Latent Inhibition is a phenomenon observed in classical conditioning in that familiar stimuli takes longer to acquire meaning (be conditioned) than unfamiliar stimuli. To use Pavlov’s famous dogs as a hypothetical example, ringing a dinner bell without following it up with some significant event (giving dinner), and then doing so again some time later, but this time attempting to condition the dogs by following it up with food, the dogs who heard the bell but were not initially conditioned would take longer to associate the dinner bell with food than dogs who are unfamiliar with the dinner bell when the conditioning takes place. The novel stimulus is essentially associated with nothing after the initial exposure, automatically determined to be insignificant, and then its potential relevance is ignored upon subsequent presentation.
At the heart of the latent inhibition effect is the automatic filtering of information deemed automatically insignificant by prior experience. This information is then ignored and is not consciously acknowledged. Thus we only experience a fraction of the information that we actually sense; the information determined by our filters to be worthy of our attention. Latent inhibition is not confined to humans and is observed in all mammalian species that have been tested for this effect, suggesting an important function of this phenomenon. This is believed to allow potentially more important environmental cues (either by association e.g. fire, or unfamiliarity, also a potential indicator of danger) to stand out and the attention to be unencumbered to react to and deal with these potentially more significant events.
Low Latent Inhibition
In the general population there are variations in the strength of latent inhibition. In some people latent inhibition is reduced, a condition known as low latent inhibition. The filtering of sensory information is reduced and the information that is usually automatically redacted by the filters and subsequently ignored in people with normal levels of latent inhibition is consciously perceived and attended to in the way a novel stimulus would usually be paid attention to. Such people are far more aware of their environment and more perceptive of subtle changes within it. Insignificant details usually missed or ignored by people with intact latent inhibition are keenly noticed and considered by those with low latent inhibition.
This diminished filtering that creates such a rich sensory experience effect comes at a price. The reduced filtering of information generates a greater cognitive load that may impede the ability of those with low latent inhibition to effectively focus on more relevant matters with the greater amount of extraneous information competing for attention. Such people are more easily irritated by background noise and other innocuous stimuli, and may be prone to overstimulation and the resulting distress.
Latent Inhibition and Creativity
The increased sensory awareness that is associated with low latent inhibition is linked to increased creativity. The greater amount of information available and paid attention to is believed to aid in creating disparate associations that would not be made if such non obvious information is ignored. Among high functioning (high intelligence) individuals in particular, those low in latent inhibition are found to have much higher rates of creative achievement compared to comparable individuals with normal levels of latent inhibition.
One’s cognitive ability is believed to be important in deriving the benefits of a reduced latent inhibition. Those with higher cognitive function are hypothesized to be able to process this greater volume of information more effectively and are less vulnerable to sensory overload compared to those with relatively lower cognitive function, and thus experience less of the negative effects of low latent inhibition. They may also be able to more effectively turn this large volume of information into creative ideas.
Low latent inhibition is found in the mental disorder schizophrenia. Occurence of the crippling disorder in a family lineage is associated with an increased prevalence of creative achievement and personality traits related to creativity, which include low latent inhibition, in healthy members of the family. Low latent inhibition may be correlated with the Five Factor personality trait Openness/Intellect, possibly because latent inhibition is significantly modulated by the activity of the mesolimbic pathway, which also modulates exploratory behaviour and reward.
Modifying Latent Inhibition
In experiments with animal and human subjects, latent inhibition has been shown to be able to be disrupted by increasing the activity of dopamine in the mesolimbic pathway via administering a dopamine reputake inhibitor (e.g. Methylphenidate). However, downregulation of the dopamine system from repeated use of a DRI may eventually void this effect. Other avenues must be pursued for viable long term modification.
Conversely, latent inhibition is reinforced when dopamine activity is reduced via a dopamine antagonist such as an antipsychotic. In schizophrenia, antipsychotics used to treat its symptoms restore latent inhibition to normal levels. Oxytocin, a peptide that shows promise in treating social deficits and ameliorating neurodevelopmental disorders (e.g. autism) and schizophrenia, might also enhance latent inhibition in those with low latent inhibition, like in the stated disorders, possibly by indirectly inhibiting dopamine activity.
The serotonin, glutamate, and acetycholine systems are also believed to play a role in modulating latent inhibition.
Depictions in Fiction
For depictions of what may resemble low latent inhibition in fiction, see the TV Tropes page Hyper Awareness.