Your brain is about the size of a head of cauliflower. It looks and feels like a three and a half pound lump of firm tofu.[1] It comprises about two percent of your body's mass, but it uses twenty-five per percent of the body's energy. Breathtakingly complex, the "tofu" is capable of the most amazing feats such as the ones performed by mnemologists (memory experts). In the 1920s a Russian named Solomon Shereshevskii performed on stage by recalling strings of more than 100 digits, long strings of nonsense syllables, poetry in unknown languages, and elaborate scientific formulae.[2]

Scientists estimate that the brain contains 100 billion cells, many of which are neurons. These cells have a thin, complicated shape like the branch of a tree. They can be as short as a millimeter or as long as a meter. At one end is the axon and at the other end are dendrites, the twigs on the branch. Neurons communicate with each other by sending chemical and electrical signals racing down the branch at 200 miles an hour. When the charge reaches the end of the cell it leaps the synapse—the space between the dendrite and the next twiggy branch. Each cell is surrounded by ten to 100,000 dendrites creating the possibility of one million billion synaptic connections—that's 10 followed by a million zeros! Compare that to the number of particles in the known universe—10 followed by 80 zeros. You can see that the brain is complex if not unfathomable. The phrase "fearfully and wonderfully made" comes to mind.

Let's take a look at some basic brain science to see how it can improve our preaching.

The Distracted Brain: Attention

The "tofu" receives about 100 million bits of information per second.[3] There's no way we can consciously process all of those bits, so one of the primary functions of the brain is to filter incoming data, allowing through only that which matters. The RAS, the Reticular Activating System, filters more than 99% of the sensory data it receives. What does the RAS allow through? Short term attention is gained by novelty, movement, and surprise, as I experienced a few years ago when I was on a cruise. I was playing paddle tennis on the outdoor sports deck. Little did I realize that that court was directly beneath the ship's horn, and when it bellowed its fearsome blast, I nearly had a heart attack. Worse, my opponent won the rally. My point is: the horn got my attention. The RAS allowed it through.

Preachers can gain attention by delivering their sermons with energy and movement—gestures, facial expression, and so forth—but movement should also be psychological. Minds drift when the sermon meanders. Transitions help convey forward progress. When I was preaching on the great kenosis passage from Philippians 2, I traced the downward path of humility our Lord took, and as I transitioned from the sermon's second movement to the third, I said: "So we have seen that Jesus surrendered, and then he served. Now look at what happens next; look at the downward path our Lord took: he sacrificed. He died an ugly death on the cross. Surrender, service, and then sacrifice. That is what verse eight says."

Short-term attention is relatively easy to gain through novelty and movement, but preachers want something deeper—engagement—and that occurs only through relevance. The brain finds it nearly impossible to pay attention for an extended period of time to anything it deems irrelevant. Boredom kills preaching. Hard-wired to help us survive, the brain scans the horizon for danger and threat, safety and reward. It rarely scans the horizon to discover what happened to the Jebusites.

This presents a challenge for preachers who do sequential exposition (working through long sections of Scripture, passage by passage). While topical preachers are able to choose issues with high relevance—how to raise kids, why does God allow suffering, and so forth—expository preachers must work hard to identify the deep existential needs the passage addresses. I've found Bryan Chapell's "FCF"—the Fallen Condition Focus—helpful in this regard. God gave us the Scriptures to address aspects of life in a fallen world such as broken relations, guilt, death, estrangement from God, and conflict. When we foreground such issues and show how the God of grace addresses them, the RAS opens to let the preacher's words through.

Preachers have known this for centuries, of course, long before the discoveries of neuroscience. Our standard practice in the introduction is to gain attention and surface need, but I've often wondered why we need both. That is, if we simply surface need, we will have plenty of attention. Spurgeon said it this way:

In order to get attention, the first golden rule is, always say something worth hearing. Give your hearers something which they can treasure up and remember; something likely to be useful to them. Do it continually and you will have all the attention you can desire. (Lectures To My Students, 131)

Pulitzer Prize willing author Annie Dillard gives similar advice to writers:

Write as if you were dying. At the same time, assume you write for an audience consisting of terminal patients. That is, after all, the case. What would you begin writing if you knew you would die soon? What could you say to a dying person that would not enrage by its triviality? (The Writing Life, 68)

Our media-saturated culture sweeps over us in a tsunami of images, ideas, promises, and persuasions, making engagement more challenging than ever. According to statisticbrain.com, 17% of webpage views last four seconds or less, and only 4% last more than ten minutes. We flit and flirt with ideas but rarely engage, so preachers must give attention to attention. We take Bonhoeffer's advice to heart concerning the opening lines of our sermons: "The first minutes on the pulpit are the most favorable, so do not waste them with generalities but confront the congregation straight off with the core of the matter." (In Eric Metaxas, Bonhoeffer, 272)

Rate these opening lines on a scale of 1 to 10 on how well they engage listeners:

• Last week we were in Isaiah 30. This week, we're in Isaiah 31.
• How do you handle trials? Let me tell you a story about a man who lost his legs.
• Um, I'm sure that all of us believe in prayer, um, I would imagine.
• I'd like to talk to you about money. Your money. Do you worship it?
• Today I would like to talk to you about something that all of us here today have probably felt very deeply about, at one time or another, in ways that have sort of impacted us quite a bit.
• Many Americans love dogs. Why? Researcher Karen Allen at the University of Buffalo School of Medicine says that dogs are better than spouses and friends at lowering stress. She says, "We perceive dogs as totally non-judgmental and accepting." Don't you wish your church could be more like your dog?

The Feeling Brain: Emotion

The old dichotomy of mind and emotions, thinking and feeling, has been obliterated by brain science. We now know that there is no thinking without feeling. Every thought carries a trace, and often more than a trace, of emotion. Emotion drives attention and a learner must feel that something is true before it is believed, and that something is relevant before it is applied.[4]

Expository preachers are interested in emotion not only because it is inseparable from cognition and volition, but also because they say what the text says and do what the text does. If the text calms the troubled spirit like a weaned child (Ps. 131), we should too. If it rises to a crescendo of doxology (Rom. 11:33-36), we should too. If it stirs hope (1 Pet. 1:3-9), we should too. Each of us has a "natural habitat" of emotion determined by our personality types, so we need to be aware of the borders of that habitat. Some texts occupy ground outside the fence so we will need to take special care not to squeeze those texts into our own mold. Preachers like myself from a fundamentalist background can find themselves turning any passage into obligation and guilt, even a passage like 1 Pet. 1:3-9: [said with a scowl] "Peter says that God has given us hope. [pause] You don't have that hope, do you? If you don't, something is wrong." Such preaching is affective eisegesis. Rather than driving the congregation to feel hope, the preacher should model and rouse it.

The best tool for doing so is delivery. Communication scholars estimate that 93% of the emotional content of a statement is communicated nonverbally. The eyes, tone of voice, posture, facial expression, and other nonverbal channels embody affect. They literally put the emotion into a body, and when that happens, listeners match the sender's emotional state. Nineteenth-century homiletician Robert Dabney called this the "law of instinctive sympathy" and said "it is the preacher's right arm in the work of persuasion" (Sacred Rhetoric). Similarly, Hugh Blair, Scottish clergyman and rhetorician said, "There is a contagion among the passions" (Lectures on Rhetoric and Belle Lettres).

Today scientists call the contagion "empathy" and explain it with mirror neurons. These are specialized cells which fire when we see someone perform an action. They help us mimic the actions of the sender as when a mother smiles at her baby and the baby smiles back. It also helps explain why yawns are contagious.

Because of the law of sympathy/contagion/empathy—call it what you will—the congregation keeps pace with the preacher. I believe that theology lies under that fact. God has placed in the heart of the sheep a desire to be shepherded, an instinct to follow. To be sure, some sheep bite and some go astray, but in every believer is the life of Christ, a life that is humble and submissive, tuned to hear the shepherd's voice. Believers want to follow a friend, mentor, leader—a pastor—who practices what he or she preaches. We gravitate to leaders who lead. Thus, when preachers display passion through the nonverbal channel, listeners catch fire.

But what happens when the nonverbal channel conflicts with the verbal? Sending mixed messages confuses the brain. A team of neuroscientists used an EEG (electroencephalograph) to measure the peaks and valleys of brain waves. One valley, dubbed N400, occurs when subjects see gestures that do not tally with the words. This is the same brain-wave pattern that occurs when people hear nonsense language.[5]

It seems that the brain is hardwired to depend on concrete, embodied communication to decipher the words it hears. We trust the nonverbal. A fascinating study done at Harvard in the early 90s by Ambady and Rosenthal demonstrates that receivers make quick and accurate decisions about people through their delivery.[6] The researchers showed Harvard undergraduates "thin slices" of video—thirty seconds—of professors lecturing. The sound was turned off or scrambled so that the students observed only body language. Then they were asked to rate the professors on attributes such as "attentive," "dominant," "likeable," "anxious," and "professional." The results were then compared to end-of-the-semester evaluations from another group of students. The second group had spent a semester with the professor in class, so they had much more "data" on which to determine their rating. How well did the two sets of evaluations match? "Remarkably well." Ambady and Rosenthal were "amazed and baffled." They then sliced thinner and thinner, getting down to five and even two second clips. The results showed only a minor drop in correlation with the end-of-semester evaluations.

In a twist on the discoveries on empathy, researchers have discovered that our nonverbal communication affects not only the listener, but the speaker as well. The speaker's emotion follows his or her physical stance, so if you want to convey conviction, compassion, or another emotion, rev up your body.

Try an experiment with yourself. Say the following sentences with two sets of physical action and listen to your voice. See if the voice follows the body, and see if your emotional state follows also:

Stand tall, lift up your ribs to display your sternum, gesture with open hands, and most importantly, smile broadly.	Hunch your shoulders, roll your eyes, sigh, shrug, use a vague, faint-hearted gesture, and most importantly, frown or scowl.
Tomorrow is the last day of the semester.
My in-laws are coming for a visit.
Let me share with you what I learned about raising kids.
Blessed are those who die in the Lord.
How can a young man keep his way pure? By guarding it according to your word.

One more word about emotion: when the brain feels threatened physically or emotionally, it has trouble paying attention to anything but the threat. If listeners feel threatened rather than accepted, they will miss much of what you are saying. To be sure, preaching at times will warn and rebuke, but it must also convey humility and compassion. When we correct listeners, they must feel that we are on their side.

The Anchored Brain: Memory

From a neuroscience perspective, memory is the repeated firing of specific combinations of neurons. Electro-chemical signals race down the dendrites and leap the synapses leaving memory traces behind. When a neural net fires a few times, the memory is short term, and when it fires repeatedly in the same sequence, it moves to long term giving rise to the neuroscience proverb: "Neurons that fire together wire together."

Neuroscientists use the term engramming to describe the electro-chemical process we call "memory." All new experiences are overlaid on top of existing engrams, and the brain instinctively tries to harmonize new information with old. The brain is lazy and chooses the electro-chemical path of least resistance, responding sluggishly to anything that does not follow pre-existing beliefs and experiences. I discovered that when a tennis coach tried to reconstruct my forehand to get me to swing with more topspin. It wasn't pretty. My brain begged me to stay with the tried and true engram, and when I wouldn't, it plotted revenge.

In psychology habituated patterns are called schemata or frames. They deal primarily with perception and create a mental structure on which we organize knowledge of the world. We tend to notice things that fit our schemata and either ignore or distort bits that don't fit. The brain craves consistency. Schemata are necessary to everyday life so that we can react, not pause to analyze bits of data. When you see the light turn red, you know without thinking that you should stop. We are generally well served by our structures, but we must stay open to exceptions. If a man rises from the dead, how will your schemata handle that?

Because perception is partial and the brain strives to be consistent with schemata, memory tends to morph over time. Memory is less like a photograph which captures something accurately, and more like a patchwork quilt. The brain selects or discards bits of cloth, and then sews a coherent whole. Memories evolve as the brain adds new patches and detaches old ones which no longer fit. The Pixar film Inside Out showed memories contained in glowing orbs, but over time many turned dull gray and were discarded into the netherworld of forgetfulness.

A vivid example of the way memory evolves is the story of the bronze serpent. You will remember that the Lord directed Moses to create the piece of metalwork when fiery serpents came among the people (Num. 21:6). Our gracious God made a way out: whoever would look upon the bronze serpent set upon a pole would live. The Israelites preserved this piece of craftsmanship for centuries and apparently stories and legends grew around it so that by the time of King Hezekiah it had become an idol. Archeology has discovered many other bronze or copper serpents in the ancient Near East, so it is possible that Israel had adopted the ways of its pagan neighbors, but Hezekiah did what was right in the eyes of the Lord. He "broke in pieces the bronze serpent that Moses had made" (2 Kings 18:4). Neuroscientist Stephen Novella could be commenting on this story when he states, "We don't recall memories as much as we reconstruct them and update them."[7] We harmonize and even invent details to make a memory harmonious with our currently held perceptions and beliefs.

To counter our malleable and fallible memories, God has inscripturated his Word. The Bible is an objective, stable communication against which we measure all doctrine and practice. Memories fade like ink aging on a handwritten letter, so the Lord reminds ministers to "guard the good deposit entrusted to you" (2 Tim 1:14). Preaching repeats, restates, recalls, recounts, rehearses, reiterates, tells and retells the old, old story. While memories can spring to mind spontaneously, in the Bible memory is depicted more as a deliberate discipline. C. S. Lewis said it this way:

One must train the habit of Faith [by making] sure that … some of its main doctrines shall be deliberately held before your mind for some time every day. That is why daily prayers and religious reading and church-going [and sermons!] are necessary parts of the Christian life. We have to be continually reminded of what we believe. Neither this belief nor any other will automatically remain alive in the mind. It must be fed. (Mere Christianity)

Thought experiment:

1. When is the last time you preached on any of the doctrines in the Apostles' Creed, or included a three to five minute portion of a sermon to any of those doctrines? (You may need to check your notes to remind yourself!)

2. If it has been a while, why? Are you afraid of boring people? Are you projecting your own level of knowledge and affections onto the congregation? Do you [wrongly] assume that once a person understands and affirms a doctrine, he or she never leaks?

3. How do these verses speak to your situation? • "I will make every effort so that after my departure you may be able at any time to recall these things" (2 Peter 1:15). • "Now I want to remind you, although you once fully knew it … . You must remember, beloved" (Jude 5, 17).

4. How might you stir the memory of your congregation on some crucial doctrines in your next two sermons?

One of the best devices on the homiletical tool belt for stirring memory is story, and the best kind of story may be testimony. Listening to a story is a whole-brain activity which rouses emotion, stimulates imagination, and prompts identification. Even when a story is outside the listeners' field of experience (perhaps they do not have a child with autism), their brains select files similar to the one being described. When the story deals with schemata common to all listeners, such as feelings of frustration and hope, the brain automatically overlays the new information onto existing memories. John Steinbeck knew that: "No story has power, nor will it last unless we feel in ourselves that it is true of us … . If the story is not about the hearer, he won't listen … . The strange and foreign isn't interesting, only the deeply personal and familiar."[8]

I hope that this article has helped you know the brain a little better and that your preaching and listeners will know gain because of it.

This science-related article was made possible through the support of a grant from the John Templeton Foundation. Opinions expressed do not reflect the views of the John Templeton Foundation.

1. An excellent laymen's introduction to neuroscience with applications for ministry is Bob Sitze, Your Brain Goes to Church: Neuroscience and Congregational Life (Herndon, VA: Alban Institute, 2005).

2. Alan Baddeley, Your Memory: A User's Guide (New York, Macmillan, 2004), 44-45.

3. Greg Boyd and Al Larson, Escaping the Matrix: Setting Your Mind Free to Experience Real Life in Christ (Grand Rapids: Baker, 2005), 31.

4. Paul MacLean, "A Mind of Three Minds: Educating the Triune Brain," in The 77th Yearbook of the National Society for the Study of Education (Chicago: Univ. of Chicago Press, 1978), 308.

5. S. D. Kelly, C. Kravits, and M. Hopking, "Neural Correlates of Bimodal Speech and Gesture Comprehension," Brain and Language 89 (2004): 253-260.

6. Nalini Ambady and Robert Rosenthal, "Half a Minute: Predicting Teacher Evaluations from Thin Slices of Nonverbal Behavior and Physical Attractiveness," Journal of Personality and Social Psychology 64, no. 3 (1993): 431-441.

7. Novella, Your Deceptive Mind, 1.

8. East of Eden (1952; rpt. New York: Penguin, 2002), 266-268.

Jeffrey Arthur is professor of preaching and communication at Gordon-Conwell Theological Seminary.