The Reticular Activating System (RAS for short) is a tiny part of the brain with a big and important job. It controls consciousness and acts as a filter. At any given moment you have approximately 2 million bits of sensory information available to you. You're only capable of absorbing about 150 bits per second. All the other bits are there, but you literally don't know it, because the RAS doesn't let them in.

So you don't actually perceive reality as much as your RAS "selectively sifts" what you perceive. Think about walking through a crowded airport. It's very noisy, people are talking, announcements are coming over the speaker system, and perhaps you're focusing on your child, making sure he stays close.

You aren't picking out any details about other conversations, or announcements, until you hear your name over the loud speaker. You immediately focus your attention on that announcement, although you didn't hear a word of what went before.

That's your RAS at work—it has an instruction that says 'Pay attention if you hear my name.' Your belief system is also controlled by the RAS. What makes your belief system so important is that your RAS is programmed, not by your conscious mind, but by your subconscious mind.

So a host of old messages, limiting thoughts and disempowering beliefs that have gotten into your subconscious are still there, controlling your RAS—and by extension your perception of reality. Worse than that those old hurts and fears blind us to what our reality can become, closing off our ability to change and forcing us into futures that exactly mirror our pasts.

For example, if I believe that I can't have what I really want, it is probably because when I was a child I was told many times by many adults that I couldn't have what I wanted. The message was well meant, to be sure, because we have maintained a cultural belief that you can't always get what you want (the Rolling Stones even wrote a song about it!). However, it's simply not true.

And yet whenever we have any negative emotion, there is some element in our belief system feeding instructions to our RAS to bring it into our consciousness. The negative emotion will, in turn, cause us to act in ways that create additional situations that once again reinforce our false programming.

And so, since the RAS acts as our "gate keeper," the first step toward sending it a new memo about its job it is to figure out what instructions it has received before. So think about it: What are the stressful thoughts that keep you up at night? With a little investigation, you'll find that the RAS is working on faulty or outdated instructions, and you'll know better how to target your re-training efforts.

The good news is that, over time, information from your conscious mind filters into your subconscious. This is why choosing "better-feeling" thoughts and affirmations (practices I've recommended in previous articles) help change our perceptions over the long run. If you've had some resistance to using these tools in the past, now that you understand the brain mechanics behind them, I hope you'll give them another chance.

With new thoughts and beliefs everything changes. Negative emotions vanish. Opportunities appear that just weren't present before and it becomes far easier for us to accomplish whatever we want. Our relationships with others (and with ourselves) improve because our mindsets completely shift.

So let's get back to the best way to re-train our RAS. Your beliefs affect what you perceive, and what's possible for you—and they are completely under your control. Again, I think finding a better-feeling thought or affirmation that you repeat frequently to yourself is the best way to do this.

You can find the perfect affirmation for you simply by "turning around" your current stressful thought. For example, if you believe that you don't have enough time to do the things you really want to do, your affirmation would be "I have plenty of time to do the things I want to do." (Or if that sounds too far-fetched, "I am creating plenty of time to do the things I want to do.")

When you find an affirmation that works for you, you become happier and healthier in every sense. While happiness is great, it doesn't end there. You become able to do things that you've never done before. You feel good and do good at the same time—and that is true success.

Author's Bio: 

Stacey Curnow works as a certified nurse-midwife in North Carolina, and over more than 15 years her career has taken her from western Indian reservations to a center-city Bronx hospital to the mountains of southwestern Mexico.
She has been an enthusiastic student of positive psychology for years and applies it to her midwifery and life coaching practices with great success. You can find out more about her services at
She is the creator of a thriving blog and many of her articles have been published in print magazines and online.
She lives in Asheville, NC with her husband, young son, and Ruby the wonder chicken.