A Controlled Single-Case Treatment of Severe Long-Term Selective Mutism in a Child With Mental Retardation

The aim of the present study was to demonstrate the efficacy of combining two operant learning procedures—shaping and fading—for treating selective mutism. The participant was a 12-year-old boy with mental retardation presenting a severe long-term selective mutism. The treatment was aimed at increasing the loudness of his vocalizations in an increasingly social milieu. The treatment was conducted over the course of about 20 weeks, with four 15-minute sessions per week. A gradual increase in speech loudness was observed. Data indicated a close correspondence between the changes in speech loudness and the criteria for reinforcement successively applied by the therapist, thereby confirming the causal link between the child's progress and the changes in reinforcement contingencies. In addition, good generalization was noted during the stimulus fading phase. Six-month follow up showed that loudness of verbalizations was still satisfactory in the classroom despite a change of school and peer group. The impressive improvement of the child's verbal behavior shows that the implementation of a treatment package including both shaping and stimulus fading is a worthwhile therapeutic option, even in the case of severe long-term selective mutism associated with mental retardation.     

Face category differentially influences face memories after a delay

ABSTRACT

Faces belonging to the same category as the perceiver are better recognised than faces from different categories when tested immediately. After a delay, the same-category benefit persists and response bias becomes more liberal for other-category but not same-category faces. These effects are typically attributed to better encoding of same-category than other-category faces. To determine whether bias effects after a delay persist when immediate accuracy differences are minimised, Hispanic and Caucasian participants were given more study time for other-category than same-category faces. Memory was tested immediately and after a two-day delay. Discrimination accuracy was higher for other-category than for same-category faces during both test sessions. Bias was equivalent immediately, but after the delay, bias was more conservative for same-category than for other-category faces, especially in Caucasian participants. These results suggest that post-encoding processes differentially influence face memories from different categories, which may have implications for evaluating face memory in everyday situations.