Differential reinforcement of lever-press durations: Effects of deprivation level and reward magnitude

Three experiments investigated the performance of rats on a task involving differential reinforcement of lever-press durations. Experiment 1, which employed a discrete-trials procedure, manipulated deprivation level between subjects and reward magnitude within subjects. The minimum lever-press duration which would result in reward was varied from .4 to 6.4 sec. It was found that low deprivation resulted in longer mean durations and less response variability at the higher criterial values than did high deprivation. The magnitude of reward was not found to affect performance. Experiment 2 manipulated reward magnitude between subjects while holding deprivation level constant, and used the same general procedures as in Experiment 1. Small reward resulted in longer mean lever-press durations and less variability in responding than did large reward at the higher criterial values. The intertrial intervals were omitted in Experiment 3 in which deprivation level was varied between subjects and reinforcement was delivered only for response durations extending between 6.0 and 7.6 sec. Low deprivation resulted in longer mean lever-press durations and less response variability than did high deprivation, but the probability of a rewarded press duration did not differ between groups. The results overall are consistent with the hypothesis that low deprivation and small reward magnitude lead to weaker goal-approach responses and, hence, to less competition with lever holding. The deprivation and reward magnitude manipulations did not appear to influence lever holding performance by affecting the ability of animals to form temporal discriminations.     

Paper and plastic in daily diary research: Comment on Green, Rafaeli, Bolger, Shrout, and Reis (2006)

The authors applaud A. S. Green, E. Rafaeli, N. Bolger, P. E. Shrout, and H. T. Reis's (2006) response to one-sided comparisons of paper versus electronic (plastic) diary methods and hope that it will stimulate more balanced considerations of the issues involved. The authors begin by highlighting areas of agreement and disagreement with Green et al. The authors review briefly the broader literature that has compared paper and plastic diaries, noting how recent comparisons have relied on study designs and methods that favor investigators' allegiances. The authors note some sorely needed data for the evaluation of the implications of paper versus plastic for the internal and external validity of research. To facilitate evaluation of the existing literature and assist in the design of future studies, the authors offer a balanced comparison of paper and electronic diary methods across a range of applications. Finally, the authors propose 2 study designs that offer fair comparisons of paper and plastic diary methods.     

Major histocompatibility complex alleles, sexual responsivity, and unfaithfulness in romantic couples

Preferences for mates that possess genes dissimilar to one's own at the major histocompatibility complex (MHC), a polymorphic group of loci associated with the immune system, have been found in mice, birds, fish, and humans. These preferences may help individuals choose genetically compatible mates and may adaptively function to prevent inbreeding or to increase heterozygosity and thereby immunocompetence of offspring. MHC-dissimilar mate preferences may influence the psychology of sexual attraction. We investigated whether MHC similarity among romantically involved couples (N= 48) predicted aspects of their sexual relationship. All women in our sample normally ovulated, and alleles at three MHC loci were typed for each person. As the proportion of MHC alleles couples shared increased, women's sexual responsivity to their partners decreased, their number of extrapair sexual partners increased, and their attraction to men other than their primary partners increased, particularly during the fertile phase of their cycles.     

Not just right experiences and obsessive-compulsive features: experimental and self-monitoring perspectives

Individuals with obsessive-compulsive disorder (OCD) often report compulsions aimed at reducing feelings of something not being just right or sensations of incompleteness. Research using self-report questionnaires has demonstrated a link between not just right experiences (NJREs) and OCD symptoms (Behav. Res. Therapy 41 (2003) 681; Anxiety, 1 (1995) 208). Extending previous work, this paper presents experimental and self-monitoring data on NJREs in an undergraduate sample. NJREs produced distress and urges to change something, but feared consequences were rare. Stronger responses were found for naturally occurring self-monitored NJREs compared to NJREs elicited in the laboratory. Several significant relationships were found between features of NJREs and OC symptoms and constructs theoretically related to OCD (e.g., responsibility, incompleteness), but no significant relationships were found between features of NJREs and non-OCD-related constructs (worry, depressive symptoms, social anxiety). Further consideration of NJREs will be useful in improving our understanding of the phenomenology, neurobiological substrates, and treatment, of OCD.     

The effectiveness of early head start for 3-year-old children and their parents: lessons for policy and programs

Early Head Start, a federal program begun in 1995 for low-income pregnant women and families with infants and toddlers, was evaluated through a randomized trial of 3,001 families in 17 programs. Interviews with primary caregivers, child assessments, and observations of parent-child interactions were completed when children were 3 years old. Caregivers were diverse in race-ethnicity, language, and other characteristics. Regression-adjusted impact analyses showed that 3-year-old program children performed better than did control children in cognitive and language development, displayed higher emotional engagement of the parent and sustained attention with play objects, and were lower in aggressive behavior. Compared with controls, Early Head Start parents were more emotionally supportive, provided more language and learning stimulation, read to their children more, and spanked less. The strongest and most numerous impacts were for programs that offered a mix of home-visiting and center-based services and that fully implemented the performance standards early.     

The impact of parental borderline personality disorder on vulnerability to depression in children of affectively ill parents

Children of parents with major depressive disorder (MDD) are four to six times more likely than other children to develop MDD. Little research has examined whether comorbid parental diagnoses further increase children's risk. This study examines whether children of parents with comorbid MDD and Borderline Personality Disorder (BPD) (1) are at greater risk for experiencing depressive symptoms and/or episodes and (2) whether such increased risk may be due, in part, to their exhibiting higher levels of cognitive/interpersonal vulnerability factors. Children (n = 140; ages 6-14) of parents with MDD completed measures assessing cognitive/interpersonal vulnerability factors. Parents completed semi-structured clinical interviews assessing severity of current depressive symptoms and BPD. Both children and parents completed a semi-structured clinical interview assessing the child's current and past history of MDD. Children of parents with comorbid MDD and BPD exhibited higher levels of current depressive symptoms and higher levels of cognitive/interpersonal vulnerability factors than children of parents with MDD but no BPD, even after controlling for parents' current levels of depressive symptoms. The relationship between parental BPD and chil-dren's current levels of depressive symptoms was partially mediated by children's cognitive/interpersonal vulnerability factors. Last, children of parents with comorbid BPD and MDD were 6.84 times more likely to exhibit a current or past diagnosis of MDD.     

Parietal lobe contributions to episodic memory retrieval

Although the parietal lobe is not traditionally thought to support declarative memory, recent event-related fMRI studies of episodic retrieval have consistently revealed a range of memory-related influences on activation in lateral posterior parietal cortex (PPC) and precuneus extending into posterior cingulate and retrosplenial cortex. This article surveys the fMRI literature on PPC activation during remembering, a literature that complements earlier electroencephalography data. We consider these recent memory-related fMRI responses within the context of classical ideas about parietal function that emphasize space-based attention and motor intention. We conclude by proposing three hypotheses concerning how parietal cortex might contribute to memory.     

Bias and expert testimony of mental health professionals in adversarial proceedings: A preliminary investigation

The role of mental health professionals testifying as expert witnesses has been the subject of increasing criticism. Cases in which opposing experts reach different conclusions are dismissed as “battles of the experts” and psychologists and psychiatrists are described as “hired guns.” This preliminary, analogue study examined the degree to which the opinions and testimony of mental health professionals may differ according to which side retains the expert. Results provided some support for the proposition that mental health professionals' testimony may vary according to the side by which they are retained.