Written by Matthew O’Malley
For numerous years, I have been following the evidence trail on the nature of stuttering. By that, I mean that I’ve worked to look at the condition as objectively as possible. I’ve consciously worked to be free from bias and to let the facts surrounding the condition inform my view. I didn’t work to support what I wanted stuttering to be nor what others may tell me it is. I have looked at its nature and allowed that to be my sole informant. That being said, I certainly use research others have done. However, I actually read the research so I can determine what can be drawn from it.
In striving to be like any good detective, I don’t fall in love with a theory nor over-pursue a “lead” that the facts don’t support.
I look at its nature from as many vantage points as possible and investigate the leads.
In doing so, this condition has become utterly fascinating. Where it has lead me I could not have predicted.
Interestingly, I have also long been fascinated with life and existence. I am in awe of “the mystery” of life and seek deeper understanding of it. In following my heart on this journey to understand stuttering, these paths are currently merging. Time and consciousness have been existential topics for spiritual traditions for millenia. They have also been sources of fascination and inquiry for scientific minds.
These concepts have come into the cross-hairs (consciousness, time) for me in following the leads to uncovering the nature of stuttering.
Let’s dive in.
Let’s first take a brief look at time. Many of the points I touch on are counter-intuitive, however, they are true.
Firstly, our experience of “now” is approximately a half second behind the physical now. Let me restate for clarity. Our conscious experience of each moment is a replay from about a half second ago. Yes you’ve read those two statements correctly. We never experience “the now” directly.
For example, let’s say a ball hits me on my arm and I feel it. When I experience the ball hitting me, it had actually already happened about a half second ago. In physical reality, the ball actually hit my skin approximately a half second before I experienced it hitting me.
Our reality; our “now” is a replay.
How could this be?!
Well, the process for creating our conscious experience isn’t simply magic. It doesn’t happen instantaneously. When I see the ball coming in; when I hear it hit me; when I feel it touch my skin; there are many process that have to happen to create my conscious experience of this. The nervous system has to process all this different sensory information from different parts of my body (eye, ear, arm, etc.) and construct it all into a reality I can understand. This “reality I can understand” is my conscious experience. It takes about a half second for the brain to “serve up” this conscious experience. As a result, my experience of “now” is on a half second delay. It actually happened in physical reality a half second earlier.
Some fancy terms used regarding this concept are “the antedating of consciousness” or “the backward referral of sensation”. Neuroscientists in this area use these terms to describe these truths that are well established at this point.
In supporting this, let’s look at some work from research in this area. Benjamin Libet was one of the pioneering researchers on this front and did some experiments which have been replicated and supported. A Dictionary of Psychology (2015), in describing Libet’s work, states that there is “a period of approximately half a second between a person’s skin being touched and the resulting conscious experience of being touched”. It continues, “even a brief stimulus applied directly to the skin is consciously experienced, but not immediately—if it is followed within less than half a second by stimulation of the somatosensory cortex, then backward masking stops the skin stimulus from being felt, confirming that the conscious experience of a skin stimulus is delayed by about half a second.” (Colman & Libet, 2015)
Sidenote: If you read those quotes carefully, there are even more implications. Even if the “touching stimulus” on the skin is registered in the brain earlier than a half second, the brain still purposefully delays you feeling it until about a half second after it actually happened. Why? All the senses have to be served up in sync for our conscious experience to make sense. Other forms of sensory information take longer to process than touch (for example visual data takes longer for the nervous system to process). So, the brain pauses the sensation of touch until it has the visual data and the sound data processed to be able to sync them. Otherwise, you’d see something touch your skin and feel it being touched at different times.
David Eagleman (2018), a neuroscientist & professor at Stanford, states, “There is no such thing as now. We live in the past by about half a second. Why? Because the brain is always collecting information from all the senses: from your eyes and ears to your fingertips and toes. These pathways process information at different speeds, so information comes streaming into different parts of your brain at slightly different times. The job of your consciousness is to collect the information, stitch it together, and serve a story of what just happened. It takes time to put everything together, and as a result, we are always living in the past. By the time you’ve processed all the information about a moment, the moment is long gone. Your conscious perception of the world is always lagging, so your experience of the moment right now is actually a delayed reality.”
We are going to dive deeper, but that already has significant implications in regards to stuttering. When we are speaking and we say a word, we actually said it about a half second earlier. We feel and hear ourselves say it in our conscious realities, but it happened in physical reality about a half second prior. In applying this, when a person who stutters experiences a stutter or block, this “stutter” actually happened a half second prior. Many attempt to “get out” of a block “in the now” however, the stutter began a half second ago. Can this help explain the helplessness and powerlessness experiences in trying “get out” of a block as in fact people who stutter are not accessing the moment we feel like we are. This has implications for how to approach treatment. We’ll dive more into this later. There is more to look at in regards to time.
Movement, Time, & Will
Prior Knowledge Needed:
Let us establish, as I have in previous posts that speaking is movement. Speech is a complex task involving the formulation of language. However the physical performance of speech is movement. When a person “speaks out loud”, movements of various parts of the person’s body are required. The speaker must move their lips, tongue, and jaw which is the contraction and relaxation of muscles. The speaker must move muscles associated with the inhalation and exhalation of the lungs. They must move muscles that enable vibration of the vocal folds. The important point here is speech is movement. When a person speaks out loud, they must move their bodies. What I am about to discuss below is research that applies to the underlying neurological processes of movement (including speech movements). For you to connect how this information can illuminate the processes of speech and stuttering, it is important to understand that speech is movement. So, keep this in mind.
Diving into Movement, Time, & Will
There is also a counter-intuitive relationship between our experience of time, decision-making, and action/movement. Our nervous system begins preparing the actions/movements we end up making before we are aware of our decision to make those movements. To restate for clarity; our nervous system begins preparing an action/movement before we are consciously aware we are going to perform the action/movement. After it has been partially prepared we become aware of our “decision” to perform that action/movement. These findings have implications in regards to the nature of free will. However, we are not going down that rabbit hole.
In looking to the science on this, research shows that the brain begins activating motor circuits responsible for a voluntary movement about 550 milliseconds before the voluntary movement is actually performed; that’s slightly more than a half second (Libet, 1985). The person’s awareness of their intention to move occurs about 200 milliseconds before the actual movement is performed. This is slightly less than a quarter of a second. Doing some basic math, you can see that the brain begins activating for a movement approximately 350 milliseconds before the person’s conscious awareness of their own intention to make that movement. The above times and information come from Libet’s study in 1985, titled “Unconscious cerebral initiative and the role of conscious will in voluntary action.” You can find that study here.
In an example: Let’s say I am sitting in a chair. Then I stand up to get some water. There was a moment in my conscious mind that I became aware that I was going to stand up to get some water. There was a moment that I “decided” to stand up. There was a moment I became aware of my intention to stand up. Libet’s findings reveal that prior to my awareness of my intention to stand up, my nervous system had already initiated the processes necessary for me to make that movement (standing up). So, my unconscious mind had already begun making the movement (standing up) prior to my own awareness that I wanted to make that movement.
This nervous system activity that prepares for movement before the decision to make a movement is called a readiness potential. There is research that shows in fluent speakers, readiness potentials precede speech movements (as you would expect as readiness potentials generally precede voluntary movement). However, in people who stutter, there is a lack of readiness potential prior to speaking. This is significant and I am not sure why more attention has not been paid to that finding. It may be that readiness potentials and movement sciences are more an area of expertise for neuroscientists/kinesiologists etc. As a result, those researching stuttering are not overly familiar with what readiness potentials are; or are unaware of the research. We’ll dive more into this research below in our discussion on readiness potentials explaining the experiment that documented it.
Wikipedia states (2018), “In neurology, the Bereitschaftspotential or BP, also called the pre-motor potential or readiness potential, is a measure of activity in the motor cortex and supplementary motor area of the brain leading up to voluntary muscle movement.”
Just to be sure that readiness potentials do indeed precede speech movements, I investigated it. In a research study in 1986, it was determined that they do. It states “The Bereitschaftspotential (BP) or readiness potential started already 2 seconds prior to the onset of speaking and was present over either hemisphere.” (Deecke, Engel, Lang, & Kornhuber, 1986) So two seconds prior to a person performing speech movements, the unconscious has generated readiness potentials in the neurological system to perform speech movements.
This preparatory-activity/readiness-potential is deviant in people who stutter preceding speech in the experiment that follows. However, the readiness potential is expectedly present in fluent speakers. (Be advised the Beritschaftsfeld potential is a term used interchangeably with readiness potential.) In supporting this brief summary, Walla, Mayer, Deecke, & Thurner (2004) state, “The motivation of this work was to investigate stuttering—a disorder of speech motor control—in the light of preparatory neural activity of voluntary movements related to speech. To this end, brain activity was recorded with a whole cortex magnetoencephalograph (MEG) in developmental stutterers and nonstutterers while three different tasks of single-word reading were performed. Visually presented words had to be silently read immediately after word presentation (condition 1), spoken aloud immediately after word presentation (condition 2), or spoken aloud after a delay of 1.3 s as indicated by a second visual stimulus (condition 3). Condition 2 clearly showed marked neurophysiological differences between stutterers and nonstutterers. Only nonstutterers showed clear neural activity before speech onset, which is interpreted as being linked to visual word presentation and to reflect focused verbal anticipation. This prespeech activity might reflect the ‘‘Bereitschaftsfeld2’’ (BF2) that is the later component of the ‘‘Bereitschaftsfeld’’, a well-known preparatory activity described for many other voluntary movements. Our results strongly link the lack of such preparatory brain activity at the single-word level to the disability of fluent speech in stutterers.”
Very brief summary/Wrap up of Part 1
Our conscious experience of now is actually on a half-second delay from physical reality. When you stutter or a person stutters, it actually happened a half second ago. Our nervous system begins preparing movement prior to our conscious awareness that we are going to make a movement. This is true of speech movements. However, this nervous system preparation activity is absent in people who stutter preceding speech (a quite notable finding). The illusions and counter-intuitive nature of our conscious experience have implications in regards to understanding stuttering and approaching its treatment. We will dive more deeply into these concepts and more in part two of this post.
Colman, A. M., & Libet, B. (2015). A dictionary of psychology. Libet’s delay. Oxford: Oxford University Press. http://www.oxfordreference.com/view/10.1093/oi/authority.20110803100104529
Eagleman, D. (2018, March). David Eagleman: On Time | Rubin Museum of Art. Retrieved from http://rubinmuseum.org/spiral/david-eagleman-on-time
Deecke, L., Marion Engel, W. Lang, and H.h. Kornhuber. “Bereitschaftspotential Preceding Speech after Holding Breath.” Experimental Brain Research 65.1 (1986).
Libet, Benjamin. “Unconscious Cerebral Initiative and the Role of Conscious Will in Voluntary Action.” Behavioral and Brain Sciences 8.04 (1985): 529.
Walla, Peter, Dagmar Mayer, Lüder Deecke, and Stefan Thurner. “The Lack of Focused Anticipation of Verbal Information in Stutterers: A Magnetoencephalographic Study.” NeuroImage 22.3 (2004): 1321-327.
Wikipedia contributors. (2018, May 14). Bereitschaftspotential. In Wikipedia, The Free Encyclopedia. Retrieved 13:55, October 25, 2018, from https://en.wikipedia.org/w/index.php?title=Bereitschaftspotential&oldid=841195356