Subvocalization
[3] It is one of the components of Alan Baddeley and Graham Hitch's phonological loop proposal which accounts for the storage of these types of information into short-term memory.
Curtis,[5] who concluded that silent reading was the only mental activity that created considerable movement of the larynx.
He concluded that newer techniques are needed to accurately record information and that efforts should be made to understand this phenomenon instead of eliminating it.
[2] Subvocalization is commonly studied using electromyography (EMG) recordings,[6] concurrent speaking tasks,[7][8][9] shadowing,[7] and other techniques.
[6][10] In the case of suppression training, the trainee is shown their own EMG recordings while attempting to decrease the movement of the articulatory muscles.
[10] In concurrent speaking tasks, participants of a study are asked to complete an activity specific to the experiment while simultaneously repeating an irrelevant word.
[7][8][9][10] The participants in the non-interference comparison group usually also complete a different, yet equally distracting task that does not involve the articulator muscles [8][10](i.e. tapping).
[7] Techniques for subvocalization interference may also include counting,[8][9] chewing[11] or locking one's jaw while placing the tongue on the roof of one's mouth.
[11] Subvocal recognition involves monitoring actual movements of the tongue and vocal cords that can be interpreted by electromagnetic sensors.
[13] This concept of a modular mind is a prevalent idea that will help explore memory and its relation to language more clearly, and possibly illuminate the evolutionary basis of subvocalization.
Evidence for the mind having modules for superior function is the example that hours may be spent toiling over a car engine in an attempt to flexibly formulate a solution, but, in contrast, extremely long and complex sentences can be comprehended, understood, related and responded to in seconds.
[14] Finally, the phonological loop; proposed by Baddeley and Hitch as "being responsible for temporary storage of speech-like information"[17] is an active subvocal rehearsal mechanism, activation originating mostly in the left hemispheric speech areas: Broca's, lateral and medial premotor cortices and the cerebellum.
[19] Subvocalization and the phonological loop interact in a non-dependent manner demonstrated by their differential requirements on different tasks.
[19] The role of subvocalization within the workings of memory processes is heavily reliant on its involvement with Baddeley's proposed phonological loop.
There have been findings that support a role of subvocalization in the mechanisms underlying working memory and the holding of information in an accessible and malleable state.
[20] The working memory span is a behavioural measure of "exceptional consistency" [21] and is a positive function of the rate of subvocalization.
[20] fMRI data suggests that a sequence of five letters approaches the individual capacity for immediate recall that relies on subvocal rehearsal alone.
It has also been found that language differences in short-term memory performance in bilingual people is mediated, but not exclusively, by subvocal rehearsal.
The see-write and hear-say conditions, however, remain in the same sensory domain and do not require translation into a different type of code.
[8] Subvocalization which translates visual reading information into a more durable and flexible acoustic code[28] is thought to allow for the integration of past concepts with those currently being processed.
Normal reading instructors often simply apply remedial teaching to a reader who subvocalizes to the degree that they make visible movements on the lips, jaw, or throat.
[30] Furthermore, fMRI studies comparing fast and slow readers (during a reading task) indicate that between the two groups there are significant differences in the brain areas being activated.
In particular, it was found that rapid readers show lower activation in the brain regions associated with speech, which indicates that the higher speeds were attained, in part, by the reduction in subvocalization.
[4] The extent to which an auditory image can influence detection, encoding and recall of a stimulus through its relationships to perception and memory has been documented.
[19] It has been suggested that auditory imagery may slow the decay of memory for pitch, as demonstrated by T. A. Keller, Cowan, and Saults (1995) [19] who demonstrated that the prevention of rehearsal resulted in decreased memory performance for pitch comparison tasks through the introduction of distracting and competing stimuli.
[37] As articulation of similar words is affecting subvocalization, there is an increase in acoustic errors for short-term memory and recall.
