Chimpanzees and bonobos exhibit divergent spatial memory development

Spatial cognition and memory are critical cognitive skills underlying foraging behaviors for all primates. While the emergence of these skills has been the focus of much research on human children, little is known about ontogenetic patterns shaping spatial cognition in other species. Comparative developmental studies of nonhuman apes can illuminate which aspects of human spatial development are shared with other primates, versus which aspects are unique to our lineage. Here we present three studies examining spatial memory development in our closest living relatives, chimpanzees (Pan troglodytes) and bonobos (P. paniscus). We first compared memory in a naturalistic foraging task where apes had to recall the location of resources hidden in a large outdoor enclosure with a variety of landmarks (Studies 1 and 2). We then compared older apes using a matched memory choice paradigm (Study 3). We found that chimpanzees exhibited more accurate spatial memory than bonobos across contexts, supporting predictions from these species’ different feeding ecologies. Furthermore, chimpanzees – but not bonobos – showed developmental improvements in spatial memory, indicating that bonobos exhibit cognitive paedomorphism (delays in developmental timing) in their spatial abilities relative to chimpanzees. Together, these results indicate that the development of spatial memory may differ even between closely related species. Moreover, changes in the spatial domain can emerge during nonhuman ape ontogeny, much like some changes seen in human children.     

Bursting with anxiety: adult social referencing in an interpersonal balloon analogue risk task (BART)

This study developed an interpersonal modification of the balloon analogue risk task (BART) to assess effects of a friend's real-time facial expressions on coparticipants' risk-taking. Twenty pairs of male friends and 20 pairs of female friends completed two counterbalanced versions of BART, one framed in terms of monetary gain, and the other framed in terms of avoiding loss. Each pair included a player who performed the task across both trials and a reference person in a separate cubicle connected via a soundless video link. In the suppression condition, reference persons were told to minimize facial expressions of anxiety as balloons inflated. In the expression condition, they were told to freely express anxiety. As predicted, players took greater risks and burst more balloons in the suppression condition, but only under the gain frame. Players' BART scores across both frames were also significantly negatively correlated with reference persons' scores on a questionnaire measure of dispositional expressivity (BEQ), confirming that other people's expressions can moderate one's own risk-taking.     

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.     

A quasi-experimental analysis of the influence of neighborhood disadvantage on child and adolescent conduct problems

A quasi-experimental comparison of cousins differentially exposed to levels of neighborhood disadvantage (ND) was used with extensive measured covariates to test the hypothesis that neighborhood risk has independent effects on youth conduct problems (CPs). Multilevel analyses were based on mother-rated ND and both mother-reported CPs across 4-13 years (n = 7,077) and youth-reported CPs across 10-13 years (n = 4,524) from the Children of the National Longitudinal Survey of Youth. ND was robustly related to CPs reported by both informants when controlling for both measured risk factors that are correlated with ND and unmeasured confounds. These findings are consistent with the hypothesis that ND has influence on conduct problems.     

INFLUENCES OF RESPONSE RATE AND DISTRIBUTION ON THE CALCULATION OF INTEROBSERVER RELIABILITY SCORES

We examined the effects of several variations in response rate on the calculation of total, interval, exact‐agreement, and proportional reliability indices. Trained observers recorded computer‐generated data that appeared on a computer screen. In Study 1, target responses occurred at low, moderate, and high rates during separate sessions so that reliability results based on the four calculations could be compared across a range of values. Total reliability was uniformly high, interval reliability was spuriously high for high‐rate responding, proportional reliability was somewhat lower for high‐rate responding, and exact‐agreement reliability was the lowest of the measures, especially for high‐rate responding. In Study 2, we examined the separate effects of response rate per se, bursting, and end‐of‐interval responding. Response rate and bursting had little effect on reliability scores; however, the distribution of some responses at the end of intervals decreased interval reliability somewhat, proportional reliability noticeably, and exact‐agreement reliability markedly.     

COMPUTER‐ASSISTED MEASUREMENT OF WOUND SIZE ASSOCIATED WITH SELF‐INJURIOUS BEHAVIOR

We evaluated an inexpensive, efficient, and noninvasive technique for measuring tissue damage produced by self‐injurious behavior (SIB). The technique involved computerized measurement of wound surface area (WSA) based on digital photographs. In Study 1, we compared photographic measurement to a more commonly used procedure, transparency measurement, in estimating WSA of 20 wound models. Results showed that both methods were reliable and that there was a high degree of correspondence between the 2 sets of measures. In Study 2, we compared photographic WSA measures to direct‐observation measures in documenting changes over time in the SIB exhibited by a woman with Prader‐Willi syndrome. Results showed that increases and decreases in observed SIB during baseline and treatment conditions corresponded with changes in WSA measures, indicating that the computer‐assisted photographic technique may be useful as a corroborative measure or as a primary measure when direct observation of SIB is not feasible.     

OBSERVER TRAINING REVISITED: A COMPARISON OF IN VIVO AND VIDEO INSTRUCTION

We compared the effects of 2 observer‐training procedures. In vivo training involved practice during actual treatment sessions. Video training involved practice while watching progressively more complex simulations. Fifty‐nine undergraduate students entered 1 of the 2 training conditions sequentially according to an ABABAB design. Results showed that the 2 training methods produced almost identical scores on a posttraining observational test; however, the video method required fewer training sessions to complete.     

Paying for positive group esteem: how inequity frames affect whites' responses to redistributive policies

This article finds that, when faced with racial inequity framed as White advantage, Whites' desire to think well of their racial group increases their support for policies perceived to harm Whites. Across 4 studies, the article provides evidence that (a) relative to minority disadvantage, White advantage increases Whites' support for policies perceived to reduce their group's economic opportunities, but does not increase support for policies perceived to increase minority opportunities; and (b) the effect of White advantage on Whites' esteem for their ingroup drives the effect of inequity frame on support for policies perceived to reduce Whites' opportunities.