Abstract
The present study investigated how different psychological factors (attention deficit hyperactivity disorder, depression, anxiety, and stress) influence individuals’ behavioural variability when under direct reinforcement. Participants played a soccer-style video game, which reinforced their repetition (REP) or variability (VAR) of responses across two conditions. In the REP condition, participants were reinforced (with points) by scoring a goal when their series of four button clicks matched one of the previous four sequences. In the VAR condition, reinforcement occurred when participants' series of four button clicks differed from the previous four response sequences. Participants then completed three different psychometric scales measuring ADHD, depression, anxiety, and stress symptoms. Their scores on these scales were then used to organise participants into groups, depending on the respective cutoffs for each scale. Based on previous research, it was predicted that individuals who were over the cutoff for ADHD would show higher levels of behavioural variability than those under the cutoff. This result was found, as participants over the cutoff for ADHD exhibited significantly higher levels of behavioural variability in the VAR condition than those under the cutoff. It was also expected that individuals over the cutoffs for depression, anxiety or stress would show lower levels of behavioural variability under reinforcement than those who were under the respective cutoffs. The opposite was found; participants who met the cutoffs for depression and stress also showed significantly higher variability than those under the cutoffs. Additionally, participants over the cutoff for anxiety showed higher variability in the VAR condition if they previously completed the REP condition. Together, these findings suggest that the direct reinforcement of behavioural variability may be more effective for those with greater ADHD, depression, stress, or anxiety symptoms.