The same-different task as a tool to study unconscious processing

Two masked prime arrows simultaneously affect a response to a target: Revealing of an additive unconscious priming effect

Since there are many sources of unconscious information in our minds, there is a possibility that multiple channels of unconscious information can affect a response at the same time. However, this question has been largely ignored by researchers. In the present study, we presented two opposite pointing arrows as the masked primes followed by a target arrow. The results suggested that the two directions in which the two prime arrows are pointing influenced the response to the target simultaneously and additively, that is, the overall priming effect caused by the two opposite pointing prime arrows was equal to the net effect of the individual congruent effect elicited by the same pointing prime arrow and the individual incongruent priming effect induced by the prime arrow poitning in the opposite direction. In addition, in Experiment 1, a biased delayed response to the target was observed when the target arrow and the opposite pointing prime arrow were closely positioned in space due to Gestalt continuity and closure grouping. According to these results, the "independent unconscious influence" and "reverse unconscious selection" hypotheses are proposed.

Multiple sources of unconscious-information processing affect a single response: independent unconscious priming effects

At present there is little knowledge on whether and how multiple pieces of unconscious information can simultaneously affect a single conscious response. In the present study, we manipulated the congruency relation between a masked prime arrow and the target arrow, as well as that between masked flankers and the target arrow. The results demonstrated that the masked prime and flankers produced independent unconscious priming effects on the response to the target. In the process of studying the above phenomenon, two secondary findings were made. First, although the prime congruency effect was obtained, the flanker congruency effect was smaller when the flankers were displayed simultaneously with the target than when they were displayed sequentially before the target. This suggested that priming stimulation required enough time to be processed to a sufficient extent to produce an unconscious priming effect. Second, when the prime stimulus was removed, leaving only the flankers, the flanker priming effect increased, suggesting that the attention attracted to the prime and its conscious mask could also reduce the flanker congruency effect. These results observed across several experiments were replicated in one within-subjects experiment. We proposed an "independent unconscious influence hypothesis" for the phenomenon. This hypothesis was further integrated into a more comprehensive unconscious information processing model. The possible causes of the observed phenomena were discussed.

Unconscious Integration of Categorical Relationship of Two Subliminal Numbers in Comparison with "5"

Many studies have shown that the brain can process subliminal numerals, i.e., participants can categorize a subliminal number into two categories: greater than 5 or less than 5. In the context of many studies on the unconscious integration of multiple subliminal stimuli, the issue of whether multiple subliminal numbers can be integrated is contentious. The same-different task is regarded as a perfect tool to explore unconscious integration. In the two experiments reported, we used a same-different task in which a pair of masked prime numbers was followed by a pair of target numbers, and participants were asked to decide whether the two target numbers were on the same (both smaller or larger than 5) or different sides (one smaller, the other larger than 5) of 5 in magnitude. The results indicated that the prime numbers could be categorized unconsciously, which was reflected by the category priming effect, and that the unconscious category relationship of the two prime numbers could affect the judgment on the category relationship of the two target numbers, as reflected by the response priming effect. The duration of the prime-to-target interstimulus interval (ISI) was also manipulated, showing a positive compatibility effect (PCE) of category priming and a negative compatibility effect (NCE) of response priming no matter whether the ISI was short (50 ms) or long (150 ms). The NCE, which occurred when the prime-to-target ISI was relatively short in this study, contradicted the conventional view but was consistent with previous results of unconscious integration based on an attention modulation mechanism. Importantly, this study provided evidence for the still-under-debate issue of numerical information integration.

The Unconscious Tug-of-War: Exploring the Effect of Stimulus Selection Bias on Creative Problem Solving with Multiple Unconscious Stimuli

Objective

This study innovatively investigated the potential selection bias involved in processing multiple subliminal stimuli during creative problem-solving (CPS). It addresses the existing gap in specialized research on how the handling of multiple unconscious stimuli influences higher-order cognitive processes, particularly creativity.

Methods

The study utilized a masked priming paradigm and a remote association task (RAT). Two experiments were conducted. Experiment 1 presented two stimuli simultaneously, with one being the correct answer, to examine whether there was a bias in the location of subliminal stimuli. In Experiment 2, two stimuli were presented sequentially, with one serving as the answer, to investigate whether there was a temporal bias in unconscious processing.

Results

Our findings revealed that when solving easy RATs, subliminal stimuli presented on the left side had a negative priming effect compared to the right side. The results revealed that unconscious processing of subliminal stimuli enhanced performance on difficult CPS. Additionally, a temporal bias was observed, with more recent subliminal stimuli having a stronger effect than earlier stimuli.

Conclusion

Unconscious processing can improve CPS, especially for difficult tasks, and there is a bias towards processing stimuli on the left and more recently presented stimuli. These findings contribute to our understanding of unconscious processing, particularly the processing of multiple subliminal stimuli in CPS, and provide insights into the biases that exist in unconscious processing.

How do irrelevant stimuli from another modality influence responses to the targets in a same-different task

It remains unclear whether multisensory interaction can implicitly occur at the abstract level. To address this issue, a same-different task was used to select comparable images and sounds in Experiment 1. Then, the stimuli with various levels of discrimination difficulty were adopted in a modified same-different task in Experiments 2, 3, and 4. The resultsshowed that only when the irrelevant stimuli were easily distinguishable, aconsistency effectcould beobservedin the testing phase. Moreover, when easily distinguishableirrelevant stimuliwere simultaneously presented with difficulttarget stimuli, irrelevant auditorystimuli facilitated responses to visual targets whereas irrelevant visual stimuli interfered with responses to auditorytargetsin the training phase,indicating an asymmetry in the role of visual and auditory in abstract multisensory integration. The results suggested that abstract multisensory information could be implicitly integrated and the inverse effectiveness principle might not apply to high-level processing of abstract multisensory integration.

The Right Inferior Frontal Gyrus Plays an Important Role in Unconscious Information Processing: Activation Likelihood Estimation Analysis Based on Functional Magnetic Resonance Imaging

Unconsciousness is a kind of brain activity that occurs below the level of consciousness, and the masked priming paradigm is a classic paradigm to study unconscious perceptual processing. With the deepening of unconscious perception research, different researchers mostly use different experimental materials and different masked priming paradigms in a single experiment but not for the comprehensive analysis of the unconscious information processing mechanism itself. Thus, the purpose of this study is to conduct a comprehensive analysis through a cross-experimental paradigm, cross-experimental materials, and cross-experimental purposes. We used activation likelihood estimation to test functional magnetic resonance imaging studies, involving 361 subjects, 124 foci in eight studies representing direct comparison of unconscious processing with baseline, and 115 foci in 10 studies representing direct comparison of unconscious priming effects. In the comparison of unconscious processing and baseline, clusters formed in the left superior parietal gyrus, the right insular gyrus, and the right inferior frontal gyrus (IFG) triangular part after correcting for familywise error (FWE). In the comparison of priming effects, clusters formed in only the right IFG triangular part after correcting for FWE. Here, we found that ventral and dorsal pathways jointly regulate unconscious perceptual processes, but only the ventral pathway is involved in the regulation of unconscious priming effects. The IFG triangular part is involved in the regulation of unconscious perceptual processing and unconscious priming effects and may be an important brain area in unconscious information processing. These preliminary data provide conditions for further study of the neural correlation of unconscious information processing.

Degree and Complexity of Non-conscious Emotional Information Processing - A Review of Masked Priming Studies

Whether and to what degree information can be processed non-consciously has been a matter of debate since the emergence of psychology as a science. Emotional information, in particular, has often been assumed to have a privileged status because of its relevance for well-being and survival (e.g., to detect a threat). Indeed, many studies have explored non-conscious processing of evaluative (i.e., "emotional" in a broad sense) or emotional (e.g., facial expressions) features using the "silver bullet" of non-consciousness research - the masked sequential priming paradigm. In its prototypical form, this paradigm involves the categorization of target stimuli according to valence (e.g., is the target positive or negative?). Each target is preceded by a briefly presented prime that is followed by a mask to constrain awareness. Non-conscious processing is inferred from subtle influences of the prime on target processing, that is, whether responses are faster if prime and target are valence-congruent or not. We will review this research with a focus on three questions: first, which methods are used in this area to establish non-conscious processing? Second, is there evidence for non-conscious extraction of evaluative information? Third, is there evidence for non-conscious processing beyond a simple valence (positive/negative) discrimination, for example, processing of emotion-specific information? We will highlight important current debates and potential directions in which the field will move in the future.