Is the mind modular?

Mind – n. the human consciousness that originates in the brain and is manifested especially in thought, perception, emotion, will, memory, and imagination. 

Architecture of the human mind

No robot can solve a crossword, or engage in a conversation, with anything like the facility the average human being can. Somehow or other we humans are capable of performing complex cognitive tasks with minimal effort. Trying to understand how this could be is the central explanatory problem of the discipline known as cognitive psychology. There is an old but ongoing debate among cognitive psychologists concerning the architecture of the human mind. 

The ‘general-purpose problem-solver’ mind

According to one view the human mind is a’ general-purpose problem-solver’. This means that the mind contains a general set of problem-solving skills or ‘general intelligence’ which it applies to an infinitely large number of different tasks. So the same set of cognitive capacities is employed, whether you are trying to count marbles, deciding what movie to see, or learning a foreign language – these tasks represent different applications of the human’s general intelligence.

The modular mind

A rival view argues that the human mind contains a number of subsystems or modules – each of which is designed to perform a very limited number of tasks and cannot do anything else. This is known as the modularity of mind hypothesis. So for example it is widely believed that there is special module for learning a language – a view deriving from the linguist Noam Chomsky. Chomsky insisted that a child does not learn to speak by overhearing adult conversation and then using ‘general intelligence’ to figure out the rules of the language being spoken; rather there is a distinct neuronal circuit – a module – which specialises in language acquisition in every human child which operates automatically and whose sole function is to enable that child to learn a language, given appropriate prompting. The fact that even those with very low ‘general intelligence’ can often learn to speak perfectly well strengthens this view.

Clues from the broken brain

Some of the most compelling evidence for the modularity of mind hypothesis comes from studies of patients with brain damage. If the human mind were a general all-purpose problem-solver we would expect damage to the brain to affect all cognitive capacities more or less equally. But this is not what we find. On the contrary, brain damage often impairs some cognitive capacities but leaves other untouched. A good example of this is damage to a part of the brain known as Wernicke’s area – following injury or viral infection – which leaves a patient unable to understand speech although they are still able to produce fluent, grammatical sentences. This strongly suggests that there are separate modules for sentence production and comprehension. Other brain-damaged patients lose their long-term memory (amnesia) but their short-term memory and their ability to speak and understand are entirely unimpaired.

Modular or ‘general purpose problem-solver’ …or both?

The evidence for a modular mind is compelling and the philosopher Jerry Fodor published a book in 1983 titled The Modularity of Mind  which explained exactly what a module is. However the modular view is controversial and is not endorsed by all philosophers. Opponents argue that even in a general purpose problem-solver brain it is still possible that distinct cognitive capacities might be differently affected by brain damage. Fodor himself even admits that the answer may not be all that clear cut and suggests that while perception and language are modular, thinking and reasoning are almost certainly not – we solve some cognitive tasks using specialised modules and others using our ‘general intelligence’. However not all psychologists agree with this. 

Is the mind scientifically inexplicable?

Exactly how many modules there are and precisely what they do, are questions that cannot be answered given the current state of brain research. Most neuroscientists equate mind and brain as one and the same thing and predict that in the not-too-distant future neuroscience will deliver a radically different type of brain science, with radically different explanatory techniques what will explain the architecture of the human mind.

 

Weekly Round-Up

Transcranial magnetic stimulation can minimize forgetfulness

Memory failure is a common occurrence yet scientists have not reached a consensus as to how it happens. However, according to a new study at Beth Israel Deaconess Medical Center, Transcranial magnetic stimulation (TMS) is able to minimize forgetfulness by disrupting targeted brain regions as they compete between memories.

A new study which will be published in an upcoming issue of Psychological Science, finds changes in brain activity after only five weeks of meditation training.

In an ongoing quest to map the brain, scientists have determined how the brain works to understand others. According to a new study, the brain generates empathy in one manner for those who differ physically and in another method for those who are similar. In a paper published online by Cerebral Cortex, researcher Dr Lisa Aziz-Zadeh, suggests empathy for someone to whom you can directly relate — (for example, because they are experiencing pain in a limb that you possess) — is mostly generated by the intuitive, sensory-motor parts of the brain. However, empathy for someone to whom you cannot directly relate relies more on the rationalizing part of the brain.

The brain holds on to false facts, even after they have been retracted according to a report in Scientific American.

Psychologists have found that thought patterns used to recall the past and imagine the future are strikingly similar. Using functional magnetic resonance imaging to show the brain at work, they have observed the same regions activated in a similar pattern whenever a person remembers an event from the past or imagines himself in a future situation. This challenges long-standing beliefs that thoughts about the future develop exclusively in the frontal lobe.

Many dementia patients being prescribed antipsychotic drugs could be better treated with simple painkillers, say researchers from Kings College, London, and Norway.

Brain damage can cause significant changes in behaviour, such as loss of cognitive skills, but also reveals much about how the nervous system deals with consciousness. New findings reported in the July 2011 issue of Cortex demonstrate how the unconscious brain continues to process information even when the conscious brain is incapacitated.

Years after a single traumatic brain injury (TBI), survivors still show changes in their brains. In a new study, researchers from the Perelman School of Medicine at the University of Pennsylvania suggest that Alzheimer’s disease-like neurodegeneration may be initiated or accelerated following a single traumatic brain injury, even in young adults.