Moving through virtual reality without moving?

Virtual reality (VR) technology is increasingly used in spatial cognition research, as it offers high experimental control and interactivity in naturalistic multi-modal environments, something that is difficult to achieve in real-world settings. Even in the most sophisticated and costly VR systems, people do not necessarily perceive and behave as they would in the real world. This might be related to our inability to use embodied (and thus often highly automated and effective) spatial orientation processes in VR. While real-world locomotion affords automatic and obligatory spatial updating of our self-to-surrounding relationships, such that we easily remain oriented during simple perspective changes, the same is not necessarily true in VR. This can lead to striking systematic and qualitative errors such as failures to update rotations ("Nonturner" behavior). Here, we investigated whether rich naturalistic visual stimuli in immersive VR might be sufficient to compensate for the lack of physical motion. To this end, 24 participants performed point-to-origin tasks after visually simulated excursions along streets of varying curvature in a naturalistic virtual city. Most (21/24) participants properly updated simulated self-motions and showed only moderate regression toward mean pointing responses. 3/24 participants, however, exhibited striking "Nonturner" behavior in that they pointed as if they did not update the visually simulated turns and their heading had not changed. This suggests that our immersive naturalistic VR stimuli were an improvement over prior optic flow stimuli, but still insufficient in eliciting obligatory spatial updating that supported correct point-to-origin responses in all participants.     

Bias in self-motion perceived speed can enhance episodic memory

Prior experiences of a stimulus facilitate reprocessing of that stimulus on a subsequent occasion. This relative ease and speed with which information is processed is defined as fluency and can constitute a basis for memory judgment. Fluency can also be manipulated on line by perceptual bias (e.g., levels of noise), leading to an increase in recognition for items processed more fluently (e.g., items with less noise). Previous experiments using Remember-Know paradigm have shown an impact of perceptual fluency only on familiarity and not on recollection. Recent episodic memory models have postulated a strong link between episodic memory and spatial processes, especially with egocentric updating (Gomez et al. in Acta Psychol 132(3):221-227, 2009). The present experiment was conducted to determine whether self-motion fluency affects recognition performance and particularly has an impact on "Remember" responses. Thirty participants learned a 4-min path movie and then had to recognize among short paths if they were part of the learned path, followed by a Remember-Know procedure for recognized items. Self-motion fluency was manipulated with the presence of nimble acceleration applied on a small part of the recognition paths. Results show that the presence of a self-motion fluency increases significantly the proportion of remember responses solely on learned paths. This study spotlights for the first time a specific fluency effect on recollection and indicates an implication of egocentric-updating processing in episodic memory retrieval.     

An overview of South African psychology

This overview of psychology in South Africa presents a concise and historical account of its science and practice, from its early origins in the late nineteenth century to the present, and traces seminal influences on the discipline. It is a review of how psychology in South Africa developed over more than a century to become one of the most popular subjects in universities and an established and recognized profession, whose members play a variety of roles in the South African polity and larger society. The impact that apartheid racism had on key aspects of psychology's development is traversed, and the influences that previous ruling party politics had on professional psychological organizations are delineated. The unification of psychology under the Psychological Society of South Africa, a few months before the advent of democracy in South Africa, is explicated. The protection of the title of psychologist in law and certain other changes in the legislative environment, enabling a greater role for psychologists, are reported. The primary research sites for psychology and its funding and the main university psychology programs are described, as are the requirements for registration and licensure. The genesis and the importance of the work of internationally acclaimed South African psychologists, such as J. Wolpe and A. A. Lazarus, are contextualized. With the increased participation of progressive black psychologists in leadership and research in the past two decades, a transformed psychology has the potential to play a significant role in addressing human issues confronting South Africa.     

Error monitoring dysfunction across the illness course of schizophrenia

Response monitoring abnormalities have been reported in chronic schizophrenia patients, but it is unknown whether they predate the onset of psychosis, are present in early stages of illness, or are late-developing abnormalities associated with illness progression. Response-synchronized event-related potentials (ERP) recorded during a picture-word matching task yielded error-related negativity (ERN), correct-response negativity (CRN), and error positivity (Pe) from 84 schizophrenia patients (SZ), 48 clinical high risk patients (CHR), and their age-matched healthy controls (HC; n = 110 and 88, respectively). A sub-sample of 35 early illness schizophrenia patients (ESZ) was compared to 93 age-matched HC and the CHR patients (after statistically removing the effects of normal aging). Relative to HC, 1) SZ, ESZ, and CHR had smaller ERNs, and 2) SZ and ESZ had larger CRNs and smaller Pes. Within the SZ, longer illness duration was associated with larger CRNs but was unrelated to ERN or Pe. CHR and ESZ did not differ on ERN or CRN, although Pe was smaller in ESZ than CHR. These results indicate that while ERN, CRN, and Pe abnormalities are present early in the illness, only the ERN abnormality is evident prior to psychosis onset, and only the CRN abnormality appears to worsen progressively over the illness course. Brain regions subserving response monitoring may be compromised early in the illness and possibly during its clinical prodrome.     

Elevated responding to safe conditions as a specific risk factor for anxiety versus depressive disorders: evidence from a longitudinal investigation

The current study evaluated the degree to which startle reflexes (SRs) in safe conditions versus danger conditions were predictive of the onset of anxiety disorders. Specificity of these effects to anxiety disorders was evaluated in comparison to unipolar depressive disorders and with consideration of level of neuroticism. A startle paradigm was administered at baseline to 132 nondisordered adolescents as part of a longitudinal study examining risk factors for emotional disorders. Participants underwent a repetition of eight safe-danger sequences and were told that delivery of an aversive stimulus leading to a muscle contraction of the arm would occur only in the late part of danger conditions. One aversive stimulus occurred midway in the safe-danger sequences. Participants were assessed for the onset of anxiety and unipolar depressive disorders annually over the next 3 to 4 years. Larger SR magnitude during safe conditions following delivery of the aversive stimulus predicted the subsequent first onset of anxiety disorders. Moreover, prediction of the onset of anxiety disorders remained significant above and beyond the effects of comorbid unipolar depression, neuroticism, and subjective ratings of intensity of the aversive stimulus. In sum, elevated responding to safe conditions following an aversive stimulus appears to be a specific, prospective risk factor for the first onset of anxiety disorders.     

High Behavioral Approach System (BAS) sensitivity, reward responsiveness, and goal-striving predict first onset of bipolar spectrum disorders: a prospective behavioral high-risk design

A prospective, behavioral high-risk design provided a theoretically guided examination of vulnerability to first onset of bipolar spectrum disorder based on the Behavioral Approach System (BAS) model. Adolescents (ages 14-19) at an "age of risk" for bipolar disorder onset were screened on BAS sensitivity by interviewers blind to current symptoms, lifetime history, and family history of psychopathology. Participants were selected with high versus moderate levels of BAS sensitivity and administered a lifetime diagnostic interview. Those with a bipolar spectrum disorder, psychosis, or hypomanic episode with onset prior to the BAS sensitivity assessment were excluded. High BAS (n = 171) and moderate BAS (n = 119) sensitivity participants in the final sample completed baseline measures of symptoms, goal-setting, and reward responsiveness and were followed prospectively with semistructured diagnostic interviews every 6 months. Consistent with the vulnerability hypothesis of the BAS model of bipolar disorder, high BAS participants had a greater likelihood, and shorter time to onset, of bipolar spectrum disorder than moderate BAS participants across an average of 12.8 months of follow-up (12.9% vs. 4.2%), controlling for baseline depressive and hypomanic symptoms, and family history of bipolar disorder. High reward responsiveness on a behavioral task and ambitious goal-striving for popular fame and financial success (but not impulsivity) also predicted first onset of bipolar spectrum disorder controlling for the covariates and BAS risk group, and ambitious goal-striving partially mediated the BAS risk group effect. We discuss implications of the findings for the BAS model of bipolar disorder and early intervention efforts.     

Spousal similarity in depression: a dyadic latent panel analysis of the panel study of Belgian households

Dyadic latent panel analysis (DLPA) was applied to eight waves of the Panel Study of Belgium Households (N = 954 couples). DLPA decomposes the observed variance of both members of a dyad into variance due to stable factors, factors that gradually change over time, and occasion-specific factors including random error. Total observed similarity between members of a dyad on one occasion is decomposed into stable similarity, similarity in factors that change over time, and occasion-specific similarity. The results show that depressive symptoms are influenced by stable and changing factors and that spousal similarity in both factors contribute to spousal similarity in depression on a single occasion. Spousal similarity in factors that change gradually over time suggests that shared-environmental factors contribute to depressive symptoms.     

An invariant dimensional liability model of gender differences in mental disorder prevalence: evidence from a national sample

Epidemiological studies of categorical mental disorders consistently report that gender differences exist in many disorder prevalence rates and that disorders are often comorbid. Can a dimensional multivariate liability model be developed to clarify how gender impacts diverse, comorbid mental disorders? We pursued this possibility in the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; N = 43,093). Gender differences in prevalence were systematic such that women showed higher rates of mood and anxiety disorders, and men showed higher rates of antisocial personality and substance use disorders. We next investigated patterns of disorder comorbidity and found that a dimensional internalizing-externalizing liability model fit the data well, where internalizing is characterized by mood and anxiety disorders, and externalizing is characterized by antisocial personality and substance use disorders. This model was gender invariant, indicating that observed gender differences in prevalence rates originate from women and men's different average standings on latent internalizing and externalizing liability dimensions. As hypothesized, women showed a higher mean level of internalizing, while men showed a higher mean level of externalizing. We discuss implications of these findings for understanding gender differences in psychopathology and for classification and intervention.     

A test of the bidirectional association between sleep and mood in bipolar disorder and insomnia

The present study investigates sleep, mood, and the proposed bidirectional relationship between the two in psychiatric disorders. Participants with interepisode bipolar disorder (n = 49), insomnia (n = 34), and no psychiatric history (n = 52) completed seven consecutive days of sleep diaries and mood measures. The interepisode bipolar and insomnia participants exhibited greater sleep disturbance than the healthy control individuals. Negative mood was equally heightened in both interepisode bipolar disorder and insomnia, and there were no differences between the three groups in positive mood. Total wake time was associated with next morning negative mood in bipolar disorder, whereas evening negative mood was associated with subsequent total wake time in both bipolar disorder and insomnia. Additionally, positive mood was associated with subsequent total wake time for the insomnia group. Results support the theory that disruptions in nighttime sleep and daytime mood may be mutually maintaining and suggest the potential importance of transdiagnostic or universal processes.