Humans may have two distinct cognitive systems

Scientists have found the strongest evidence yet that humans have separate and distinct cognitive systems with which they can categorise, classify and conceptualise their world.
The question of whether humans have discrete cognitive systems operating on different levels has been debated for years.
"This issue of whether there are separate cognitive systems famously arose regarding humans' declarative and procedural memory and in the field of categorisation," said lead researcher, cognitive psychologist J David Smith, of the University at Buffalo.
"Cognitive neuroscientists have hypothesised that humans have distinguishable systems for categorising the objects in their world - one more explicit (ie, conscious and available to introspection), one less so, or more implicit," said Smith.

To grasp the differences between these two types of learning, Smith recommends that we remember certain distinctions in our performance of the tasks of daily life.
"For instance, when you select a cereal named 'Chocoholic' from the store shelf consider why you are doing so," Smith said.

"Is it a deliberate, explicit choice, or is it possibly an implicit-procedural chocolate reaction, one triggered by processes, memories and so on, of which you are generally unaware?" he said.
"Because of the considerable controversy surrounding the question of whether we have more than one cognitive system, researchers have continued to seek models that distinguish the processes of explicit and implicit category learning and this study presents the clearest distinction yet found between these systems," he said.

In the study, researchers asked participants to work for blocks of trials without any corrective feedback, and then deliver feedback when they were finished.
Smith likened this process to an undergraduate testing situation in which the student taking a test does not get item-by-item feedback, but receives a summary score once the test is completed.
Because this manipulation prevents the formation of automatic (implicit) stimulus-response associations, Smith and his colleagues hypothesised that it would undermine the processes of conditioning and eliminate the possibility of implicit category learning.
Researchers found that facing a task that could only be learned implicitly, participants with blocked feedback turned futilely to conscious strategies that were inadequate, because this was all they could do when implicit category learning was defeated.

"In the area of categorisation research the issue of single vs multiple systems is nearly closed," Smith said.
"The evidence is now very strong that there are multiple category-learning systems - in particular, the explicit-conscious and the implicit-procedural system," he said.
The study was published in the journal Psychological Science.