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A comparison of masking by visual and transcranial magnetic stimulation: implications for the study of conscious and unconscious visual processing.

Visual stimuli as well as transcranial magnetic stimulation (TMS) can be used: (1) to suppress the visibility of a target and (2) to recover the visibility of a target that has been suppressed by another mask. Both types of stimulation thus provide useful methods for studying the microgenesis of object perception. We first review evidence of similarities between the processes by which a TMS mask and a visual mask can either suppress the visibility of targets or recover such suppressed visibility. However, we then also point out a significant difference that has important implications for the study of the time course of unconscious and conscious visual information processing and for theoretical accounts of the processes involved. We present evidence and arguments showing: (a) that visual masking techniques, by revealing more detailed aspects of target masking and target recovery, support a theoretical approach to visual masking and visual perception that must take into account activities in two separate neural channels or processing streams and, as a corollary, (b) that at the current stage of methodological sophistication visual masks, by acting in more highly specifiable ways on these pathways, provide information about the microgenesis of form perception not available with TMS masks.

Consciousness↗

Unconscious symmetrical inferences: A role of consciousness in event integration.

Explicit and implicit learning have been attributed to different learning processes that create different types of knowledge structures. Consistent with that claim, our study provides evidence that people integrate stimulus events differently when consciously aware versus unaware of the relationship between the events. In a first, acquisition phase participants sorted words into two categories (A and B), which were fully predicted by task-irrelevant primes-the labels of two other, semantically unrelated categories (C and D). In a second, test phase participants performed a lexical decision task, in which all word stimuli stemmed from the previous prime categories (C and D) and the (now nonpredictive) primes were the labels of the previous target categories (A and B). Reliable priming effects in the second phase demonstrated that bidirectional associations between the respective categories had been formed in the acquisition phase (A<-->C and B<-->D), but these effects were found only in participants that were unaware of the relationship between the categories! We suggest that unconscious, implicit learning of event relationships results in the rather unsophisticated integration (i.e., bidirectional association) of the underlying event representations, whereas explicit learning takes the meaning of the order of the events into account, and thus creates unidirectional associations.

Adult↗

The effects of music exposure and own genre preference on conscious and unconscious cognitive processes: a pilot ERP study.

Did Beethoven and Mozart have more in common with each other than Clapton and Hendrix? The current research demonstrated the widely reported Mozart Effect as only partly significant. Event-related brain potentials (ERPs) were recorded from 16 professional classical and rock musicians during a standard 2 stimulus visual oddball task, while listening to classical and rock music. During the oddball task participants were required to discriminate between an infrequent target stimulus randomly embedded in a train of repetitive background or standard stimuli. Consistent with previous research, the P3 and N2 ERPs were elicited in response to the infrequent target stimuli. Own genre preference resulted in a reduction in amplitude of the P3 for classical musicians exposed to classical music and rock musicians exposed to rock music. Notably, at the pre-attentive stage of processing (N2) beneficial effects of exposure to classical music were observed for both groups of musicians. These data are discussed in terms of short and long-term music benefits on both conscious and unconscious cognitive processes.

Acoustic Stimulation↗

Zap! Magnetic tricks on conscious and unconscious vision.

Blindsight, the remarkable capability to react to unseen visual stimuli, has thus far only been demonstrated in patients and monkeys with a lesion to primary visual cortex. A recent study by Boyer, Harrison and Ro demonstrates blindsight in normal human observers, using TMS to block visual processing. Combined with other work, this opens new vistas towards understanding mechanisms of conscious and unconscious vision.

Animals↗

Unconscious semantic priming from pictures.

Three experiments examined the effects of unconsciously presented picture primes on semantic categorization and naming responses to both word and picture targets. Picture naming and word categorization responses to targets were faster and more accurate when the picture primes belonged to the same semantic category as the targets, so called priming effect. No priming was found when subjects performed a word reading task. When priming was evident, no difference was found between responses to targets that were nominally identical to primes (e.g. the picture of a lion followed by either the word LION or the picture of a lion) compared with nominally different targets from the same semantic category as the primes (e.g. the picture of an ELEPHANT followed by either the word LION or the picture of a lion). Responding did not differ significantly from chance when subjects were asked to categorize the primes as natural objects vs. artifacts or as meaningful vs. meaningless objects in three distinct forced-choice unspeeded tasks.

Adult↗

Unconscious influences on amnesics' word-stem completion.

Amnesic patients and control subjects were asked to complete three-letter word-stems under one of three retrieval conditions. In a direct condition, they were told to use the stems as retrieval cues for words that had just been presented in a study list. In an indirect condition, they were told to use the first word that came to mind with no reference made to the study list. Finally, in an oppositional condition, they were told to use the first word that came to mind unless it had appeared on the study list. During the study list presentation, the patients and controls had analyzed each word according to either semantic (associating to each word) or graphemic (counting letters with enclosed spaces) instructions. The results revealed that the control subjects produced a different number of study words during retrieval as a function of retrieval instructions and encoding condition. The amnesics, however, did not vary their performance as a function of retrieval instructions. Under all conditions, they completed the word-stems far more frequently with words from the study list than would be expected by chance and they consistently produced more semantic than graphemic responses. We concluded that semantic analysis might affect the fluency with which an item occurs for the amnesic, but that the item itself remains independent of the source of that fluency for these patients. Thus, the level of analysis performed on a word during study can affect the unconscious performance of amnesic patients but is unavailable for use during conscious retrieval.

Aged↗

[Value of cervical plain radiography in unconscious trauma patient].

INTRODUCTION: The aim of this study was to evaluate the diagnostic value of cervical spine standard radiographs, performed in emergency, and compared with entire cervical helical CT with multiplanar reconstructions as reference. STUDY DESIGN: Open prospective study. PATIENTS AND METHODS: We conducted a six months prospective study including all patients over 15 years of age and unconscious (Glasgow Coma Scale < or = 12). Each patient underwent standard radiographs as well as helical CT of the entire cervical spine. Three senior surgeons and one senior radiologist evaluated the standard radiographs quality. The interpretation was performed by 7 different groups of judges. Two radiologists interpreted the helical CT. For each group, the sensibility, the specificity and the count of correct diagnosis for the standard radiographs were evaluated. The results of the correct diagnosis of each group were then compared to determine the most performant group. RESULTS: Fifty-one patients were included. Helical CT diagnosed spine injuries in 11 patients. The quality of standard radiographs was poor with less than 10% judged correct and 90% of the C7-D1 junction not visible. In the best group (radiologist), the sensibility was 50%, the specificity was 85% and the count of correct diagnosis was 78%. For the correct diagnosis, senior radiologist was significantly better than anaesthetist students, radiologist students and emergency physicians. CONCLUSION: The diagnostic value of standard radiographs was weak whatever the physician. Therefore, helical CT of the entire cervical spine is absolutely necessary and must be performed during the initial evaluation, if the haemodynamic conditions are required.

Adult↗

Unconscious orientation processing.

Recent findings have shown that certain attributes of visual stimuli, like orientation, are registered in cortical areas when the stimulus is unresolvable or perceptually invisible; however, there is no evidence to show that complex forms of orientation processing (e.g., modulatory effects of orientation on the processing of other features) could occur in the absence of awareness. To address these questions, different psychophysical paradigms were designed in six experiments to probe unconscious orientation processing. First we demonstrated orientation-selective adaptation and color-contingent orientation adaptation for peripheral unresolvable Gabor patches. The next experiments showed the modulatory effects of perceptually indiscriminable orientations on apparent motion processing and attentional mechanisms. Finally we investigated disappearance patterns of unresolvable Gabor stimuli during motion-induced blindness (MIB). Abrupt changes in local unresolvable orientations truncated MIB; however, orientation-based grouping failed to affect the MIB pattern when the orientations were unresolvable. Overall results revealed that unresolvable orientations substantially influence perception at multiple levels.

Adaptation, Physiological↗

Conscious and unconscious sensory inflows allow effective control of the functions of the human brain and heart at the initial ageing stage.

The authors of the present article based their assumption on the concept that the sensory systems are the "windows to the brain" through which various functions of the human organism can be controlled. Comprehension of the fundamental mechanisms of the optimization of the sensory systems, brain, and cardiac functions has increased based on the prolonged sensory flows using conscious and unconscious aromatherapy and multimodal sensory activation. Sensory flow evoked stable systemic responses, including adaptive alteration of psycho-emotional state, attention, memory, sensorimotor reactions, intersensory interaction, visual information processing, statokinetic stability, and autonomic heart rhythm control. The efficacy and expediency of the use of sensory flow for non-medicinal correction of vital functions of the human organism at the initial stages of ageing was revealed.

Afferent Pathways↗

Retrospective self-reports of childhood accidents causing unconsciousness in phallometrically diagnosed pedophiles.

The present study investigated whetherhead injuries in childhood might increase the risk of pedophilia in males. The subjects were 1206 patients referred to a clinical sexology service for assessment of their erotic preferences. These were classified, on the basis of phallometric test results, as pedophilic (n = 413) or nonpedophilic (n = 793). Information regarding early head injuries, other signs of possible neurodevelopmental problems, and parental histories of psychiatric treatment were collected with self-administered questionnaires. The results showed that childhood accidents that resulted in unconsciousness were associated with pedophilia and with lower levels of intelligence and education. These associations were statistically significant for accidents that occurred before the age of 6, but not for accidents that occurred between the ages of 6 and 12. These results are compatible with the hypothesis that neurodevelopmental perturbations in early childhood may increase the risk of pedophilia. They are also, however, compatible with the alternative explanation that prior neurodevelopmental problems lead to accident-proneness and head injury, on the one hand, and to pedophilia, on the other, and that head injury has no causal influence on pedophilia. A secondary finding was that the pedophiles were more likely to report that their mothers had undergone psychiatric treatment. This finding suggests that pedophilia may be influenced by genetic factors, which are manifested in women as an increased risk of psychiatric problems, and in their sons, as an increased risk of erotic interest in children.

Adult↗

Integration of the cognitive and the psychodynamic unconscious.

Cognitive-experiential self-theory integrates the cognitive and the psychodynamic unconscious by assuming the existence of two parallel, interacting modes of information processing: a rational system and an emotionally driven experiential system. Support for the theory is provided by the convergence of a wide variety of theoretical positions on two similar processing modes; by real-life phenomena--such as conflicts between the heart and the head; the appeal of concrete, imagistic, and narrative representations; superstitious thinking; and the ubiquity of religion throughout recorded history--and by laboratory research, including the prediction of new phenomena in heuristic reasoning.

Cognition↗

"Unconscious anxiety": phobic responses to masked stimuli.

We tested the hypothesis that an unconscious preattentive perceptual analysis of phobic stimuli is sufficient to elicit human fear responses. Selected snake- and spider-fearful Ss, as well as normal controls, were exposed to pictures of snakes, spiders, flowers, and mushrooms. A separate forced-choice recognition experiment established backward masking conditions that effectively precluded recognition of experimental stimuli both for fearful and nonfearful Ss. In the main experiment, these conditions were used to compare skin conductance responses (SCRs) to masked and nonmasked phobic and control pictures among fearful and nonfearful Ss. In support of the hypotheses, snake- and spider-fearful Ss showed elevated SCRs to snake and spider pictures as compared with neutral pictures and with responses of the nonfearful Ss under both masking conditions. Ratings of valence, arousal, and dominance indicated that the fearful Ss felt more negative, more aroused, and less dominant in relation to both masked and nonmasked phobic stimuli.

Adult↗

Unconscious mood-congruent memory bias in depression.

The purpose of this study was to investigate an unconscious or implicit mood-congruent memory (MCM) bias in clinical depression. Many studies have shown an explicit memory bias, but no study has yet found an implicit MCM bias in clinical depression. The authors compared depressed and control group participants on a conceptually driven implicit memory test. After studying words of positive, neutral, and negative affective valences, participants produced free associations to various cues. Implicit memory or priming was demonstrated by the production of more studied than unstudied words to the association cues. Depressed participants showed more priming of negative words, whereas controls showed more priming of positive words, thus supporting the MCM pattern. Also, no implicit memory deficit was found in depressed participants. These findings are discussed in the context of several prominent theories of cognition and depression.

Adolescent↗

Deep cognitive activation: a new approach to the unconscious.

Deep cognitive activation occurs when a thought is so accessible as to have measurable effects on behavior or judgement, but is yet not consciously reportable. This state of mind has unique properties mimicking some characteristics of the psychoanalytic unconscious, but following theoretically from a consideration of processes of cognitive activation. The sources and consequences of deep cognitive activation are examined, with a view toward understanding how this state is implicated in the assessment, etiology, and treatment of psychopathology.

Awareness↗

Conscious and unconscious retrieval in picture recognition: a framework for exploring gender differences.

The authors explored gender differences by examining 2 distinct memory processes involved in recognizing pictures that were scenes captured from videotapes. For Study 1, the authors used a process dissociation procedure (L.J. Anooshian & P.S. Seibert, 1995; L.L. Jacoby, 1991) to obtain separate estimates of the contributions of recollection (conscious retrieval) and sense of familiarity (unconscious retrieval) in recognizing scenes along previously viewed routes of travel. Women obtained higher familiarity scores than did men, whereas no gender difference emerged for conscious recollection. In Study 2, the authors tested both preschool children and adults and found results similar to those in Study 1 for a task with pictures captured from children's cartoons, regardless of age. The results from these studies illustrate the need for greater attention to diverse memory processes when investigating individual differences, including gender differences, in diverse task domains.

Adult↗

More thoughts on the unconscious: reply to Brody and to Lewicki and Hill.

Brody (1989) and Lewicki and Hill (1989) present commentaries on my central thesis (Reber, 1989) that there exist powerful induction routines that operate largely independently of awareness and yield rich and complex tacit knowledge that resists attempts to make it conscious, although these commentaries are of dramatically different kinds. Because there is a fairly clear basis of agreement between Lewicki and Hill and the points that I made, this reply deals almost entirely with the issues raised by Brody. The focus is on two classes of issues: (a) those of a methodological nature that surround the general problem of doing experiments on unconscious cognition and (b) those that derive from considerations of evolutionary biology that provide a basis for arguing that implicit operations are primary and form the foundation for conscious processes.

Concept Formation↗

Conscious and unconscious strategy discoveries: a microgenetic analysis.

We examined second graders' strategy discoveries on a task that could be solved either by arithmetic computation or by a simple insight. Strategy use was assessed on each trial through both an implicit measure and an explicit one. The results provided unambiguous evidence that strategies can be discovered without conscious awareness. Almost 90% of children showed the insight at an implicit, unreportable level before they showed it at an explicit, reportable one. When children received the relevant problems on each trial, 80% reported the insight within 5 trials of when their solution times indicated that they first generated it. Implications for understanding the relation between unconscious and conscious discoveries and for the role of competing activations in strategy discovery are discussed.

Awareness↗

The negative compatibility effect: unconscious inhibition influences reaction time and response selection.

In the negative compatibility effect (NCE) a masked prime arrow, pointing left or right, is followed by an unmasked (visible) target arrow. The task is to press the left or right switch corresponding to the visible arrow. Surprisingly, reaction time is longer (slowed) when the prime and target indicate the same, rather than different, responses. By contrast, the effect of an unmasked prime is positive-opposite to the NCE. This indicates that the NCE is not attributable to incomplete masking; to the extent that the prime is visible, the NCE would be reduced by this positive influence. Thus, the NCE appears to result from unconscious processing of the prime and, in that sense, may be a form of subliminal perception. Additional findings show that the NCE is due to inhibition of a response code, that it is automatic in that it occurs even if the information in the prime and target could be ignored, and that it also influences response selection.

Awareness↗