Communicative and other cognitive characteristics of bottlenose dolphins

Scientists have tried to capture the rich cognitive life of dolphins through field and laboratory studies of their brain anatomy, social lives, communication and perceptual abilities. Encopheliration quotient data sugest a level of intelligence or cognitive processing in the large-brained dolphin that is closer to the human range than are our nearest primate relatives. Field studies indicate a fission-fusion type of social structure, showing social complexity rivaling that found in chimpanzee societies. Notably, cetaceans are the only mammals other than humans that clearly demonstrate vocal learning and parallels in stages of vocal learning have been reported for humans, birds and dolphins. The dolphin's vocal plasticity from infancy through adulthood, in what is probably an 'open' communication system, is likely to be related to their fission-fusion social structure and, specifically, to the fluidity of their short-term associations. However, conflicting evidence exists on the composition and organization of the dolphins whistle repertoire. In general, the level of dolphin performance on complex auditory learning and memory tasks has been compared with that of primates on similar visual tasks; however, dolphins have also demonstrated sophistrcated visual processing abilities. Laboratory studies have also provided suggestive, evidence of minor self-recognition in the dolphin, an ability previously thought to be exclusive to humans humans and apes.     

Whistle rates of wild bottlenose dolphins (Tursiops truncatus): influences of group size and behavior

In large social groups acoustic communication signals are prone to signal masking by conspecific sounds. Bottlenose dolphins (Tursiops truncatus) use highly distinctive signature whistles that counter masking effects. However, they can be found in very large groups where masking by conspecific sounds may become unavoidable. In this study we used passive acoustic localization to investigate how whistle rates of wild bottlenose dolphins change in relation to group size and behavioral context. We found that individual whistle rates decreased when group sizes got larger. Dolphins displayed higher whistle rates in contexts when group members were more dispersed as in socializing and in nonpolarized movement than during coordinated surface travel. Using acoustic localization showed that many whistles were produced by groups nearby and not by our focal group. Thus, previous studies based on single hydrophone recordings may have been overestimating whistle rates. Our results show that although bottlenose dolphins whistle more in social situations they also decrease vocal output in large groups where the potential for signal masking by other dolphin whistles increases.     

Understanding of the concept of numerically "less" by bottlenose dolphins (Tursiops truncatus)

In 2 experiments, bottlenose dolphins (Tursiops truncatus) judged the ordinal relationship between novel numerosities. The dolphins were first trained to choose the exemplar with the fewer number of items when presented with just a few specific comparisons (e.g., 2 vs. 6, 1 vs. 3, and 3 vs. 7). Generalization of this rule was then tested by presenting the dolphins with all possible pairwise comparisons between 1 and 8. The dolphins chose the exemplar with the fewer number of items at levels far above chance, showing that they could recognize and represent numerosities on an ordinal scale. Their pattern of errors was consistent with the idea of an underlying analog magnitude representation.     

Testing the validity of conflict drift-diffusion models for use in estimating cognitive processes: A parameter-recovery study

Researchers and clinicians are interested in estimating individual differences in the ability to process conflicting information. Conflict processing is typically assessed by comparing behavioral measures like RTs or error rates from conflict tasks. However, these measures are hard to interpret because they can be influenced by additional processes like response caution or bias. This limitation can be circumvented by employing cognitive models to decompose behavioral data into components of underlying decision processes, providing better specificity for investigating individual differences. A new class of drift-diffusion models has been developed for conflict tasks, presenting a potential tool to improve analysis of individual differences in conflict processing. However, measures from these models have not been validated for use in experiments with limited data collection. The present study assessed the validity of these models with a parameter-recovery study to determine whether and under what circumstances the models provide valid measures of cognitive processing. Three models were tested: the dual-stage two-phase model (Hübner, Steinhauser, & Lehle, Psychological Review, 117(3), 759–784, 2010), the shrinking spotlight model (White, Ratcliff, & Starns, Cognitive Psychology, 63(4), 210–238, 2011), and the diffusion model for conflict tasks (Ulrich, Schröter, Leuthold, & Birngruber, Cogntive Psychology, 78, 148–174, 2015). The validity of the model parameters was assessed using different methods of fitting the data and different numbers of trials. The results show that each model has limitations in recovering valid parameters, but they can be mitigated by adding constraints to the model. Practical recommendations are provided for when and how each model can be used to analyze data and provide measures of processing in conflict tasks.     

Sex differences on use of associative and dissociative cognitive strategies among male and female athletes

This study assessed whether men and women differed in using associative and dissociative cognitive strategies during athletic performance. Athletes (31 men, M age = 23.2 yr., SD = 3.9 and 29 women, M age = 22.9 yr., SD = 4.3) who practiced endurance activities (running, swimming, and cycling) were considered high-level performers because they participated in national or international competition. The athletes were interviewed, and Schomer's 1986 method of measurement was used to evaluate and quantify two cognitive strategies. Most specifically, categories of association concerned the way the athlete paid close attention to bodily signals, and categories of dissociation described how the athlete shunned sensory inputs. Analysis of variance and the t test showed that women tend to be more dissociative than men and men more associative than women. The results suggest that pain perception in these sports may be a function of sex.     

Treatment outcome of a group cognitive therapy program for depression

A 12-session group program of cognitive therapy, designed by the first author, was evaluated with 35 persons suffering from major or minor depressive disorders. Effect-size scores were generated using the method of Nietzel, Russel, Hemmings, and Gretter (1987) and compared with cut-off points calculated using the method of Jacobson and Revenstorf (1988) and the norms established by Nietzel et al. (1987) in their meta-analysis. The effects of the Group Cognitive Therapy Program were found to be clinically significant according to the criteria of Jacobson and colleagues (Jacobson and Revenstorf, 1988; Jacobson, Follette and Revenstorf, 1984) for 73% of patients. It is concluded that the Group Cognitive Therapy Program is a clinically efficacious and cost-effective treatment for persons suffering from nonpsychotic, primary, unipolar depression.     

Opportunistic use of cognitive smokescreens by araneophagic jumping spiders

Little is known about how a prey species' cognitive limitations might shape a predator's prey-capture strategy. A specific hypothesis is investigated: predators take advantage of times when the prey's attention is focussed on its own prey. Portia fimbriata, an araneophagic jumping spider (Salticidae) from Queensland, is shown in a series of 11 experiments to exploit opportunistically a situation in which a web-building spider on which it preys, Zosis genicularis (Uloboridae), is preoccupied with wrapping up its own prey. Experimental evidence supports three conclusions: (1) while relying on optical cues alone, P. fimbriata perceives when Z. genicularis is wrapping up prey; (2) when busy wrapping up prey, the responsiveness of Z. genicularis to cues from potential predators is diminished; and (3) P. fimbriata moves primarily during intervals when Z. genicularis is busy wrapping up prey. P. fimbriata's strategy is effective partly because the wrapping behaviour of Z. genicularis masks the web signals generated by the advancing P. fimbriata's footsteps and also because, while wrapping, Z. genicularis' attention is diverted away from predator-revealing cues. Electronic Publication     

Effects of environmental enrichment on cognitive performance of pigs in a spatial holeboard discrimination task

This study investigated the effects of environmental enrichment on the cognitive performance of female conventional farm (growing) pigs in a spatial holeboard task. Ten pairs of littermates matched for weight were used. From each litter, one piglet was randomly assigned to a barren environment; the other was assigned to an enriched environment from 4 weeks of age. The enriched environment was double the size of the barren environment, had a floor covered with straw, a rooting area filled with peat, and one of the four different enrichment toys which were exchanged daily. Starting at 11 weeks of age, all pigs were tested in a spatial holeboard discrimination task in which 4 out of 16 holes were baited. Furthermore, basal salivary cortisol levels of all pigs were determined after the end of all testing. All pigs were able to acquire the pattern of baited holes (acquisition phase, 40 trials) and the diagonally mirrored pattern (reversal phase, 20 trials). During the acquisition phase, the reference memory performance of the enriched-housed pigs was better than that of their barren-housed littermates, i.e. they reduced visits to the unbaited set of holes. During the reversal phase, enriched-housed pigs had a better general working memory performance than the barren-housed pigs as indicated by reduced revisits to holes already visited during a trial, irrespective of whether they were of the baited or the unbaited set. The enriched-housed pigs also searched for the hidden bait faster during both phases. The environments did not affect basal salivary cortisol levels. In conclusion, environmental enrichment slightly improved the cognitive performance of pigs in a spatial learning task. We hypothesise that the long period of habituation to and testing in the holeboard acted as enrichment that partially reduced the effects of barren housing.     

Reducing cognitive biases in probabilistic reasoning by the use of logarithm formats

Research on probability judgment has traditionally emphasized that people are susceptible to biases because they rely on “variable substitution”: the assessment of normative variables is replaced by assessment of heuristic, subjective variables. A recent proposal is that many of these biases may rather derive from constraints on cognitive integration, where the capacity-limited and sequential nature of controlled judgment promotes linear additive integration, in contrast to many integration rules of probability theory (Juslin, Nilsson, & Winman, 2009). A key implication by this theory is that it should be possible to improve peoples’ probabilistic reasoning by changing probability problems into logarithm formats that require additive rather than multiplicative integration. Three experiments demonstrate that recasting tasks in a way that allows people to arrive at the answers by additive integration decreases cognitive biases, and while people can rapidly learn to produce the correct answers in an additive formats, they have great difficulty doing so with a multiplicative format.     

A first step toward cognitive remediation of voices: a case study

Several studies have shown that source-monitoring errors are related to verbal hallucinations in schizophrenia. An exploratory pilot study has been carried out to investigate the possibility of training patients in how to avoid errors in source-monitoring. One patient with paranoid schizophrenia and persistent thought insertions was trained for 6 hours to use mnemonic techniques to compensate specific deficits in source-monitoring. Results show that the patient was able to improve his performance and maintain the acquired progress at a 1-month follow-up assessment. These preliminary results are interesting for developing a larger controlled study of cognitive remediation of source-monitoring deficits.     

In situ repeated measures of affect and cognitive performance facilitated by use of a hand-held computer

The advent of hand-held computers means that it is now feasible to administer standard measures of affect and cognitive performance in field studies without the direct intervention of the investigator. The functional requirements for such an instrument are set out, and a set of programs developed for an electronic Organiser to meet those requirements are described. The programs include alarm scheduling, subjective rating scales, a sleep diary, and choice reaction time and memory search tasks. Compliance rates and usability of the instrument are assessed and judged satisfactory on the basis of examples from three field studies of shiftworkers.     

Evidence of teaching in atlantic spotted dolphins (Stenella frontalis) by mother dolphins foraging in the presence of their calves

Teaching is a powerful form of social learning, but there is little systematic evidence that it occurs in species other than humans. Using long-term video archives the foraging behaviors by mother Atlantic spotted dolphins (Stenella frontalis) were observed when their calves were present and when their calves were not present, including in the presence of non-calf conspecifics. The nine mothers we observed chased prey significantly longer and made significantly more referential body-orienting movements in the direction of the prey during foraging events when their calves were present than when their calves were not present, regardless of whether they were foraging alone or with another non-calf dolphin. Although further research into the potential consequences for the naïve calves is still warranted, these data based on the maternal foraging behavior are suggestive of teaching as a social-learning mechanism in nonhuman animals.     

The role of cognitive variables in psychological functioning after the death of a first degree relative

The present study sought to explore the relationship between negative cognitions and emotional problems after bereavement, with a group of 329 adults who had suffered the loss of a first degree relative. The following cognitions were assessed: global negative beliefs, cognitions about self-blame, negative cognitions about other people's responses after the loss, and negative cognitions about one's own grief reactions. Results showed that each of these cognitive variables was significantly related to the severity of symptoms of traumatic grief, depression and anxiety, even when background and loss-related variables that were initially found to influence symptom severity, were statistically controlled. When the shared variance between the cognitive variables was controlled, it was found that global negative beliefs about life, the world, and the future, and threatening interpretations of grief reactions each explained a unique proportion of variance in traumatic grief symptom severity. Global negative beliefs about life, the self and the future, and threatening interpretations of grief explained most variance in depression, while negative beliefs about the self and threatening interpretations of grief explained most variance in anxiety. Overall, the findings are in support of cognitive theories of grief, and suggest that effective treatment of problematic grief will need to address negative cognitions.     

Evaluation of a cognitive behavioral group intervention program for spouses of stroke patients

This study investigated the effectiveness of a cognitive behavioral group program for spouses of stroke patients. The program consists of 15 bi-monthly 112h sessions. The goal of the intervention is to reduce the prevalence of mental disorders and burnout among care-giving spouses of stroke patients. The sample (stroke patients and their spouses) consisted of one intervention group (n=38 couples) and two different control conditions, those receiving informational support (n=35 couples) and those receiving standard care (n=51 couples). We used the following instruments to measure spouses' mental health and quality of life: Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI), WHO Quality of Life Questionnaire. Measurements were taken before the intervention (Time 1), directly following the intervention (Time 2) and 6 months after Time 2 (Time 3). Several regression analyses allowed for examination of the short-term and long-term effects of the intervention. The spouses' participation in the intervention program was associated with significant short-term changes in care-giving spouses' quality of life and with long-term changes in their quality of life and depression. The presented multi-component intervention appears to have an immediate effect on care-giving spouses' quality of life. In contrast, the intervention-related changes in more resistant mental-health-related variables did not appear until after a latent stage in the later post-intervention phase.     

The use of the self in group leadership: a relational perspective

This article, written from a relational perspective, describes a shift that is taking place in the thinking of many psychodynamically oriented psychotherapists regarding the practice of therapy and the implications it has for group therapists. The shift, from one-person to two-person and multi-person theory, has particular importance for group leaders since it recommends making the subjective involvement of the therapist in the interactional field of the group much more a part of the treatment process. Theory and research on the use of countertransference, non-interpretive interventions, humor, and spontaneity by the leader are reviewed and vignettes are presented to illustrate the application of these ideas. Guidelines regarding the application of such ideas in group therapy are also discussed.     

The inadvertent use of prior knowledge in a generative cognitive task

In four experiments with 332 participants, participants were asked to generate novel nonwords for English categories. When participants were shown examples embedded with regular orthographic structures, participants’ nonwords tended to conform orthographically to the examples, despite instructions to avoid using features of the examples. The effect was found with immediate testing (Experiment 1) and delayed testing (Experiment 2). The effect was also found with arbitrary features (Experiments 1–4), as well as with naturally occurring orthographic regularities (Experiment 4). Participants had difficulty avoiding the use of this prior knowledge, despite being able to list the features they were asked to avoid (Experiment 3). The results are discussed in terms of the inadvertent use of prior knowledge in generative cognitive tasks.     

Thirty-year secular trends in the cognitive abilities of Danish male school-leavers at a high educational level

A nationally representative sample of Danish males finishing school in 1989, or shortly before, with a studentereksamen (the highest qualification in the Danish school system) was found to score generally lower on a battery of four cognitive tests than a comparable sample of Danish males who had taken the same tests shortly after finishing school in the late 1950s or early 1960s. This decline appears attributable to the increasing proportions of students who obtain the stundentereksamen and is quite compatible with an overall increase in test scores, also found in our data, for the general population over the same time period. For those who obtain the stundentereksamen , the decline has been most marked in a test of verbal analogies. It has been smaller for tests of logical and spatial reasoning, and scores on a test of numerical ability have actually improved over the 30 years. This differential pattern may be the result of both student changes and auricular changes within Danish schools.     

Effects of restricting first graders' TV-viewing on leisure time use,IQ change,and cognitive style

Middle-class 6-year-olds matched for sex, age, pretest WPPSI IQ, and TV-viewing time were blindly assigned to a restricted TV-viewing group or an unrestricted group. Restricted parents halved subjects' previous TV-viewing rates and interacted 20 min./day with subjects for a 6-week period. Unrestricted TV parents provided similar interactions but did not limit viewing. Results tentatively suggest that TV restriction enhanced Performance IQ, reading time, and reflective Matching Familiar Figures scores.     

Validation of a novel cognitive bias task based on difference in quantity of reinforcement for assessing environmental enrichment

Cognitive bias tasks purport to assess affective states via responses to ambiguous stimuli. We hypothesized that a novel cognitive bias task based on positive reinforcement using quantity differences would detect changes in affect in captive grizzly bears (Ursus arctos horribilis). We trained bears (n = 8) to respond differently (nose or paw touch) to two stimuli (light or dark gray cue cards), with responses counterbalanced across bears. The two cues signaled a small or large food reward, respectively. Responses to ambiguous probe stimuli (i.e., shades of gray) intermediate to the trained stimuli were classified as either ‘optimistic,’ appropriate for the larger reward, or ‘pessimistic,’ appropriate for the smaller reward. In Experiment 1, we explored the contrast in reward size necessary to detect a change in response across probe stimuli (large reward, 3 or 6 apple slices: small reward, 1 slice). We observed a change in response across probe stimuli, with no difference in response between reward-value groups, indicating that a contrast of 3:1 apple slices was sufficient to affect responses. In Experiment 2, we investigated cognitive bias after 2.1 h of exposure to enrichment items varying in attractiveness. Results were unaffected by enrichment type or time spent interacting with enrichments, indicating that the task failed to demonstrate criterion validity for comparing mood following exposure to different enrichment items. However, greater time spent pacing prior to testing was associated with ‘optimistic’ judgments. The data provide some support for use of cognitive bias tasks based on quantity differences in animal welfare assessments involving captive wildlife.