Culture in whales and dolphins

Studies of animal culture have not normally included a consideration of cetaceans. However, with several long-term field studies now maturing, this situation should change. Animal culture is generally studied by either investigating transmission mechanisms experimentally, or observing patterns of behavioural variation in wild populations that cannot be explained by either genetic or environmental factors. Taking this second, ethnographic, approach, there is good evidence for cultural transmission in several cetacean species. However, only the bottlenose dolphin (Tursiops) has been shown experimentally to possess sophisticated social learning abilities, including vocal and motor imitation; other species have not been studied. There is observational evidence for imitation and teaching in killer whales. For cetaceans and other large, wide-ranging animals, excessive reliance on experimental data for evidence of culture is not productive; we favour the ethnographic approach. The complex and stable vocal and behavioural cultures of sympatric groups of killer whales (Orcinus orca) appear to have no parallel outside humans, and represent an independent evolution of cultural faculties. The wide movements of cetaceans, the greater variability of the marine environment over large temporal scales relative to that on land, and the stable matrilineal social groups of some species are potentially important factors in the evolution of cetacean culture. There have been suggestions of gene-culture coevolution in cetaceans, and culture may be implicated in some unusual behavioural and life-history traits of whales and dolphins. We hope to stimulate discussion and research on culture in these animals.     

The Public and Private Use of Consensus-Raising Excuses

ABSTRACT Two experiments tested the proposition that people use consensus-raising excuses more in private than in public when the audience has information that could refute subjects' claims about others In Experiment 1, subjects received success or failure feedback and made public or private attributions to ability, effort, task difficulty, and luck In Experiment 2, subjects received positive or negative feedback and evaluated themselves and others on the trait Task difficulty attributions and evaluations of others are consensus-raising measures Consistent with our hypothesis, subjects receiving negative feedback in Experiment 1 claimed that the task was more difficult, and in Experiment 2 evaluated the other more negatively in private than in public.     

Galef’s Transfer-of-Information Effect Occurs in a Free-Foraging Situation

Galef and his colleagues have repeatedly shown that one rat may transfer information regarding the type of food it has consumed to other conspecifics. Such experiments typically have been conducted in wire-mesh cages or a wooden maze. The present experiments sought to extend this paradigm to the open-field foraging situation having six food patches to choose from. Following interaction with a demonstrator that had consumed either a cocoa or a cinnamon diet, single observers (Experiment 1) were tested in the foraging situation. Food-consumption scores indicated that observers consumed significantly more of their specific demonstrator’s diet than a second diet that was available also. Experiment 2 involved the simultaneous testing of two observers in the foraging laboratory. In Experiment 3 two observers were once again tested, but each had been provided a different food-type message prior to foraging. Positive results, mirroring those of Experiment 1, were obtained in both Experiments 2 and 3. The results of these three experiments underscore the robustness of this phenomenon and its generalizability to other testing conditions.

     

Categorization and cognitive deficits in compulsive hoarding

According to the cognitive-behavioural model of compulsive hoarding, information-processing deficits in the areas of attention, memory, decision-making, and categorization contribute to hoarding behaviour. The purpose of the current study was to examine whether individuals with compulsive hoarding exhibited impairment on executive functioning and categorization tasks. Three groups of participants were recruited (N = 60): individuals with compulsive hoarding syndrome, individuals with an Axis I mood or anxiety disorder, and non-clinical control participants. All participants completed self-report measures of cognitive difficulties, neuropsychological tests of executive functioning and decision-making, and four categorization tasks. Results suggested that hoarding participants reported more cognitive failures and more problems with attention and decision-making than non-clinical control participants. In addition, hoarding participants performed worse than both control groups on the Stockings of Cambridge (SOC), a neuropsychological test of planning ability, and were slower and more anxious during a categorization task. These findings suggest that specific deficits in executive functioning may be associated with the difficulties hoarding patients have organizing their possessions.     

The structure of PTSD among two cohorts of returning soldiers: before, during, and following deployment to Iraq

Evidence suggests either a four-factor emotional numbing or dysphoria model likely reflects the underlying structure of posttraumatic stress disorder (PTSD). Questions remain as to which of these structures best represents PTSD, how the structure changes with time, the applicability of models to returning veterans, and the validity of the symptom clusters. The present study addresses these questions among two longitudinal samples of National Guard soldiers assessed prior to, during, and following a combat deployment to Iraq. Findings support a four-factor intercorrelated dysphoria model of PTSD that remains stable across samples and time points. Differential associations were observed among PTSD symptom clusters over time and between symptom clusters and both depression and combat exposure, supporting important distinctions between symptom clusters.     

Race and Girls’ Self-Evaluations: How Mothering Matters

Research conducted in the United States shows that Black adolescent girls have higher self-esteem and, to a lesser extent, a higher sense of control than White girls. However, few studies conducted with representative samples of Black and White girls systematically examine why Black girls may have higher self-esteem and sense of control. Drawing on Black feminist thought, we posit that Black mothers’ socialization of their daughters may explain Black girls’ higher self-esteem and sense of control. Using survey data collected in 1994 from a nationally representative sample of U.S. Black (N?=?1,330) and White (N?=?3,797) girls and their mothers, we examine racial differences across two key components of the self-concept: self-esteem and sense of control. We ask: 1) Do Black girls have higher self-esteem and sense of control than White girls? 2) Do Black girls have more positive relationships with their mothers and receive more encouragement of academic achievement and independence from their mothers than White girls? and 3) Do more positive mother-daughter relationships and mothers’ encouragement help to explain Black girls’ higher self-esteem and sense of control in comparison to White girls? Findings indicate that Black girls have higher self-esteem and sense of control than White girls, and Black mothers’ relationship with their daughters and stronger encouragement of daughters’ independence in part explain race differences in self-evaluations.     

Tracking the first two seconds: three stages of visual information processing?

We compared visual priming and comparison tasks to assess information processing of a stimulus during the first 2 s after its onset. In both tasks, a 13-ms prime was followed at varying SOAs by a 40-ms probe. In the priming task, observers identified the probe as rapidly and accurately as possible; in the comparison task, observers determined as rapidly and accurately as possible whether or not the probe and prime were identical. Priming effects attained a maximum at an SOA of 133 ms and then declined monotonically to zero by 700 ms, indicating reliance on relatively brief visuosensory (iconic) memory. In contrast, the comparison effects yielded a multiphasic function, showing a maximum at 0 ms followed by a minimum at 133 ms, followed in turn by a maximum at 240 ms and another minimum at 720 ms, and finally a third maximum at 1,200 ms before declining thereafter. The results indicate three stages of prime processing that we take to correspond to iconic visible persistence, iconic informational persistence, and visual working memory, with the first two used in the priming task and all three in the comparison task. These stages are related to stages presumed to underlie stimulus processing in other tasks, such as those giving rise to the attentional blink.     

Numerical approximation abilities correlate with and predict informal but not formal mathematics abilities

Previous research has found a relationship between individual differences in children’s precision when nonverbally approximating quantities and their school mathematics performance. School mathematics performance emerges from both informal (e.g., counting) and formal (e.g., knowledge of mathematics facts) abilities. It remains unknown whether approximation precision relates to both of these types of mathematics abilities. In the current study, we assessed the precision of numerical approximation in 85 3- to 7-year-old children four times over a span of 2 years. In addition, at the final time point, we tested children’s informal and formal mathematics abilities using the Test of Early Mathematics Ability (TEMA-3). We found that children’s numerical approximation precision correlated with and predicted their informal, but not formal, mathematics abilities when controlling for age and IQ. These results add to our growing understanding of the relationship between an unlearned nonsymbolic system of quantity representation and the system of mathematics reasoning that children come to master through instruction.