Operant stimulus control applied to maze behavior: heat escape conditioning and discrimination reversal in alligator Mississippiensis

Eight alligators were trained to escape heat by traversing an 8-ft runway containing right or left approaches to a water tank. All subjects were run until they had satisfied three criteria of stable response time, after which the predominant escape path was blocked, requiring discrimination reversal. Seven subjects again met the criteria; three also met them in a second reversal.     

“There's more love between us”: The parental experience of attending Mellow Babies,a targeted,early intervention program for parents and their babies

It is recognized that parenthood in the context of psychosocial adversity can have negative implications for infant development. Parenting programs are the first line of intervention to improve outcomes for families; however, evidence for the effectiveness of group-based, targeted early interventions is still scarce. Preliminary findings indicate Mellow Babies (MB) as a promising group-based parenting program for families at risk for parenting difficulties. Using thematic analysis, we aimed to understand: (i) the aspects of the intervention that enabled parents to complete the program and (ii) the relational and behavioral changes perceived as valuable for parents and their babies post-intervention. In total, 68 parents residing in the United Kingdom were interviewed after completing MB (49 mothers and 19 fathers; 88% self-identified as British). Three themes and six subthemes were generated from the data. Parents identified several intervention components as beneficial, including the facilitators' interpersonal skills and multi-dimensional, group-based approach. Participant reflections highlighted three underlying mechanisms that enabled positive change: (i) the sense of community cultivated within the group, (ii) the process of formulating and re-conceptualizing one's difficulties, and (iii) the opportunity to reshape interpersonal interactions. Findings are discussed within the context of perinatal and infant mental health.     

WOMEN WHO USE DOMESTIC VIOLENCE SHELTERS Changes in Depression Over Time

This study examined the levels of depression reported by women who had used a domestic violence shelter. Depressive symptoms were assessed three times: immediately after shelter exit, 10 weeks thereafter, and 6 months later. Whereas 83% of the women reported at least mild depression on the Center for Epidemiological Studies Depression (CES-D) scale upon shelter exit, only 58% were depressed 10 weeks later. This did not change at the 6–month follow-up. An ecological, longitudinal model was evaluated to predict battered women's depression 8/12 months postshelter exit. Results of hierarchical regression analyses suggested that, after controlling for previous levels of depression, the women's feelings of powerlessness, experience of abuse, and decreased social support contributed to their depression symptoms. The women's scores on these three variables (feelings of powerlessness, abuse, and social support) at 10 weeks postshelter exit and at 6-month follow-up predicted depression at 6 months. Thus, there were both predictive and concurrent effects for these constructs. Implications for clinical and community interventions are discussed.     

An Exploration of a Possible Physiological Explanation for Stressor Aftereffects1

The present study examined the relationship between performance deficits that occur following exposure to uncontrollable stressors and activation of the endogenous opioid system. Subjects were given an injection of saline or naloxone, an opioid antagonist, prior to exposure to 23 min of unpredictable intermittent bursts of noise or silence. Changes in mood were assessed following the injection and the stressor. Performance was measured during and after stressor exposure. Measures of performance following the stressor included a proofreading, an encoding, and a puzzle task. Results replicated previous work on the effects of noise on performance; exposure to noise was associated with performance deficits during and after the stressor. Although naloxone had no effect on performance following the noise, it was associated with greater performance deficits during exposure to the stressor. Further, although all subjects became more hostile, anxious, and depressed following exposure to noise or silence, naloxone improved mood before the stressor began.     

Acute Stressors and Chronic Response: The Case of Traumatic Stress1

The nature of acute and chronic stress is explored, including analysis of three different ways of categorizing the duration of a stressful episode: the duration of the physical stressor, the duration of threat perception or demand, and the persistence of response. Of particular interest here are situations characterized by brief stressor exposure but long-term threat perception and/ or stress response. Traumatic events are ordinarily very brief but frequently give rise to chronic threat and stubborn response patterns. In many of these cases, distress clearly outlives the event and the “normal” postevent recovery period. Possible mechanisms for such situations are discussed, as are implications for the study of traumatic stress.     

Approach-withdrawal and cerebral asymmetry: emotional expression and brain physiology. I

In this experiment, we combined the measurement of observable facial behavior with simultaneous measures of brain electrical activity to assess patterns of hemispheric activation in different regions during the experience of happiness and disgust. Disgust was found to be associated with right-sided activation in the frontal and anterior temporal regions compared with the happy condition. Happiness was accompanied by left-sided activation in the anterior temporal region compared with disgust. No differences in asymmetry were found between emotions in the central and parietal regions. When data aggregated across positive films were compared to aggregate negative film data, no reliable differences in brain activity were found. These findings illustrate the utility of using facial behavior to verify the presence of emotion, are consistent with the notion of emotion-specific physiological patterning, and underscore the importance of anterior cerebral asymmetries for emotions associated with approach and withdrawal.