If I say “strawberry ice cream”, the odds are that strawberry ice cream will be the first thing that pops into your mind. It’ll probably start with a visual mental image, but you might go on to recall its sweet fruity taste and frosty sensation too. If I instead told you not to think of strawberry ice cream, you’d probably end up in the exact same boat. Mental imagery is often an involuntary phenomenon, and it’s hugely influenced by what people around us say. Sometimes, frustratingly so. The reason we cover our ears when people start talking about repulsive or terrifying scenes is because we know what our mischievous brains will do at that moment or later that night when we are trying to sleep in our dark bedroom.
Language interacts with our mind in stimulating mental imagery and influencing how we handle the world. Verbal communication is primarily a device for sharing important information, so our brains accordingly use language to guide where we should focus our attention. You can see this effect at work when people are looking for hidden objects. If you say the word “square”, people are faster and more accurate in detecting square-like visual images, but slower in detecting circle-like images. And the reverse is true if you say the word “circle”. Despite presenting random words that don’t necessarily predict which object is being presented, people can’t help but use the language in their attention and decision-making. Language and other communicative signals (whether meaningful or misleading) create expectations or “sensory templates” about how an upcoming event should look or sound. Other people’s language has privileged access to our brain.
Speaking of privileged access, you may have noticed throughout your life that certain words are particularly good at grabbing your attention. The first and most obvious example of this is known as the cocktail party effect. When we stand in a noisy bar with friends, we’re usually good at narrowing our attention to focus exclusively on the words that a friend is saying, while filtering out all the nonsense coming out of other people’s mouths. When we avoid paying active attention to the many conversations around us, they essentially sound like one big monotonous buzz. However, if our name pops up within that buzz, many of us immediately and automatically prick up our ears. This means that despite everything sounding like meaningless noise in the background, our brains continue processing something about the unattended information, without us being aware of it. And when that information is suddenly relevant to us (nothing is more relevant than our own name), then our conscious attention shifts from the conversation with our friend, to “is this stranger talking about me?”.
Another type of word with a priority pass into our consciousness is the taboo type. I don’t want to use any of these words directly in this article so I’ll exchange a commonly used example for the rhyming euphemism “cluck”. Even when you are not listening to a conversation, it’s hard to stay tuned out if it suddenly features a cluck. If we are with close friends who regularly swear, it can become a more normal word, but of course then it’s no longer taboo. If we are in more polite company or at a formal event, then we have no choice but to immediately notice and recoil when someone exclaims “cluck this” or talks about their clucking boss at work. It’s another great example of the involuntary effects that language can have on us, not only at a mental imagery level but also an emotional and behavioral level.
Taboo words connect with our emotional brain systems in a way that more neutral words do not, and they elicit automatic stress-related physiological reactions. It may be that we have two distinct language systems in the brain: one closely related to emotional vocalizations which is more likely to handle swearing and cursing, and another for our more advanced information-filled communicative abilities. Neurological disorders like aphasia are characterized by an inability to speak or understand language, and yet patients can often curse and swear with less difficulty. This may be because their brain damage is confined to the informational language system rather than the emotional system.
We have more in common with other animals when it comes to our emotional vocalizations than our more informational communication. We know that language can have direct and automatic impacts on our own behavior and mental imagery, so perhaps bird calls have similar effects on a bird’s mind. One major reason for birds to call is to raise an alarm. For the Japanese tit, one of the biggest concerns is the Japanese rat snake, which can move up a tree to capture its prey. So could there be a bird call that makes other birds in the area specifically watch out for snakes, or are there only general urgency signals?
One researcher decided to test this for himself by hanging a speaker in a tree, broadcasting alarm calls, and examining how birds would react to a stick that moved like a predatory snake. With general alarm calls, a bird would ignore the stick. But with snake-specific calls, it would fly within a meter of the stick to survey exactly what was going on. In fact, it would only be interested in this stick if it moved in a snake-like way up a tree. It showed no interest in the same stick if it was swinging from the tree in a way that didn’t resemble a snake. Upon spotting a real snake, a bird would normally hover over it and try to look big in an attempt to deter it from progressing further up the tree. Of course, they didn’t need to do that with the stick when their closer inspection revealed it was harmless. But their approach behavior showed that snake-specific alarm calls automatically stimulated the mental image of a snake (or at least something analogous since we don’t know the bird’s direct experience), and shifted their visual attention towards objects in the environment that most resembled that particular dangerous template.
Communicative signals directly and specifically affect our next moves, and the benefits of communication clearly apply across many animal species. There are several practical uses to human language including emotional expressions, information exchange, negotiations, and warning signals. In normal circumstances, other people’s signals often predict something meaningful about what may be about to happen, and what we need to look out for in our environment. It is therefore a useful adaptation to use language quickly and automatically when it may be useful. Although this can open the door to frustrating deceptions and false alarms, we have gained a lot more from communicating freely with our fellow humans than we have lost to their occasional bad intentions.