Masked Priming Effects Research Articles

A prospective view of the impact of prime validity on response speed and selection in the arrow classification task with free choice trials

Bodner and Masson (2001, 2003, 2004) demonstrated that masked priming effects in many cognitive tasks become larger when the proportion of related trials increases (prime validity effects). Those authors claimed that these effects are due to participants' recruiting prime information to aid target processing when it is useful to do so (e.g., there are a large number of related trials-the memory recruitment account). Bodner and Mulji (in press) recently reported similar effects in an arrow classification task with free choice trials. In the present research, we examined whether the memory recruitment account can adequately explain prime validity effects in that task. In this experiment, participants classified arrow direction (i.e., left-right) and responded to free choice stimuli (i.e., two-sided arrows that allow either a left or right response) following arrow primes when the prime-target relationship for the arrow target trials was always congruent, always incongruent, or unpredictive. Prime validity effects for the either-way targets emerged with both 77- and 165-msec prime-target intervals. The results in the unpredictive conditions, however, suggest that those effects were due to the impact of automatic response biases initially created by the prime, which participants attempt to suppress when it is advantageous to do so.

Masked priming effect reflects evidence accumulated by the prime

In the same-different match task, masked priming is observed with the same responses but not different responses. Norris and Kinoshita's (2008) Bayesian reader account of masked priming explains this pattern based on the same principle as that explaining the absence of priming for nonwords in the lexical decision task. The pattern of priming follows from the way the model makes optimal decisions in the two tasks; priming does not depend on first activating the prime and then the target. An alternative explanation is in terms of a bias towards responding "same" that exactly counters the facilitatory effect of lexical access. The present study tested these two views by varying both the degree to which the prime predicts the response and the visibility of the prime. Unmasked primes produced effects expected from the view that priming is influenced by the degree to which the prime predicts the response. In contrast, with masked primes, the size of priming for the same response was completely unaffected by predictability. These results rule out response bias as an explanation of the absence of masked priming for different responses and, in turn, indicate that masked priming is not a consequence of automatic lexical access of the prime.

The time course of orthography and phonology: ERP correlates of masked priming effects in Spanish

One key issue for computational models of visual-word recognition is the time course of orthographic and phonological information during reading. Previous research, using both behavioral and event related brain potential (ERP) measures, has shown that orthographic codes are activated very early but that phonological activation starts to occur immediately afterward. Here we report an ERP masked priming experiment in Spanish that investigates this issue further by using very strict control conditions. The critical phonological comparison was between two pairs of primes having the same orthographic similarity to the target words but differing in phonological similarity (e.g., conal-CANAL vs. cinal-CANAL vis à vis ponel-PANEL vs. pinel-PANEL), whereas the critical orthographic contrast was between pairs of primes that had the same phonological similarity to the target but differing in orthographic similarity (e.g., conal-CANAL vs. konal-CANAL). Orthographic priming was mainly observed in the 150-250-ms time window whereas phonological priming occurred in the 350-550-ms window.

Short article: Is morphological decomposition limited to low-frequency words?

On the basis of data from masked priming experiments, it has been argued that an automatic process of decomposition is applied to all morphologically structured stimuli, irrespective of their lexical characteristics (Rastle, Davis, & New, 2004). So far, this claim has been tested only with respect to low-frequency primes and nonword primes. This is a limitation because some models of morphological processing postulate that only high-frequency complex words are recognized as whole forms. Thus, a more stringent test would be to determine whether high-frequency complex words also show evidence of masked priming. We report an experiment that compares masked-priming effects observed when the primes constitute morphologically structured nonwords (e.g., alarmer-ALARM), low-frequency words with a mean frequency of 2 per million (e.g., notional-NOTION), and high-frequency words with a mean frequency of 60 per million (e.g., national-NATION). These three conditions yielded significant and equivalent effects, lending strong support to the notion of a routine form of decomposition that is applied to all morphologically structured stimuli.

Positive and negative congruency effects in masked priming: A neuro-computational model based on representation, attention, and conflict

Studies on masked and unmasked priming have long shown reliable positive effects of the congruent prime on target processing. Paradoxically, a negative effect has also been found, showing faster and more accurate responses in the incongruent compared to the congruent trials. Positive effects have been found with a short time between the prime and the target, while negative effects have been found with a long time between the prime and the target. This has been modeled by assuming that the prime initiates a motor self-inhibitory process that causes these effects (Bowman, H., Schlaghecken, F., Eimer, M., 2006. A neural network model of inhibitory processes and cognitive control. Vis. Cogn. 13, 401–480). We have developed an alternative explanation based on attentional neuro-modulation. In this paper we show that attentional neuro-modulation can be used to model a wide range of findings in this area.

The role of neighbourhood density in transposed-letter priming

We investigated how transposed-letter (TL) priming effects are modulated by neighbourhood density in lexical decision task and cross-case same-different task. Robust identity priming and TL priming effects were observed in both tasks. Neighbourhood density facilitated ‘word’ decisions and reduced the size of identity priming effect in the lexical decision task. It had no effect on the same-different task, and did not modulate identity or TL priming. We take these results as indicating that neighbourhood density modulates priming during lexical access. In the lexical decision task, the difference between identity priming and TL priming was reduced for words from high-density neighbourhood. The last finding is at odds with the ‘lexical tuning’ hypothesis which has been used to explain modulatory effects of neighbourhood density on masked form priming effects. We also discuss implication of the results for various letter position coding schemes.

Beyond alphabetic orthographies: The role of form and phonology in transposition effects in Katakana

In the past years, there has been growing interest in how the order of letters is attained in visual word recognition. Two critical issues are: (1) whether the front-end of the recently proposed models of letter position encoding can be generalised to non-alphabetic scripts, and (2) whether phonology plays an important role in the process of letter position encoding. In the present masked priming lexical decision experiments, we employed a syllabic/moraic script (Katakana), which allows disentangling form and phonology. In Experiment 1, we found a robust masked transposed-mora priming effect: the prime a.ri.me.ka facilitates the processing of the word a.me.ri.ka relative to a double-substitution prime (a.ka.ho.ka, ). In Experiment 2, we failed to obtain any signs of a masked phoneme transposition effect (a.re.mi.ka-a.me.ri.ka vs. a.ke.hi.ka-a.me.ri.ka). In Experiment 3, we failed to find any signs of a masked phonological priming effect when the order of the consonant/vowel phonemes of the internal morae was the right one (e.g., a.ma.ro.ka-a.me.ri.ka vs. a.ka.ho.ka-a.me.ri.ka). Thus, masked transposed-mora priming effects are orthographic (rather than phonological) in nature. We discuss how the recently proposed input coding schemes can be generalised to a syllable-based script.

Does darkness lead to happiness? Masked suffix priming effects

Masked affix priming effects have usually been obtained for words sharing the initial affix (e.g., re action- RE FORM). However, prior evidence on masked suffix priming effects (e.g., bak er -WALK ER ) is inconclusive. In the present series of masked priming lexical decision experiments, a target word was briefly preceded by a morphologically or orthographically related prime, or by an unrelated prime. In Experiment 1, the prime words in the suffix priming condition were formed by their suffixes (e.g., er -WALK ER ). In Experiment 2, the primes included the suffix inserted in a nonsense symbol string (e.g., %%%% er -WALK ER ). In Experiment 3, the primes were formed by a real word that shared the suffix with the target (e.g., bak er -WALK ER ). The results showed that, when compared with an orthographic priming condition, masked suffix priming can be obtained independently of the degree of segmentation of the prime. Furthermore, the present experiments reveal a clear dissociation between orthographic priming and morphological priming.

Positive and Negative Congruency Effects in Masked Priming: A Neuro-computational Model Based on Representation Strength and Attention

AbstractPositive priming effects have been found with a short time between the prime and the target, while negative priming effects (i.e., a congruent prime causes longer RTs) have been found with a long time between the prime and the target. In the current study, positive and negative priming effects were found using stimuli that have strong and weak representations, respectively, without changing the time between prime and target. A model was developed that fits our results. The model also fits a wide range of previous results in this area. In contrast to other approaches our model depends on attentional neuro-modulation not motor self-inhibition.

ERP effects of short interval masked associative and repetition priming

In a previous study we used event-related potentials to dissociate semantic (associative) and repetition priming when prime words were masked below (40 ms primes) and above (80 and 120 ms primes) levels of awareness (Holcomb, P. J., Reder, L., Misra, M., & Grainger, J. (2005). Masked priming: an event-related brain potential study of repetition and semantic effects. Cognitive Brain Research, 24, 155--172.). While robust priming effects were present on the N400 component regardless of the prime duration in the repetition priming experiment, in the semantic priming experiment significant priming effects were only obtained when primes were consciously detected. In the current study we again compared associative and repetition priming, but this time within a single experiment and using a short interval priming paradigm. As in several recent studies we again found robust repetition priming effects on both the N400 and an earlier index of priming, the N250. However, there was no evidence of any priming effect in the semantic/associative condition. The findings are discussed in the context of the functional significance of masked priming effects.

Top-down modulation of unconscious 'automatic' processes: A gating framework

In classical theories of automaticity, automatic processes are usually thought to occur autonomously and independently of higher level top-down factors (e.g., Posner & Snyder, 1975). However, already Neumann (1984) pointed out that the cognitive system has to be configured in a certain way for automatic processes to occur. In extension of his work, I propose a gating framework to account for the influence of top-down factors such as attention, intention and task set on automatic processes such as masked response or semantic priming. It is assumed that task representations held in prefrontal cortex regulate the gain of neurons in visual and sematic association cortex thereby modulating the effects of unconsciously perceived masked stimuli on further ‘automatic’ information processing steps. In support of the postulated gating framework, recent studies demonstrated a top-down modulation of automatic processes. Behavioral and electrophysiological studies with the masked response priming and semantic priming paradigms show that masked priming effects crucially depend (i) on temporal attention to the masked prime, (ii) on intentions or action plans and (iii) on the task set active immediately before masked prime presentation. For instance, masked semantic priming was only observed when the preceding task set required the orientation to semantic word features, but not when it required orientation to perceptual word features. These results support the view that unconscious automatic processes are modulated by top-down factors. They are suggestive of a gating mechanism which orchestrates the conscious and unconscious information processing streams.

Event-related Potentials Associated with Masked Priming of Test Cues Reveal Multiple Potential Contributions to Recognition Memory

The relationship between recognition memory and repetition priming remains unclear. Priming is believed to reflect increased processing fluency for previously studied items relative to new items. Manipulations that affect fluency can also affect the likelihood that participants will judge items as studied in recognition tasks. This attribution of fluency to memory has been related to the familiarity process, as distinct from the recollection process, that is assumed by dual-process models of recognition memory. To investigate the time courses and neural sources of fluency, familiarity, and recollection, we conducted an event-related potential (ERP) study of recognition memory using masked priming of test cues and a remember/know paradigm. During the recognition test, studied and unstudied words were preceded by a brief, masked word that was either the same or different. Participants decided quickly whether each item had been studied ("old" or "new"), and for items called old, indicated whether they "remembered" (R) the encoding event, or simply "knew" (K) the item had been studied. Masked priming increased the proportion of K, but not R, judgments. Priming also decreased response times for hits but not correct rejections (CRs). Four distinct ERP effects were found. A medial-frontal FN400 (300-500 msec) was associated with familiarity (R, K Hits > CRs) and a centro-parietal late positivity (500-800 msec) with recollection (R Hits > K Hits, CRs). A long-term repetition effect was found for studied items judged "new" (Misses > CRs) in the same time window as the FN400, but with a posterior distribution. Finally, a centrally distributed masked priming effect was visible between 150 and 250 msec and continued into the 300-500 msec time window, where it was topographically dissociable from the FN400. These results suggest that multiple neural signals are associated with repetition and potentially contribute to recognition memory.

Early decomposition in visual word recognition: Dissociating morphology, form, and meaning

The role of morphological, semantic, and form-based factors in the early stages of visual word recognition was investigated across different SOAs in a masked priming paradigm, focusing on English derivational morphology. In a first set of experiments, stimulus pairs co-varying in morphological decomposability and in semantic and orthographic relatedness were presented at three SOAs (36, 48, and 72 ms). No effects of orthographic relatedness were found at any SOA. Semantic relatedness did not interact with effects of morphological decomposability, which came through strongly at all SOAs, even for pseudo-suffixed pairs such as archer-arch. Derivational morphological effects in masked priming seem to be primarily driven by morphological decomposability at an early stage of visual word recognition, and are independent of semantic factors. A second experiment reversed the order of prime and target (stem-derived rather than derived-stem), and again found that morphological priming did not interact with semantic relatedness. This points to an early segmentation process that is driven by morphological decomposability and not by the structure or content of central lexical representations.

Unconscious cognition isn’t that smart: Modulation of masked repetition priming effect in the word naming task

Masked repetition primes produce greater facilitation in naming in a block containing a high, rather than low proportion of repetition trials. [Bodner, G. E., & Masson, M. E. J. (2004). Beyond binary judgments: Prime-validity modulates masked repetition priming in the naming task. Memory & Cognition, 32, 1–11] suggested this phenomenon reflects a strategic shift in the use of masked prime as a function of its validity. We propose an alternative explanation based on the Adaptation to the statistics of the environment (ASE) framework, which suggests the proportion effect reflects adaptation of response-initiation processes to recent trial difficulty. Consistent with ASE’s prediction, (1) stimuli that produce the proportion effect also produced an “asymmetric blocking effect”, showing a smaller fall in response latencies of hard items than the rise of easy items when the two item types were intermixed relative to pure blocks comprised of only one item type, and (2) manipulation of prime validity was neither necessary nor sufficient to modulate the size of masked-priming effect.

Modulating the masked congruence priming effect with the hands and the mouth.

The authors report a series of experiments in which they use the masked congruence priming paradigm to investigate the processing of masked primes in the manual and verbal response modalities. In the manual response modality, they found that masked incongruent primes produced interference relative to both congruent and neutral primes. This finding, which replicates the standard finding in the masked congruence priming literature, is presumed to reflect the conflict that arises between two incompatible responses and, thus, to index the extent of processing of the masked prime. Somewhat surprisingly, when participants were asked to respond verbally in the same task, masked incongruent primes no longer produced interference, but masked congruent primes produced facilitation. These findings are surprising because they suggest that the processing of nonconsciously perceived primes extends to the response level in the manual, but not verbal, response modality. The authors propose that the modulation of the masked congruence priming effect by response modality is due to verbal, but not manual, responses being mediated by the lexical-phonological production system.

Masked priming with orthographic neighbors: A test of the lexical competition assumption.

In models of visual word identification that incorporate inhibitory competition among activated lexical units, a word's higher frequency neighbors will be the word's strongest competitors. Preactivation of these neighbors by a prime is predicted to delay the word's identification. Using the masked priming paradigm (K. I. Forster & C. Davis, 1984, J. Segui and J. Grainger (1990) reported that, consistent with this prediction, a higher frequency neighbor prime delayed the responses to a lower frequency target, whereas a lower frequency neighbor prime did not delay the responses to a higher frequency target. In the present experiments, using English stimuli, it was found that this pattern held only when the primes and targets had few neighbors; when the primes and targets had many neighbors, lower frequency primes delayed responses to higher frequency targets essentially as much as higher frequency primes delayed responses to lower frequency targets. Several possible explanations for these findings are discussed along with their theoretical implications. Considered together, the results are most consistent with activation-based accounts of the masked priming effect.

Conscious and unconscious proportion effects in masked priming

The global neuronal workspace theory [Dehaene, S., & Naccache, L. (2001). Towards a cognitive neuroscience of consciousness: basic evidence and a workspace framework. Cognition, 79, 1–37.] proposes that it is impossible for an unconscious stimulus to be used strategically to enhance task performance (bottom–up effect), while a fully consciously perceived stimulus can be used to improve task performance (top–down effect). Two experiments were designed to investigate these hypotheses. In a first experiment we investigated whether a manipulation of the proportion of Arabic/number word targets had a top–down effect. Since the subjects were fully aware of the target, we expected that this manipulation could be used to enhance task performance. In a second experiment we determined whether a manipulation of the proportion of Arabic/number word primes had a bottom–up effect. Since the subjects were unaware of the prime, we hypothesized that they would be unable to use the manipulation to enhance task performance and therefore the manipulation would have no effect. Both hypotheses were largely confirmed.

Masked priming effect with canonical finger numeral configurations

Discrete numerosities can be represented by various finger configurations. The impact of counting strategies on these configurations and their possible semantic status were investigated in young adults. Experiment 1 showed that young adults named numerical finger configurations faster when they conformed to their own canonical finger-counting habits than when they did not. Experiment 2 showed that numeral finger configurations used as unconsciously presented primes speeded up numerical comparative judgements of Arabic numeral targets. Participants responded faster and made fewer errors with numerical than with non-numerical primes, and when primes and targets were congruent (i.e., leading to the same response). Moreover, this priming effect generalised to novel never consciously seen numerosities for canonical configurations but not for non-canonical ones. These results support the idea that canonical finger configurations automatically activate number semantics whereas non-canonical ones do not.

Mask‐ and distractor‐triggered inhibitory processes in the priming of motor responses: An EEG study

Masked stimuli presented near the threshold of conscious awareness may act as primes, affecting responses to subsequent targets. With arrows as primes and targets, the prime-mask-target sequence has been shown to evoke triphasic lateralized readiness potentials (LRP) with two phases of imbalance between hemispheres preceding the target-related contralateral preponderance of negativity: first a negative, then a positive preponderance contralateral to prime direction. The present article provides evidence that the second wave is related to mask presentation and reflects inhibitory processing independent of reductions in prime visibility, even being evoked by nonmasking distractors that leave the prime fully accessible for consciousness. Of all hypotheses put forward to account for inverse effects in masked priming, this finding is most compatible with the mask-triggered inhibition hypothesis suggested by P. Jaśkowski (2007).

Masked onset priming effect for high-frequency words: Further support for the speech-planning account

Two experiments investigated whether priming due to a match in just the onset between a masked prime and target is found with high-frequency target words. Forster and Davis (1991, Exp. 5) reported that the masked onset priming effect was absent for high-frequency words and used the finding to argue that the effect has its locus in the grapheme-phoneme mapping process that operates serially within the nonlexical route. Experiment 1 used primes that were unrelated to targets and found a masked onset priming effect of equal size for high-frequency and low-frequency target words. Experiment 2 used form-related primes as used by Forster and Davis, and again found that the effect of onset mismatch was not dependent on target word frequency. These results are interpreted in terms of an alternative view that the masked onset priming effect has its origin in the process of preparing a speech response.