Friday, May 6, 2016

Executive functions – where do they fit within CHC terminology?


 

Executive functions are cognitive functions needed to deal with new and unfamiliar tasks.  Examples of executive functions would be identifying a goal or a problem, planning how to reach that goal or how to solve that problem, choosing an action plan among alternatives, initiating the plan, monitoring the plan's execution, responding flexibly when problems arise, and inhibiting automatic responses that are not conducive to reaching the solution. 

In Adele Diamond's conceptualization (4), executive functions are composed of three components:

Inhibition:  behavioral inhibition (self control and the ability to resist temptation) and cognitive inhibition (controlling internal and external distractions and inhibiting automatic responses).

Working memory – which enables planning and monitoring progress towards   goal attainment.

Flexible thinking – which enables us to think about new solutions and to change strategy if the chosen one doesn't  lead to the preferred results. 


Where do executive functions fit within CHC terminology?

When we speak about "executive functions" and about "CHC abilities" we use two different languages.  The concept "Executive functions"  belongs to neuropsychological theories.  CHC abilities are concepts belonging to psychometric theory.  Thus, asking "Where do executive functions fit within CHC terminology?" is like asking "How do you say "caucus" in French"?  There probably is no French concept which exactly parallels the meaning of "caucus" in American English. 

Nevertheless, executive functions can be placed between Fluid Ability and Short Term Memory.  The relations between them are presented in the slide below:

  

 


The relation between Executive Functions and Fluid Ability:

Flanagan and her colleagues (1) define Fluid Ability as "mental operations that an individual may use when faced with a relatively novel task that cannot be performed automatically".  These thinking processes include identifying and constructing concepts and relations, deriving conclusions, understanding consequences, abstract thinking, problem solving, reorganizing or restructuring information, inductive and deductive reasoning, classifying, creating hypotheses and quantitative reasoning.

According to this conceptualization, the common element of Fluid Ability and Executive Functions is the Flexibility in reasoning.

McGrew, in the CHC version 2 definitions, defines Fluid Ability like this:  "The deliberate but flexible control of attention to solve novel “on the spot” problems that cannot be performed by relying exclusively on previously learned habits, schemas, and scripts".

  

This conceptualization emphasizes the control of attention, and through it, the inhibition component, as a common component of Fluid Ability and Executive Functions, along with the Flexibility component.

Thus, this conceptualization brings Fluid Ability and Executive Functions closer together.  According to this conceptualization, in order to solve new problems successfully, we must recruit attentional resources and inhibit automatic and well practiced responses.

Salthouse writes:  "Contextual analyses have … revealed very strong relations of fluid cognitive ability (Gf) to constructs hypothesized to represent executive functioning  and to assorted variables postulated to represent specific aspects of executive functioning.  These patterns suggest that Gf may reflect nearly the same dimension of individual differences as executive functioning".

 

What about the relation between Executive Functions and Short Term Memory?

Short Term Memory is "the ability to apprehend and hold information in immediate awareness and then use it within a few seconds" (1).  The broad ability Short Term Memory contains two narrow abilities:  Memory Span (the ability to attend to and immediately recall temporally ordered elements in the correct order after a single presentation) and Working Memory (the ability to temporarily store and perform a set of cognitive operations on information that requires divided attention and the management of the limited capacity of short term memory".

Thus, the common element of Executive functions and Short Term Memory is the Working Memory component (by Adele Diamond's conceptualization, according to which one of the components of Executive Functions is Working Memory).

"Executive function deficits may be most noticeable in the capacity of the individual to allocate and sustain attentional resources…Attentional capacity, and to some extent divided attention, are characteristic of working memory tasks that require an individual to keep two or more sets of elements "alive" in short term memory and alternate between performing operations on the two sets of information" (5).

 

We've discussed the relations between Executive Functions and Fluid Ability, and between Executive Functions and Short Term Memory.  Now we can come full circle and discuss the relations between Fluid Ability and Short Term Memory.
 
Researchers find high correlations (0.8-0.88) between measures of working memory and measures of Fluid Ability (2).

 Lohman and his colleagues (2) note that "critics complained that some tasks used to estimate working memory in … studies were indistinguishable from tasks used to estimate reasoning" (2).

"In part, this is a problem of words. The term working memory connotes too small a construct; reasoning connotes too large a construct—especially given the way each is typically measured. Consider first the reasoning construct. In the best of these studies, reasoning is estimated by performance on a series of short, puzzle-like tasks. More commonly, it is estimated by a single test such as the Raven Progressive Matrices that uses a single item format.  Indeed, figural reasoning tests such as the Raven are typically much poorer predictors of both real-world learning and academic achievement than measures of verbal and quantitative reasoning. Whether measured by one task or several short tasks, the reasoning construct is usually underrepresented. 

On the other hand, the construct measured by the series of working memory tests is much more complex than its label suggests. These tasks generally require participants to understand and follow a sometimes complex set of directions; to assemble and then revise a strategy for performing a difficult, attention-demanding task; to maintain a high level of effort across a substantial number of trials; and then to repeat the process for a new task with a new set of directions. In addition, many working memory tasks require individuals to process simultaneously one set of ideas while remembering another set. Although the individual tasks are generally thought to be easy, they are certainly not trivial, especially when performed under memory load. These tasks elicit executive functions such as the monitoring of processes, controlling their rate and sequence of operation, inhibiting inappropriate response processes, coordinating information from different domains, and integrating ideas into a coherent mental model. Such executive functions clearly overlap with many researchers’ conception of reasoning or even of general intelligence" (2).  

This is quite convincing, but studiesshow that even tasks that measure only Memory Span, without any manipulation, correlate significantly with Fluid Ability (3).


To summarize, from the point of view of CHC abilities, we see a great closeness between Fluid Ability and Short Term Memory.  We also see a great closeness between Executive functions,  Fluid Ability and Short Term Memory. 

It may be that these three concepts will merge in the future to form one psychometric ability.  Maybe this ability will be named "Executive Functions", and Fluid Ability and Short Term Memory will be narrow abilities within it.


References:

1.  Flanagan, Dawn p., Ortiz, Samuel O. and Alfonso, Vincent C.  Essentials of cross battery assessment.  Second edition, 2007, Wiley and sons
2.  Lohman, D. F., Lakin, J. M., Sternberg, R. J., & Kaufman, S. B. (2009).Reasoning and intelligence. Handbook of intelligence, 419-441. 
3.  Fukuda, K., Vogel, E., Mayr, U., & Awh, E. (2010). Quantity, not quality: The relationship between fluid intelligence and working memory capacity.Psychonomic bulletin & review, 17(5), 673-679.
4.    Diamond, Adele.  Executive functions. Annu. Rev. Psychol. 2013. 64:135–68


5.  WJ3COG examiner's manual.

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