In psychology, visual capture is the dominance of vision over other sense modalities in creating a percept. In this process, the visual senses influence the other parts of the somatosensory system, to result in a perceived environment that is not congruent with the actual stimuli. Through this phenomenon, the visual system is able to disregard what other information a different sensory system is conveying, and provide a logical explanation for whatever output the environment provides. Visual capture allows one to interpret the location of sound as well as the sensation of touch without actually relying on those stimuli but rather creating an output that allows the individual to perceive a coherent environment. One example of visual capture is known as the ventriloquism effect which refers to the perception of speech sounds as coming from a direction other than their true direction, due to the influence of visual stimuli from an apparent speaker. Thus, when the ventriloquism illusion occurs, the speaker's voice is visually captured at the location of the dummy's moving mouth (rather than the speaker's carefully unmoving mouth). Another example of visual capture occurs when a sound that would normally be perceived as moving from left to right is heard while a person is viewing a visual stimulus that is moving from right to left; in this case, both sound and stimulus appear to be moving from right to left.
Defining criteria
Theory When two sensory stimuli are presented simultaneously, vision is capable of dominating and capturing the other. This occurs as visual cues can distract from other sensations, causing the origin of the stimulus to appear as if it is being produced by the visual cue. Therefore, when an individual is in an environment, and multiple stimuli reach the brain at once, there is a hierarchy that vision will guide the rest of the somatosensory cues to be perceived as though they align with the visual experience, despite where their original source may be. Research has found that the visual and auditory reflexive spatial orienting are controlled through a common underlying neural substrate. Furthermore, studies have shown that vision has an effect in cognitive neuroscience, and provides for a significant effect when visually attended to. This dominance is seen again through a visual-haptic task that vision is capable of making better judgements of an object that physically touching it. It has also been determined, that there are certain amounts of visual capture that occur depending on the task, sometimes allowing the visual system to be entirely dominant, while others provide haptic cues to be prominent.
Brain regions The thalamus is a section of the brain responsible for relaying sensory and motor signals to the cerebral cortex. As stimuli pass through the thalamus, there are specific regions dedicated to each sense, and therefore is able to sort out the multiple parts of an environment an individual experiences in a given moment. Two of these regions are specific to vision and hearing respectively, which may be responsible for the order in which sensory information is coded and then perceived within the cerebral cortex. The retina at the back of the eye is what perceives stimuli, allowing them to travel through the occipital tract to the lateral geniculate nucleus (LGN) within the thalamus. The data is then transmitted to the occipital lobe where the orientation and other recognizable factors are processed. The LGN is located near the medial geniculate nucleus (MGN) which is responsible for organizing auditory stimuli after one hears a specific sound. Because these two systems are closely located to each other, research has shown that this might be where vision is responsible for taking over the perception of an environment and resulting in visual capture. As the multiple senses are organized and the response is sent further into the brain for processing, it is possible that the visual cues were recorded stronger, and therefore everything is perceived in a way that all other senses are a function of this visual cue, resulting in a cohesive experience for the individual, driven by the visual system, therefore fitting the definition of visual capture.
Origin of research This phenomenon was first demonstrated by Frenchman J. Tastevin in 1937, after studying the tactile Aristotle illusion in 1937. This illusion produces the sensation of touching two objects by crossing one's fingers and then holding a spherical object between them. Visual capture was used to explain how vision could overcome this effect and determine what is actually going on. Attention was again tied to visual cues during an experiment conducted by Michael Posner in 1980. By indicating visually in which direction a stimulus will appear, response time will improve (decrease) if the correct direction is attended to. (Conversely, if the indicator is misleading, response time increases.) This ability to attend to a specific direction allows for a faster reaction time, despite the participant not physically shifting their visual focus during the pre-stimulus indicator. The evidence that vision has an impact on reaction time demonstrates that vision has a neurological effect on the attentional process. Thus, it is clear that vision is capable of manipulating the perception an individual has of an environment —— this perceptual manipulation is what Tastevin considered visual capture.
Examples
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