Altered sensitivity to positive reinforcement has been hypothesized to contribute to the symptoms of attention-deficit hyperactivity disorder (ADHD). In this study, we evaluated the ability of children with and without ADHD to adapt their behavior to changing reinforcer availability.
Of one hundred sixty-seven children, 97 diagnosed with ADHD completed a signal-detection task in which correct discriminations between two stimuli were associated with different frequencies of reinforcement. The response alternative associated with the higher rate of reinforcement switched twice during the task without warning. For a subset of participants, this was followed by trials for which no reinforcement was delivered, irrespective of performance.
Children in both groups developed an initial bias toward the more frequently reinforced response alternative. When the response alternative associated with the higher rate of reinforcement switched, the children’s response allocation (bias) followed suit, but this effect was significantly smaller for children with ADHD. When reinforcement was discontinued, only children in the control group modified their response pattern.
Children with ADHD adjust their behavioral responses to changing reinforcer availability less than typically developing children, when reinforcement is intermittent and the association between an action and its consequences is uncertain. This may explain the difficulty children with ADHD have adapting their behavior to new situations, with different reinforcement contingencies, in daily life.
Everyone experiences anxiety at some point in response to threatening or challenging situations. The anxious response can range from mild physiological symptoms such as rapid breathing and heart rate through to panic attacks. Anxiety becomes a problem when it is chronic and out of proportion to the threat or challenge.
Causes of anxiety
There are likely to be numerous factors involved in causing anxiety. It is also likely that most individuals will experience a different mix of causal factors, which may include genetic factors, unique life experiences, disruption of neurochemicals in the brain, personality, and individual behavioural and thinking styles.
In most cases it is useful to consider that anxiety results from one’s perception of a situation, rather than the situation per se. Imagine yourself in a room with Steve Irwin (the late, great Crocodile Hunter) and a brown snake. Your response may be an initial perception of extreme threat, followed by intense fear and physiological reactions such as increased automatic nervous system responses (e.g., heart rate, breathing, blood rushing from the extremities to the vital organs), followed by a behavioural response such as running from the room. That your physiological and emotional responses diminish once you are safely outside the room reinforces the idea in your mind that snakes are inherently dangerous creatures and that when one sees a snake one needs to run away. In contrast, Steve’s perception of the same situation would most likely have prompted excitement and a strong desire to touch and look more closely at a beautiful animal. His successful behavioural response reinforces his idea that snakes are animals requiring respect but that he is competent to deal with their threat. The same situation, but very different emotion and behaviour. This example shows that it is the perception of the situation that is most important, not the situation itself.
Perhaps a more correct way of putting is that it is the learning experiences one has had in certain situations that are most important. Steve Irwin was born with the inbuilt human trait to fear the unknown. Therefore the first time he saw a snake he would have experienced the same burst of fear as the typical person. However, because of his exposure to the animals and because he learned to handle them competently he also learned not to fear them. In contrast, many people fear snakes despite having never seen one “in the wild”. One could argue that their fear is a ‘failure of learning’ because they have not yet learned that snakes can be avoided or handled competently. Therefore, their default response is the inbuilt human flight mechanism.
Symptoms of Anxiety
Anxiety can be acute (as in the snake example above) or a pattern of chronic worrying. Physiological and behavioural symptoms include:
When symptoms reach a level of frequency and intensity that interferes with daily functioning (i.e., it creates impairment in job, school or interpersonal functioning) the patient may be diagnosed with an anxiety disorder, or which there are several, including:
Evidence-based treatment tends to differ between the different anxiety disorders. However, all good clinicians will use a combination of some of the following:
A psychotherapist or a GP who specialises in mental health is usually necessary to diagnose and treat anxiety disorders. Still, there are many things that the patient can do to help themselves.
Take part in a pleasant activity every day.
Increase gentle exercise.
Reduce caffeine and alcohol intake.
Improve time-management skills.
Rather than pressuring yourself to finish jobs, set a time limit on your work and try to be satisfied with doing a good job within that period.