Stress and emotional valence effects on children's versus adolescents’ true and false memory

Despite considerable interest in understanding how stress influences memory accuracy and errors, particularly in children, methodological limitations have made it difficult to examine the effects of stress independent of the effects of the emotional valence of to-be-remembered information in developmental populations. In this study, we manipulated stress levels in 7–8- and 12–14-year-olds and then exposed them to negative, neutral, and positive word lists. Shortly afterward, we tested their recognition memory for the words and false memory for non-presented but related words. Adolescents in the high-stress condition were more accurate than those in the low-stress condition, while children's accuracy did not differ across stress conditions. Also, among adolescents, accuracy and errors were higher for the negative than positive words, while in children, word valence was unrelated to accuracy. Finally, increases in children's and adolescents’ cortisol responses, especially in the high-stress condition, were related to greater accuracy but not false memories and only for positive emotional words. Findings suggest that stress at encoding, as well as the emotional content of to-be-remembered information, may influence memory in different ways across development, highlighting the need for greater complexity in existing models of true and false memory formation.     

NATURAL MUSICAL INTERVALS:

Abstract— Ancient and medieval scholars considered tones related by simple (small-integer) ratios to be naturally pleasing, but contemporary scholars attribute the special perceptual status of such sounds to exposure. We investigated the possibility of processing predispositions for some tone combinations by evaluating infants' ability to detect subtle changes to patterns of simultaneous and sequential tones Infants detected such changes to pairs of pure tones (intervals) only when the tones were related by simple frequency ratios. This was the case for 9-month-old infants tested with harmonic (simultaneous) intervals and for 6-tnonth-old infants tested with melodic (sequential) intervals. These results are consistent with a biological basis for the prevalence of particular intervals historically and cross-culturally.     

Attitudes Toward Homosexuals Among Students at a Canadian University

We examined attitudes toward homosexuals amonga broad selection of undergraduates (101 men, 98 women)attending a Canadian university, where a vast majorityof the students are from working- or middle-class families of European descent. Attitudes towardgay men were more negative than attitudes towardlesbians. Compared to Science or Business students,students in the faculties of Arts or Social Science had more positive attitudes toward gay men, andwomen were more positive than men. Attitudes toward gaymen also improved with time spent at college, but onlyfor male students. Although attitudes toward lesbians improved with time at college, they were notassociated with students' gender or faculty ofenrollment. Thus, a college education may promote areduction in anti-homosexual prejudice among youngpeople, particularly among young men.     

EXTINCTION OF SELF-INJURIOUS ESCAPE BEHAVIOR WITH AND WITHOUT INSTRUCTIONAL FADING

Three individuals with developmental disabilities participated in a study of the treatment of self-injurious behavior (SIB) maintained by negative reinforcement (escape from educational tasks). Treatment was implemented in a multiple baseline design across subjects, in which two treatments were compared in a multielement format. Both treatment conditions included an escape-extinction component in which SIB no longer produced escape. One of the conditions also included a fading component in which the frequency of instructions was initially reduced to zero and then was gradually faded back in across sessions until the instructional rate matched that of the original baseline. Results indicated that extinction alone reduced SIB to the end-of-treatment criterion in fewer sessions than did extinction plus fading for all 3 subjects. For 2 of the 3 subjects, however, there was an initial increase in the frequency of SIB at the outset of treatment with extinction (an extinction burst) that was not observed when extinction was combined with the fading component.     

ANALYSIS OF THE REINFORCEMENT AND EXTINCTION COMPONENTS IN DRO CONTINGENCIES WITH SELF-INJURY

Previous research has shown that self-injurious behavior (SIB) maintained by positive reinforcement may be reduced under differential-reinforcement-of-other-behavior (DRO) contingencies. In this study, we conducted an analysis of the reinforcement and extinction components of DRO while treating the self-injury of 3 women with developmental disabilities. A functional analysis revealed that each subject's SIB was maintained by positive reinforcement in the form of attention. Subsequent reinforcer assessments identified preferred and nonpreferred stimuli for later use in conjunction with DRO. Results showed high rates of SIB for all 3 subjects during baseline, which persisted when DRO was implemented without the relevant extinction component (withholding of attention for SIB) for 2 of the subjects. Low rates of SIB were observed for all subjects when DRO plus extinction was implemented or when extinction was implemented alone, suggesting that extinction may be a critical component of DRO schedules.     

THE FUNCTIONS OF SELF-INJURIOUS BEHAVIOR: AN EXPERIMENTAL-EPIDEMIOLOGICAL ANALYSIS

Data are summarized from 152 single-subject analyses of the reinforcing functions of self-injurious behavior (SIB). Individuals with developmental disabilities referred for assessment and/or treatment over an 11-year period were exposed to a series of conditions in which the effects of antecedent and consequent events on SIB were examined systematically by way of multielement, reversal, or combined designs. Data were collected during approximately 4,000 experimental sessions (1,000 hr), with the length of assessment for individuals ranging from 8 to 66 sessions (M = 26.2) conducted over 2 to 16.5 hr (M = 6.5). Differential or uniformly high responding was observed in 145 (95.4%) of the cases. Social-negative reinforcement (escape from task demands or other sources of aversive stimulation) accounted for 58 cases, which was the largest proportion of the sample (38.1%). Social-positive reinforcement (either attention or access to food or materials) accounted for 40 (26.3%) of the cases, automatic (sensory) reinforcement accounted for 39 (25.7%), and multiple controlling variables accounted for 8 (5.3%). Seven sets of data (4.6%) showed either cyclical or inconsistent patterns of responding that were uninterpretable. Overall results indicated that functional analysis methodologies are extremely effective in identifying the environmental determinants of SIB on an individual basis and, subsequently, in guiding the process of treatment selection. Furthermore, an accumulation of assessment data from such analyses across a large number of individuals provides perhaps the most rigorous approach to an epidemiological study of behavioral function.     

PROTECTIVE EQUIPMENT AS TREATMENT FOR STEREOTYPIC HAND MOUTHING: SENSORY EXTINCTION OR PUNISHMENT EFFECTS?

We examined the effects of noncontingent and contingent protective equipment as treatment for self-injurious hand mouthing exhibited by 2 individuals with profound mental retardation. Results of a functional analysis assessment revealed that neither subject's self-injury was maintained by social reinforcement: One subject's self-injury was cyclical in nature; the other's occurred during all assessment conditions but most frequently when left alone. In the noncontingent-equipment condition, oven mitts were placed on the individual's hands at the beginning of a session and remained on throughout. In the contingent-equipment condition, the mitts were briefly placed on the individual's hands following occurrences of hand mouthing. For 1 subject, noncontingent mitts produced a large decrease in the rate of hand mouthing and contingent mitts produced similar results following a return to baseline. Hand mouthing was also reduced in the 2nd subject, but this individual was exposed only to the contingent-equipment condition (i.e., there was no prior history with the noncontingent-equipment condition). These results suggest either a punishment or a time-out interpretation rather than an extinction interpretation to account for the behavior-reducing effects of contingent protective equipment on self-injury.     

Using behavior contracts to improve behavior of children and adolescents in multiple settings

Research has shown that behavior contracts, a form of contingency management, can promote a wide range of behavior changes for individuals in varied populations; however, relatively few studies have been conducted in nonacademic settings. In the context of two service projects, we evaluated the extent to which behavior contracts improved problem behavior for 11 children and adolescents in residential treatment facilities and foster homes using nonconcurrent multiple baseline across participants’ designs with three or more tiers and supplemental statistical analysis for each tier. Practitioners in each setting implemented individualized behavior contracts for 5 to 59 weeks. Results show that behavior improved substantially for six participants but was relatively unchanged for the other five participants. We discuss the limitations of this clinically driven study, as well as clinical implications of our mixed findings.