Do you think in words? Narrate to yourself what you intend to do? When we talk about an inner voice, or internal monologue, most of us mean it literally. Our internal monologue accompanies us as we navigate the world crystalising our thoughts. If until just now you always thought the little voice inside somebody’s head was a metaphor you might be experiencing anendophasia. US brain scientists jumped head first into this fascinating phenommenon with some intriguing results…
The experience of inner speech is surprisingly diverse. While some people engage in near-constant self-talk, others rarely experience an inner voice, revealing a spectrum of inner dialogue. “Until you start asking the right questions you don’t know there’s even variation,” says Dr. Gary Lupyan, a cognitive scientist at the University of Wisconsin–Madison in a recent press release.1
Recent research challenges the long-held belief that everyone uses an inner voice. A study published in Psychological Science by Drs. Nedergård of the University of Copenhagen, and Lupyan of the University of Wisconsin-Madison, investigated the phenomenon of “anendophasia,” the absence of inner speech, and its impact on cognitive abilities.2
Surprisingly, the strength of one’s inner voice can impact their cognitive abilities. People with less inner speech struggled with tasks like verbal memory. The researchers, who proposed calling this lack of inner voice “anendophasia,” emphasized the growing evidence of the diversity of human inner experience. “It speaks to the surprising diversity of our subjective experiences,” Lupyan added in the press release.1
Not only does our inner voice, or lack-of, tell us more about the amazing variation humans experience, but this discovery could provide brain researchers with clues to some surprising puzzles. Could these findings lead to a new way to look at speech rehabilitation, dyslexia and some types of psychotherapy?
Thinking outside the voice-over
Nedergård and Lupyan assessed 1,037 people using a measure called the Internal Representations Questionnaire (IRQ), which measures the extent to which individuals rely on inner speech. From this, they recruited participants based on their scores on the Internal Representations Questionnaire scores. They selected individuals with either very high (47 participants) or very low (46 participants) scores on the verbal factor of the Internal Representations Questionnaire, ensuring the groups were similar in terms of age, gender, education, and language background.
The pair conducted four experiments to assess cognitive performance based on their belief that these tasks are influenced by inner speech.2
The first experiment focused on verbal memory, requiring participants to recall lists of words. The participants were shown a list of five words and then asked to repeat them back. The second experiment involved rhyme judgment, where participants determined if pairs of objects had rhyming names.
The third task explored how participants switched between cognitive tasks, requiring them to rapidly shift from addition to subtraction. This skill is believed to be facilitated by inner speech, which helps individuals direct their mental efforts. Finally, the fourth task investigated visual discrimination, examining participants’ ability to discern subtle differences between similar images, such as distinguishing between silhouettes of different cats versus a cat and a dog. This explored the influence of language and categorization on visual perception.
Stronger inner voice, stronger memory?
In the verbal memory and rhyme judgment tasks, individuals with weaker inner voices demonstrated lower accuracy compared to those who reported strong inner speech. Furthermore, those with stronger inner voices were quicker at making rhyme judgments. “This wide-ranging study really tests what inner speech gives us in terms of cognitive benefits,” said Charles Fernyhough, a psychologist at Durham University, UK, in the press release.1
The results revealed that individuals without an inner voice/internal monologue performed significantly worse in the verbal memory and rhyme judgment tasks. This suggests that inner speech plays a role in both processes. However, there were no significant differences between the groups in the task-switching and visual discrimination experiments, indicating that individuals without an inner voice might use alternative strategies for these tasks.
Anendophasia– absence of internal monologue
The study’s findings have implications for understanding how cognitive processes may differ depending on the presence or absence of inner speech. While its impact on daily life remains unclear, the researchers suggest that inner speech may be relevant in specific contexts, such as therapy.
The implications of this research extend to individual differences in language processing and learning. Lupyan suggests that “someone with more inner speech might be more reliant on language in their thinking,” meaning “language impairment from stroke could have a more severe effect, and they may benefit from different treatments.”
Neuroscientist Ladislas Nalborczyk, who was not involved in the study, highlights the educational implications in the press release: “Variations in children’s ability to represent speech sounds may impact the ability to learn the relation between sounds and writing,” he explains, adding that this “may impact the way they learn to read and write, which probably has tremendous impact on their education.”2
The researchers acknowledge limitations in their study, including reliance on self-reported measures and a relatively small sample size. Future research will explore the impact of anendophasia on other language areas and investigate potential compensatory strategies used by individuals without an inner voice.
References
- Makin, S. (2024) Not everyone has an inner voice streaming through their head, Scientific American. Available at: https://www.scientificamerican.com/article/not-everyone-has-an-inner-voice-streaming-through-their-head/ (Accessed: 14 October 2024).
- Nedergaard, J.S. and Lupyan, G. (2024) ‘Not everybody has an inner voice: Behavioral consequences of anendophasia’, Psychological Science, 35(7), pp. 780–797. doi:10.1177/09567976241243004.
