand) to the target (e.g., 4) is congruent with the position of the prime on a mental number line (e.g., 6) than when it is incongruent (e.g., 1). This number-line congruency effect reflects the notion that the coactivation of spatial-numerical association of prime and target occurs even when the prime is masked and presented so rapidly that it cannot be processed via participants’ use of strategies.     

Even frequent and expected words are not identified without spatial attention

Previous studies have disagreed about the extent to which people extract meaning from words presented outside the focus of spatial attention. The present study examined a possible explanation for such discrepancies inspired by attenuation theory: Unattended words can be read more automatically when they are expected within a given context (e.g., due to frequent repetition). We presented a brief prime word in lowercase, followed by a target word in uppercase. Participants indicated whether the target word belonged to a particular category (e.g., “sports”). When we used a visual cue to draw attention to the location of the prime word, it produced substantial priming effects on target responses (i.e., especially fast responses when the prime and target words were identical or from the same category). When prime words were not attended, however, they produced no priming effects. This finding replicated even when there were only four words, each repeated 160 times during the experiment. It appears that very little word processing is possible without spatial attention, even for words that are expected and frequently presented.     

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.     

Negative priming in a gender decision task and in a semantic categorization task

In three experiments, we tested the hypothesis that negative priming (NP) can occur without prime or target selection, when conflicting properties are associated with the prime and the target, and when the experimental conditions allow the encoding of the target as a separate episode from the prime. These predictions were confirmed in Experiment 1, using a gender decision task. Responses were slower when prime and target had the same gender than when they had different genders, with an inter-stimulus interval (ISI) of 600 ms but not with an ISI of 25 ms. Experiment 2 eliminated a possible explanation of the NP obtained in Experiment 1, in terms of response inhibition during the prime processing. Finally, Experiment 3 demonstrated the replicability and the generality of our NP, in a semantic categorization task. Empirical and theoretical consequences of our results for studies using the priming paradigm are discussed.     

Unconscious semantic priming extends to novel unseen stimuli

Many subliminal priming experiments are thought to demonstrate unconscious access to semantics. However, most of them can be reinterpreted in a non-semantic framework that supposes only that subjects learn to map non-semantic visual features of the subliminal stimuli onto motor responses. In order to clarify this issue, we engaged subjects in a number comparison task in which the target number was preceded by another invisible masked number. We show that unconscious semantic priming occurs even for prime stimuli that are never presented as target stimuli, and for which no stimulus–response learning could conceivably occur. We also report analyses of the impact of the numerical relation between prime and target, and of the impact of learning on priming, all of which confirm that unconscious utilization of semantic information is indeed possible.     

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.     

The error protection impact of inhibitory after-effects in a location-based task and its preservation with practice

In location-based tasks, responses related to (prime trial) distractor-occupied locations automatically undergo activation, followed by inhibition, which causes these responses to become execution-resistant (ER). Distractor-response ER takes time to override, delaying target reactions that later require this response (e.g., probe, ignored-repetition trials), causing the spatial negative priming (SNP) phenomenon. We learned in this study that distractor-response ER affords this output a degree of error protection. Specifically, when the probe target appeared at a new location, former (prime) distractor responses were used erroneously significantly less often than their control response counterparts, likely due to their ER feature, which discourages their inappropriate selection (i.e., “ER” provides error protection). This error protection also was evident when a previous distractor response was activated by a distractor on the probe (i.e., distractor-repeat trial). Notably, error protection remained effective over extensive practice, as did SNP size (i.e., ER override time) after an initial decline.     

Connection between the evaluation of positive or negative valence and verbal responses to a lexical decision making task]

Evaluation of the positive or negative valence of a stimulus is an activity that is part of any emotional experience that has been mostly studied using the affective priming paradigm. When the prime and the target have the same valence (e.g. positive prime and positive target), the target response is facilitated as a function of opposing valence conditions (e.g. negative prime and positive target). These studies show that this evaluation is automatic but depends on the nature of the task's implied response because the priming effects are only observed for positive responses, not for negative responses. This result was explained in automatic judgmental tendency model put forth by Abelson and Rosenberg (1958) and Klauer and Stern (1992). In this model, affective priming assumes there is an overlap between both responses, the first response taking precedence as a function of the prime-target valence, and the second response one that is required by the task. We are assuming that another type of response was not foreseen under this model. In fact, upon activating the valence for each of the prime-target elements, two preliminary responses would be activated before the response on the prime-target valence relationship. These responses are directly linked to the prime and target evaluation independently of the prime-target relationship. This hypothesis can be linked to the larger hypothesis whereby the evaluative process is related to two distinct motivational systems corresponding to approach and avoidance behaviour responses (Lang, Bradley, & Cuthbert, 1990; Neuman & Strack, 2000; Cacciopo, Piester & Bernston, 1993). In this study, we use the hypothesis that when a word leads to a positive valence evaluation, this favours a positive verbal response and inversely, a negative valence word favours a negative response. We are testing this hypothesis outside the affective priming paradigm to study to what extent evaluating a word, even when it is not primed, activates both motivational systems and consequently, positive verbal responses for approach and negative responses for avoidance. To validate this hypothesis, we are re-using both versions of the lexical decision task proposed by Wentura (2000). The classic version leads participants to a positive response for words, and the modified version leads to a no response. This experiment, carried out with thirty-two participants, measures the influence on response time of two experimental factors, the intrasubject valence of words (positive and negative) and the inter-subject factor (yes and no responses to words). Results show an interaction between the type of response and word valence. It is temporally more onerous to give a no response to positive words than to negative words. This result confirms that there is a direct relation between the evaluation of a valence stimulus and the response to this stimulus, a relation that had up to now been essentially observed with motor behaviours, and more rarely with verbal responses. We propose integrating the existence of this link between evaluation and verbal response (yes and no) in interpreting the effects of affective priming.     

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.     

Time course of free-choice priming effects explained by a simple accumulator model

Unconscious visual stimuli can be processed by human observers and modulate their behavior. This has been shown for masked prime stimuli that influence motor responses to subsequent target stimuli. Beyond this, masked stimuli can also affect participants' behavior when they are free to choose one of two response alternatives. This finding demonstrates that an apparently free-choice between alternative behaviors can be subject to influences that are outside of awareness. We report three experiments which exhibit that the temporal dynamic of free-choice priming effects corresponds to that of forced-choice priming effects. Forced-choice priming effects were relatively robust against variations of prime stimuli but sensitive to physical features of target stimuli. Free-choice priming effects, in contrast, depended largely on the stimulus-response compatibility of the prime. A simple accumulator model which accounts for forced-choice response priming can also explain free-choice priming effects by the assumption that unconscious stimuli can initiate motor responses when participants are engaged in a speeded choice-reaction time task. According to our analyses free-choice priming results from a response selection mechanism which integrates conscious and unconscious information from external, stimulus driven sources and also from internal sources.     

Selection and inhibition in infancy: evidence from the spatial negative priming paradigm

We used a spatial negative priming (SNP) paradigm to examine visual selective attention in infants and adults using eye movements as the motor selection measure. In SNP, when a previously ignored location becomes the target to be selected, responses to it are impaired, providing a measure of inhibitory selection. Each trial consisted of a prime and a probe, separated by 67, 200, or 550 ms interstimulus intervals (ISIs). In the prime, a target was accompanied by a distractor. In the probe, the target appeared either in the location formerly occupied by the distractor (ignored repetition) or in another location (control). Adults exhibited the SNP effect in all three ISI conditions, producing slower saccade latencies on ignored repetition versus control trials. The SNP effect obtained for infants only under 550 and 200 ms ISI conditions. These results suggest that important developments in visual selection are rooted in emerging inhibitory mechanisms.     

Recently inhibited responses are avoided for both masked and nonmasked primes in a spatial negative priming task

Responding to the location of a target is delayed when the target arises at a position previously occupied by a distractor (ignored-repetition trial), relative to when it occurs at a formerly unoccupied location (control trial) [i.e., the spatial negative priming (SNP) effect]. Speculation has held that recently inhibited (distractor) responses resist future execution (i.e., execution resistance [ER]), and thus cause SNP. Evidence for ER has been reported for identity-based tasks using masked prime distractor events. The purpose of this study was to examine the potential impact of ER on response selection in an SNP task for both nonmasked (traditional) and masked primes. We employed a modified SNP task that included nonmasked and masked target-only and distractor-only visual primes (first trial), along with forced choice and free choice probes (second trial). On free choice trials, a selection bias against the prime-distractor-assigned response was evident (same-hand competition, for both nonmasked and masked primes). This selection avoidance was held to reflect ER operating with inhibited prime distractor responses. Further, inhibitory aftereffect patterns were the same for nonmasked and masked distractor primes, and masking target primes transformed a positive to a negative aftereffect, as predicted by the self-inhibition model of mask function set out by Schlaghecken and Eimer (Psychonomic Bulletin & Review, 11, 463-468, 2004).     

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。     

Negative priming depends on ease of selection

Negative priming effects have been offered as evidence that distractor stimuli are identified. We conducted two experiments to determine if such effects occur even when it is easy to discriminate target from distractor stimuli. In Experiment 1, we found the usual negative priming effect when target and distractor positions varied from trial to trial, but not when these positions remained fixed. Experiment 2 extended these results to a situation where the ease of selection varied only in the prime display. These findings argue that irrelevant inputs can be filtered out prior to stimulus identification under certain circumstances and therefore pose problems for strict late selection theories.     

Does Location Uncertainty Modulate Unconscious Processing Under Continuous Flash Suppression?

Previous research suggests that selective spatial attention is a determining factor for unconscious processing under continuous flash suppression (CFS), and specifically, that inattention toward stimulus location facilitates its unconscious processing by reducing the depth of CFS (Eo et al., 2016). The aim of our study was to further examine this modulation-by-attention model of CFS using a number priming paradigm. Participants (N = 26) performed a number comparison task on a visible target number (“compare target to five”). Prime-target pairs were either congruent (both smaller or larger than five) or incongruent. Spatial attention toward the primes was varied by manipulating the uncertainty of the primes’ location. Based on the modulation-by-attention model, we hypothesized the following: In trials with uncertain prime location, RTs for congruent prime-target pairs should be faster than for incongruent ones. In trials with certain prime location, RTs for congruent versus incongruent prime-target pairs should not differ. We analyzed our data with sequential Bayes factors (BFs). Our data showed no effect of location uncertainty on unconscious priming under CFS (BF0+ = 5.16). However, even visible primes only weakly influenced RTs. Possible reasons for the absence of robust number priming effects in our study are discussed. Based on exploratory analyses, we conclude that the numerical order of prime and target resulted in a response conflict and interfered with the predicted priming effect.     

The interaction between response effects during the acquisition of response priming

In three experiments we investigated the role of associative learning in the acquisition of response priming by effect stimuli, by examining their interaction during response-effect learning. Having replicated the ability of visual effect stimuli to prime their associated responses, we paired a response with a compound consisting of visual and auditory effects before assessing the ability of the auditory effect stimulus to prime the response. This priming was reduced if the visual stimulus had been pre-trained as an effect of the response. By contrast, priming by the visual effect stimulus was potentiated when the auditory effect had been pre-trained. We interpret these interactions in terms of contemporary associative learning theory derived from studies of conditioning.     

启动刺激含有多个靶子条件下的负启动效应

采用数字命名任务,在通常的负启动范式基础上增加启动刺激靶子数目．进行了两个实验。实验一发现,当启动刺激靶子个数为1个和2个时。出现负启动效应;当启动刺激靶子个数为3个和4个时。则不出现负启动效应。这提示靶子所获注意资源数量的作用。实验二发现．当启动刺激有2个和3个靶子时．如果未被选择来反应的靶子成为探测刺激的靶子,其反应时与控制组无显著差异。即不出现负启动。这表明在启动刺激中未被选择来反应的靶子与干扰项所受到的加工是有差别的。     

Perceptual learning can reverse subliminal priming effects

Masked primes presented prior to a target can result in inverse priming (i.e., benefits on trials in which the prime and the target are mapped onto opposite responses). In five experiments, time-of-task effects on subliminal priming of motor responses were investigated. First, we replicated Klapp and Hinkley's (2002) finding that the priming effect is initially straight (i.e., it benefits congruent trials, in which the prime and targets are mapped onto the same response) or absent, and only later reverses (i.e., faster responses in incongruent than in congruent trials). We show that the presentation of the mask plays a crucial role in this reversal and that the reversal occurs later if the mask pattern is very complex. We suggest that perceptual learning improves the recognition of task-relevant features. Once recognized, these features can trigger the preparation of the alternative response and/or inhibit the prime-activated response. These findings support an active role of the mask in priming.     

A negative compatibility effect in priming of emotional faces

The negative compatibility effect (NCE) is the surprising result that low-visibility prime arrows facilitate responses to opposite-direction target arrows. Here we compare the priming obtained with simple arrows to the priming of emotions when categorizing human faces, which represents a more naturalistic set of stimuli and for which there are no preexisting response biases. When inverted faces with neutral expressions were presented alongside emotional prime and target faces, only strong positive priming occurred. However, when the neutral faces were made to resemble the target faces in geometry (upright orientation), time (flashing briefly), and space (appearing in the same location), positive priming gradually weakened and became negative priming. Implications for theories of the NCE are discussed.