Reinforcement

Reinforcement is a psychological concept that explains the process of a behaviour becoming a habit. At its simplest, it means an action that’s followed by a pleasant outcome is likely to be repeated, and an action followed by an unpleasant outcome is unlikely to be repeated. The brain’s dopamine reward system is critical in this process, and reinforcement can be positive or negative.

What is Reinforcement?

Our understanding of reinforcement began in the 1890s with Ivan Pavlov’s work on classical conditioning. Classical conditioning, which is still sometimes called Pavlovian conditioning, was uncovered through Pavlov’s groundbreaking experiments with dogs. Through repetition, Pavlov trained dogs to associate the sound of a bell ringing with food. Classical conditioning is the process of learning by association. 

BF Skinner took this one step further, introducing the concept of operant conditioning. This worked in a very similar way to classical conditioning but introduced a new element—instead of just learning to link one thing with another, like associating a bell with food, operant conditioning attempted to create certain behaviours via rewards or punishment.

Later discoveries built on the foundations of this behavioural research with new findings in the fields of neuroscience. The importance of the brain’s dopamine reward system was discovered via reinforcement experiments on rats that incorporated neuroimaging that allowed scientists to examine what was happening in their brains.

Reinforcement and Addiction – The link

Our understanding of reinforcement’s role in addiction began in the 1970s, with famous experiments on the self-administration of drugs in rats. Scientists gave rats the option of dosing themselves with addictive and non-addictive drugs. They found that they would choose to dose themselves with addictive drugs like heroin and methamphetamine repeatedly, not bothering with the non-addictive drugs. They discovered that the dopamine reward pathway was heavily involved in this behaviour, and one of the reasons the rats self-administered these drugs was that it activated the brain’s reward system. The rats in these studies would choose ‘unnatural’ rewards, like drugs or artificial brain stimulation, over natural rewards, like food. Brain imaging in these studies further highlighted the role of the dopamine reward system and how it became dysregulated over time as the behaviour was repeated and reinforced.

There is additional rat research that adds more context to this. In the original studies on rats self-administering drugs, they were alone in their cages. The American psychologist Bruce Alexander suspected that the environment the rats were in played a role in their behaviour, and decided to find out in his ground-breaking Rat Park study.

Alexander wanted to make a paradise for rats. He created rich environments for them to live in where they could play, roam, socialise and have sex. He placed two bottles for the rats to drink from in this environment – one laced with morphine and one with plain water. He found that the rats in his rat paradise chose not to drink from the drugged bottle and chose plain water.

Bruce Alexander’s experiment enhanced and expanded our understanding of addiction and showed that there were more factors at play than just reinforcement. Genetics, biology and environment all play a role, and today, our understanding of addiction is multifaceted as a result. Our brain reward circuits respond to drugs in a way that can cause addiction to develop through reinforcement, and for some of us, our genetics give us brain reward pathways that are more susceptible to this process. But our environment still plays a key role, and by changing our surroundings and our relationships, we can control some of the variables that leave us open to addiction.

Positive Reinforcement vs Negative Reinforcement

Simply put, positive reinforcement involves getting a positive reward after performing an action, like getting a piece of food after pushing a button. Negative reinforcement still involves getting a reward after performing an action, but the reward is getting something unpleasant to stop – like the ability to stop a harsh noise by pressing a button. Both of these processes have roles to play in the context of addiction.

The American psychologist Edward Thorndike discovered the basics of positive and negative reinforcement in the late 1800s. These experiments were an attempt to understand how animals learn. Thorndike set up a series of puzzle boxes that animals had to escape to get a reward, usually food. He found that they were able to repeat their escape more quickly each successive time and theorised that this was because actions that didn’t result in a positive reward were eliminated and actions that did result in a positive reward were retained. This means that the animals weren’t using reasoning – it was a mechanical process of trial and error where inefficient actions were discarded, and useful ones were repeated. 

Thorndike’s experiment involved both positive and negative reinforcement. The animals started the experiments confined to a puzzle box, an unpleasant state where they were effectively imprisoned, and were given the positive outcomes of both food and freedom once they escaped.

Positive reinforcement and addiction

The concept of positive reinforcement in addiction is easy to understand. When a person takes a drug, the drug feels good, and the positive sensation incentivises them to take it again. Positive reinforcement is based on the attainment of a pleasant sensation.

Negative reinforcement and addiction

The other side of this process is the avoidance of withdrawal. Withdrawal feels unpleasant, and the unpleasant effects of withdrawal can be alleviated by taking more drugs. As a result, people struggling with addiction are doubly reinforced – by wanting the positive effects of a substance, and wanting to avoid the negative effects of drug withdrawals. Negative reinforcement is based on the avoidance of pain.

Incentive sensitisation theory posits that not only do reinforcing behaviours become ingrained as habits, but we also get more sensitive to them over time. Repeatedly taking a substance causes drastic changes in the brain. Over time, the brain has an exaggerated reaction to drugs, releasing more dopamine in response to them (positive reinforcement). At the same time, brain pathways associated with stress also become sensitised. Additionally, dopamine receptors actually get less sensitive – meaning we can’t feel the exaggerated dopamine response in our brain as intensely as before. These processes cause withdrawals and anhedonia when abstinent, and because these are unpleasant sensations, they further negatively reinforce drug-taking behaviour.

Reinforcement-informed treatments

Addiction is a complex condition that often requires comprehensive treatment strategies. Reinforcement-informed treatments are an important category of interventions that leverage the principles of reinforcement to promote abstinence and support recovery. These treatments focus on modifying behaviour through the systematic application of rewards and consequences, thus influencing the motivational dynamics underlying substance use. Two prominent examples of reinforcement-informed treatments are Contingency Management (CM) and Medication-Assisted Therapy (MAT).

Contingency management: 

Contingency Management (CM) is a behavioural therapy approach that seeks to alter the reinforcement patterns associated with substance use and abstinence. This method provides tangible rewards for meeting specific treatment goals, such as maintaining sobriety, attending therapy sessions, or achieving other recovery milestones. The rewards can vary widely and may include vouchers, monetary incentives, or other desirable items. Conversely, CM may also involve withholding rewards or implementing punitive measures when individuals engage in substance use or fail to meet treatment goals.

The efficacy of CM is well-documented, with numerous studies indicating its effectiveness in increasing abstinence rates, reducing relapse, and improving treatment retention. By directly linking positive behaviours with immediate rewards, CM helps rewire the brain’s reward system, which has often been hijacked by addiction. Despite its success, the use of CM is not without controversy. Critics argue that it may lead to dependency on external rewards and question the ethical implications of providing financial incentives for sobriety. Nonetheless, CM remains a valuable tool in the addiction treatment arsenal, particularly when integrated with other therapeutic modalities.

Medication-assisted therapy: 

Medication-assisted therapy (MAT) aims to mitigate the negative reinforcement associated with addiction, primarily the discomfort and distress of withdrawal symptoms. MAT involves the use of medications such as methadone, buprenorphine, or naltrexone to replace more addictive opioids with substances that have a lower potential for abuse. By alleviating withdrawal symptoms and reducing cravings, MAT helps stabilise individuals, making it easier for them to participate in and adhere to treatment programmes.

MAT has been shown to improve treatment outcomes, including increased retention in therapy significantly and reduced illicit opioid use. This approach not only addresses the physiological aspects of addiction but also provides a foundation upon which psychological and social interventions can build. The use of MAT, however, has its detractors. Some argue that it merely substitutes one addiction for another and express concerns about long-term dependence on medication. Despite these concerns, MAT is widely recognised as a crucial component of evidence-based addiction treatment, endorsed by numerous health organisations for its ability to enhance recovery and save lives..

Reinforcement-informed treatments represent a promising approach in the battle against addiction, leveraging the principles of behavioural psychology to promote recovery. Contingency Management and Medication-Assisted Therapy exemplify how reinforcement can be harnessed to modify behaviour and support individuals in overcoming substance use disorders. 

While these methods are not without controversy, their efficacy is supported by substantial research, underscoring their value in comprehensive addiction treatment programmes. By addressing both the rewarding and punishing aspects of substance use, reinforcement-informed treatments offer a balanced strategy that can significantly enhance the prospects of long-term addiction recovery.