5 August 2005
Is Subconscious Perception the Root of All Evil?
By Rusty Rockets
Recent studies have suggested that the brain resembles a big, powerful simulation machine. Using the various paths of perception at our disposal we create a mental picture of our environment, but not all of the brain's data acquisition occurs consciously. Research has shown that much of the visual data that we are exposed to slips past us without being consciously registered, but still manages to continue on to the brain's processing network. In light of this, does it follow that the incessant unchecked stream of data entering our brain's neural pathways can have the effect of significantly influencing our behavior? Do television, cinema and video games actually have a subliminal effect on viewers? Do we, if we put our, ahem, minds to it, have the ability to monitor and control what we perceive?
In a paper published recently in Current Biology, University of Sydney scientists Dr. Colin Clifford and Dr. Justin Harris investigated just how far visual signals from our eyes can penetrate into our brain's processing network without being consciously registered. They found that visual signals can actually travel farther under the radar of consciousness than many scientists had previously thought.
Vision begins with the formation of an image on the back of the eye that stimulates a flow of nerve impulses destined for the brain's visual cortex, where the signals are interpreted. In their study, Clifford and Harris examined the influence on conscious vision of an "invisible" image - in their experiment, an image was masked and could be perceived by the brain, but not consciously detected. They showed that such an invisible image received in one eye can influence the appearance of an image in the other eye, thus demonstrating that signals from the invisible image must travel into the brain at least as far as the point at which signals from the two eyes are processed. To reach this point, signals from each eye must be relayed through the mid-brain to the brain's occipital lobe at the back of the head. While it has long been known that the occipital lobe is specialized for visual processing, many scientists believe that it is also the seat of visual consciousness. The results of the Clifford and Harris study challenge this belief, showing instead that activity in the occipital lobe can occur in the absence of conscious visual perception.
The current climate of terror is one example of our brains being flooded with media images, many of which must get through to our subconscious neural pathways and affect our emotions and behavior. Perhaps it is consciousness that is there to prevent hysteria in the face of an impending threat to society - an ability to keep a level head in times of stress. Unfortunately this seems to be a skill that is not employed equally throughout the population. When a society is faced with a perceived threat, reasoned conscious thought seems to succumb to a set of primal instinctual behaviors. In doing so, an otherwise tolerant civil society tends to fall back on paranoid tribal policies, primed to trade off their hard won liberties and moral codes for what they perceive to be greater security. A recent study on the psychology of "perceived threat" stands as an example of this phenomenon.
One aspect of the study, published in the latest issue of American Journal of Political Science, examined how the psychological reaction of "perceived threat" in regard to terrorism plays a role in the public's support of anti-terrorist policies. The authors found that perceived threat increases a desire for retaliation and promotes animosity towards a threatening enemy. As the perception increased, people became more supportive of restricting the rights of groups broadly associated with terrorism and policies that limit the civil liberties of all citizens. The study focused on the individual feelings of the U.S., as a country, being at threat. It involved more than 1,500 adults during the period between early October 2001 and early March 2002. Higher levels of perceived threat were also linked to greater support of U.S. military intervention, policies that would restrict the number of foreign visitors to the U.S. and the singling out of Arabs for special attention after entry. "Over the long term, perceived threat provides the government with greater leeway to increase domestic surveillance and restrict civil freedoms in its fight against terrorism," said lead author Leonie Huddy.
In the most part, the behaviors highlighted in the study in regard to a perceived threat could be construed as emotive overreactions, where instinctive emotional responses dominate reason. Is it that simple though? Walter Freeman, from the Department of Molecular and Cell Biology, at the University of Berkley California, says that emotion and rational thought are not so easily separated, arguing that both rational and emotional responses to external stimuli exist as an intrinsic part of the human species. Both emotion and rational thought patterns will determine the behavior of an individual faced with a critical choice or traumatic event.
Furthermore, Freeman sees emotion as an intentional response to a set of circumstances that relates specifically to past experiences specific to a particular individual. These are combined with present contextual cues, and those of the future. "At a more complex level, emotions are experiences. They are the feelings that accompany the emergent actions that address the anticipated futures of gain or loss in one's attachments to others, one's livelihood and safety, and the perceived possibility or impossibility of changing the world to one's liking or advantage: joy, grief, fear, rage, hope and despair," says Freeman.
"Such states are easily recognized and explained as intentional in many situations, but in others they seem to boil up spontaneously and illogically within an individual in defiance of intent. The behaviors may be in apparent contradiction to sensory triggers that seem trivial, contrary, or insufficient to account for the intensity of actions. Yet they may have an internal logic that comes to light only after probing into and reflecting on the history of the individual," he added.
The role of consciousness has a different role to that of the various emotional states that well up inside an individual's brain. "Consciousness does not generate emotion. It has much more to do with the control of emotion," says Freeman. Emotions are, of course, important to us. They provide a communicative as well as cathartic outlet. Other studies have shown the significant responses that people have toward others whose faces express a series of emotions like anger, happiness and surprise. Without these basic expressions of emotion it would be difficult to communicate feelings adequately. This said, however, it appears that one of the reasons that we have been endowed with consciousness is so that we can overrule the beast within us all. Consciousness gives us the opportunity to pull rank on a raft of negative emotions that, in the end, make society a less attractive place to live. Unfortunately, just possessing consciousness is not enough to guarantee control over negative emotional responses, and its finer points need to be refined and exercised to be effective.
Are we helpless then, in the face of a torrent of data streaming into the neural pathways of our subconscious? Perhaps not.
In a recent study, reported by Olivia Carter and Jack Pettigrew of the University of Queensland, Australia, and colleagues at the University of California, Berkeley, it was demonstrated that it may come down to our ability to vet and control the things that we see in the first place, as well as the way that we observe our environment. In an unusual collaboration between Tibetan Buddhist monks and neuroscientists, researchers have uncovered clues as to how mental states - and their underlying neural mechanisms - can impact conscious visual experience. In their study, reported in Current Biology, the researchers found evidence that the skills developed by Tibetan Buddhist monks in their practice of a certain type of meditation can strongly influence their experience of a phenomenon, termed "perceptual rivalry," that deals with attention and consciousness.
Perceptual rivalry arises when two different images are presented to each eye, and it is manifested as a fluctuation - typically, over the course of seconds - in the "dominant" image that is consciously perceived. The neural events underlying perceptual rivalry are not well understood but are thought to involve brain mechanisms that regulate attention and conscious awareness.
Some previous work had suggested that skilled meditation can alter certain aspects of the brain's neural activity, though the significance of such changes in terms of actually understanding brain function remains unclear. To gain insight into how visual perception is regulated within the brain, researchers in the new study chose to investigate the extent to which certain types of trained meditative practice can influence the conscious experience of visual perceptual rivalry. The monks taking part in the study possessed meditative training ranging in length from 5 to 54 years.
The most impressive results from the experiment were provided by monks practicing a type of mediation called "one-point" meditation, described as the maintained focus of attention on a single object or thought, a focus that leads to a stability and clarity of mind. Major increases in the durations of perceptual dominance were experienced by monks practicing one-point meditation. Within this group, three monks reported complete visual stability during the entire five-minute meditation period. Increases in duration of perceptual dominance were also seen following a period of one-point meditation.
The findings suggest that processes associated with one-point meditation - perhaps involving the ability to stabilize the mind - contribute to the prolonged perceptual control demonstrated by the monks. The researchers conclude from their study that individuals trained in meditation can considerably alter the normal fluctuations in conscious state that are induced by perceptual rivalry and suggest that, in combination with previous work, the new findings support the idea that perceptual rivalry can be modulated by high-level, top-down neural influences.
The results of experiments such as these are encouraging in that they may offer a way to maintain focus and control during some of our darkest emotional upsets. Taking a leaf out of the monks' meditative lives may result in avoiding altogether climates of fear induced paranoia, hatred and xenophobia. But then again, that would involve turning off the television.
Emotion is Essential to All Intentional Behaviors: http://sulcus.berkeley.edu/wjf/CE.%20Neurodynamics.and.Emotion.pdf