Wiers & Stacy (2006). Implicit cognition and addiction. Summary

Until recently, it was thought that drug-abusers keep using drugs because they like the benefits more than the disadvantages, but most drug-abusers are well aware of the disadvantages of abusing drugs. The problem is that most drug-abusers cannot resist the automatically triggered impulses. If there is little room for conscious control in a situation, the action tendency (using drugs or substances) might be stronger than the conscious control.

There are two semi-independent systems:

1. A fast associative impulsive system
   This includes the automatic appraisal of stimuli in terms of their emotional and motivational significance.
2. A slower reflective system
   This includes controlled processes related to conscious deliberation, emotion regulation and expected outcomes.

The brain changes as a result of continued substance abuse. Some of these changes involve neural substrates related to emotion and motivation. The impulsive system becomes sensitised to the drug and other cues that predict use following prolonged drug abuse. The result is that drug-related cues automatically capture their attention. This may result in automatic action tendencies (use the substance or drug). This action tendency can still be inhibited if the person has enough motivation or ability to do so. Impulsive people are more likely to develop addictions.

Implicit cognition is measured by testing the attention bias and memory associations. The best attentional-bias task is the drug Stroop task. The visual probe test is also used for testing attentional bias. Memory associations can be tested by providing participants with cues and to see which they associate with and another way is presenting participants with affective phrases that can be alcohol or drug-related. Spontaneous associations reflect impulsive, automatic processes in addictive behaviours, assess unique information beyond more explicit expected outcomes.

Cognitive interventions are better suited to change explicit cognitive processes than to change implicit ones. New interventions are being developed focussed on the two semi-independent systems and substance abuse is being predicted by the results on the attentional bias and memory association tasks. This focusses on changing implicit associations and attention towards more neutral stimuli, rather than drug-related stimuli. The newly developed interventions are proper supplements to already existing interventions, rather than a good alternative.

Implicit measures may better reflect deeper affective mechanisms that operate outside awareness than may explicit measures and thus may provide a unique window on these processes in the development of human addiction. Long-term effects of alcohol and drugs on systems of emotion and motivation are particularly pronounced during adolescence.