Do You Have a Voice Inside Your Head?

Post by Shireen Parimoo

Our inner auditory world

Inner speech - also known as the "voice inside our head" or an internal dialogue - is a part of our subjective experience of thinking that is often taken for granted. Much like mental visual imagery (often referred to as ‘the mind’s eye’), those of us who have experienced inner speech may find it difficult to imagine a time without this form of internal auditory imagery. So, why do we have inner speech at all? According to Vygotsky’s social origin theory of inner speech, speech is initially social in nature during childhood and its main purpose is communication, typically with parents. Over time, children develop egocentric or private speech where they verbalize their thoughts out loud, often while engaging in problem-solving activities. In late childhood, egocentric speech is internalized and transforms into inner speech that children can use flexibly for various cognitive functions. Inner speech is therefore separate from private speech, or “talking to ourselves out loud”, even though both are forms of language directed toward the self rather than toward others.

Theoretical perspectives vary in the extent to which inner speech is thought to differ from outer speech. Motor simulation theories state that inner speech shares all the same characteristics of outer speech production except for the actual articulation of speech. This view is supported by studies showing the activation of muscles that would be used to produce those words out loud. Alternatively, abstraction theories take the view that the processes underlying inner speech are independent of articulatory processes associated with outer speech, as inner speech first occurs with the activation of abstract linguistic concepts. This idea is supported by the fact that silent reading is faster than reading aloud and that articulatory suppression does not necessarily impact inner speech. 

What are the components of inner speech?

Vygotsky originally differentiated inner speech from outer speech based on four main characteristics: 

1. Word sense: words used in inner speech capture the overarching context and sentiments rather than precise meanings (e.g., the statement, “waves!” alone can capture the sense of awe at watching big waves while on the beach). 

2. Agglutination: individual words are combined into complex new ideas while retaining the meaning of the individual words (e.g., help-less-ness). 

3. Word senses flow from and influence each other during inner speech.

4. Predication: the absence of subjects from the contents of inner speech (e.g., “waves!” as opposed to “wow, I am so in awe of these huge waves!”). 

Newer perspectives on inner speech have also included a distinction between inner speaking (e.g., self-talk) which is intentional and strategic in nature as the individual ‘produces’ the speech, and inner hearing (e.g., remembering something), which occurs passively as the individual ‘receives’ the contents of speech. Similarly, inner speech is now thought to include distinct speaker positions (e.g., voices of other people during an internal dialogue), rather than a self-referential perspective alone.

Inner speech is notoriously difficult to study because its study relies mainly on self-report and experience sampling measures. For example, the Descriptive Experience Sampling approach involves prompting individuals at random time points to note down what they were thinking at that moment, which is later followed by an interview that probes the contents of their thoughts in more detail. This method has been useful in providing insights into the phenomenological characteristics of inner speech, such as the distinction between inner speaking and inner hearing. In contrast, the Varieties of Inner Speech Questionnaire-Revised measures the quality of inner speech according to five dimensions:

1. Dialogicity, or the extent to which inner speech is conversational.

2. Condensation, or the use of abbreviations that are normally absent in overt speech (such as the “waves!” example above). 

3. The degree to which other voices are present in the inner speech.

4. Critical or evaluative quality.

5. Positive or regulatory quality.

Is inner speech useful?

Different dimensions of inner speech are related to different aspects of the self. For example, the evaluative component is associated with lower self-esteem, depression, anxiety, and generally a negative self-concept. Individuals with a higher frequency of evaluative or critical inner speech are also likely to show perfectionistic and ruminative tendencies. On the other hand, higher rates of regulatory inner speech correspond to increased motivational self-talk and a positive self-concept, which may benefit individuals in performance-related domains like sports and public speaking. Indeed, inner speech is important for the formation and evolution of our self-concept. Thinking about the past and imagining the future can involve both inner speaking and inner hearing, which in turn, are related to the cognitive processes of metacognition and introspection that all contribute to our sense of self. 

Inner speech also serves various cognitive functions. Positive or regulatory inner speech, for instance, likely supports the ability to regulate emotions as people process their feelings through an inner monologue. Relatedly, self-talk during sports boosts performance by increasing motivation and maintaining engagement with the actions required to play. Inner speech is also useful for planning actions (e.g., thinking through the steps required to complete a task), problem-solving (e.g., considering different outcomes), creative thinking, cognitive flexibility, and language learning. During development, children can use inner speech to build upon their knowledge base by adding newly acquired words and concepts through a process known as linguistic bootstrapping. Similarly, internal monitoring of dialogue is beneficial for perceptual discrimination and categorization when it involves processing abstract concepts. 

However, not everyone has the experience of inner speech. Anendophasia is the lack of inner speech and is associated with lower verbal working memory, but only when participants are not allowed to process the words out loud. The use of inner speech is also not related to task-switching ability or perceptual discrimination performance, suggesting that it may not be necessary for cognitive functioning or that individuals with anendophasia may have developed compensatory strategies for carrying out these cognitive functions that otherwise rely on inner speech. 

Lastly, patterns of inner speech are related to psychopathological symptoms. In autism spectrum conditions, there is a lower frequency of inner speech overall. This pattern is thought to underlie lower performance on executive functioning tasks such as planning and cognitive flexibility, as well as emotional regulation. On the other hand, individuals with schizophrenia who experience auditory hallucinations tend to report a higher frequency of intrusive inner speech which, in turn, is related to worse executive functioning because it interferes with cognitive processing. Thus, inner speech is not only important for helping us maintain our sense of self but also supports various cognitive functions and provides numerous benefits to aspects of our day-to-day lives.

References +

Abend et al. (2017, Cognition). Bootstrapping language acquisition.

Albein-Urios et al. (2021, Journal of Autism and Developmental Disorders). Inner speech moderates the relationship between autism spectrum traits and emotion regulation.

Alderson-Day et al. (2018, Consciousness and Cognition). The Varieties of Inner Speech Questionnaire – Revised (VISQ-R): Replication and refining links between inner speech and psychopathology.

Ehrich, J. F. (2006, Australian Journal of Educational and Developmental Psychology). Vygotskian inner speech and the reading process.

Fernyhough & Alderson-Day. (2016). Chapter 6: Descriptive experience sampling as a psychological method. In Callard, Staines, Wilkes (Eds.). The Restless Compendium: Interdisciplinary Investigations of Rest and its Opposites. Basingstoke, UK: Palgrave Macmillan.

Fernyhough & Borghi. (2023, Trends in Cognitive Sciences). Inner speech as a language process and cognitive tool.

Hemmers et al. (2022, Frontiers in Psychiatry). Are executive dysfunctions relevant for autism-specific cognitive profile?

Hurlburt et al. (2013, Consciousness and Cognition). Toward a phenomenology of inner speaking.

Nedergaard & Lupyan. (2023). Not everyone has an inner voice: Behavioral consequences of anendophasia. In Goldwater, Anggoro, Hayes, & Ong (Eds.). Proceedings of the 45th Annual Conference of the Cognitive Science Society.

Petrolini et al. (2020, Frontiers in Psychology). The role of inner speech in executive functioning tasks: Schizophrenia with auditory verbal hallucinations and autism spectrum conditions as case studies.