Prime Visibility Research Articles

Prime-induced illusion of control: The influence of unconscious priming on self-initiated actions and the role of regression to the mean

To what degree human cognition is influenced by subliminal stimuli is a controversial empirical question. One striking example was reported by Linser and Goschke (2007): participants overestimated how much control they had over objectively uncontrollable stimuli when masked congruent primes were presented immediately before the action. Critically, however, unawareness of the masked primes was established by post hoc data selection. In our preregistered study we sought to explore these findings while adjusting prime visibility based on individual thresholds, so that each participant underwent both visible and non-visible conditions. In experiment 1, N = 39 participants engaged in a control judgement task: following the presentation of a semantic prime, they freely selected between two keys, which triggered the appearance of a colored circle. The color of the circles, however, was independent of the key-press. Subsequently, participants assessed their perceived control over the circle’s color, based on their key-presses, via a rating scale that ranged from 0 % (no control) to 100 % (complete control). Contrary to Linser and Goschke (2007)'s findings, this experiment demonstrated that predictive information influenced the experience of agency only when primes were consciously processed. In experiment 2, utilizing symbolic (arrow) primes, N = 35 participants had to rate their feeling of control over the effect-stimulus’ identity during a two-choice identification paradigm (i.e., they were instructed to press a key corresponding to a target stimulus; with a contingency between target and effect stimulus of 75 %/25 %). The results revealed no significant influence of subliminal priming on agency perceptions. In summary, this study implies that unconscious stimuli may not exert a substantial influence on the conscious experience of agency, underscoring the need for careful consideration of methodological aspects and experimental design's impact on observed phenomena.

Interaction between top-down decision-driven congruency effect and bottom-up input-driven congruency effect is correlated with conscious awareness.

In a conventional (Stroop) priming paradigm, it was well documented that objective prime-target incongruency delays response time (RT) to target compared to prime-target congruent condition. Recent evidence suggests that incongruency between the target and subjectively reported prime identity also delays RT over and above the classic congruency effect. When the prime is rendered invisible, the former effect is fundamentally a bottom-up (BU) stimulus-driven congruency effect and the latter a top-down (TD) guess-driven congruency effect. An influential theory of consciousness, global neuronal workspace theory, postulates that the long-lasting simultaneous and reciprocal interaction between TD decision network and BU input network is preserved during conscious processing and disabled during unconscious processing. Current study is focused on testing this theoretical postulation using two behavioral experiments. Our results showed that indeed TD-congruency and BU-congruency produced additive RT effects on prime-invisible trials, which implies that TD and BU prime representations are activated in independent neuronal populations. Meanwhile, an underadditive interaction effect was observed as prime visibility rose, which is a signature that TD and BU prime representations recruited overlapping neuronal populations during conscious perception. In addition, we suggest that current behavioral paradigm might be a financially friendly alternative to detect the presence of representational overlap in the brain between a wide range of mental representations, such as expectation, prediction, conscious/unconscious perception, and conscious/unconscious working memory. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Masked priming under the Bayesian microscope: Exploring the integration of local elements into global shape through Bayesian model comparison

To investigate whether local elements are grouped into global shapes in the absence of awareness, we introduced two different masked priming designs (e.g., the classic dissociation paradigm and a trial-wise probe and prime discrimination task) and collected both objective (i.e., performance based) and subjective (using the perceptual awareness scale [PAS]) awareness measures. Prime visibility was manipulated using three different prime-mask stimulus onset asynchronies (SOAs) and an unmasked condition. Our results showed that assessing prime visibility trial-wise heavily interfered with masked priming preventing any prime facilitation effect. The implementation of Bayesian regression models, which predict priming effects for participants whose awareness levels are at chance level, provided strong evidence in favor of the hypothesis that local elements group into global shape in the absence of awareness for SOAs longer than 50 ms, suggesting that prime-mask SOA is a crucial factor in the processing of the global shape without awareness.

<p>Fear and Anger Prime Effects on Cognitive Performance: The Role of Prime Visibility</p>

Based on the Implicit-Affect-Primes-Effort (IAPE) model (Gendolla, 2012, 2015), the present experiment investigated the role of prime visibility as a moderator of fear and anger primes’ effect on cognitive performance. Previous research has revealed inconsistent effects. Participants worked on a d2 mental concentration task with integrated pictures of fearful vs. angry faces, which were presented either masked (25 ms) or clearly visible (775 ms). Cognitive performance was assessed in terms of response accuracy and reaction times. Prime visibility significantly moderated the affect primes’ effect on response accuracy: When the primes were visible, fear expressions resulted in significantly lower response accuracy than anger primes. The opposite pattern occurred when the affect primes were masked. Additionally, visible primes led to slower responses in general, suggesting controlled prime processing. The observed performance effects corroborate recent findings on physiological measures of resource mobilization in the context of the IAPE model. Highlights Participants were presented with masked (25 ms) vs. clearly visible (775 ms) primes of anger or fear during a mental concentration task. The visibility of the primes significantly moderated the effect of affect primes on response accuracy. When the primes were visible, fear primes resulted in significantly lower response accuracy than anger primes. The opposite pattern occurred when the affect primes were masked. The performance results corroborate recent physiological findings related to the IAPE model.

Assessing subjective prime awareness on a trial-by-trial basis interferes with masked semantic priming effects.

Ratings of perceptual experience on a trial-by-trial basis are increasingly used in masked priming studies to assess prime awareness. It is argued that such subjective ratings more adequately capture the content of phenomenal consciousness compared to the standard objective psychophysical measures obtained in a session after the priming experiment. However, the concurrent implementation of the ratings within the priming experiment might alter magnitude and processes underlying semantic priming, because participants try to identify the masked prime. In the present study, we therefore compared masked semantic priming effects assessed within the classical sequential procedure, in which prime identification is psychophysically assessed after the priming experiment, with those obtained in a condition, in which prime awareness is rated within the priming experiment. Two groups of participants performed a lexical decision task (LDT) on targets preceded by masked primes of 20, 40, or 60 ms durations, to induce the variability of prime awareness. One group additionally rated prime visibility trials-wise using the Perceptual Awareness Scale (PAS), whereas the other group only performed the LDT. Analysis of reaction times (RTs) as well as drift diffusion modeling revealed general priming effects on RT and drift rate only in the PAS-absent group. In the PAS-present group, residual priming effects on RT and the non-decisional component t0 were obtained for trials with rated prime awareness. This shows that assessing subjective perceptual experience on a trial-by-trial basis heavily interferes with semantic processes underlying masked priming, presumably due to attentional demands associated with concurrent prime identification. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The impact of minimal exposure to affective information on mood and its moderation by prime visibility: a meta-analysis

ABSTRACT This article presents a meta-analysis of the impact of minimal exposure to affective stimuli on the emergence of enduring conscious affective feelings. Theories often assume that such affective feelings are linked to automatic appraisals of events (i.e. in the absence of an evaluative processing goal). However, few studies have tested this hypothesis. Moreover, they have provided divergent results. We propose a meta-analysis of these studies to get a clearer picture on this issue. The meta-analysis includes 22 studies (37 effect sizes; combined N = 2159) in which participants were repeatedly exposed to affective stimuli in the absence of an evaluative processing goal before their mood was measured. In this analysis, we focused on the type of stimulus presentation (i.e. visible vs. masked) as well as on the type of stimulus (i.e. faces, pictures, words). The results indicate that the effect of a stimulus is moderated by the visibility of the stimuli. Repeated exposure to visible stimuli leads to congruency effects (i.e. positive stimuli lead to positive feelings), whereas exposure to masked stimuli leads to contrast effects (i.e. positive stimuli lead to negative feelings). Moreover, these effects seem to be restricted to some types of stimuli, with no detectable effects of emotional faces.

Emotion misattribution from complex scene pictures: Evidence for affective processing beyond valence.

The present experiments employed an emotion misattribution procedure to investigate if, and to what extent, emotional pictures are automatically processed on an emotion-specific level. We employed emotional pictures from the International Affective Picture System (Lang, Bradley, & Cuthbert, 2008) depicting joy-, anger-, fear-, and sadness-related contents as prime stimuli in the four-category emotion misattribution procedure (Rohr, Degner, & Wentura, 2015). Pictures were presented briefly and masked to avoid intentional responding. The pattern of results across all experiments provides evidence for an unfolding of emotion specificity along with the degree of visibility of primes. When presentation duration allowed for relatively good prime visibility (40 ms; Experiment 1), we observed emotion-specific misattribution effects for each prime category. With shorter prime presentation reducing prime visibility (30 ms; Experiment 2a and 2b), misattribution effects became less specific: While anger-related emotional scenes were clearly differentiated from fear and sadness-associated scenes, the latter two were not differentiated from one another. This pattern cannot be explained by simple semantic processing, but fits to an early appraisal of the coping ability associated with the emotion triggered by the pictorial content highlighting that specific, emotion-related processes are involved at the very early stages of emotional information processing. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Priming of natural scene categorization during continuous flash suppression

Continuous Flash Suppression (CFS) reduces conscious awareness of stimuli. Whether stimuli suppressed by CFS are processed at categorical or semantic levels is still debated. Here, we approached this question using a large set of indoor and outdoor scene photographs in a priming paradigm. Perceptually suppressed primes were followed by visible targets. Participants rapidly reported whether the targets showed an indoor or an outdoor scene. Responses were faster (and fast responses more accurate) when primes and targets came from a congruent superordinate category (e.g., both were outdoor scenes). During CFS, priming effects were relatively small (up to 10 ms) and modulated by prime visibility and stimulus onset asynchrony (SOA) of prime and target. Without CFS, the stimuli elicited consistent and more robust priming effects (about 24 ms). Our results imply that scene category is processed during CFS, although some residual prime visibility is likely necessary for significant priming effects to occur.

Unconscious preparation: Effects of prime visibility on semantic generalization of task priming.

Studies found that subliminal primes can be associated with specific tasks to facilitate task performance, and such learning is highly adaptive and generalizable. Meanwhile, conditioning studies suggest that aversive/reward learning and generalization actually occur at the semantic level. The current study shows that prime-task associations can also be generalized to novel word/neighbour primes from the same semantic category, and this occurs without contingency awareness. Previous studies have counterintuitively suggested that both the learning of task priming and the semantic priming of word neighbours depend on the lack of visibility. Here, we show that semantic generalization indeed depends on reduced visibility, but cannot occur subliminally. The current study shows for the first time that semantic learning and generalization can occur without any emotional or motivational factors, and that semantic priming can occur for arbitrary-linked stimuli in a context completely devoid of semantics.

Induced dissociations: Opposite time courses of priming and masking induced by custom-made mask-contrast functions.

We present a new experimental technique to induce dissociations between the visibility of a masked prime and its ability to induce a priming effect in response times. In three experiments, we systematically couple an independent variable known to influence the priming effect (prime-mask SOA) with a variable expected to influence prime visibility but not priming (mask contrast). This way, we create mask-contrast functions where mask contrast either increases with SOA, decreases, or remains constant at maximum or minimum levels. We show that different mask-contrast functions can lead to qualitatively different time courses of masking without affecting the time course of priming, allowing for double dissociations (e.g., increasing priming effects under decreasing prime visibility). For the first time, we demonstrate such double dissociations for response priming by color as well as shape stimuli. We also show that the technique requires stimuli that decouple the mask's ability to mask the prime from its ability to activate the response. We conclude that mask-contrast functions can accentuate or even induce dissociations between priming and masking, opening new possibilities for studying perception without awareness.

Action priming is linked to visual perception in continuous flash suppression.

Visual prime stimuli can affect the processing of following target stimuli even if their visibility is reduced due to visual masking. Prime visibility depends on the stimulus parameters of the prime and those of the mask. Here we explored the effects of prime stimuli and modulated their visibility by continuous flash suppression (CFS). CFS reduces the visibility of a stimulus presented to one eye by simultaneously presenting a series of high-contrast masking stimuli to the other eye. We manipulated the strength of CFS effects on perception and examined how action priming effects of the masked stimuli varied under the same conditions. Prime visibility was modulated by the contrast of the primes (Experiments 1 and 2), the contrast of the masks (Experiments 2 and 3), and by the stimulus onset asynchrony between prime and target stimuli (all experiments). Surprisingly, action priming effects were modulated by these experimental variables in a parallel way. In addition, individual differences between participants in prime visibility correlated with individual differences in action priming. Our findings suggest that action priming and prime perception depend in similar ways on prime contrast, mask contrast, stimulus onset asynchrony, and individual dispositions in CFS. These findings distinguish CFS from other perceptual suppression techniques, such as backward masking, that allow reducing prime visibility without parallel effects on action priming. Our results corroborate the view that CFS interferes with visual processing at early stages in the cortical hierarchy with similar effects on later processing for perception and action.

Action priming suppression by forward masks.

Visual stimuli may produce strong and reliable effects on subsequent actions irrespective of their visibility. This dissociation between action priming and conscious perception of the stimuli suggests two ways of processing of visual stimuli. One way of processing leads to the emergence of conscious visual perception, and another way leads to action priming effects. Here we examined the influence of forward masks that precede the prime on processing for action. In three experiments, we found that forward masks can suppress and even abolish priming effects. Suppression was larger with strong rather than weak forward masks and with short rather than long prime durations. Similar suppression effects occurred with surrounding paracontrast masks and with overlapping pattern masks. Our findings emphasize that processing for action depends crucially on preceding stimuli suggesting that action priming may depend on the initial part of the response to the prime. Results indicate that the use of forward masks to reduce prime visibility may also reduce action priming and potentially other priming effects.

Masking procedures can influence priming effects besides their effects on conscious perception.

Masked priming has been employed to study the role of consciousness for different levels of visual processing. However, masking procedures differ systematically between studies. To examine these procedural differences we contrasted priming effects with metacontrast masking, which is often applied in the context of perceptual priming, and priming effects with sandwich pattern masking, frequently used in studies on semantic priming. Results indicate that the amount of masking neither affects perceptual nor semantic priming effects in a semantic categorization task when a metacontrast masking paradigm was used. However, perceptual and semantic priming effects increased with increasing prime visibility when a sandwich pattern masking paradigm was used. Findings suggest that different types of masking procedures affect the processing of the masked stimuli in substantially different ways even if the masking effect on conscious perception of these stimuli is comparable.

The Effect of Negative Implicit Affect, Prime Visibility, and Gender on Effort-Related Cardiac Response

Based on the Implicit-Affect-Primes-Affect (IAPE) model (Gendolla 2012, 2015), we investigated the effect of affect primes’ visibility on effort-related cardiac response. Participants worked on a cognitive “parity task” with integrated pictures of sad vs. angry faces that were briefly flashed (25 ms) vs. clearly visible (780 ms). We recorded cardiac pre-ejection period (PEP) to assess effort mobilization. As expected, PEP reactivity in the sadness-prime condition was stronger than in the anger-prime condition when the primes were briefly flashed, while the opposite pattern occurred when the affect primes were clearly visible. However, these effects only occurred for men, but not for women, as indicated by a significant prime x prime visibility x gender interaction. These findings provide new evidence for the role of prime visibility as a moderator of automatic effort mobilization—and suggest that this moderator effect applies especially to men.

No evidence for dorsal-stream-based priming under continuous flash suppression.

Previous studies have proposed that potentially action-relevant visual features of masked images are processed along the dorsal visual pathway, and can thus prime responses to images of man-made manipulable objects (tools). According to the "category priming by elongation" hypothesis, (invisible) stimulus elongation is the basis for how the dorsal stream can affect the categorization of tools. In our study, prime stimuli were rendered invisible using continuous flash suppression (CFS) and anaglyphs for dichoptic stimulation. We found that participants' reaction times were only weakly affected by CF-suppressed prime stimuli. If anything, the RT data were more consistent with response priming based on shape. Moreover, when prime visibility was low, participants were not able to infer the prime's category but its shape. We recommend that future CFS priming studies should use crosstalk-free setups for dichoptic stimulation, and that awareness measures should be tailored to the stimulus feature of interest.

Prime visibility moderates implicit anger and sadness effects on effort-related cardiac response

Based on the Implicit-Affect-Primes-Effort (IAPE) model (Gendolla, 2012, 2015), an experiment investigated the effect of affect primes’ visibility on effort mobilization during cognitive processing. Participants worked on a short-term memory task with integrated sadness vs. anger primes that were presented suboptimally (briefly and masked) vs. optimally (long and visible). Effort was assessed as cardiovascular response, especially cardiac pre-ejection period (PEP). To monitor performance, we assessed response accuracy and reaction times. In accordance with the IAPE model, PEP reactivity was stronger in the sadness-prime condition than in the anger-prime condition—but only when the primes were suboptimally presented. Effects on response accuracy revealed a corresponding pattern. The results suggest that prime visibility is a boundary condition of anger and sadness primes’ effect on effort mobilization.

Unconscious Processing of Facial Emotional Valence Relation: Behavioral Evidence of Integration between Subliminally Perceived Stimuli.

Although a few studies have investigated the integration between some types of unconscious stimuli, no research has yet explored the integration between unconscious emotional stimuli. This study was designed to provide behavioral evidence for the integration between unconsciously perceived emotional faces (same or different valence relation) using a modified priming paradigm. In two experiments, participants were asked to decide whether two faces in the target, which followed two subliminally presented faces of same or different emotional expressions, were of the same or different emotional valence. The interstimulus interval (ISI) between the prime and the target was manipulated (0, 53, 163 ms). In Experiment 1, prime visibility was assessed post-experiment. In Experiment 2, it was assessed on each trial. Interestingly, in both experiments, unconsciously processed valence relation of the two faces in the prime generated a negative priming effect in the response to the supraliminally presented target, independent of the length of ISI. Further analyses suggested that the negative priming was probably caused by a motor response incongruent relation between the subliminally perceived prime and the supraliminally perceived target. The visual feature incongruent relation across the prime and target was not found to play a role in the negative priming. Because the negative priming was found at short ISI, an attention mechanism as well as a motor inhibition mechanism were proposed in the generation of the negative priming effect. Overall, this study indicated that the subliminal valence relation was processed, and that integration between different unconsciously perceived stimuli could occur.

Experience a conflict-either consciously or not (commentary on Desender, Van Opstal, and Van den Bussche, 2014).

Experience a conflict-either consciously or not (commentary on Desender, Van Opstal, and Van den Bussche, 2014).

Thresholds of visibility for masked lexical, non-lexical, and non-linguistic items in aphasia

Thresholds of visibility for masked lexical, non-lexical, and non-linguistic items in aphasia

Comparing unconscious processing during continuous flash suppression and meta-contrast masking just under the limen of consciousness.

Stimuli can be rendered invisible using a variety of methods and the method selected to demonstrate unconscious processing in a given study often appears to be arbitrary. Here, we compared unconscious processing under continuous flash suppression (CFS) and meta-contrast masking, using similar stimuli, tasks and measures. Participants were presented with a prime arrow followed by a target arrow. They made a speeded response to the target arrow direction and then reported on the prime’s visibility. Perception of the prime was made liminal using either meta-contrast masking (Experiment 1) or CFS (Experiments 2 and 3). Conscious perception of the prime was assessed using a sensitive visibility scale ranging from 0 to 3 and unconscious processing was measured as the priming effect on target discrimination performance of prime-target direction congruency when prime visibility was null. Crucially, in order to ensure that the critical stimuli were equally distant from the limen of consciousness, we sought stimulus and temporal parameters for which the proportion of 0-visibility trials was comparable for the two methods. We found that the method used to prevent conscious perception matters: unconscious processing was substantial with meta-contrast masking but absent with CFS. These findings suggest that CFS allows very little perceptual processing, if at all, and that previous reports of high-level and complex unconscious processing during CFS may result from partial awareness.