Cognitive Psychology And Executive Functioning
Attention is an important function of our everyday life. William James (1890) distinguished between active and passive modes of attention, with active attention being controlled by the individual’s goals and expectations and passive being controlled by external stimuli such as loud noise. Focused and divided is also an important distinction, with focused (selected) attention being when an individual focuses on one source of information while ignoring another and divided attention being when two tasks are performed at the same time (multi-tasking). Looking at selective attention allows us to understand how we can select certain inputs over others and what factors are involved in this (Eysenck and Keane, 2013).
Broadbent’s Filter Theory is an early theory of attention, which poses that there is a filter in early processing that allows information from one input through to the Short Term Memory (STM) for further processing (Eysenck and Keane, 2013). The input enters and is recognised within the sensory register before moving through to a selective filter where it is filtered based on physical characteristics. The input that is filtered is then processed in more detail in STM. This theory assumes that unattended information is not extracted at all, which is challenged by Grey and Wedderburn (1960 as cited in Eysenck and Keane, 2013.) who found that participants did in fact select based on meaning. Focused Auditory Attention theory poses that full unconscious processing of objects is possible and supposes that we cannot choose to semantically analyse some but not others. It poses that the selection of attention occurs after full semantic analysis. This theory of late processing hypothesises that selective processing occurs within STM. (Eysenck and Keane, 2013).
Treisman’s Focused Auditory Attention Theory suggests that there is a attenuator early in processing that allows one input through to STM but attenuates the other input. This is more flexible that Broadbent’s theory and the selection is said to be based on physical cues, syllable pattern and meaning (Eysenck and Keane, 2013).
Lavie (2005) presented the Perceptual Load Theory which poses that attention is dynamic and flexible and that whether the filtering occurs during early or late processing depends upon the circumstances. It assumes that attention is limited and that attentional capacity is primarily given to the main task, while spare attentional capacity is allocated to irrelevant stimuli. High Load information would mean that attention must be selected early in order to process the target information and low load information would allow the target information to be processed alongside irrelevant information and late selection would occur (Lavie, 2005).
There are numerous reasons why it is important for Speech and Language Therapists (SLTs) to have an understanding of the cognitive neuropsychology that underpins attention. Attention is one of the fundamental cognitive processes and functions as an implicit prerequisite for the successful execution of a variety of operations (Villard and Kiran, 2016). Cherry et al (1983) compared the selective auditory attention skills of children with learning disabilities with those of normally developing children. The children were asked to point to pictures of monosyllabic words, which were presented diotically and alongside three noise distractor conditions (non-linguistic, linguistic non-semantic, semantic). The performance of the children with learning disabilities was affected more than the control group consistently across all conditions.
Steven’s et al (2006) highlighted that children with Specific Language Impairment (SLI) have marked and specific deficits in the neural mechanisms of attention and that this deficit occurred in early sensory processing. This could explain the diverse range of sensory and linguistic impairments seen in children with SLI. It is important that SLTs are aware of this variation in ability and plan intervention accordingly.
The attentional model of aphasia proposed by McNeil (as cited in, Murray, 1999) specifies that attention deficits can negatively affect the linguistic performance of adults with Aphasia. Much data supports this negative relation between attention difficulties and aphasic language performance (Murray, 1999). While Aphasia is characterised as impairment in language processing, individuals with Aphasia have consistently been found to exhibit impaired performance in measures assessing a variety of cognitive skills. This suggests that its characterisation as an impairment in language processing may be incomplete (Murray, 1999).
It is widely accepted that individuals with aphasia do not respond uniformly to therapy. There is recent evidence to support the fact that cognitive skills (including attention) are able to reliably predict language treatment outcomes in individuals with Aphasia (Murray, 1999). Neuroimaging based theories of aphasia and its recovery have highlighted the link between cognitive abilities in language rehabilitation and imply that attention is a critical aspect of language therapy (Murray, 1999.) There is also evidence that good attention in stroke patients is predictive of overall functional recovery (Villard and Kiran, 2016). For an individual who experiences substantial fluctuations in attention there may be barriers to their benefiting from language intervention (Murray, 1999).
The human attention system is thought to consist of a limited-capacity of resources that are flexibly allocated across various types of tasks, with the most attention directed to wards one task. This helps to explain why individuals have slower response times during dual-task than single-task situations (Murray, 1999). It is then proposed that the extent to which sustained attention contributes to tasks such as picture naming, could be a result of situational demands. Research suggests that attention may be required for language tasks to different degrees depending on the specific task. It is important for SLTs to be aware of this in assuring that the assessments and interventions used, as well as the environment, are appropriate and optimal for the individual.
Executive functions refer to mental processes needed to concentrate and pay attention, when relying on instinct and intuition is not appropriate (Diamond, 2016). Executive function is an umbrella term that encompasses various cognitive functions including, working memory, inhibitory control and cognitive flexibility (Diamond, 2016). Inhibitory control involves being able to control our attention, behaviour and thoughts to override an internal lure and to do what is needed. It makes it possible for us to choose how we react and behave. Inhibitory control of attention enables us to selectively attend, focusing on what we want and ignoring other stimulus. Self-control is an element of inhibitory control and involves having the discipline to remain on task and delay gratification. Allowing a person more time is said to help the inhibitory control and this is critical in ensuring that we are not premature in responding. Allowing a child more time to attend to a task would allow their impulse to fade and a planned response or behaviour to occur (Diamond, 2016). Working memory involves being able to make sense of something and hold it in mind to establish understanding. It is necessary to make sense of written or spoken language and thus is certainly applicable for SLTs when communicating and assisting someone with impairment. Cognitive flexibility builds on these and comes later in development. It involves being able to change perspectives and to inhibit our previous perspective. It involves changing the way we think about something and adapting to new environments and problems (Diamond, 2016).
Executive functions are essential for mental and physical health, including success in education, social and psychological development (Diamond, 2016). Executive function can be improved at any age, including in infants and in the elderly for example, by improving physical fitness later in life. Executive functioning is critical for many skills including creativity, flexibility, self-control and discipline. Because of our Executive Functioning skills we are able to flexibly adapt to changing circumstances, consider our next tasks, resist temptations and meet novel challenges (Bangera, 2015) If emotional, social or physical needs are unmet they can work against the executive functions. Stress, tiredness and lack of exercise can all impact our Executive Functions and their presence in early life has been found to predict lifelong health and quality of life (Bangera, 2015). Executive Functions have an impact in a number of areas of life including school readiness, job success, marital harmony and a number of mental health conditions including addiction, depression and Schizophrenia (Diamond, 2016).
It is of utmost importance that SLTs have a good understanding of the relationship between executive functioning and language. Language learning is closely linked to higher cognitive functions and executive function disorders can provide a wealth of information about clinical practice and evidence-based interventions (Bangera, 2015).
Bernier et al (2012) found, in a study looking at the caregiving relationships and security of mother child attachment, that attachment security was relevant in predicting executive function. Higher quality parenting and child-adult interactions were also associated with better executive function. Cognitive flexibility was also linked to children’s verbal abilities and it was suggested that family involvement should be considered in programmes aimed to improve executive functions in children (Bernier, 2012).
Metacognitive strategies such as self-regulation, monitoring, planning and execution of tasks are all mediated by language (Bangera, 2015.) During formative years of development children talk to themselves about the activities they are engaged in which is eventually internalised as they grown older. In a study looking at the relationship between executive functions and narrative ability in preschool children, a correlation was found between oral narratives and executive functioning (particularly working memory and planning) which demonstrates a link between expressive language and executive functioning (Bangera, 2015.) Story telling and discourse are said to involve inhibitory control, organisation, flexibility and planning which further supports this. The link between executive function and language is undeniable and skills such as joint attention are crucial for language development (Bangera, 2012).
We are also able to observe the impact of executive functioning in children with Executive Function Disorders. Henry (2012, as cited in Bangera 2015) found that children with SLI had poorer executive functioning skills compared to typically developing children, specifically that they showed difficulties with working memory, fluency and planning on both verbal and non-verbal tasks. Children with low language fluency had significant executive functioning difficulties, which further suggests a link between language impairment and executive function skills. Adam (2014, as cited in Bangera 2015) looked at the relationship between executive functioning and language ability in children with ASD and found that the core language ability and pragmatic language ability significantly predicted a child’s working memory performance. Carney (2013) compared the executive functioning skills of children with Down syndrome and found that they had significant difficulties in working memory and inhibition tasks. He also looked at children with William Syndrome and found that they had vast difficulties in executive functioning tasks including inhibition measures. These inhibition difficulties could cause problems in behaviour control and impact academic and social wellbeing (Carney, 2013). Similar difficulties in executive functioning have been noted in children with ADHD when compared to normally developing children (Bangera, 2015). It has also been found that there are executive functioning difficulties in deaf children which have been linked to delayed language acquisition and underlying difficulty in internal speech, rather than the deafness itself (Bangera, 2015). The executive functioning impairments noted in these client groups and the distinctions between them provide a wealth of information to the SLT in regards to assessment and intervention planning and should not be underestimated.
It is very important for the SLT to be aware of the individual needs of children with executive function disorders and to understand the cognitive neuropsychology that underpins these. Adopting a multidisciplinary approach is vital and overlooking the role of executive functioning when assessing an individual’s difficulties could hinder the diagnosis of developmental language impairments. The use of speech and language assessments alongside dynamic assessments and assessments of executive functioning could help to differentiate between language impairments and difficulties due to linguistic context (Bangera, 2015). Strategies aimed at improving metacognitive skills would have a strong impact on language learning and development.
Further implications of Executive Functioning on Speech and Language Therapy and on SLTs role comes from research into the effects of Executive Functioning on Aphasia. It is important to understand the influence of executive function skill on communicative performance and an understanding of the cognitive abilities that underlie can help SLTs to determine which patients are better suited to intervention and how this intervention should look (Purdy, 2002).
Fridrikson et al. (2006) found that there was a clear relationship between scores on executive functioning measures and the functional communication abilities of individuals with Aphasia. Decreased executive functioning was suggested to coincide with decreased functional communication ability in individuals with Aphasia. Purdy (2002) found that deficits in cognitive flexibility and planning were found in a number of patients with Aphasia. It is important therefor to consider the influence of executive function on performance, as communication does not rely solely on language-specific processes but on numerous non-linguistic processes such as attention, sequencing and flexibility. Clinicians must be cautious not to generalise these difficulties to all clients, as there is a great deal of variation within a client group. It is however, crucial to be aware of the relationship between language and executive functioning in order to provide the most effective and appropriate management of clients with varying communicative impairments (Purdy, 2002).