How New Technologies are Changing our View of What Listening is

During the last decade, new imaging technologies have radically altered our understanding of how the brain works and learns. The new digital imaging techniques allow neuroscientists to study the living, working brain in ways that earlier imaging technologies, like X-rays and CAT scans, could not. Where these technologies provided primarily static, fixed images of the brain, new imaging techniques like PET, fMRI, and magnetoencephalography (MEG) can generate dynamic, interactive images. These kinds of images allow viewing of not only the anatomy of the brain but also the way it functions in the course of different cognitions and behaviors. This provides great insight into the brain’s operations, including how listening works.

In this section, we illustrate some of the new understandings about listening and learning to listen that have emerged from this research. We will show that listening is much more complex than most people had imagined. To simplify somewhat, we will distinguish three broad aspects of listening, which correspond to three broad regions of the brain as described by neurologists and neuropsychologists (Luria, 1973; Rose & Meyer, 2002) and also by educational psychologists like Vygotsky (1978). Collectively, these three networks coordinate how we listen and learn to listen.

View Video — Neuropsychologist David Rose, Chief Scientist of Cognition and Learning at CAST, describes the three broad regions of the brain — the recognition network, the strategic network, and the affective network — that coordinate how we listen and learn.

The digital image in Figure 1 illustrates cortical activity while someone hears words. Several activation areas appear, mainly within the posterior (rear) regions of the cortex. These areas form a network of brain processors that are involved in the task of hearing words. What is happening in this part of the brain? What makes it active? The role of this posterior part of the cortex, which we will call recognition cortex, is to categorize the many sound patterns that reach the ears so that we can recognize and understand them.

Most of the posterior half of the brain’s cortex is devoted to pattern recognition (Farah, 2000; Mountcastle, 1998), with one region specialized for recognizing the patterns that we call sound (Figure 1). This auditory region makes it possible to identify what an auditory stimulus pattern is—to know that a particular pattern is a dog’s bark, the sound of car brakes or a melody from Beethoven.

Figure 1. Computer image of a brain showing areas of intense activity when words are being heard. (Posner & Raichle, 1994; Used with permission.)

These pattern recognition capabilities are essential for identifying many basic patterns in the ways things sound—their pitch, duration, timbre, location, sequence, and so forth. In language, the auditory cortex is responsible for recognizing sound patterns in language—the phonemes, morphemes, syntax and semantics. Within slightly different regions, even higher-level patterns are recognized, patterns that help us identify a specific speaker’s voice, style, place or origin, and even intent.

To take one example, consider the way in which we use our voices to emphasize critical information. We use variance in loudness, pitch, length, and accent to punctuate sentence structure and instill speech with emphasis and nuance. These variables are unique to speech and convey rich information to the listener. For example, pauses can designate grammatical significance (pauses are longer between sentences than between clauses or phrases) or general significance (a pause before a phrase to add emphasis). Changes in pitch and tone also mark the structure of phrases and sentences. A typical declarative phrase begins with a jump in pitch, and the pitch diminishes in an undulating fashion until the end. Questions are tagged with an ending rise in pitch. Recognizing the shifts in meaning that result from a simple change in emphasis is another essential part of listening.

Damage to the posterior cortex can affect the brain’s capacity to recognize sound and language in general or very specific ways. Depending on the degree and kind of damage, an individual may lose the ability to recognize sounds, to recognize words, to recognize a speaker’s voice or to recognize verbs but not nouns. Because the varied speech cues seem to be processed in different locations within the recognition cortex, individuals can have deficits affecting very specific aspects of phrase recognition. Normal variation in the ability to recognize the information in sound and language can occur by virtue of differences in the amount of cortex or the extent of neural networks allocated to auditory recognition or a particular facet of auditory recognition. A small minority of people, for example, have a large region of recognition cortex devoted to pitch, resulting in what is called “perfect pitch”; others (including the authors!) have very small regions devoted to pitch, with the result that our pitch recognition is far from perfect.

Obviously, listening critically depends on the recognition cortex. The brain’s ability to quickly recognize the auditory pattern of a word, the syntax of a sentence and the pattern of meaning in speech is critical to listening. But it is not enough.

Listening is qualitatively different from hearing. Hearing seems effortless, automatic and nonselective. Our brains recognize and categorize sounds even when we are sleeping, which is why we wake to a faint but unexpected noise in the next room but sleep peacefully through the blast of the regular midnight train. On the other hand, listening feels intentional; it is effortful, focused and selective. We need to be awake to listen. Hearing is reactive, while listening is strategic. The strategic, effortful, selective aspect of listening recruits a different part of the brain than the posterior regions with which we recognize sounds.

Modern imaging technologies show that when we really listen, when we are strategic and effortful in what we hear, we engage areas of the brain that are located at the very front of the brain, in the prefrontal cortex. The prefrontal cortex is specialized for organizing and prioritizing actions and movements into goal-directed activity. Beyond purposeful action, the prefrontal cortex is also important for organizing and prioritizing what we attend to and what we remember. Overall, the prefrontal cortex, often called executive cortex, allows us to be strategic rather than reactive, such that our own goals and plans dominate the way we interact with the environment and with other people (Fuster, 2003; Goldberg, 2001; Jeannerod, 1997; Stuss & Knight, 2002).

Planning and organization are essential features of listening. Effective listening involves setting priorities (e.g. attending to a single woman’s voice at a cocktail party), being purposeful and strategic (e.g. listening to find out whether her ideas are conservative or liberal), and sustaining effort and monitoring progress (e.g. continuing to selectively listen until you have understood her politics but switching to something else when you have learned enough). Because speech is ephemeral, listening is particularly dependent on the attention- and memory-related functions of the prefrontal cortex. To extract meaning from speech we must effortfully hold the information in memory, compare it to background knowledge, predict what is ahead and sustain attention. This is what we call active listening, and cognitive neuroscientists have shown that it engages a large portion of the prefrontal cortex (Osaka et al., 2004).

Individuals who have a damaged prefrontal cortex are often poor listeners. They can hear speech but have difficulty following or understanding it, because they cannot organize the strategies and skills necessary for selective listening, attention and maximization of memory resources (Semrud-Clikeman, 2005). On the other hand, individuals with strong strategic listening skills can compensate to an extent for problems with speech recognition by predicting, hypothesizing, and filling gaps in what they hear. Thus, strengths and weaknesses in an individual’s strategic networks impact how well he or she is able to listen to and understand speech.

An effective listener knows what is important to listen to; he or she cares about what is being said. Identifying what is important to listen to is no simple task. In the cocktail party scenario, a conversation with the man with the yellow hat may seem important, but our brains must also monitor the other sounds in the room in case a more urgent or important event occurs, such as someone mentioning our name, in which case our attention shifts rapidly! What we regard as important to listen to changes over time, depending on our status, history, expectations and the many features of what we call our personality. What is important can shift rapidly with changes in the environment, for example, whether we are in a dangerous place or a romantic one. And it varies with the speakers, not only with what they are saying but with how they are saying it. The speaker’s tone and emotion bear directly on the importance of the content to the speaker and to us.

Speech and music carry emotional content that is separable from the words or syntax, and understanding the meaning, the importance, of that emotional content requires its own processing. Affective networks, part of the extended limbic system at the central core of the brain, process this content in order to determine the value, importance, and significance of what we listen to. They determine whether information and events matter to us, whether they are important, and help us to decide which actions and strategies to pursue, on the basis of their value and significance (Damasio, 1994; Lane & Nadel, 2000; Ledoux, 2003; Ochsner, Bunge, Gross, & Gabrieli, 2002; Panksepp, 1998).

View Video — The following set of videos demonstrate the power of music to convey emotional content that requires its own processing apart from what is seen. Visually, each clip shows the same scene of a helicopter taking off, however, the soundtrack is changed to evoke a different emotion.

Individuals clearly differ in their ability to employ and interpret emotional cues when they are listening, just as they differ in their ability to understand semantic content or to apply strategies for listening and remembering. In particular, many individuals with emotional disabilities have difficulty in social situations because they fail to recognize the emotional cues in what is being said.

In summary, affective cortex plays a key role in effective listening. Without it, we are impaired in our ability to recognize what is important in what is being said, but also we are impaired in our ability to establish a priority for listening, to focus attention appropriately, to select what is of value, and to remember what is important.

Next Section – How New Technologies are Changing the Relationship Between Literacy and Listening