The early development of self‐injurious behaviour in three young boys (aged 17,25, and 30 months at start of study) with Lesch‐Nyhan syndrome was examined by means of parental interviews and by direct observations completed at 3 to 4 monthly intervals over an 18‐month period. Results suggest that the self‐injury began in a different way from that of other young children with autism and/or developmental disabilities in that, from the start, self‐injurious responses were sudden and violent, rather than emerging gradually over time. Drastic measures, such as removal of the teeth or provision of tooth guards, were often taken to prevent further tissue damage. Direct observations showed that the boys’self‐injury occurred at lower rates, but their carers were highly concerned about the behaviour. Sequential analysis of the observational data indicated that on some occasions the children were more likely to self‐injure during periods of low social interaction, suggesting that their self‐injury may have been influenced by environmental factors. The theoretical and practical implications of these findings are discussed.

Operant conditioning or behaviour modification has stressed the role that the immediate environment has in influencing individual behaviour. The central concepts in operant conditioning theory are those of punishment and reward. In this area theory has suggested how behaviour can be strengthened (reinforced) by paying systematic attention to the immediacy and the frequency of the environmental consequences that follow the performance of required behaviours. While these behavioural principles have been widely applied in solving various educational and health problems, it is only recently that behaviourists have become interested in work related problems. This paper reviews recent applications of operant conditioning techniques to absenteeism and concludes that these techniques systematically reduced absenteeism.