The effects of distributed training on retention of operant conditioning in human infants

Long-term retention of operant footkicking acquired in the mobile conjugate reinforcement paradigm was assessed as a function of the distribution of training time. In the first study, 3-month-old infants were trained for either one 18-min session or for two 9-min or three 6-min sessions separated by 24-hr intervals. All infants exhibited retention during a test administered immediately after training, but only those trained in a single session continued to perform the conditioned response during cued-recall tests 7 or 14 days later. Infants trained in three sessions showed no evidence of remembering the contingency even after a week. A warm-up decrement, seen in the day-to-day performance of infants in the distributed conditions, was eliminated in the second study by the interpolation of a nonreinforcement period at the outset of daily sessions. This procedure also enhanced long-term retention such that infants trained in three 6-min session now remembered the contingency for 14 days and did not differ from infants who had received a single 18-min session. Whether distributed training facilitates or impairs long-term retention appears to depend on the opportunity for infants to acquire a sufficient number (or kind) of effective retrieval cues during original learning.     

CREATION AND EVOLUTION: ANOTHER ROUND IN AN ANCIENT STRUGGLE

Abstract. Creation and evolution were historic allies against eternalism. However, Darwinism seemed to undercut cosmological theism and human dignity, and modern reconcilers of evolution and theology have not convinced opponents that they can preserve these concerns. Creationists find divine handiwork in natural order and freedom in human uniqueness. For them, even entropy and continuity of kinds are emblematic of the unity of nature and the needfulness of salvation. Anti-evolutionists' impatience and frustration are not well answered by dogmatic or mythicized science. Neither is creation well served by reduction to merely empiric facts. Because creationism and evolutionism rest on the unabstractable categories of contingency and necessity, neither will disappear.     

Homelessness as psychological trauma. Broadening perspectives.

Most mental health literature on homelessness has focused on characteristics that may be risk factors for homelessness. The authors of this article argue that homelessness itself is a risk factor for emotional disorder and use the construct of psychological trauma--focusing on social disaffiliation and learned helplessness--to understand the potential effects of homelessness. Psychological trauma is likely among homeless individuals and families for three reasons. (a) The sudden or gradual loss of one's home can be a stressor of sufficient severity to produce symptoms of psychological trauma. (b) The conditions of shelter life may produce trauma symptoms. (c) Many homeless people--particularly women--become homeless after experiencing physical and sexual abuse and consequent psychological trauma. Research suggests that negative psychological responses to traumatic events can be prevented or mitigated by a supportive and empowering posttrauma environment. The implications of trauma theory for improving the psychosocial conditions of homeless people are discussed.     

Personality diagnostic questionnaire-revised (PDQ-R) personality disorder scores and negative life events independently predict changes in hopkins symptom checklist (SCL-90) Psychopathology Scores

The present study employed a prospective design to investigate whether Personality Diagnostic Questionnaire—Revised (PDQ-R) scores and/or Hassles Scale—Revised (HS-R) scores predict changes in Axis I psychopathology levels over 1 month, in a nonclinical sample of young adults. The PDQ-R, HS-R, and Hopkins Symptom Checklist (SCL-90) were administered to a mixed-sex sample of 100 undergraduate students on two occasions separated by 1 month. Hierarchical multiple regression analyses indicated that (1) time 1 PDQ-R composite scores predicted changes in scores on 11 SLC-90 scales; (2) time 1 PDQ-R impairment/distress index scores predicted changes in SCL-90 general symptom index scores; (3) only one of the individual PDQ-R personality disorder subscales—the schizotypal personality disorder subscale—predicted changes in SCL-90 general symptom index scores; (4) HS-R scores predicted changes in scores on 9 SCL-90 scales; and (5) in only 3 of the 27 analyses conducted did the statistical interaction between PDQ-R and HS-R scores predict changes in SCL-90 scores. These findings indicate that personality disorder symptomatology and negative life events may independently predict changes in Axis I psychopathology levels and, thus, support the continued inclusion of Axis II and Axis IV in future versions of the Diagnostic and Statistical Manual of Mental Disorders.     

The philosophical works of wilfrid sellars

Expanded bibliography fromThe Metaphysics of Epistemology. Lectures by Wilfrid Sellars, edited by Pedro V. Amaral, Ridgeview Publ. Co., Atascadero, Calif. 1989, pp. 343–353, with addenda and corrigeda.