used an NPU shock model that measured predictable and unpredictable threat. This had three conditions: a no shock condition, where no shocks were given; a predictable shock, where a shock could only be given when a stimulus appeared; and an unpredictable shock condition, where a shock could be given at any time. The reward task used a computerized slot machine game, which had two possible outcomes: a reward condition (in order to induce reward anticipation), where a monetary reward was available; and a no-incentive condition, where no reward was available no matter the outcome. Results indicated that participants with PD showed a significantly heightened sensitivity to threat compared to controls. MDD participants showed significant reduction in sensitivity to reward compared to controls. Response to punishment in depression Far less research has examined depressed individuals’ responsiveness to punishment. A further personality system proposed by Gray is the Behavioural Inhibition System (BIS). Gray proposed that feelings of anxiety are related to individual’s sensitivity to the BIS. Punishments, non-rewards, and fear are common components that elicit activation of the BIS (Gray, 1987a; Matthews et al, 1999). Due to symptoms in depression such as reduction in interest and pleasure, and anhedonia, the tendency has been to delve into the sensitivity and responsiveness to reward, with less research looking at sensitivity and responsiveness to punishment. Nonetheless, research has indicated that depressed individuals tend to show maladaptive responses when exposed to punishment. Beats, Sahakian & Levy (1996) conducted experiments looking for impairment across multiple cognitive functions in recovering depression patients. A variety of neuropsychological tests were used. Results showed that depressed individuals were experiencing deficits in a number of cognitive areas, such as attention shifting in processing, visuospatial recognition memory and attention shifting in motor tasks. Beats et al. (1996) noted throughout testing that if a depressed participant made an error or mistake in a test, their performance in the following questions would significantly decrease and they would continue to get the following items wrong. They concluded that participants who were depressed showed a negative response to failure and would perform worse immediately after.. A study conducted by Elliott et al. (1996) also found similar effects when testing for cognitive impairments in depressed individuals, using the CANTAB battery of neuropsychological tests. A key finding was the damaging effect failure on a task would have on following performance. After scoring a trial incorrectly, depressed participants were more likely to fail the following trial than the control group. Following this observation, Elliot et al. (1997) conducted a study to further assess potential motivational deficits in depressed individuals that might cause oversensitivity to failure. Depressed participants and controls were given two neuropsychological tests to complete, and were then given feedback of their performance. Results showed that the depressed individuals who perceived failure on a problem dramatically increased their chances of incorrectly answering the following problem. The authors concluded that this abnormal response to negative feedback may be a trait of the disorder. Sensitivity to reward and punishment in other psychological disorders Studies have been conducted looking at sensitivity to rewards and punishers
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Together these studies might indicate whether similar traits across disorders link to similar patterns of sensitivity to reward and punishment, or whether differences in such sensitivity is commonly related to the phenomenology of the symptoms of each disorder.
Tripp and Alsop (1999) found rewards in a signal-detection task had different influences on the performance of boys with ADHD than boys without ADHD. Once the boys without ADHD (control) created a pattern of response bias towards the option that was more frequently rewarded, they continued to follow this pattern even when there were sometimes local changes in the reward frequencies. In contrast, the boys with ADHD did not establish a stable pattern of response bias. They tended to show shifts in their response bias to rewards based on local changes in reward frequency. They had more difficulty remaining on task and tended to act more impulsively than controls in an attempt to acquire some sort of immediate satisfaction. This supports the notion that the behaviour of individuals with ADHD is likely to be reinforced via immediate reinforcers more so than history of reinforcement, as well as needing large amounts of instant reinforcers to more effectively encourage on-task behaviours in these individuals (Tripp & Alsop,
Together these studies might indicate whether similar traits across disorders link to similar patterns of sensitivity to reward and punishment, or whether differences in such sensitivity is commonly related to the phenomenology of the symptoms of each disorder.
Tripp and Alsop (1999) found rewards in a signal-detection task had different influences on the performance of boys with ADHD than boys without ADHD. Once the boys without ADHD (control) created a pattern of response bias towards the option that was more frequently rewarded, they continued to follow this pattern even when there were sometimes local changes in the reward frequencies. In contrast, the boys with ADHD did not establish a stable pattern of response bias. They tended to show shifts in their response bias to rewards based on local changes in reward frequency. They had more difficulty remaining on task and tended to act more impulsively than controls in an attempt to acquire some sort of immediate satisfaction. This supports the notion that the behaviour of individuals with ADHD is likely to be reinforced via immediate reinforcers more so than history of reinforcement, as well as needing large amounts of instant reinforcers to more effectively encourage on-task behaviours in these individuals (Tripp & Alsop,