Robert L. Matchock

The presence of a dog attenuates cortisol and heart rate in the Trier Social Stress Test compared to human friends

Limited research has addressed how social support in the form of a pet can affect both sympathetic and hypothalamic–pituitary–adrenal reactivity in response to a psychological challenge. The present study examined the effects of social support on salivary cortisol and heart rate (HR). Forty-eight participants were randomly assigned to three different conditions (human friend, novel dog, or control). All participants completed the Trier Social Stress Test and provided cortisol, HR, and State-Trait Anxiety Inventory measures. For participants paired with a dog, overall cortisol levels were attenuated throughout the experimental procedure, and HR was attenuated during the Trier Social Stress Test. For all groups, state anxiety increased after the Trier Social Stress Test, and HR during the Trier Social Stress Test was a predictor of cortisol. These results suggest that short-term exposure to a novel dog in an unfamiliar setting can be beneficial. They also suggest a possible mechanism for the beneficial effect associated with affiliation with pets.

Low digit ratio (2D:4D) is associated with delayed menarche

The prenatal environment of the human fetus is now known to have lasting physiological and behavioral effects into childhood and adulthood. The objective of this study was to examine the relationship between early testosterone exposure, as measured by the ratio of the length of the 2nd and 4th digits (2D:4D ratio), and age of menarche. Retrospective, self‐report data on menarcheal age were obtained from 206 healthy female college students, as well as finger length ratio data from both hands. Low right‐hand 2D:4D ratios (but not left‐hand) were associated with delayed menarche. The results provide evidence for an androgen‐delayed menarche link and suggest that this relationship can be continuous in nature and not always categorical as occurs in congenital adrenal hyperplasia, hyperandrogenism, or polycystic ovary syndrome. Am. J. Hum. Biol., 2008.

Susceptibility to Nausea and Motion Sickness as a Function of the Menstrual Cycle

PURPOSE The present study examined whether susceptibility to nausea and other symptoms of vection-induced motion sickness vary as a function of phase of the menstrual cycle, as research findings in this area are sparse and contradictory. DESIGN Ninety young women (42 current users of oral contraceptives) were exposed to a rotating optokinetic drum during the peri-menses or peri-ovulatory phase of the menstrual cycle in an independent-groups, quasi-experimental design. Nausea and motion sickness symptoms were assessed using the Nausea Profile (NP) and the Subjective Symptoms of Motion Sickness (SSMS) questionnaire. RESULTS Among women not on oral contraceptives, reports of nausea and motion sickness by women in the peri-menses phase were more severe than reports by women in the peri-ovulatory phase. By contrast, among women taking oral contraceptives, reports of nausea and motion sickness did not differ by the same categorical phase of the menstrual cycle. CONCLUSIONS We speculate that fluctuating estrogen levels over the course of the menstrual cycle may influence the experience of or susceptibility to nausea and motion sickness during illusory self-motion and other nauseogenic contexts.

Circadian and sleep episode duration influences on cognitive performance following the process of awakening.

The process of waking up from an episode of sleep can produce temporary deficits in cognitive functioning and low levels of alertness and vigilance, a process referred to as sleep inertia. Cognitive ability varies as a function of time-of-day; cognitive ability associated with sleep inertia also shows circadian influences with deleterious effects most pronounced when awakened from biological night, possibly paralleling the core body temperature minimum. The length of the sleep episode may contribute to the severity of sleep inertia. Short sleep episodes (<20 min) produce little cognitive impairment, probably because of a lack of slow-wave sleep in the sleep episode. With longer sleep episodes, aspects of sleep depth such as percentage of slow-wave sleep or total length of the sleep episode may be important. Finally, myriad tasks have been used to measure sleep inertia effects, and cognitive deficits associated with waking up have been demonstrated on both simple and complex tasks for both speed and accuracy. More research is needed on how the type of task may interact with sleep inertia. Tests that measure known specific aspects of cognition and that can be mapped to brain systems and neurotransmitters (e.g., the Attentional Network Test: ANT) are recommended to further understand how information processing during the process of awakening is distinct from other aspects of awareness.

A Cross-Sectional Evaluation of Student Achievement Using Standardized and Performance-Based Tests.

Three groups of undergraduates (42 senior graduating psychology majors, 27 first-year premajors taking introductory psychology, and 24 first-year, high-performing nonmajors taking introductory psychology) completed the Psychology Major Field Test (MFT) and a short-answer (SA) essay test on reasoning about core knowledge in psychology. Graduating majors significantly outperformed both first-year groups using raw and covariate-corrected scores (adjusted for group differences in SAT-Verbal and high school grade point average). On the MFT, graduating majors scored above the 50th percentile, whereas high-performing nonmajors and premajors scored in the 25th and 20th percentiles, respectively. On the SA test, graduating majors averaged good-to-excellent quality responses, whereas premajors and high-performing nonmajors averaged only fair-to-good quality responses. Discussion focuses on the design and implementation of value-added, academic program assessments with limited data collection resources.