Abstract:
The use of punishment remains to be a topic of controversy in applied settings. Although punishment-based procedures are effective in rapidly reducing unwanted behaviours, the use of such procedures is often reserved for when less or non-aversive interventions fail to control behaviour. This is because punishers, traditionally defined as aversive stimuli, can cause pain, discomfort, fear, aggression and emotional distress. However, basic research findings suggest that punished do not need to be aversive to reduce behaviour. When made contingent on responding, neutral discriminative stimuli associated with unwanted outcomes (i.e., S-; negative discriminative stimuli) can reduce responding, and affect choice behaviour in the same way as aversive stimuli. Although the punishing effects of S- stimuli have been demonstrated using a variety of outcomes, rarely has research directly compared the punishing effects of the same stimulus when associated with different outcomes. Furthermore, although studies have shown that S- stimuli can function as effective punishers of non-human animal behaviour, research has yet to show the punishing effects of S- stimuli on human choice. In this thesis, we assessed and compared the suppressive effects of an S- stimulus when associated with no point gain and when associated with point loss on human choice behaviour. We trained human participants to discriminate between an S+ stimulus and an S- stimulus. We reinforced responses in the presence of the S+ stimulus, and punished responses in the presence of the S- stimulus using no point gain for some participants, and point loss in other participants. Then, using a concurrent schedule, we punished choice on both alternatives with response-contingent brief presentations of the Sstimulus. In general, we found that S- stimulus presentations, regardless of the outcome it was associated with, had no effects on choice behaviour or how reinforcers impacted choice behaviour in human participants.
