CiteULike: Tag subliminal

Subliminal anchoring: Judgmental consequences and underlying mechanisms

Thomas Mussweiler — 2005-10-27T13:08:10-00:00

Organizational Behavior and Human Decision Processes, Vol. 98, No. 2. (November 2005), pp. 133-143.

Judgmental anchoring--the assimilation of a numeric estimate towards a previously considered standard--is an exceptionally ubiquitous effect that influences human judgment in a variety of domains and paradigms. Three studies examined whether anchoring effects even occur, if anchor values are presented subliminally, outside of judges' awareness. Studies 1 and 2 demonstrate such subliminal anchoring effects: judges assimilated target estimates towards the subliminally presented anchor values. Study 3 further demonstrates that subliminal anchors produced a selective increase in the accessibility of anchor-consistent target knowledge. The implications of these findings for the ubiquity of judgmental anchoring, its different underlying mechanisms, and comparative information processing are discussed.

Subliminal anchoring: The effects of subliminally presented numbers on probability estimates

Reitsma-Van — 2005-08-02T09:06:19-00:00

Journal of Experimental Social Psychology, Vol. In Press, Corrected Proof

Previous research demonstrated that if attention is paid to a supraliminally presented number, a subsequent quantitative estimate assimilates towards this number (the anchor effect). One explanation states that this effect is merely caused by the heightened accessibility level of the anchor value itself. Based on this numeric priming account and generalizing from subliminal priming studies, we expected a short-lived subliminal anchor effect. We presented participants subliminally with a low or high anchor value (10 or 90) and next they had to estimate the probability of an epidemic. Half of them were pressed to do this quickly. Only under time pressure, a significant anchor effect emerged.

Subliminal Speech Priming

Sid Kouider — 2005-08-05T12:01:45-00:00

Psychological Science, Vol. 16, No. 8. (August 2005), pp. 617-625.

Attentional Load Modulates Responses of Human Primary Visual Cortex to Invisible Stimuli.

Bahador Bahrami — 2007-03-11T20:25:46-00:00

Curr Biol (7 March 2007)

Visual neuroscience has long sought to determine the extent to which stimulus-evoked activity in visual cortex depends on attention and awareness. Some influential theories of consciousness maintain that the allocation of attention is restricted to conscious representations [1, 2]. However, in the load theory of attention [3], competition between task-relevant and task-irrelevant stimuli for limited-capacity attention does not depend on conscious perception of the irrelevant stimuli. The critical test is whether the level of attentional load in a relevant task would determine unconscious neural processing of invisible stimuli. Human participants were scanned with high-field fMRI while they performed a foveal task of low or high attentional load. Irrelevant, invisible monocular stimuli were simultaneously presented peripherally and were continuously suppressed by a flashing mask in the other eye [4]. Attentional load in the foveal task strongly modulated retinotopic activity evoked in primary visual cortex (V1) by the invisible stimuli. Contrary to traditional views [1, 2, 5, 6], we found that availability of attentional capacity determines neural representations related to unconscious processing of continuously suppressed stimuli in human primary visual cortex. Spillover of attention to cortical representations of invisible stimuli (under low load) cannot be a sufficient condition for their awareness.

The Neural Basis of Love as a Subliminal Prime: An Event-related Functional Magnetic Resonance Imaging Study

S Ortigue — 2007-07-02T12:50:44-00:00

J. Cogn. Neurosci., Vol. 19, No. 7. (1 July 2007), pp. 1218-1230.

Throughout the ages, love has been defined as a motivated and goal-directed mechanism with explicit and implicit mechanisms. Recent evidence demonstrated that the explicit representation of love recruits subcorticocortical pathways mediating reward, emotion, and motivation systems. However, the neural basis of the implicit (unconscious) representation of love remains unknown. To assess this question, we combined event-related functional magnetic resonance imaging (fMRI) with a behavioral subliminal priming paradigm embedded in a lexical decision task. In this task, the name of either a beloved partner, a neutral friend, or a passionate hobby was subliminally presented before a target stimulus (word, nonword, or blank), and participants were required to decide if the target was a word or not. Behavioral results showed that subliminal presentation of either a beloved's name (love prime) or a passion descriptor (passion prime) enhanced reaction times in a similar fashion. Subliminal presentation of a friend's name (friend prime) did not show any beneficial effects. Functional results showed that subliminal priming with a beloved's name (as opposed to either a friend's name or a passion descriptor) specifically recruited brain areas involved in abstract representations of others and the self, in addition to motivation circuits shared with other sources of passion. More precisely, love primes recruited the fusiform and angular gyri. Our findings suggest that love, as a subliminal prime, involves a specific neural network that surpasses a dopaminergic-motivation system.

Can one suppress subliminal words?

S Dehaene — 2007-06-09T02:31:33-00:00

Neuron, Vol. 52, No. 3. (9 November 2006), pp. 397-399.

Subliminal words cause behavioral priming, yet the depth of their processing remains debated. Using transcranial magnetic stimulation (TMS), Nakamura et al. demonstrate in this issue of Neuron that this subliminal priming effect can be selectively disrupted. Distinct TMS sites disrupt priming in lexical decision and pronunciation tasks, suggesting that task set influences subliminal processing.

Task-guided selection of the dual neural pathways for reading.

K Nakamura — 2007-06-09T02:31:21-00:00

Neuron, Vol. 52, No. 3. (9 November 2006), pp. 557-564.

The visual perception of words is known to activate the auditory representation of their spoken forms automatically. We examined the neural mechanism for this phonological activation using transcranial magnetic stimulation (TMS) with a masked priming paradigm. The stimulation sites (left superior temporal gyrus [L-STG] and inferior parietal lobe [L-IPL]), modality of targets (visual and auditory), and task (pronunciation and lexical decision) were manipulated independently. For both within- and cross-modal conditions, the repetition priming during pronunciation was eliminated when TMS was applied to the L-IPL, but not when applied to the L-STG, whereas the priming during lexical decision was eliminated when the L-STG, but not the L-IPL, was stimulated. The observed double dissociation suggests that the conscious task instruction modulates the stimulus-driven activation of the lateral temporal cortex for lexico-phonological activation and the inferior parietal cortex for spoken word production, and thereby engages a different neural network for generating the appropriate behavioral response.

How the Brain Translates Money into Force: A Neuroimaging Study of Subliminal Motivation

Mathias Pessiglione — 2007-05-22T08:39:27-00:00

Science, Vol. 316, No. 5826. (11 May 2007), pp. 904-906.

Unconscious motivation in humans is often inferred but rarely demonstrated empirically. We imaged motivational processes, implemented in a paradigm that varied the amount and reportability of monetary rewards for which subjects exerted physical effort. We show that, even when subjects cannot report how much money is at stake, they nevertheless deploy more force for higher amounts. Such a motivational effect is underpinned by engagement of a specific basal forebrain region. Our findings thus reveal this region as a key node in brain circuitry that enables expected rewards to energize behavior, without the need for the subjects`awareness. 10.1126/science.1140459

Conscious, preconscious, and subliminal processing: a testable taxonomy.

S Dehaene — 2007-05-03T20:18:34-00:00

Trends Cogn Sci, Vol. 10, No. 5. (May 2006), pp. 204-211.

Of the many brain events evoked by a visual stimulus, which are specifically associated with conscious perception, and which merely reflect non-conscious processing? Several recent neuroimaging studies have contrasted conscious and non-conscious visual processing, but their results appear inconsistent. Some support a correlation of conscious perception with early occipital events, others with late parieto-frontal activity. Here we attempt to make sense of these dissenting results. On the basis of the global neuronal workspace hypothesis, we propose a taxonomy that distinguishes between vigilance and access to conscious report, as well as between subliminal, preconscious and conscious processing. We suggest that these distinctions map onto different neural mechanisms, and that conscious perception is systematically associated with surges of parieto-frontal activity causing top-down amplification.

Unconscious processes, subliminal stimulation, and anxiety.

B Mayer — 2007-05-12T05:14:18-00:00

Clin Psychol Rev, Vol. 19, No. 5. (August 1999), pp. 571-590.

Ever since Poetzl's studies, subliminal stimulation has been used as a paradigm to explore the connection between unconscious processes and psychopathology. Inspired by the psychodynamic tradition, folk psychology attributes a dramatic power to subliminal stimulation. In contrast, most modern researchers argue that effects of subliminal stimulation are rather limited. Does that mean that the unconscious is irrelevant to psychopathology? Not necessarily. Ohman and Soares' hypothesis about the preattentive origins of phobic reactions represents a good example of a model in which a "quick and dirty" unconscious may produce pathogenic effects. Although the empirical basis of this model is still meagre, its attractiveness hinges on the assumption that "quick and dirty" processes that make up the first second of human information processing are essential for higher level analysis and performance. In line with this, recent studies have indicated that the attentional bias that accompanies pathological anxiety, might be an unconscious phenomenon. Theories that focus on unconscious cognitive processes involved in pathological anxiety are certainly interesting, but it should be emphasized that there are other aspects of automaticity (i.e., involuntariness) that may be as relevant to psychopathology as absence of awareness.

Sublimal Visual Priming

Moshe Bar — 2007-04-10T18:59:24-00:00

Psychological Science, Vol. 9, No. 6. (1998), pp. 464-469.

Masked pictures of objects were flashed so briefly that only 13.5% of them could be named. Forced-choice accuracy for the unidentified objects was at chance. When the pictures were shown again, about 15 min and 20 intervening trials later, without any indication of possible repetitions, naming accuracy increased to 34.5%. The priming was completely visual, rather than semantic or verbal, as there was no priming of same-name, different-shape images. This is the first demonstration of facilitatory visual recognition priming by unidentified pictures when the subject could not anticipate if, when, or where the previously unidentified picture was to be shown again. A change in the position of the object reduced but did not eliminate the priming, allowing a speculation that the locus of subliminal visual priming is at an intermediate stage in the ventral cortical pathway for shape recognition.

A direct intracranial record of emotions evoked by subliminal words

Lionel Naccache — 2008-01-22T01:45:35-00:00

Proceedings of the National Academy of Sciences, Vol. 102, No. 21. (24 May 2005), pp. 7713-7717.

A classical but still open issue in cognitive psychology concerns the depth of subliminal processing. Can the meaning of undetected words be accessed in the absence of consciousness? Subliminal priming experiments in normal subjects have revealed only small effects whose interpretation remains controversial. Here, we provide a direct demonstration of semantic access for unseen masked words. In three epileptic patients with intracranial electrodes, we recorded brain potentials from the amygdala, a neural structure that responds to fearful or threatening stimuli presented in various modalities, including written words. We show that the subliminal presentation of emotional words modulates the activity of the amygdala at a long latency (>800 ms). Our result indicates that subliminal words can trigger long-lasting cerebral processes, including semantic access to emotional valence. 10.1073/pnas.0500542102

The history of subliminal channels

GJ Simmons — 2008-04-01T10:03:19-00:00

Selected Areas in Communications, IEEE Journal on, Vol. 16, No. 4. (1998), pp. 452-462.

In 1978 the United States was considering adopting a national security protocol designed to enable the USSR to verify how many Minuteman missiles the United States had emplaced in a field of 1000 silos without revealing which silos actually contained missiles. For this protocol to have been acceptable to the USSR, the messages would have had to be digitally signed with signatures which the USSR could verify were authentic, but which the United States could not forge. Subliminal channels were the discovery that these digital signatures could host undetectable covert channels. In general, any time redundant information is introduced into a communication to provide an overt function such as digital signatures, error detection and/or correction, authentication, etc. it may be possible to subvert the purported function to create a covert (subliminal) communications channel. This paper recounts the development of subliminal channels from their origins when only a couple of bits could be communicated covertly to today when potentially a couple of hundred bits can be concealed in signatures generated using the most popular digital signature schemes