Illusions that produce perceptual suppression despite constant retinal input are used to manipulate visual consciousness. Here we report on a powerful variant of existing techniques, Continuous Flash Suppression. Distinct images flashed successively around 10 Hz into one eye reliably suppress an image presented to the other eye. Compared to binocular rivalry, the duration of perceptual suppression increased more than 10-fold. Using this tool we show that the strength of the negative afterimage of an adaptor was (...) reduced by half when it was perceptually suppressed by input from the other eye. The more likely the adaptor was completely suppressed, the larger the reduction of the afterimage intensity. Paradoxically, trial-to-trial visibility of the adaptor did not correlate with the degree of suppression. Our results imply that formation of afterimages involves neuronal structures that access input from both eyes, but that do not correspond directly to the neuronal correlates of perceptual awareness. (shrink)

The interocular suppression technique termed continuous flash suppression (CFS) has become an immensely popular tool for investigating visual processing outside of awareness. The emerging picture from studies using CFS is that extensive processing of a visual stimulus, including its semantic and affective content, occurs despite suppression from awareness of that stimulus by CFS. However, the current implementation of CFS in many studies examining processing outside of awareness has several drawbacks that may be improved upon for (...) future studies using CFS. In this paper, we address some of those shortcomings, particularly ones that affect the assessment of unawareness during CFS, and ones to do with the use of ‘visible’ conditions that are often included as a comparison to a CFS condition. We also discuss potential biases in stimulus processing as a result of spatial attention and feature-selective suppression. We suggest practical guidelines that minimize the effects of those limitations in using CFS to study visual processing outside of awareness. (shrink)

Little is known about the time of development of the binocular suppression. In the present study, we evaluated the emergence of binocular suppression in infants by using continuous flash suppression (CFS, Tsuchiya & Koch, 2006). In our experiment, one eye of infants presented with a static face image at one side of the screen, while another eye is presented with dynamic Mondrian patterns in full screen. Adult observers confirmed that the static face image was consciously (...) repressed by the changing Mondrian patterns. If binocular suppression were functional, the infant would not perceive the face as did the adults, and thus would not show any preference in the experiment. However, if binocular suppression in the infants were not yet acquired, they would perceive the face and the Mondrian patterns at the same time, and would thus show preference for the side where the face was presented. The results showed that infants aged 2–3 months, but not those aged 4–5 months, detected the position of the face. Furthermore, this detection was not due to weak contrast sensitivity to the dynamic Mondrian mask. These results indicated that the immature binocular visual system may perceive different images from different eyes simultaneously, and that infants may lose this ability after establishing binocular suppression at 4–5 months of age. (shrink)

Though emotional faces preferentially reach awareness, the present study utilised both objective and subjective indices of awareness to determine whether they enhance subjective awareness and “blindsight”. Under continuous flash suppression, participants localised a disgusted, fearful or neutral face (objective index), and rated their confidence (subjective index). Psychopathic traits were also measured to investigate their influence on emotion perception. As predicted, fear increased localisation accuracy, subjective awareness and “blindsight” of upright faces. Coldhearted traits were inversely related to subjective (...) awareness, but not “blindsight”, of upright fearful faces. In a follow-up experiment using inverted faces, increased localisation accuracy and awareness, but not “blindsight”, were observed for fear. Surprisingly, awareness of inverted fearful faces was positively correlated with coldheartedness. These results suggest that emotion enhances both pre-conscious processing and the qualitative experience of awareness, but that pre-conscious and conscious processing of emotional faces rely on at least partially dissociable cognitive mechanisms. (shrink)

Previous studies suggested that emotions can be correctly interpreted from facial expressions in the absence of conscious awareness of the face. Our goal was to explore whether subordinate information about a face’s gender and race could also become available without awareness of the face. Participants classified the race or the gender of unfamiliar faces that were ambiguous with regard to these dimensions. The ambiguous faces were preceded by face-images that unequivocally represented gender and race, rendered consciously invisible by simultaneous (...) class='Hi'>continuous-flash-suppression. The classification of ambiguous faces was biased away from the category of the adaptor only when it was consciously visible. The duration of subjective visibility correlated with the aftereffect strength. Moreover, face identity was consequential only if consciously perceived. These results suggest that while conscious awareness is not needed for basic level categorization, it is needed for subordinate categorization. Emotional information might be unique in this respect. (shrink)

This study examines whether human gaze lacking the confounding factor of eye whites can be processed unconsciously and explores the critical aspects for such process. Utilizing the continuous flash suppression paradigm, a schematic face—with direct or averted gaze, and with neutral, fearful or happy expressions—was presented to one eye while dynamic masks rendered it invisible to the other eye. Schematic faces were used to avoid unwanted influence from salient eye whites. Participants’ detection time of anything other than (...) the masks was used as an index of unconscious processing time. Faster detection was found for faces with direct gaze than those with averted gaze. However, there was no difference between detection times for different facial expressions and upright-face, inverted-face, and eyes-only conditions . These results confirm that, with schematic faces, gaze can be processed unconsciously regardless of facial expression, and eyes alone are sufficient for such process. (shrink)

Previous research has shown implicit semantic processing of faces or pictures, but whether symbolic carriers such as words can be processed this way remains controversial. Here we examine this issue by adopting the continuous flash suppression paradigm to ensure that the processing undergone is indeed unconscious without the involvement of partial awareness. Negative or neutral words projected into one eye were made invisible due to strong suppression induced by dynamic-noise patterns shown in the other eye through (...) binocular rivalry. Inverted and scrambled words were used as controls to provide baselines at orthographic and feature levels, respectively. Compared to neutral words, emotion-described and emotion-induced negative words required longer time to release from suppression, but only for upright words. These results suggest that words can be processed unconsciously up to semantic level since under interocular suppression completely invisible words can lead to different processing speed due to the emotion information they carry. (shrink)

According to the predictive coding theory of psychosis, hallucinations and delusions are explained by an overweighing of high-level prior expectations relative to sensory information that leads to false perceptions of meaningful signals. However, it is currently unclear whether the hypothesized overweighing of priors represents a pervasive alteration that extends to the visual modality and takes already effect at early automatic processing stages. Here, we addressed these questions by studying visual perception of socially meaningful stimuli in healthy individuals with varying degrees (...) of psychosis proneness. In a first task, we quantified participants’ prior for detecting faces in visual noise using a Bayesian decision model. In a second task, we measured participants’ prior for detecting direct gaze stimuli that were rendered invisible by continuous flash suppression. We found that the prior for detecting faces in noise correlated with hallucination proneness as well as delusion proneness. The prior for detecting invisible direct gaze was significantly associated with hallucination proneness but not conclusively with delusion proneness. Our results provide evidence for the idea that overly strong high-level priors for automatically detecting socially meaningful stimuli might constitute a processing alteration in psychosis. (shrink)

Emotion modulates our time perception. So far, the relationship between emotion and time perception has been examined with visible emotional stimuli. The present study investigated whether invisible emotional stimuli affected time perception. Using continuous flash suppression, which is a kind of dynamic interocular masking, supra-threshold emotional pictures were masked or unmasked depending on whether the retinal position of continuous flashes on one eye was consistent with that of the pictures on the other eye. Observers were asked (...) to reproduce the perceived duration of a frame stimulus that was concurrently presented with a masked or unmasked emotional picture. As a result, negative emotional stimuli elongated the perceived duration of the frame stimulus in comparison with positive and neutral emotional stimuli, regardless of the visibility of emotional pictures. These results suggest that negative emotion unconsciously accelerates an internal clock, altering time perception. (shrink)

Hassin recently proposed the “Yes It Can” (YIC) principle to describe the division of labor between conscious and unconscious processes in human cognition. According to this principle, unconscious processes can carry out every fundamental high-level cognitive function that conscious processes can perform. In our commentary, we argue that the author presents an overly idealized review of the literature in support of the YIC principle. Furthermore, we point out that the dissimilar trends observed in social and cognitive psychology, with respect to (...) published evidence of strong unconscious effects, can better be explained by the way how awareness is defined and measured in both research fields. Finally, we show that the experimental paradigm chosen by Hassin to rule out remaining objections against the YIC principle is unsuited to verify the new default notion that all high-level cognitive functions can unfold unconsciously. (shrink)

Successful interactions between people are dependent on rapid recognition of social cues. We investigated whether head direction – a powerful social signal – is processed in the absence of conscious awareness. We used continuous flash interocular suppression to render stimuli invisible and compared the reaction time for face detection when faces were turned towards the viewer and turned slightly away. We found that faces turned towards the viewer break through suppression faster than faces that are turned (...) away, regardless of eye direction. Our results suggest that detection of a face with attention directed at the viewer occurs even in the absence of awareness of that face. While previous work has demonstrated that stimuli that signal threat are processed without awareness, our data suggest that the social relevance of a face, defined more broadly, is evaluated in the absence of awareness. (shrink)

The 20th century bears witness to the extent to which the potential scale of destruction is proportional to the dimensions of human knowledge. Simultaneously, an ethical disarray grows prevalent within a civilization obliged to do away with the hopes and ideals of the Enlightenment. Continuous entertainment is replacing models capable of nourishing the leisure of human thought and learning. We are threatened with ‘the loss of the different perspectives of human memory’, which can but ‘facilitate the repetition of past (...) mistakes’. (shrink)

Saccadic eye movements create (at least) two related but distinct problems for the visual system: they cause rapid image motion and a displacement of the retinal image. Although it is often assumed that the motion is too fast to be resolved, this is certainly not the case for low-spatial-frequency images. Recent experiments have suggested that the reason we are unaware of the motion during saccades is because motion channels are selectively suppressed, possibly by suppression of the magno-cellular (but not (...) the parvocellular) pathway. This suppression may explain why there is no sensation of motion during saccades, but it leaves open the problem of perceiving a stable world despite continual image displacements. (shrink)

Originally published in Russian in 1981, this unique history of early Soviet philosophy is now available for the first time in English, translated by Frederick Choate.Yehoshua Yakhot (1919-2003) was a professor of philosophy in the Soviet Union until forced to emigrate to Israel in 1975. While in emigration, he finished writing the book begun in Moscow years before. Yakhot's book is essential reading for an understanding of the counter-revolutionary role of Stalinism and its devastating impact on every aspect of Soviet (...) thought. Rare among works dealing with this period, Yakhot presents an objective account of the theoretical role of the major figures in the early Soviet Union—including, most significantly, that of Leon Trotsky, co-leader with Lenin of the Russian Revolution of October 1917.The book describes the flourishing of philosophical discussion after the revolution and ensuing Civil War. By 1922, the major theoretical journal Under the Banner of Marxism had been founded at Trotsky's urging. The first two issues contained letters from Trotsky and Lenin that constituted the program of the journal. By the mid-1920s, two contending camps had formed in philosophy: the mechanists and dialecticians. The relatively free debate between them on many complex issues was followed by Stalin's intervention in December 1930. In a ferocious reaction against the theoretical foundations of the October Revolution, Stalin sent countless genuine Marxists to their deaths during the Great Terror of 1936-38. Prior to the opening of the archives in the late 1980s and early 1990s, Yakhot presents the largely unknown history of many of the Marxist philosophers victimized by Stalinism.The subjects covered in the book include: the subject matter of Marxist philosophy; the problem of contingency; the principle of partisanship in philosophy; Hegel and Marxist dialectics; Spinoza's place in the discussions of the 1920s and 1930s; the rejection of ideology by Marx and Engels; the influence of Bogdanov's ideas; the inevitable crisis of Soviet ideology; and continued attempts to conceal the crimes of Stalinism in the USSR.This new English edition contains photographs, biographical information, an index and two letters by Trotsky and Lenin. (shrink)

The present study investigated the role of thought suppression in incubation, using a delayed incubation paradigm. A total of 301 participants were tested over five conditions, viz., continuous work control, incubation with a mental rotations interpolated task, focussed suppression, unfocussed suppression and a conscious expression condition. Checks were made for intermittent work during the incubation condition. The target task was alternative uses for a brick. In the incubation and suppression conditions, participants worked for 4 minutes, (...) then had a break during which suppression or the mental rotations interpolated task was carried out for 3 minutes before conscious work was resumed for a further 4 minutes on the alternative uses task. Results indicated that both incubation with an interpolated distractor task and incubation with suppression were effective in enhancing performance relative to controls. The intermittent work hypothesis (that effects of an incubation period are simply due to illicit con.. (shrink)

Iris Murdoch’s The Sovereignty of Good—especially the first essay, “The Idea of Perfection”—is often associated with a critique of a certain picture of agency and its proper place in ethical thought. There is implicit in this critique, however, an alternative, much richer one. I propose a reading of Murdochian agency in terms of the continuous activity of cultivating and refining a distinctive practical standpoint, and I apply this reading to her account of moral progress. For Murdoch moral progress depends (...) on transcending egoism and achieving clear perception of a normatively-saturated reality, but it would be a mistake to think of egoism in terms of selfishness, or clarity in terms of altruism. Rather, I argue, Murdochian moral progress requires overcoming socially-conditioned and often ideological forms of alienation, and making the social conditions that inform our practical standpoints self-conscious. (shrink)

An object in continuous motion is perceived ahead of the briefly flashed object, although the two images are physically aligned , the phenomenon called flash-lag effect. Flash-lag effects have been found also with other continuously changing features such as color, pattern entropy, and brightness as well as with streamed pre- and post-target input without any change of the feature values of streaming items in feature space . We interpret all instances of the flash-lag as a consequence (...) of a more fundamental property of conscious perception in general: acceleration of the speed with which samples of perceptual information become represented in explicit format immediately after the stimulation onset. Decreased visual latency of the samples of stimulus information from the streamed input leads to the relative perceptual lag for the separately flashed stimulus because it is not preceded by adjacent sensory input that would have accelerated its perception. Experimental support for the notion of perceptual acceleration is reviewed. (shrink)

Zygmunt Bauman said of 1968 that he could not empathize with the enthusiasm of the Western Left, that this was some kind of party. In Eastern Europe 1968 stood for an end, not a hope. Soon Bauman would be forced into exile, opening a new and brilliant phase of his intellectual trajectory. Sketches in the Theory of Culture was his last Polish book. It was suppressed in 1968, the contract cancelled in retaliation against his support for reforming politics. Now it (...) has been rediscovered, originally in galley proofs, and translated by Dariusz Brzezinski for Polity Press. Like much of Bauman’s work, it is sprawling and inclusive, taking in anthropology, sociology of culture, ethnology and semiotics. It anticipates his life-long enthusiasm for Lévi-Strauss; and it also foreshadows some of the themes much later to be identified as liquid modern, though it may be the case that the theme of continuity is rather social turbulence from postwar reconstruction to the travails of socialist Poland. In this paper I review some of its themes and its status in the body of his work, and offer some introductory remarks on its importance to the study of culture. (shrink)

Heterocyst spacing in blue -green bacteria is widely assumed to be due to a diffusible inhibitor. The inhibitor, a nitrogen-rich compound, probably glutamine, is produced via the N2-fixing enzymes of the heterocyst and in turn serves to suppress the induction of these enzymes and of the differentiation of vegetative cells to heterocysts. This simple morphogenetic mechanism operating in growing cellular filaments ofAnabaena species is investigated on the basis of a continuous and a discrete cellular model, as well as by (...) cell-by-cell simulation of the inhibitor transport. The resulting distances between heterocysts and kinetics of their production are compared with observations, and the values of physical parameters are estimated from the models. (shrink)