Metacontrast masking does not change with different display technologies: A comparison of CRT and LCD monitors.

Most vision labs have had to replace the formerly dominant CRT screens with LCDs and several studies have investigated whether changing the display type leads to changes in perceptual phenomena, since fundamental properties of the stimulation, e.g., the transition time between frames, differ between these different display technologies.

The Ring Rotation Illusion: Properties and Links of a Novel Illusion of Motion.

We report a novel visual illusion we call the (RRI). When a ring of stationary points replaces a circular outline, the ring of points appears to rotate to a halt, although no actual motion has been displayed. Three experiments evaluate the clarity of the illusory rotation.

No effect of very brief exposure to masked food pictures on fear of food in anorexia nervosa.

Objective: Very brief exposure to masked images of spider stimuli can facilitate approach behaviour towards spiders in fearful subjects. We hypothesized that a similar effect might occur for fear of food in patients with anorexia nervosa (AN), possibly offering a new treatment approach, with advantages over other methods of food exposure.

Methods: Patients with AN (n = 60) were randomly assigned to one of three experimental conditions and received a single session of exposure to either masked and very briefly presented food images, clearly visible food images, or masked non-food images (i.

Encoding Information From Rotations Too Rapid To Be Consciously Perceived as Rotating: A Replication of the Motion Bridging Effect on a Liquid Crystal Display.

A ring of points that is rotated so rapidly is perceived as a stationary outline circle that can induce an illusory rotation with the same spin direction in a subsequently presented ring of stationary points. This motion bridging effect (MBE) demonstrates that motion information can be conveyed by temporal frequencies generally thought to exceed the processing capabilities of the human visual system. It was first described in displays shown with an analog oscilloscope, but the rapid rotation rates needed to produce the MBE have heretofore prevented it from being investigated with conventional raster scan monitors.

Visual experience forms a multidimensional pattern that is not reducible to a single measure: Evidence from metacontrast masking.

A metacontrast masking paradigm was employed to provide evidence for the richness and diversity of our visual experience. Square- and diamond-shaped targets were followed by square- and diamond-shaped masks at varying stimulus onset asynchronies (SOAs), resulting in shape-congruent and shape-incongruent trials. In Experiment 1, participants reported in each trial how they perceived target and mask.

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).

Stimulus dependencies of an illusory motion: Investigations of the Motion Bridging Effect.

The Motion Bridging Effect (MBE) is an illusion in which a motion that is not consciously visible generates a visible motion aftereffect that is predominantly in the same direction as the adapter motion. In the initial study of the MBE (Mattler & Fendrich, 2010), a ring of 16 points was rotated at angular velocities as high as 2250°/s so that observers saw only an unbroken outline circle and performed at chance when asked to report the ring's rotation direction. However, when the rotating ring was replaced by a veridically stationary ring of 16 points, the stationary ring appeared to visibly spin to a halt, principally in the same direction as the initial ring's rotation.

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.

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.

Myocardial T-mapping at 3T using saturation-recovery: reference values, precision and comparison with MOLLI.

Background: Myocardial T-mapping recently emerged as a promising quantitative method for non-invasive tissue characterization in numerous cardiomyopathies. Commonly performed with an inversion-recovery (IR) magnetization preparation at 1.5T, the application at 3T has gained due to increased quantification precision.

Individually different weighting of multiple processes underlies effects of metacontrast masking.

Metacontrast masking occurs when a mask follows a target stimulus in close spatial proximity. Target visibility varies with stimulus onset asynchrony (SOA) between target and mask in individually different ways leading to different masking functions with corresponding phenomenological reports. We used individual differences to determine the processes that underlie metacontrast masking.

On the source and scope of priming effects of masked stimuli on endogenous shifts of spatial attention.

Unconscious stimuli can influence participants' motor behavior as well as more complex mental processes. Previous cue-priming experiments demonstrated that masked cues can modulate endogenous shifts of spatial attention as measured by choice reaction time tasks. Here, we applied a signal detection task with masked luminance targets to determine the source and the scope of effects of masked stimuli.

Masked stimuli modulate endogenous shifts of spatial attention.

Unconscious stimuli can influence participants' motor behavior but also more complex mental processes. Recent research has gradually extended the limits of effects of unconscious stimuli. One field of research where such limits have been proposed is spatial cueing, where exogenous automatic shifts of attention have been distinguished from endogenous controlled processes which govern voluntary shifts of attention.

Neural correlates of control operations in inverse priming with relevant and irrelevant masks.

The inverse priming paradigm can be considered one example which demonstrates the operation of control processes in the absence of conscious experience of the inducing stimuli. Inverse priming is generated by a prime that is followed by a mask and a subsequent imperative target stimulus. With "relevant" masks that are composed of the superposition of both prime alternatives, the inverse priming effect is typically larger than with "irrelevant" masks that are free of task-relevant features.

Individual differences in subjective experience and objective performance in metacontrast masking.

When participants discriminate stimuli that are masked by a following stimulus via metacontrast masking, stable individually different masking functions have been found despite identical stimulation conditions.In the present study, in one group of observers objective performance increased with increasing target-mask stimulus onset asynchrony (SOA), whereas in another group performance decreased with increasing SOA. In addition, a group of overachievers showed ceiling effects whereas a group of underachievers hardly exceeded chance levels of performance irrespective of SOA.

Individual differences in metacontrast masking regarding sensitivity and response bias.

In metacontrast masking target visibility is modulated by the time until a masking stimulus appears. The effect of this temporal delay differs across participants in such a way that individual human observers' performance shows distinguishable types of masking functions which remain largely unchanged for months. Here we examined whether individual differences in masking functions depend on different response criteria in addition to differences in discrimination sensitivity.

Inverse cue priming is not limited to masks with relevant features.

Apart from positive priming effects, masked prime stimuli can impair responses to a subsequent target stimulus which shares response-critical features in contrast to a target assigned to the opposite response. This counterintuitive phenomenon is called inverse priming (or negative compatibility effect). Here we examine the generality of this phenomenon beyond priming of motor responses.

Time course of free-choice priming effects explained by a simple accumulator model.

Unconscious visual stimuli can be processed by human observers and modulate their behavior. This has been shown for masked prime stimuli that influence motor responses to subsequent target stimuli. Beyond this, masked stimuli can also affect participants' behavior when they are free to choose one of two response alternatives.

Neuro-cognitive mechanisms of conscious and unconscious visual perception: From a plethora of phenomena to general principles.

Psychological and neuroscience approaches have promoted much progress in elucidating the cognitive and neural mechanisms that underlie phenomenal visual awareness during the last decades. In this article, we provide an overview of the latest research investigating important phenomena in conscious and unconscious vision. We identify general principles to characterize conscious and unconscious visual perception, which may serve as important building blocks for a unified model to explain the plethora of findings.

A PRP-study to determine the locus of target priming effects.

Visual stimuli that are made invisible by a following mask can nonetheless affect motor responses. To localize the origin of these target priming effects we used the psychological refractory period paradigm. Participants classified tones as high or low, and responded to the position of a visual target that was preceded by a prime.

PRP-paradigm provides evidence for a perceptual origin of the negative compatibility effect.

Visual stimuli (primes) that are made invisible by masking can affect motor responses to a subsequent target stimulus. When a prime is followed by a mask which is followed by a target stimulus, an inverse priming effect (or negative compatibility effect) has been found: Responses are slow and frequently incorrect when prime and target stimuli are congruent, but fast and accurate when prime and target stimuli are incongruent. To functionally localize the origins of inverse priming effects, we applied the psychological refractory period (PRP-) paradigm which distinguishes a perceptual level, a central bottleneck, and a level of motor execution.

Consciousness mediated by neural transition states: how invisibly rapid motions can become visible.

When observers view a rapidly moving stimulus they may see only a static streak. We report that there can be a transient percept of motion if such a moving stimulus is preceded or followed by a stationary image of that stimulus. A ring of dots was rotated so rapidly observers only saw a continuous outline circle and could not report its rotation direction.

Individual differences in metacontrast masking are enhanced by perceptual learning.

In vision research metacontrast masking is a widely used technique to reduce the visibility of a stimulus. Typically, studies attempt to reveal general principles that apply to a large majority of participants and tend to omit possible individual differences. The neural plasticity of the visual system, however, entails the potential capability for individual differences in the way observers perform perceptual tasks.

Priming by motion too rapid to be consciously seen.

When a rapidly rotating ring of dots was briefly flashed, observers saw only a solid ring with no discriminable rotation. However, when this stimulus served as a prime that was followed by a target that consisted of a clearly rotating ring of dots, response times (RTs) to report the target's rotation were shorter when the prime and target directions were congruent than when they were incongruent. In accord with shape priming data, this priming effect increased monotonically with the prime-target stimulus-onset asynchrony (SOA).

Inverse target- and cue-priming effects of masked stimuli.

The processing of a visual target that follows a briefly presented prime stimulus can be facilitated if prime and target stimuli are similar. In contrast to these positive priming effects, inverse priming effects (or negative compatibility effects) have been found when a mask follows prime stimuli before the target stimulus is presented: Responses are facilitated after dissimilar primes. Previous studies on inverse priming effects examined target-priming effects, which arise when the prime and the target stimuli share features that are critical for the response decision.