The cortisol awakening response and the big five personality dimensions

The present study investigated the association between the big five personality dimensions and the cortisol awakening response (CAR), a physiological parameter reflective of HPA axis activity. One hundred and seven participants completed the big five inventory (BFI; John, Donahue, & Kentle, 1991) and collected salivary cortisol samples at 0, 30, and 60 min after awakening on a weekday morning. The cortisol awakening response under the curve (CARauc) and the cortisol awakening response with respect to increase (CARi) were used as outcome variables in the statistical analyses. Hierarchical linear regression analyses were conducted using the data of 92 participants. Gender and age were included as covariates in block one of the regressions, followed by the personality dimensions in block two. Extraversion emerged as a significant predictor of CARauc. No other personality dimensions were significantly predictive of CARauc or CARi. Interestingly, gender emerged as the strongest predictor in the CARauc, with females exhibiting greater cortisol release across the awakening period than males. Our results suggest that extraversion and gender may be particularly important variables to consider in the regulation of the HPA axis.     

The awakening cortisol response: methodological issues and significance

The awakening cortisol response (ACR) is a discrete and distinctive part of the cortisol circadian cycle. In healthy adults salivary free cortisol concentrations increase by between 50 and 160% in the first 30 min immediately post-awakening (approximate average increase of 9 nmol/l, range 4-15 nmol/l, estimated to be equivalent to about three secretory episodes). However there are no agreed norms for the absolute concentrations of free cortisol in saliva either immediately post-awakening (range of 4.7-18.5 nmol/l) or 30 min post-awakening (range of 8.6-21.9 nmol/l). This review explores reasons for these discrepancies in normative data including confounding factors such as gender, age, awakening time, light and participant adherence. Although the physiological role of the ACR has not been clearly defined evidence is discussed that suggests it is under a distinct regulatory influence, different from the rest of the diurnal cortisol secretory cycle. Despite the difficulties associated with its measurement a range of studies have demonstrated an association between the ACR and psychosocial variables, stress and health. However it remains unclear whether positive affect and good health are consistently associated with larger or smaller awakening responses. It is early days in the search for the role and significance of the ACR. Its putative role in the regulation of physiological function across the day (e.g. the immune system) and its sensitivity to psychosocial variables make it a prime candidate as an intermediary linking mind and health.     

Newborn right-holding is related to depressive symptoms in bottle-feeding mothers but not in breastfeeding mothers

This study examines the relationships between infant holding preferences and maternal depression according to the newborn feeding mode. Links between depression and infant holding biases have been observed in mothers [Vauclair, J., Scola, C. (in press). Dépression, alexithymie et latéralisation dans la fa?on de porter un nouveau-né [Infant holding biases in relation to depression, alexithymia and laterality]. Annales Médico-psychologiques; Weatherill, R. P., Almerigi, J. B., Levendosky, A. A., Bogat, G. A., von Eye, A., & Harris, L. J. (2004). Is maternal depression related to side of infant holding? International Journal of Behavioral Development, 28, 421-427] but the fact that breastfeeding has never been studied in relation to these two factors is surprising as breastfeeding has some influence on depression (e.g., [Mezzacappa, E. S., Guethlein, W., Vaz, N., & Bagiella, E. (2000). A preliminary study of breast-feeding and maternal symptomatology. Annals of Behavioral Medicine, 22, 71-79]) and must also affect holding biases. Mothers who just gave birth (N=100) were tested few days after delivery. Measures of handedness, infant holding-side preferences, and level of depressive symptoms expressed by mothers (assessed with the CES-D scale) were collected via questionnaires. Asymmetries in emotional perception were assessed via a Chimeric Figure Task and a Dichotic Listening Task. Results showed that breastfeeding (1) reduced left-side bias for holding newborns and (2) was associated with lowest levels of depressive symptoms. Moreover, holding biases were related to maternal depression in bottle-feeding but not in breastfeeding mothers, namely that holding on the right-side while bottle-feeding was associated with higher levels of depressive symptoms. These results were not due to hemispheric specialization as auditory and visual asymmetries were similar between breastfeeding and bottle-feeding mothers. The discussion emphasizes the striking role of the early mother/child relationship's establishment on infant holding biases.     

The cortisol awakening response: Associations with trait anxiety and stress reactivity

This study investigated the extent to which trait anxiety and state anxiety in response to stress are associated with the cortisol awakening response (CAR).Fifty-one healthy participants were recruited. State anxiety measures were taken in anticipation of and during a laboratory stressor. Salivary cortisol levels were measured immediately upon awakening (at 0, 15, 30, and 45 min) on two consecutive mornings. Cortisol awakening response was assessed by the area under the curve with respect to zero (AUC_G).The magnitude of the CAR was found to be negatively associated with both trait anxiety and anticipatory anxiety. Moreover, regression analysis showed that the effects of trait anxiety on the AUC_G were mediated by anticipatory anxiety.These results suggest that the CAR is influenced by trait anxiety. Moreover, the effect of trait anxiety on the CAR seems to operate by impacting on psychological stress reactivity (i.e., anticipatory anxiety).     

Job satisfaction and cortisol awakening response in teachers scoring high and low on burnout

The burnout syndrome is an important psychosocial risk in the job context, especially in professions with a strong social interaction, as in the case of teaching. High levels of burnout have been related to negative psychological indicators and hormonal alterations. This study compares job satisfaction and the cortisol awakening response (CAR) in teachers scoring high (HB) and low (LB) on burnout. HB teachers showed lower job satisfaction and no significant differences in the CAR when compared with the LB group. The results of the study suggest a general dissatisfaction with work along with a different functioning of the hypothalamo-pituitary-adrenocortical axis in HB teachers. Although non significantly, they showed a lower magnitude of the CAR than LB teachers. When considering the whole sample, emotional exhaustion and depersonalization correlated negatively and personal accomplishment positively with each subscale of the job satisfaction questionnaire whereas cortisol levels or CAR did not correlate significantly with both burnout subscales and job satisfaction. These results should be taken into account when working to prevent burnout in teachers, as the modified parameters could be considered indicators of the onset or development of the syndrome.     

Response-to-stimulus interval does not affect implicit motor sequence learning, but does affect performance

Nissen and Bullemer (1987) reported that implicit motor sequence learning was disrupted by the addition of a secondary task. They suggested that this effect was due to the attentional load that the secondary task adds. Recently it has been suggested that the attentional load is not critical, but rather that the secondary task affects timing, either by lengthening or by making inconsistent the response-tostimulus interval (RSI)-that is, the delay between when a subject makes a response and when the next stimulus appears. In six experiments we manipulated the RSI and found no support for these two hypotheses. An inconsistent RSI did not adversely affect implicit motor sequence learning. A long RSI did not affect learning, although under some conditions subjects did not express learning if the RSI was long. These results are interpreted as reflecting the effects of attention.     

The role of awakening cortisol and psychological distress in diurnal variations in affect: a day reconstruction study

People often feel unhappy in the morning but better later in the day, and this pattern may be amplified in the distressed. Past work suggests that one function of cortisol is to energize people in the morning. In a study of 174 students, we tested to see whether daily affect patterns, psychological distress, and awakening cortisol levels were interlinked. Affect levels were assessed using the Day Reconstruction Method and psychological distress was measured using the Depression Anxiety Stress Scales. On average, positive affect increased markedly in a linear pattern across the day, whereas negative affect decreased linearly. For the highly distressed, this pattern was stronger for positive affect. Lower than average morning cortisol, as assessed by two saliva samples at waking and two samples 30 min after waking, predicted a clear increasing pattern of positive affect throughout the day. When we examined the interlinkages between affect patterns, distress, and cortisol, our results showed that a pronounced linear increase in positive affect from morning through to evening occurred chiefly among distressed people with below average cortisol levels upon awakening. Psychological distress, although not strongly associated with morning cortisol levels, does appear to interact with cortisol levels to profoundly influence affect.     

C-reactive protein polymorphisms are associated with the cortisol awakening response in basal conditions in human subjects

Cortisol affects the acute-phase response, but it is unknown whether C-reactive protein (CRP), an acute-phase reactant, also affects hypothalamus?pituitary?adrenal axis activity. In the present study, associations were explored between CRP haplotypes with plasma CRP concentrations and basal salivary cortisol level. We included 266 physically healthy Caucasian subjects (103 females and 163 males) aged between 18 and 65 years of whom 94 had a psychiatric disorder in a genetic association study. Six tag single-nucleotide polymorphisms capturing the common genetic variation of the CRP gene were genotyped (i.e. rs2808628, rs2808630, rs1205, rs1800947, rs1417938, and rs3091244) to yield common CRP haplotypes. Plasma CRP concentrations, the salivary cortisol awakening response (CAR) (0, 30, 45, and 60?min after awakening), and the diurnal cortisol decline (11:00, 15:00, 19:00, and 23:00 h) were assessed for 2 days. rs2808628, rs1205, rs1417938, and rs3091244 showed expected associations not only with CRP concentrations, but also with salivary cortisol levels during the CAR. Five well-characterized CRP haplotypes were arranged in ascending order according to increasing CRP levels. There was an inverse linear association between CRP haplotypes and cortisol levels during the CAR, but no association with the diurnal cortisol decline. Hence, genetic variants in the CRP gene that are associated with lifetime plasma CRP levels were also associated with salivary cortisol levels after awakening, in basal, non-inflammatory conditions.     

Stimulus-set location does not affect orthogonal stimulus-response compatibility

In two-choice tasks for which stimuli and responses vary along orthogonal dimensions, one stimulus-response mapping typically yields better performance than another. For unimanual movement responses, the hand used to respond, hand posture (prone or supine), and response eccentricity influence this orthogonal stimulus-response compatibility (SRC) effect. All accounts of these phenomena attribute them to response-related processes. Two experiments examined whether manipulation of stimulus-set position along the dimension on which the stimuli varied influences orthogonal SRC in a manner similar to the way that response location does. The experiments differed in whether the stimulus dimension was vertical and the response dimension horizontal, or vice versa. In both experiments, an advantage of mapping up with right and down with left was evident for several response modes, and stimulus-set position had no influence on the orthogonal SRC effect. The lack of effect of stimulus-set position is in agreement with the emphasis that present accounts place on response-related processes. We favor a multiple asymmetric codes account, for which the present findings imply that the polarity of stimulus codes does not vary across task contexts although the polarity of response codes does.     

Increasing stimulus intensity does not affect sensorimotor synchronization

When people synchronize taps with isochronously presented stimuli, taps usually precede the pacing stimuli [negative mean asynchrony (NMA)]. One explanation of NMA [sensory accumulation model (SAM), Aschersleben in Brain Cogn 48:66–79, 2002] is that more time is needed to generate a central code for kinesthetic-tactile information than for auditory or visual stimuli. The SAM predicts that raising the intensity of the pacing stimuli shortens the time for their sensory accumulation, thereby increasing NMA. This prediction was tested by asking participants to synchronize finger force pulses with target isochronous stimuli with various intensities. In addition, participants performed a simple reaction-time task, for comparison. Higher intensity led to shorter reaction times. However, intensity manipulation did not affect NMA in the synchronization task. This finding is not consistent with the predictions based on the SAM. Discrepancies in sensitivity to stimulus intensity between sensorimotor synchronization and reaction-time tasks point to the involvement of different timing mechanisms in these two tasks.     

Changing environmental context does not reliably affect memory

Most current theories of human memory propose that context, defined here as the time and place at which an event was experienced, forms an integral feature of the mnemonic representation of events. One way of investigating context is by manipulating the environmental context (which typically means the room in which the experiment takes place). The predominant result of this manipulation reported in the literature has been consistent with theory: Memory performance is better when the learning and testing environments are the same than when they differ. This article reports eight experiments that in aggregate challenge the reliability of this same-context advantage. Experiment 1 reported a failure to obtain a same-context advantage. Experiments 2–7 investigated various features of the design that might have reduced the effect. None of these experiments produced a reliable same-context advantage. Experiment 8 repeated the methodology of a published report of a same-context advantage with more than double the number of subjects, but failed to replicate the effect. An analysis of features of the experiments led to two suggestions for future investigations of the effects of changes in environmental context on memory.     

Movement duration does not affect automatic online control

Pisella et al. (2000) have shown that fast aiming movements are automatically modified on-line in response to a change in target position. Specifically, when a movement is less than 300 ms in duration the reach is completed to a target’s new location even when one never intended to respond to the target jump. In contrast, when movements are slower, the reach is completed according to instructions. At present, it is unclear if it is possible for one’s intentions to guide the initial stages of these slow movements. To determine if the intentional control mechanism can guide the initial stages of a slow aiming movement, participants aimed to targets that could jump at movement onset, with a slow and very slow movement time goal. In particular, participants were to point towards (“pro-point”) or away from (“anti-point”) the target jump, with a movement time goal of 500 or 1200 ms. Results showed that in the anti-point condition, movement trajectories first deviated in the same direction as the target jump, followed by a response in the intended (opposite) direction. This suggests that while movement outcome is controlled by the intentional system, even in these slow aiming movements the automatic system is engaged at movement onset.     

Motion-induced blindness does not affect the formation of negative afterimages

Aftereffects induced by invisible stimuli constitute a powerful tool to investigate what type of neural information processing can occur in the absence of visual awareness. This approach has been successfully used to demonstrate that awareness of oriented gratings or translating stimuli is not necessary to obtain a robust orientation-specific or motion-specific aftereffect. We exploit motion-induced blindness (MIB, Bonneh, Cooperman, & Sagi, 2001) to investigate the related question of the influence of visual awareness on the formation of negative afterimages. Our results show that MIB does not affect the persistence and intensity of afterimages. Thus, there is no significant contribution to the formation of afterimages beyond the sites mediating MIB.     

Spatial cuing does not affect the magnitude of the attentional blink

Identification of the second of two targets is impaired when the second target is presented less than about 500 msec after the first. Nieuwenstein, Chun, van der Lubbe, and Hooge (2005, Experiment 4) reported that the magnitude of this attentional blink (AB) is reduced when the location of the second target is precued. Here we show how that finding resulted from an artifact brought about by a ceiling imposed by data limitation. Instead of using an accuracy measure, the present work used a dynamic threshold-tracking procedure that was not constrained by a performance ceiling. The results show that, when the ceiling is removed, spatial cuing does not affect and is not affected by the AB. These results are consistent with the hypothesis that cue localization and target identification may take place along separate (dorsal and ventral) visual pathways.     

Familiarity does not affect the unilateral field advantage for repetition detection

We have previously reported evidence that repetitions of letters, colors, sizes, and common motion paths are more rapidly detected when they are presented unilaterally (i.e., both in the same visual field) versus bilaterally (one element in each visual field; Butcher and Cavanagh (Attention, Perception, & Psychophysics 70:714?C724, 2008). Here, we report evidence that this unilateral field advantage (UFA) for repetition detection does not depend on prior experience with the elements that comprise the repetition. In Experiment 1, native English, Persian, and Japanese speakers were tested on a repetition detection task involving characters from Western, Arabic, and Japanese character sets. The character sets were tested in blocks, in each of which subjects were presented with four characters for 16 ms and asked to report whether any two of the characters were identical. The subjects were faster detecting repetitions that were presented unilaterally rather than bilaterally, and there was no interaction with stimulus familiarity. A second experiment replicated this finding with native English speakers only, using a longer stimulus duration (150 ms). We had previously proposed that the UFA arises because the low-level processes that group physically identical items operate more efficiently within than across hemifields. Our data now indicate that this grouping process is insensitive to item familiarity, supporting the claim that the process is low-level.     

Causal order does not affect cue selection in human associative learning

Waldmann and Holyoak (1992) presented evidence in support of the claim that cue selection does not emerge in “diagnostic” human learning tasks in which the cues are interpretable as effects and the outcomes as the causes of those effects. Waldmann and Holyoak argued that this evidence presents a major difficulty for associationist theories of learning and instead supports a “causal model” theory. We identify a number of flaws in Waldmann and Holyoak’s experimental procedures and report three new experiments designed to test their claim. In Experiment 1, cue selection was observed regardless of causal order and regardless of whether the cues were abstractly or concretely specified. In Experiments 2 and 3, cue selection was again observed when subjects predicted causes from effects. We conclude that our results are consistent with simple associationist theories of learning but contradict Waldmann and Holyoak’s causal model theory.     

Explicit risk of getting caught does not affect unethical behavior

Research showed that given the opportunity, people behave dishonestly only to the degree that will allow them to maintain a positive self‐concept. These experiments did not include the probability of getting caught cheating, although in everyday life, this risk always exists. If it is shown that people behave more honestly when faced with an explicit risk of getting caught, the ecological validity of these experiments may be at risk. This study showed that explicit risk, framed as the probability of getting caught or as the complementary probability of not getting caught, did not reduce participants’ dishonest behavior relative to no risk. These findings support the ecological validity of previous research on unethical behavior.     

Embedding lies into truthful stories does not affect their quality

When given the opportunity, liars will embed their lies into otherwise truthful statements. In what way this embedding affects the quality of lies, however, remains largely unknown. This study investigated whether lies that are embedded into truthful stories are richer in detail and contain higher quality details compared to lies that are part of entirely fabricated statements. Participants (N = 111) were asked to provide a statement that was either entirely truthful, entirely fabricated, or had the fabricated element of interest embedded into an otherwise truthful story. Results indicated that lies embedded in a fabricated statement are not qualitatively different from lies embedded in an otherwise truthful statement. Supporting Bayes factors provided moderate to strong evidence for this conclusion. Accordingly, verbal credibility assessment tools based on the verbal content measured in this study may be robust against the embedding of lies.     

Blunted cortisol response to awakening in mild to moderate depression: regulatory influences of sleep patterns and social contacts

Cortisol is elevated during severe depression. However, some studies of outpatients suggest reduced cortisol levels, either basal or poststress. More definite evidence of this phenomenon is needed, and correlates that may explain the disparate findings should be identified. Women from the community (37 depressed and 36 nondepressed) completed electronic diaries in order to help researchers assess the cortisol awakening response (CAR), sleep, and social contacts. Depressed women had a blunted CAR compared with nondepressed women. Among the nondepressed but not among depressed women, time of waking, and number of social contacts (especially positive ones) were independently associated with CAR. These psychosocial factors may contribute to a normal CAR, but their regulatory influence may become disrupted during mild to moderate clinical depression.