Overpopulation and its Potential Effects on Humanity

overpopulation: John B Calhoun rat universes

Overpopulation and Humanity’s Destiny

If we don’t halt population growth with justice and compassion, it will be done for us by nature, brutally and without pity- and will leave a ravaged world.

-Nobel Laureate Dr. Henry W. Kendal

 

By the year 2050, the Earth’s population is estimated to reach a staggering 9.6 billion people. Many scientists would consider this to be overpopulation of the planet. It is currently believed that there are 7.2 billion people on Earth, but this is just a guess. In reality, we don’t really have any idea how many people are on the planet, just a lot of supposedly “good guesses”. And unless we make some major breakthroughs in the fields of energy, ecology, climatology, and agriculture the human race has a good chance of experiencing a severe decline in population, possibly even extinction because of overpopulation. A lot of things need to change in our civilization’s infrastructure if the human race wants to survive for the next millennia and even more if we are to prosper.

I’m not an alarmist. There’s no need to panic. But you should probably reconsider your consumption patterns, because you will be economically pressured to change them in the next 20 years. Especially if you live in the United States. But the world isn’t going to end in the next 6 months. In fact, Earth will be fine, especially in the long run. We live on a planet that is incredibly good at balancing itself, which we are seeing now with the effects of climate change (see my review of ‘Chasing Ice’ if you want some good evidence of what is happening to the glaciers of the planet). But weather patterns are going to get more and more severe unless we can find ways to mitigate the greenhouse gas effect and humanity’s consumption of fossil fuels.

A Tipping Point for Humanity’s Population?

It is entirely possible that human’s have reached what scientists call “peak oil”. At this point, we might be running out of oil, even though in the last 6 months we have isolated and reproduced a fungus that can produce petroleum. We might also be able to clean up the world’s largest oil spills with a different type of fungus. Advancements in science are what is going to save us. If you don’t know about the scientific method, you should read this article.

All of these developments can be attributed to the massive growth in human population at the cost of our environment. These problems WOULD NOT exist if humanity was better at living symbiotically with our environment. Yes, I say this with 100% certainty. We tend not to look at situations holistically and see only what is in front of us. In this overpopulated state, we need to either mitigate the effects of our oil use while simultaneously finding sustainable sources of it, or we need to find an alternate, sustainable fuel source for the world’s transportation.

Alan Watts said that the fundamental problem with the current state of society is man’s isolation from nature. This allows for our overpopulation of the planet. Things like A/C, cars, roads, airplanes, deforestation, warehouses, skyscrapers, and dams are all examples of destruction of the environment rather than cultivation. Some of these things can be symbiotic with nature if architected properly (ie climate regulation, terraforming, sustainable fuels, nuclear fusion, etc.). Watts said that in the 60s.

The problem with humans is that we view ourselves as separate from our environment, when in fact the two are the same. Religion is a huge cause of this. For some reason, we feel like we are better than our environment, better than animals, because god made us special. In my last article on human microbiota, I explained how humans have a hole inside of us, called the gastrointestinal tract or gut, that is really a part of the outside environment. So in reality, humans and our environment are the same thing. It is largely our ego and search for control that has led us to believe that we are ‘superior to’ or greater than our environment.

The problems are rather simple. Yet people have a tendency to  be so over-reactive to seeing how humans have affected our environment. This allows news companies and especially shitty internet journalism to get an emotional rise out of us. And after this emotional reaction, we tend to become inactive and hopeless, rather than adjusting our behavior. I’ve witnessed this personally within myself. I waste energy on an emotional reaction, rather than thinking about how much waste I create on a daily basis. There are examples in our modern culture. Water consumption in southern California is an excellent example. Some people don’t even believe that there is really a drought.

Americans, as only 5% of the world’s population, use 24% of the world’s energy; some sources estimate the average American uses as much as 160 gallons of water a day. So instead of writing emotional facebook posts, being reactive and emotional about the issue take matters into your own hands; take shorter showers, try to drive less (obviously you have to drive to work and to get your kids to soccer and all that stuff because our infrastructure isn’t setup symbiotically). Try to use less energy, wash only dirty clothes, turn off your lights. Then you can stop worrying about our planet because that’s all you can do. Manage yourself.

We need to consider what it might be like if we had to live in 100% unity with our environment; which sooner or later will become a necessity if we are to survive with such a large population. Cities will be rebuilt. Freeways will be redesigned. We are already seeing the beginning of some amazing developments.

Answers to the problem of overpopulation?

Nuclear fusion might be the answer to our energy problems, but that technology is expensive and we’re going to have to wait for it. However, creating and harnessing the power of stars is how we will survive for the next millennia. There are a few awesome projects happening that might excite you for the future, rather than scare you away from it. The international thermonuclear reactor project is an exciting project underway and Lockheed Martin has somewhat suspiciously said that they have an even more compact reactor on the way (the scientific community is very skeptical because they haven’t yet released data). Our ingenuity will be the key to our survival.

I am trying to say that hopelessness is a silly conclusion and that hope is key to survival and prosperity. One way to inform yourself of some of the negative possibilities in our future is to learn about John Calhoun’s mouse paradise experiments on overpopulation. It is a concept known as the behavioral sink, or societal collapse due to overpopulation. However, even Calhoun left his studies with hope for the future of humanity, especially considering that there were rats that seemed to be resilient to the effects of overpopulation. His studies involved creating mouse utopias, then allowing the mice to overpopulate. In his studies he found

“Many [female mice] were unable to carry pregnancy to full term or to survive delivery of their litters if they did. An even greater number, after successfully giving birth, fell short in their maternal functions. Among the males the behavior disturbances ranged from sexual deviation to cannibalism and from frenetic overactivity to a pathological withdrawal from which individuals would emerge to eat, drink and move about only when other members of the community were asleep. The social organization of the animals showed equal disruption. […]

The common source of these disturbances became most dramatically apparent in the populations of our first series of three experiments, in which we observed the development of what we called a behavioral sink. The animals would crowd together in greatest number in one of the four interconnecting pens in which the colony was maintained. As many as 60 of the 80 rats in each experimental population would assemble in one pen during periods of feeding. Individual rats would rarely eat except in the company of other rats. As a result extreme population densities developed in the pen adopted for eating, leaving the others with sparse populations.

[…] In the experiments in which the behavioral sink developed, infant mortality ran as high as 96 percent among the most disoriented groups in the population.”

-John B Calhoun from “Population density and social pathology”(1970). California medicine 113

We have Hope for the Future

Over-reactivity from fear is something you should actively fight within yourself. Overpopulation is a problem that humanity can work together to solve. There is no need for fear. Find hope, reasons to belief in your own ability to consume less, if no one else’s. Fear and panic are the enemies to social order. Stop believing the news, especially internet articles aimed at reactivity. That’s what they want, to shock you into reading. If you can fight your fear with hope and action you will lead yourself to more action oriented at personal results, therefore affecting the collective in the greatest possible way that you personally can. See what  you can do, challenge yourself, experiment with alternate lifestyle behaviors. You’ll surprise the shit out of yourself 😉

Constructs of the Imagination

Dali_imagination

The human mind is constructive. We create our world, inside of our own heads. To understand the way that we as individuals think, the way that we construct reality, we have to examine some of the moving parts of the consciousness system that are involved. Some of these parts are cognitive, some emotional; things like abstract reasoning, probability prediction, sampling,  grouping, chunking, compartmentalization, and relationship architectures are all necessary to understand how we construct the world around us.

The first and easiest places to examine when talking about the functioning of consciousness are the senses. Foremost is sight, simply because we have more built-in equipment for sight than any of the other sense. We fill in the blanks with out eyes, sometimes seeing things that aren’t there to make sense of patterns. Then sound, which is continually processed; touch, which is a pressure system that is built to feel things outside, but simultaneously internalize them as part of ourselves, such as hugs, touching which releases oxytocin, kissing, etc. The senses construct the mental world inside of our brains and allow us to interact with it.

We also construct socially. We imagine what others may think about us, or even what others may be doing in comparison to our own activities. There is also a an imagined hierarchy that normally forms due to various reasons; usually strength is a deciding factor. We have groups of people that we consider to be part of us, clicks, friend groups, religious communities, etc. This helps to give us a sense of worth by belonging to something, which is why community is such an important aspect of healthy living.

Humans also have a sometimes tragic flaw, called hubris, or pride. We believe ourselves to have accomplished something when we put forth great effort and achieve desired results, which can lead to a sense of accomplishment. This is most certainly a constructive process where we place a sense of value on ourselves for something that has been completed or finished with our participation. This also provides us with a sense of worth and accomplishment.

Humans also project our judgements onto the things around us, sometimes in terms of morals, sometimes in terms of positive or negative. This gives the object a perceived value and allows us to make judgement calls for very important things (i.e. the quality of food that you eat). This also allows us to manipulate the environment in a positive way for our own circumstances, in a similar way to a bird building a nest. It helps us to survive in a very real way.

Humans also have an ability to reason abstractly to plan. It allows us to save food and other resources during harder times and to effectively project ourselves into the future to deal with our environment. This is probably the reason for our massive success on the planet; we have the ability to forego now for later. This is tremendously valuable in social situations, especially those involving trade and bartering, because we can amass specific resources in an efficient manner to trade them for other valuables. This concept is what originally allowed humans to begin agriculture, which then provided us with free time and the ability to work less because we don’t have to always be focused on survival.

However, this amazing ability to plan also has a dark side; fear, anxiety, and idealization. We always want to hope for the best, even if it is an unreasonable outcome of our current situation. We sometimes create false realities because of our own fears and idealizations which then can cause negative effects. We get anxiety for future situations because of past situations that we have already experienced, or we think we know the outcome of a given situation simply because we have experienced a similar one. Fear is the epitome of this dark side, sometimes leading us to create false realities known as neurosis. But in judgement for survival, fear is absolutely necessary.

Fear is possibly the most constructive aspect of the human mind. It gives us the ability to avoid things we have experienced, to efficiently escape certain environments, and to react effectively when faced with danger. However, in social situations, fear has almost no value and can completely degrade relationships. Have you ever been in a relationship where the other person is overly jealous, or protective? This is a perfect example of a fear that degrades a relationship and that is completely unnecessary until some kind of evidence appears.

Humans can construct completely different realities. You can see this in cultural and religious values, where some people believe that the “right” way to live is what they have been taught; or when someone goes into neurosis because of over-stress, or simply genetic factors combined with the environment. In the modern world, stress is almost always the result of imagined or projected fears, which is why it is such a powerful force in our lives. Our ability to deal with the stress physiologically is almost always dependent upon our beliefs about the stress. Sometimes, this can force us to construct completely different realities to allow us to cope with the stress from the environment.

There are a few other things that we make up to deal with the environment; time, measurements, communities, languages, mathematics, mythologies, religion, and stories. Stories are incredibly fascinating, because they allow us to ‘tap in’ to the experiences of another consciousness through communication with our ability to reason and construct abstractly. This can allow us to learn, without really experiencing anything significant in the environment (of course you are reading a book, which is a part of the environment).

These are some of the different ways that we construct reality within our minds. This is why the concept Maya exists in eastern religions. Fear is an extremely interesting phenomenon in humans, almost certainly one to be avoided in social situations. So while you are out there, remember that YOU are constructing the subjective world that you live in and that it is specific to each individual.

Yoga and Drugs (Part 3: anxiety)

anxiety physiology

Anxiety is something that yoga vigorously attacks. Anxiety is essentially a lack of presence and ability to act in the present moment due to the consequences of the past or expectations for the future. Yoga has been clinically proven to reduce anxiety and seems to be more effective than meditation in the scientific literature, but long-term studies are still needed for determining obsessive compulsive disorder and anxiety attacks. I know people with PTSD that practice and they say yoga is life-changing for them. Long term clinical trials with strict controls are needed to really see the positive effects and long-term benefits of yoga on these symptoms.

Yoga forces concentration upon the present moment; it is nigh impossible to do handstands, arm balances, and back-bends without complete focus. Especially when you are pushing the limits of your own body, you need to give it the complete attention it deserves. Yoga trains the brain to ignore “what-if” situations, giving your mind the capacity to be completely present inside of your body. “What if my foot cramps?”, “What if my leg hurts?”. These no longer become possible because you are reacting to the feeling in your foot and leg rather than predicting an outcome.

But it’s not your fault that you are anxious. American society feeds on it, telling you about the things that you need to prepare for and all of the bad things that could happen to you and have happened to others. The news is an amazingly good example. They literally go around finding things to make you startled and uneasy so that you listen to their advice and keep watching. Commercials are another good one. They tell us what we need these things and that if we don’t have them, our lives will not be complete, happy, or fulfilling. American culture also tells us that we should be busy on our cell phones so that we look important, which leads to an inability to focus on what is actually happening in our lives. All of these sources lead us further away from the truth that is inside.

Really, peace and contentment is something that you cultivate and grow. The more time you spend being present, discerning feelings as they pass, and bringing yourself to a place of gratitude, the more ability you will have to over-rule anxiety. Being grateful that you are alive can help alleviate the anxiety over work, take time to consider the circumstances of your life and how lucky you are. It doesn’t come naturally and consumerism fights your ability to be content with what is.

It comes back to the dopamine, serotonin, and over-exciting the central nervous system. Anxiety is almost 100% created by a perception, but is accompanied by physical symptoms like muscular tension (which yoga definitely helps), problems with concentration (which yoga definitely helps), and fatigue/restlessness (which yoga definitely helps). People with symptoms of obsessive compulsive disorder claim that yoga helps, though long terms studies have yet to be done on reducing obsession. One of the most debilitating symptoms of anxiety disorder is fear of death, which is one of the most important parts of yoga. In yoga, Shivasana, or final corpse pose is a meditation upon death and liberates the mind and soul into the present.

All of this comes back to yoga as a treatment option for anxiety, possibly more effective than any other for its symptoms. Being content with the present is about breathing and finding beauty in the small things around you, not buying cars and houses or throwing huge parties and getting wasted. Anxiety is fought by sitting still for a few minutes in the morning, taking a walk in the afternoon, and regular yoga practice will be sure to expedite anything you are already doing.  The bliss of not worrying about anything comes from breaking away from the things that you think you need, and detaching from them. This is how the detachment taught in yoga is the ultimate freedom, especially from things such as anxiety.

This concludes the three-part section on psychiatric drugs and the clinically proven effects of yoga on DSM spectrum disorders of anxiety, depression, and hyperactivity.

Here are some resources for you to reference
Yoga health benefits:
http://www.discovery.org.in/PDF_Files/IJS_20130101.pdf
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768207/

Yoga for Anxiety:
http://web.b.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=09735666&AN=89437925&h=FMvHxKjTmtz2ZnN9F8GZqJYPqQStNO2S41uSObyls8nyYJ3beQRCe5czz87Mb6qI6jFBuo4SuiZrCSHKcPtlLw%3d%3d&crl=c
http://link.springer.com/article/10.1186/1751-0759-8-1
http://chp.sagepub.com/content/18/1/15.short
http://www.ijsr.net/archive/v2i12/MDIwMTM1MTM=.pdf

Perception Across the Senses

Perception Across the Senses

Introduction

The perception of the environment does not occur within a single sense.  The world is perceived through interactions between the senses integrated and cueing the other senses (Fairhall & Macaluso, 2009).  These interactions between the auditory, visual, and tactile sensory systems have been a field of rampant growth within the field of cognition in the last couple of decades.  Indeed, a few decades earlier, the interaction between modalities would have been viewed as somewhat exotic. (Spence, 2004)  How the brain represents space is of a particular interest to modern psychology, has been used in the creation of multitudes of new technologies, and is integral to the understanding of consciousness.  Of particular relevance to the studies of the brain’s construction of space is attention; therefore, the properties of attention must also be examined in detail to explain how the attention is modulated between the sensory modalities.  Multisensory attention can be viewed as a way that human beings control their senses to perceive the world.

The senses are linked together, in a regulatory process that allows for attention to pass through multiple modalities, while simultaneously drawing information from each one.  These cross-modal links among vision, touch, and audition have been tested to reveal an underlying cortical system devoted to multisensory integration  (Kida, 2009).  The brain seems to use the senses in concert, with each sense able to activate or primes the other senses and integrate sensory information from multiple modalities (Fairhall and Macaluso, 2009) This paper will examine many of the underlying mechanisms of multisensory integration, as well as the base senses themselves, especially vision.  The properties of attention must also be examined to understand multisensory attentions; therefore an in depth review of the properties of attention is a necessary first step to understand how the different senses communicate to create a complete and seamless conscious stream.  

Properties of Attention

            Attention and its various principles are some of the most researched principles of psychology, especially cognitive psychology.  Attention is required in almost any conscious process, and some have indeed equated attention with consciousness itself.  The properties of this locus of sensation interpreted into conscious perception and further reactive capabilities have many aspects yet to be resolved. (Lavie, 1995)  One controversial subject within the field of attention studies is the late attention model versus the early selection model.  This is an argument that focuses on where the “bottleneck” of attention is.  This is the study of the limits of attention and how its capacity is limited.  The early and late selection models were created to explain why irrelevant stimuli are perceived and why certain stimuli will be perceived whereas others will not.   In 1995, Lavie took these two approaches to attention and combined them into a hybrid theory of selective attention based on load and task difficulty.  This effectively combined the two concurrent models of attention and provides us with a consistent and well-based beginning of an approach to the modulation of attention resources by the perceptual systems.

            Lavie’s theories of attention should be examined in more detail so that the study of uni-modal and cross-modal sensory integration and attention can be more completely understood.  One problem that is not solved by this approach is the ability to perceive certain information even under high load conditions (Lavie, 2010).  It seems as though the properties of attention are also specific and subjective for each individual and therefore are very hard to study comprehensively.  But the hybrid model has solved many of the internal disputes of the two opposing views of late and early attention models by allowing for the limited capacity of attention and the assumption that perception is somewhat automatic, allowing for the limited capacity of attention and the assumption that perception is somewhat automatic cannot consciously shut it shut down (Lavie, 2010).  According to Lavie, the locus of attention shifts with the difficulty of the task, with easier tasks allowing more irrelevant stimuli to be perceived than more difficult tasks, which would mean a constantly shifting “filter” that has a threshold and limitations on what can be perceived.

            The shifting locus of attention seems to be viewed as somewhat of a filter for irrelevant stimuli while simultaneously having a built in “alarm system” that responds quickly to important stimuli.  This filter has been the subject of the majority of Lavie’s studies because of her studies on task difficulty and the effective limitations that attention has to be able to capture or receive stimulus input.  It has been shown that even the perception of biological stimuli like optic flow is reduced by demanding yet separate tasks. (Lavie, 1997)  This would lead to the belief that the resources of attention are inter-modal, and distributed between the senses based on what can be perceived by each modality.  The information is then integrated across multiple levels in various different parts of cortex.  This multisensory integration between the three primary senses of touch, audition, and vision is the next step in the study of cross-modal attention.

Multisensory Integration 

            Multisensory integration is necessary to recognize different inputs from sensory modalities as pertaining to the same object (Koelewijn, 2010) Results have even demonstrated that during multisensory integration, the brain combines inputs not only from sensory modalities, but acts upon these inputs in concert with the peripheral nervous system to allow for perceptual enhancements (Lugo, Doti, Wittich, & Faubert, 2008).  However, this multisensory integration is not the same thing as attention, even though many studies have shown correlations between the two.  Some studies have suggested that multisensory integration is preattentive and immune to top-down influences (Fairhall & Macaluso, 2009).  However, it is probable that the integration and cortical communication between modalities is not comprehensively understood, which is the position many researchers have taken on the issue.

Integration of multisensory inputs occurs when different senses are detecting the same stimulus at about the same time, at about the same location.  One example of this as an illusion is ventriloquism, which tricks vision into integrating movement information with a sound produced in a slightly different (but unnoticeable) location.  Because the movement takes place simultaneously with lip movement from the puppet, the sound is perceived as emanating from the puppet. Shams, Kamitani, and Shimojo developed another illusory effect that proves that audition biases the visual system in 2000.  They showed that multiple short auditory beeps transformed the visual perception of an event into multiple flashes.  These examples of illusory events show that the multisensory integration systems can be fooled, now they systems themselves must be examined in detail to understand how the senses work across modalities in unison to control attention.

            Multisensory integration can enhance visual search enhance the salience of objects (Koelewijn, 2010).  When a short sound is shown simultaneously with a color change of a target stimulus, the stimulus seems to become separate from the display proving that visual search is enhanced by audition (Koelewijn, 2010).  What these experiments show is the strength of the multisensory integration system to bias, enhance, or facilitate the other senses.  It is a kind of additive process that increases the perceiver’s ability to discriminate, search, and react to the surrounding environment.  However, there are constraints to how the senses can integrate, namely temporal and spatial limitations.

            It is believed that the multisensory integration sites converge unimodal information into unimodal or multimodal sites.  This is believed to only occur with certain constraints pertaining to the location and time between stimulus presentations.  There is also believed to be a rule of inverse effectiveness, which states that the multisensory integration effect is larger with less perceptually powerful stimuli, or less salient stimuli.  The temporal and locational constraints upon the multisensory integration system have been the study of previous research and the constraints upon the multisensory systems are relatively well known.  The results of the studies have shown that there is about a 100-millisecond time window in which the stimuli must be presented, or the multisensory integration will be significantly reduced.  This provides a fairly clear difference from preparatory states, or cueing and alerting of the different sensory systems (Koelewijn, 2010).  

The location of the stimulus is also very important for integration to occur.  However, these spatial constraints seem to be limited to the periphery; if the target is within the region of the fovea multisensory integration will almost certainly occur.  Auditory sounds will enhance the visual perception of objects if the sound is only temporally relevant and the visual stimulus is at the center of fixation.  This implies that sound works in concert with vision in the periphery to enhance the salience of objects, but in the center of the visual field the object will always be enhanced by simultaneous multimodal stimuli.  This infers that multimodal integration occurs at many cortical sites and is indeed shown to do so by many researchers.

            The cortical sites know to integrate multisensory events are not modal specific.  The primary visual cortex integrates auditory information just as there are sites specific for multisensory integration.  The primary brain regions involved in multisensory integration are the superior temporal sulcus and gyrus, the ventral and lateral intraparietal areas, and sub cortical areas such as the superior colliculus (Koelewijn, 2010).  However, the typically unimodal sites are also involved in the processes of multisensory integration, such as the primary visual cortex and primary visual cortex. The superior temporal sulcus is primarily involved in audiovisual integration and is one of the most highly studied cortical areas involved with multisensory integration.  However, it is believed that all of these areas communicate using feed forward connections and polysynaptic feedback loops, creating an additive integration process that increases in effectiveness as the stimuli decrease in intensity (Fairhall & Macaluso, 2009).

            The audiovisual integration effect is one of the more studied and probably the most often used of the multimodal integration effects.  We use this when attending to the visible speech patterns of another person.  The superior temporal sulcus is the brain area shown to integrate speech and visual patterns of movement.  A direct integration effect exists between vocal tract shape, speech acoustics, and deformation of the face, which can signal the starting and stopping of words, sentences, and ideas.  The biological motion of the mouth, neck, and head provide enormous amounts of information for the sound information that is going to be received.  Indeed, the activity of the superior temporal sulcus is super additive with congruent stimuli, as are the primary visual and auditory cortices.  (Callan, D.E.,Jones, Munhall, Kroos, Callan, A.M., & Bateson, 2004).

            Another brain area that has important implications for audiovisual integration is the superior colliculi, which is known as a brain area that reorients visual gaze, especially in saccadic eye movements.  The colliculus’ ability to reorient gaze to peripheral events shows that the brain integrates multisensory information in many cortical areas that are also devoted largely to one mode of perception.  The superior colliculus is known to reorient gaze to a visual movement with a saccade, but also receives input from other modalities, making it a polymodal integration site (Nelson, Hughes, & Aronchick, 1997) The summation, or additive effects of the multimodal inputs to the superior colliculus was observed by Nelson and Hughes’ study, confirming both the spatial constraints of multimodal integration and the role of the superior colliculus in multimodal perception.  Multimodal integration has been studied effectively over the last decade, but the ability for imaging of the brain has greatly increased during this time, so an fMRI study would greatly increase the knowledge of how audiovisual stimuli are integrated in the cortex.

            Moving back to the superior temporal sulcus, it has been shown that voxels of fMRI data show interactions of audio and visual inputs have a mixture of unisensory and multisensory subpopulations, some with uniquely unisensory inputs and some with uniquely multisensory inputs, whose subpopulations were not visible until high resolution fMRI was used to image the activations in cortex (Attenveldt, Blau, Blomert, & Gloebel, 2010).  This means that there are certain areas of cortex completely devoted to multisensory integration, as well as sites that process both a singular modality and multiple modalities, such as the primary visual or auditory cortex.  Pertaining to this research of intermodal connections within brain sites is the brain activity of the blind and deaf in terms of the plasticity of the brain.

            It seems that the brain can compensate for lacking in one type of modality. fMRI data has shown that cross-modal plasticity occurs predominantly in the right auditory cortex for the deaf.  Studies have shown that the auditory cortex in the deaf has visual activation in response to lip movements that are normally used for auditory processing in hearing patients (Finney, Fine, & Dobkins).  Therefore, the right auditory cortex of the deaf, because there is no auditory input received by the cortex, might be able to process motion in the visual modality.  But perhaps the most important aspect of this finding is the reciprocal findings in blind subjects.  In many blind patients, moving auditory stimuli have been observed to activate the right visual cortex.  This occurs again in the right hemisphere of cortex leading to the possibility that plasticity for motion processing in that hemisphere, as well as supporting the right visual cortex’s predisposition towards motion processing (Finney, Fine, & Dobkins).  This neuroplasticity supports the idea of an integrated and connected system of sensory processing that works in parallel to create a conscious perception of the world, especially between the two modalities of vision and audition.  There is even more evidence of such plasticity in the multisensory dorsal stream functioning.

            Localizing objects and navigating motor functions in the environment have been shown to be a part of the dorsal visual stream of information that receives input from the early visual areas (primary visual cortex) and projecting to the posterior parietal cortex Fiehler & Rosler, 2010).  The posterior parietal cortex works is believed to work as an integrator for multiple senses that guides movement in space and can even provide a unified representation of space.  It seems that this dorsal pathway is highly used by the brain to process how to use motor movements to correctly interact with the environment, whereas the ventral stream would be implied for the accurate perception of the object, such as size or distance.  In Fiehler and Rosler’s (2010) study, evidence for the polymodal integration system in the dorsal stream was found that parallels the ideas of multisensory integration already discuss.  This study provides another example of the everyday usage of multisensory information and obvious and necessarily useful integration of the tactile and visual modalities. 

So far, we have examined various aspects of the integrator systems of the senses, the various properties of attention, and how many of the primary sensory areas of cortex are multimodal.  This is but a brief examination of the subject matter, the knowledge and complexity of this field is extraordinarily complex and intricate with large amounts of information on the integration of information within the brain.  There is much research left to be done in the fields of attention and the integration of the senses, but this review should provide a basic overview of the knowledge obtained thus far in the two fields discussed.  However, to fully understand how the senses work in unison, we must step out of the constraints of multisensory integration and the basic tenets of attention into the realm of cross-modal attention.

Cross-modal Attention

Construction, maintenance, and updating of the cognitive representations of space surrounding an organism are essentially for higher functioning and adaption to the environment and the combination of cues of sensory data from the different modalities is often the best way to achieve an adaptive, representative perception of the environment (Spence, 2005).  The fields of multisensory integration and cross-modal attention are highly overlapping; however, it would seem that the main difference between the two fields of research is temporal.  Indeed, cross-modal attention necessarily implies the use of attentive resources, whereas multisensory integration does not necessarily.  This may be due to modern scientific techniques of testing reaction times and cueing, because the differences between the two ideas are minimal and possibly fabricated due to the constraints of laboratory settings.  It is possible that in the real world, such a dichotomy does not exist, which is the view I put forward.  However, for the sake of maintaining consistency with the research in the field, I have provided a dichotomy for the two. 

The difference between multisensory integration and cross-modal attention as defined by Koelewijin (2010) is that multisensory integration is preattentive, occurring at many different levels, whereas cross modal attention has to do with the focusing of the resources of attention.  Multisensory integration only occurs when the cue in one modality and target of a different modality are close together and nearly simultaneous.  Cross-modal cueing effects occur when the cue precedes the target by at least some time, between about fifty and three hundred milliseconds (Spence, 2010). But as discussed earlier, multisensory integration takes place between zero and one hundred milliseconds; therefore, multisensory integration and cross modal attention overlap. 

Cross modal attention has been the subject of a large body of research over the past couple decades.  Spence claims in his research (2004) that the interaction between the senses is the essence of the perceptual construction of the environment.  There is indeed good evidence for a neural system underlying cross-modal links (Kida, Inui, Tanaka, & Kakigi, 2010).  fMRI studies have shown that the intraparietal sulcus and the temporoparietal junction is activated in spatial cueing tasks, and TMS (transcranial magenetic imaging) has also provided support for the intraparietal region (Kida, Inui, Tanaka, & Kakigi, 2010).  However, just as multisensory integration was shown to affect the primary receivers for unimodal sensations, these areas are also responsive to cueing from different modalities.  This means that attention is not only involved with the processing of the primary modality, but also the modality specific brain areas in an irrelevant modality (Nager, Estorf, & Munte, 2006).  There does seem to be one area of cortex that is devoted to modulating the field of attention that is not dependent upon a modality.  This is referred to as the supramodal effect of cross modal attention, and it still highly debatable in the field of cognitive neuroscience.

Supramodal Model of attention

            The supramodal model of attention is a theory that insists that there is a common neural pathway that can control the spatial shifts of the field of attention within and between different modalities (Macaluso, Frith, & Driver).  Driver and Frith (2000) also found that both vision and touch share a supramodal effect for vision and touch in the intraparietal sulcus.  There has also been evidence that the right hemisphere controls for the shifting and general allocation of attention to different modalities, but this is not absolute, because both hemispheres show activation for crossmodal attention tasks.  The inferior premotor cortex was also found to be active during crossmodal tasks, giving reasons to believe that attention primes the motor cortex to react to the environment (Macaluso, Frith, & Driver).  Many studies have also found that the superior premotor cortex and superior temporo-parietal junction were active during visual attention tasks, showing that they are possibly responsible for major shifts of attention.  This shifting of attention between the senses is not automatic, as many researchers had thought prior to 2007.

            Experiments have shown that the crossmodal cueing effects are eliminated under conditions where the participants have to attend to high load tasks in a single modality (Spence, 2010).  This is consistent with Lavie’s load theory and helps to expand the limitations of attention across modalities.  It seems that tactile cueing as a whole can be eliminated when the participant monitors a rapid series visual stream, meaning that crossmodal attention is not automatic.

References

Beauchamp, M. S., Argall, B. D., Bodurka, J., Duyn, J. H., & Martin, A. (2004). Unraveling multisensory integration: patchy organization within human STS multisensory cortex. Nature Neuroscience, 7, 1190-1192.

Callan, D. E., Jones, J. A., Munhall, K., Kroos, C., Callan, A. M., & Vatikiotis-Bateson, E. (2004). Multisensory Integration Sites Identified by Perception of Spatial Wavelet Filtered Visual Speech Gesture Information. Journal of Cognitive Neuroscience, 16, 805-816.

Fairhall, S. L., & Macaluso, E. E. (2009). Spatial attention can modulate audiovisual integration at multiple cortical and subcortical sites. European Journal of Neuroscience, 29, 1247-1257.

Fiehler, K., & Rösler, F. (2010). Plasticity of multisensory dorsal stream functions: Evidence from congenitally blind and sighted adults. Restorative Neurology & Neuroscience, 28(2), 193-205. 

Finney, E. M., Fine, I., & Dobkins, K. R. (2001). Visual stimuli activate auditory cortex in the deaf. Nature Neuroscience, 4, 1171.

Hughes, H., Nelson, M., & Aronchick, D. (1998). Spatial characteristics of visual- auditory summation in human saccades. Vision Research, 38, 3955-3963.

Kida, T., Inui, K., Tanaka, E., & Kakigi, R. (2011). Dynamics of within-, inter-, and cross-modal attentional modulation. Journal Of Neurophysiology, 105(2), 674-686.

Lavie, N. (1995). Perceptual load as a necessary condition for selective attention. Journal of Experimental Psychology: Human Perception and Performance, 21, 451-468.

Lavie, N. (2010). Attention, distraction, and cognitive control under load. Current Directions in Psychological Science, 19, 143-148.

Lavie, N., Hirst, A., de Fockert, J. W., & Viding, E. (2004). Load Theory of Selective Attention and Cognitive Control. Journal of Experimental Psychology: General, 133, 339-354

Lavie, N. (2005). Distracted and confused?: Selective attention under load. Trends in Cognitive Sciences, 9, 75-82

Lugo, J. E., Doti, R. R., Wittich, W., & Faubert, J. (2008). Multisensory integration: Central processing modifies peripheral systems. Psychological Science, 19, 989-997.

Macaluso, E. E., Frith, C. D., & Driver, J. J. (2002). Supramodal Effects of Covert Spatial Orienting Triggered by Visual or Tactile Events. Journal of Cognitive Neuroscience, 14(3), 389-401. 

Nager, W., Estorf, K., & Münte, T. F. (2006). Crossmodal attention effects on brain responses to different stimulus classes. BMC Neuroscience, 731-738.

Rees, G., Frith, C. D., & Lavie, N. (1997). Modulating irrelevant motion perception by varying attentional load in an unrelated task. Science, 278, 1616-1619.

Sotto-Faraco, S. (2005). Book review. European Journal of Cognitive Psychology, 17(6), 882-885. 

Spence, C. (2010). Crossmodal spatial attention. Annals Of The New York Academy Of Sciences, 119, 1182-200.

Spence, C., & Parise, C. (2010). Prior-entry: a review. Consciousness and Cognition, 19(1), 364-379. 

Van Atteveldt, N. M., Blau, V. C., Blomert, L., & Goebel, R. (2010). fMR-adaptation indicates selectivity to audiovisual content congruency in distributed clusters in human superior temporal cortex. BMC Neuroscience.

You don’t own anything

I just keep coming back to this, the idea that you don’t really own things in this world. I mean, you can have a car, or a house, but in the end you won’t have it anymore. And whether you had a big house, or a little house won’t really matter.

“The things that you own end up owning you.” – Fight Club

Material possessions are far less valuable than time or love or relationships, and to a certain extent you only need so much. Maslow, a 19th century psychologist, created a hierarchy of needs, and I think the second level of safety would be the level where material possessions are most important. Too much of it can take away from self-actualization, the highest point on the pyramid.

Maslow's Hierarchy

Self-actualization could also be considered enlightenment, self-knowledge such as the Buddha describes. Getting there requires a great deal of balance in life that is hardly obtained from obsession with material possessions. Sometimes having less can lead to more happiness. And often, people are wealthy for a reason. But the key is to detach from wealth altogether. Neither path is better nor worse, but each is beautiful in its own merits. Appreciate where you are and what life offers you.