It is uncontroversial to say that the cognitive sciences do not exclusively deal with directly observable phenomena, but nonetheless aim to study the physical causes of behavior and cognition scientifically. "Grasping", for instance, is directly observable, but cognitive science also studies "intelligence," which is not directly observable, at least not for all conceptualizations of intelligence.
When cognitive science studies such an unobserved quantity, the difference between the general concept, the unobserved construct, and the direct measure is sometimes rendered implicit. More colloquially: go far enough down the methodological rabbit hole for an unobserved construct, and you will likely eventually find a patient zero paper that defines a broad folk concept, then makes a spherical-cow or just-so statement that a construct maps on to the concept.
Example: Working memory
For an illustration of a just-so definition, take Baddeley and Hitch's definition of working memory in their seminal 1974 work as a replacement for the classical short-term/long-term memory model:
a system that provides temporary storage and manipulation of information
(The relationship rendered implicit here is ["memory" -> STM/LTM -> WM/LTM].)
To be fair to Baddeley & Hitch, and so as not to single them out, Baddeley has later defended this problem with their model on productivity and guide to discovery grounds (Baddeley, 2007). I find this quite reasonable, and I do not mean to impugn their excellent research or the model's productivity in any way, only to use the example as an illustration for the question.
Problem of implicit relations
Implicit relations are antithetical to the practice of science because they engender unstated assumptions and hidden theoretical incompatibilities. It is also antithetical to science communication and scientific literacy, because important words like "intelligence" and "memory" become effectively polyvalent, with subtly different meanings that are not apparent without considerable study. The relationship between IQ and intelligence is the prototypical example.
What is the relation between measures, constructs and concepts as actually used in the cognitive sciences? (Contrast intelligence or memory with grasping or walking, if concrete examples are helpful.)
Please read my comments to the question and current answer before asking for additional information.
- What is the correlation between objective indexes and aggregated self-report measures of life satisfaction?
- What is the difference between biological and artificial neural networks?
- What is the difference between social anxiety disorder and shyness?
- Baddeley, A. (2007). Working memory, thought, and action. Oxford University Press.
- Baddeley, A. D., & Hitch, G. (1974). Working memory. Psychology of learning and motivation, 8, 47-89.