Atypical birdsong and artificial languages provide insights into how communication systems are shaped by learning,use, and transmission

In this article, I argue that a comparative approach focusing on the cognitive capacities and behavioral mechanisms that underlie vocal learning in songbirds and humans can provide valuable insights into the evolutionary origins of language. The experimental approaches I discuss use abnormal song and atypical linguistic input to study the processes of individual learning, social interaction, and cultural transmission. Atypical input places increased learning and communicative pressure on learners, so exploring how they respond to this type of input provides a particularly clear picture of the biases and constraints at work during learning and use. Furthermore, simulating the cultural transmission of these unnatural communication systems in the laboratory informs us about how learning and social biases influence the structure of communication systems in the long run. Findings based on these methods suggest fundamental similarities in the basic social–cognitive mechanisms underlying vocal learning in birds and humans, and continuing research promises insights into the uniquely human mechanisms and into how human cognition and social behavior interact, and ultimately impact on the evolution of language.     

Mice optimize timed decisions about probabilistic outcomes under deadlines

Optimal performance in temporal decisions requires the integration of timing uncertainty with environmental statistics such as probability or cost functions. Reward maximization under response deadlines constitutes one of the most stringent examples of these problems. The current study investigated whether and how mice can optimize their timing behavior in a complex experimental setting under a response deadline in which reward maximization required the integration of timing uncertainty with a geometrically increasing probability/decreasing cost function. Mice optimized their performance under seconds-long response deadlines when the underlying function was reward probability but approached this level of performance when the underlying function was reward cost, only under the assumption of logarithmically scaled subjective costs. The same subjects were then tested in a timed response inhibition task characterized by response rules that conflicted with the initial task, not responding earlier than a schedule as opposed to not missing the deadline. Irrespective of original test groups, mice optimized the timing of their inhibitory control in the second experiment. These results provide strong support for the ubiquity of optimal temporal risk assessment in mice.     

Witnesses appearing live versus on video: effects on observers' perception,veracity assessments and memory

The study is an experiment examining how different presentation modes (live vs. video) affect observers' perception, veracity assessments and memory of witnesses and their statements. Three weeks after seeing a staged accident, six truth telling and six lying witnesses testified about the event. Mock jurors (N = 122) viewed the witnesses' testimony either live or on video and rated their perception of the witnesses' statement and appearance as well as the credibility of the witnesses. Live observers rated the witnesses' appearance in a more positive way and perceived them as being more honest than did video observers. Truth tellers were rated as having to think less hard than liars. Moreover, observers were not better than chance in assessing veracity, regardless of presentation mode. Live observers incorrectly believed they had a better memory of the witnesses' statements than video observers. Observers who had watched truthful statements showed a significantly better memory performance than observers who had watched deceptive statements. Copyright © 2005 John Wiley & Sons, Ltd.     

Congenital absence of vasopressin and age-dependent changes in ACTH and corticosterone stress responses in rats

The hypothalamic components of the hypothalamo-pituitary-adrenal axis (HPA) are corticotropin-releasing hormone (CRH) and vasopressin. To test the hypothesis that HPA regulation changes with age, we compared ether and bacterial lipopolysaccharide (LPS) injection induced stress reactions in adult and 10-day-old Brattleboro rats, which naturally lack vasopressin owing to mutation of the gene (di/di). The LPS stimulus was used also with V(1b) receptor antagonist pretreatment (SSR149415). In adult di/di or V(1b) pretreated rats, we observed normal pituitary and adrenocortical secretory responses, while in all 10-day-old rats stress-induced serum corticosterone increases were marked, but adrenocorticotropin (ACTH) increases were significantly smaller. Compared to control pups the adenohypophysis of the 10-day-old di/di rats responded normally to CRH, but their adrenal glands were hyper-responsive to ACTH, while in adults there was greater secretion at both levels with no difference between the genotypes. The serum transcortin level was higher in adults than pups, with the di/di pups having higher transcortin levels than controls. Hence, using the same stressors in adults and pups with both a genetic model and pharmacological pretreatment, we have shown that the role of vasopressin in ACTH regulation is more important during the neonatal period than in adulthood. Blunted hypophysial sensitivity to CRH and similar adrenal gland sensitivity to ACTH in the pups compared to adults suggest that hypothalamic factors could be responsible for the neonatal stress hyporesponsive period.     

Subjective time: cognitive and physical secondary tasks affect timing differently

Humans were trained on a temporal discrimination to make one response when the stimulus duration was short (2 s) and a different response when the stimulus duration was long (8 s). They were then tested with stimulus durations in between to determine the bisection point. In Experiment 1, we examined the effect of a secondary cognitive task (counting backwards by threes) on the bisection point when participants were trained without a cognitive load and were tested with a cognitive load or the reverse (relative to appropriate controls). When the cognitive load increased from training, the psychophysical function plotting long responses against the increase in stimulus duration shifted to the right (as if the internal clock slowed down), and when the cognitive load decreased from training the psychophysical function shifted to the left (as if the internal clock speeded up). In Experiment 2, when the secondary task consisted of exerting continuous force on a transducer (a physically effortful task), it had the opposite effect. When the required force increased from training, the psychophysical function shifted to the left (as if the internal clock speeded up), and when the required force decreased from training, the psychophysical function shifted to the right (as if the internal clock slowed down). The results support an attentional view of the subjective passage of time. A cognitive secondary task appears to decrease attention to temporal cues, resulting in the underestimation of the passage of time, whereas a force requirement appears to increase attention to temporal cues, resulting in the overestimation of the passage of time.     

Problematic video game use: estimated prevalence and associations with mental and physical health

A nationwide survey was conducted to investigate the prevalence of video game addiction and problematic video game use and their association with physical and mental health. An initial sample comprising 2,500 individuals was randomly selected from the Norwegian National Registry. A total of 816 (34.0 percent) individuals completed and returned the questionnaire. The majority (56.3 percent) of respondents used video games on a regular basis. The prevalence of video game addiction was estimated to be 0.6 percent, with problematic use of video games reported by 4.1 percent of the sample. Gender (male) and age group (young) were strong predictors for problematic use of video games. A higher proportion of high frequency compared with low frequency players preferred massively multiplayer online role-playing games, although the majority of high frequency players preferred other game types. Problematic use of video games was associated with lower scores on life satisfaction and with elevated levels of anxiety and depression. Video game use was not associated with reported amount of physical exercise.     

Asymmetrical scepticism towards criminal evidence: The role of goal‐ and belief‐consistency

Previous demonstrations of asymmetrical scepticism (i.e., that investigators perceive evidence inconsistent [vs. consistent] with the focal hypothesis of a case as less reliable) have failed to account for the underlying mechanism. This study examined whether inconsistent evidence is discredited due to its inconsistency with a prior belief or because it conflicts with the goal to reach closure in a case. Police trainees (N = 107) were presented with a homicide case and judged the reliability of incriminating or exonerating evidence while entertaining a ‘guilty’ or ‘innocent’ hypothesis concerning a suspect. Asymmetrical scepticism was observed in the guilty condition, but not in the innocent condition, partially supporting the goal‐consistency explanation. Implications for the organization of criminal investigations are discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

Investigators under influence: How social norms activate goal‐directed processing of criminal evidence

Previous research has shown that exposure to social information can influence behaviour through the automatic activation of goals. In the first study to examine such influences in a legal setting, an experiment with 104 experienced criminal investigators tested the idea that exposure to occupational norms can activate distinct information‐processing goals. As predicted, exposure to norms associated with efficiency (vs. thoroughness) sped up and reduced the depth of investigators' processing of criminal evidence, thus reducing their openness to sequentially late witness evidence. In addition, the goal activation operated outside investigators' awareness, illustrating the insidious cognitive influence of occupational norms. The results are discussed in terms of practical significance and contributions to the goal activation literature and the applied study of criminal investigations. Copyright © 2010 John Wiley & Sons, Ltd.     

Perceptual training strongly improves visual motion perception in schizophrenia

Schizophrenia patients exhibit perceptual and cognitive deficits, including in visual motion processing. Given that cognitive systems depend upon perceptual inputs, improving patients’ perceptual abilities may be an effective means of cognitive intervention. In healthy people, motion perception can be enhanced through perceptual learning, but it is unknown whether this perceptual plasticity remains in schizophrenia patients. The present study examined the degree to which patients’ performance on visual motion discrimination can be improved, using a perceptual learning procedure. While both schizophrenia patients and healthy controls showed decreased direction discrimination thresholds (improved performance) with training, the magnitude of the improvement was greater in patients (47% improvement) than in controls (21% improvement). Both groups also improved moderately but non-significantly on an untrained task—speed discrimination. The large perceptual training effect in patients on the trained task suggests that perceptual plasticity is robust in schizophrenia and can be applied to develop bottom-up behavioral interventions.