Sensory Input & Sensory Memory
This the second installment in the Information Processing Model series that describes how I conceptualize many of the issues that my clients come to work on at Brainsight. In this post, I’ll be talking in more detail about sensory input and sensory memory.
When we talk about sensory input, we’re talking about the information that is picked up by our five senses—taste, touch, sound, smell, and sight. Provided all of those senses work properly, we should be able to gather a great deal of information about our surroundings. But suppose there’s a problem with sensory input. I remember testing a little boy years ago. He was probably 9 or 10 years old, and we were doing the old Stroop Color Word Test. In the first part of the test, he’s asked to read a list of words as fast as he can. He aced this without any trouble. Next, he was presented with a five columns of XXXX in different colors—red, green, and blue. It’s a simple task—just tell me what color the Xs are as fast as you can. He starts, “Pink, Brown, Gray…” I stopped the timer after about five seconds and asked him to point to the pink Xs for me and the brown ones. And then he tells me that he might not do so well on this test because he’s color blind. This kind of sensory input problem is going to make some tasks hard. Some sensory input problems are easy to solve—getting glasses or hearing aids—and others can’t necessarily be fixed, such as color blindness, so we need to figure out strategies to work around them.
Maybe the problem isn’t with the input but is with the filtering. This is the sensory memory part of the equation. Sensory memory acts as a filter in a lot of ways. It helps us to reduce the amount of stimuli that we need to actively process once it gets to our short-term memory. Sensory memory helps explain why you grow accustom to environmental sounds and don’t even notice them after a while. For example, if you live in the city, you might not even notice the traffic sounds—your sensory memory has filtered them out—but when you go out to the country you can’t believe that anyone can stand all the noise that the crickets and frogs make all night long.
But what happens when the filtering doesn’t work right? When there’s not enough filtering, sometimes people are overwhelmed by too much stimuli. Sometimes we describe this phenomenon in children as sensory avoidant. Sometimes they can can’t stand the feeling of tags in clothing or certain food textures, or they are highly sensitive to the sounds of people eating or breathing. Someone with auditory processing difficulties, particularly when they have difficulty with filtering out background noise, might be overwhelmed, nervous, or reactive in noisy environments. These same people may have no trouble with hearing acuity—that is, they might have pass a hearing test with flying colors, but they might have trouble processing auditory input under certain conditions.
Alternatively, when the filter works too well, they don’t get enough input. This plays out for people in at least two ways. Some become sensory seeking—they want more input, so they go looking for it. These are kids that touch everything and can’t keep their hands to themselves, or some of them engage in risky behaviors to get the sensory input they desire. For some people depression might blunt sensory input, and some of the may even engage in self-injurious behaviors to feel something. In other instances when the filter works too well, people don’t desire more sensory input but risk other problems, such as a pain threshold that’s so high that some people don’t realize when they’re injured.
When someone has sensory input or sensory memory/filtering difficulties, it’s important that interventions target this part of the model. For example, if a child is struggling with reading, and it turns out that she needs glasses, you wouldn’t go out and get reading tutor (at least not until after you got her vision corrected to whether there was still a reading problem). Likewise, some people who have auditory processing disorders look and act like they have ADHD, but if we provide interventions that target attention—remember from the last blog post that attention is the link between sensory memory and short-term memory—we’re not likely to see the kind of improvements we’d like. This is mostly because the interventions that improve attention aren’t likely to improve auditory processing.
As this series of blog posts continues, we’ll revisit the idea of using this model to identify problem areas and develop targeted treatment recommendations.