Coping with a changing soundscape: avoidance,adjustments and adaptations

Since the industrial age, background anthropogenic noise has become a pervasive feature of many habitable environments. This relatively recent environmental feature can be particularly challenging for organisms that use acoustic forms of communication due to its propensity for masking and decreasing the potential acoustic space of signals. Furthermore, anthropogenic noise may affect biological processes including animal interactions, physiological and behavioural responses to stimuli and cognitive development. However, animals’ cognitive abilities may enable them to cope with high levels of anthropogenic noise through learning, the employment of acoustic and behavioural flexibility as well as the use of multi-modal sensory systems. We are only just beginning to understand how neural structures, endocrine systems and behaviour are mechanistically linked in these scenarios, providing us with information we can use to mitigate deleterious effects of pervasive noise on wildlife, along with highlighting the remarkable adaptability of animals to an increasingly anthropogenic world. In this review, I will focus mainly on birds, due to the amount of literature on the topic, and survey recent advancements made in two main spheres: (1) how anthropogenic noise affects cognitive processes and (2) how cognition enables animals to cope with increasingly noisy environments. I will be highlighting current gaps in our knowledge, such as how noise might impact behavioural traits such as predation, as well as how noise causes physical damage to neurotransmitters and affects stress levels, in order to direct future studies on this topic.     

Visual object agnosia as a problem in integrating parts and part relations

Current models of vision generally assume that the recognition of visual objects is achieved by encoding their component parts, as well as the spatial relations among parts. The current study examined how the processing of parts and their configurations may be affected in visual agnosia due to brain damage. Both a visual agnosic patient (AR) and healthy control subjects performed a visual search task in which they had to discriminate between targets and distractors that varied according to whether they shared their parts and/or their configuration. The results show that AR's visual search rates are disproportionally slow when targets and distractors share the same configuration than when they have different configurations. AR is also found to be disproportionately slow in discriminating targets and distractors that share identical parts when the targets and distractors share the same configuration. With differently configured targets and distractors, AR shows no part sharing effect. For controls, in contrast, the part and configuration sharing effects occur independently of one another. It is concluded that AR's object recognition deficit arises from difficulties in discriminating objects that share their configuration, and from an abnormal dependency of part information processing upon object configuration.     

Contribution of the dorsal subiculum to memory for temporal order and novelty detection using objects,odors, or spatial locations in the rat

The contribution of the dorsal subiculum (DS) to memory for temporal order and novelty detection was assessed using a spontaneous exploration paradigm with objects (visual/tactile stimuli), odors, or spatial locations (Hunsaker, Fieldsted, Rosenberg, & Kesner, 2008). Rats with selective excitotoxic lesions of the DS were compared to sham-operated rats (SHAM) in the two exploration tests. In temporal order tests, two previously explored stimuli were presented and normal rats typically show a preference for exploring the stimulus that was first explored compared to the other stimulus. In novelty detection tests, a familiar and a new stimulus were presented and normal rats typically have a preference for exploring new stimuli. In temporal order tests, results indicated that Group SHAM explored significantly more the first than the last stimulus they met when the stimuli were odors or objects. In addition, SHAM rats predictably displayed a significant preference for the new stimulus in the novelty detection tests with objects, odors, and spatial locations. Group DS did not differ from controls on the temporal order and the novelty detection tests with objects or odors. However, on the novelty detection test with spatial locations, Group DS differed from Group SHAM. These results suggest that the DS is necessary for the memory of spatial locations but not of objects and odors.     

Influence of achievement goals and self‐efficacy on students' self‐regulation and performance

It is widely admitted that low self‐efficacy has a detrimental impact on the functioning and performance of a person mainly concerned with performance goals but has no impact when a person is mainly concerned with learning goals (Dweck, 1986 ). However, results from both correlational and experimental studies are divergent. Since these studies examined very few indicators of participants' cognitive functioning, they may have failed to detect those aspects that could be more vulnerable to a negative impact of the combination of performance goals and low self‐efficacy. Another concern is the lack of most studies to clearly distinguish the type of performance goal examined, particularly the performance‐avoidance versus the performance‐approach goal. In the current study, we decided to focus on performance‐approach and learning goals in order to examine how self‐efficacy intervenes in their effects on participants' self‐regulation and performance on a cognitive task. One hundred and forty participants (85 females and 55 males) were examined. They were randomly assigned either to the learning or the performance‐approach goals condition. In each condition, half of the participants received feedback aimed at inducing either high or low self‐efficacy beliefs with regard to the task prior to executing it aloud. Examination of participants' verbal reports, direct observation of some of their behaviours while solving the task, and responses to a retrospective questionnaire allowed the assessment of several indicators of their self‐regulation and performance. As already reported by many studies, self‐efficacy influenced various aspects of participants' self‐regulation and performance. However, contrary to Dweck's hypothesis ( 1986 ), when interaction effects between self‐efficacy and goals were observed, they always involved learning instead of performance‐approach goals. Findings of this study suggest that the nature of the goal might not matter as much as its personal significance or value.     

The influence of horizontal velocity on interlimb symmetry in normal walking

Changes in horizontal velocity (HV) are known to influence many biomechanical characteristics of human locomotion. The purpose of the present study was to investigate this phenomenon with respect to the interlimb symmetry of walking in a normal population. Peak and temporal ground reaction force data from both feet of 20 able-bodied males were collected at each of three relative velocity conditions (slow, normal and fast). These data were analyzed using of a series of 2 x 3 repeated measures ANOVAs, which revealed a high degree of interlimb (bilateral) symmetry across HV conditions despite significant intralimb (unilateral) changes. In contrast to this primary finding were two significant interaction effects for the stance time and peak vertical force at push-off measures respectively. These interactions indicated greater asymmetries at the slow HV condition with a trend toward improved symmetry at higher velocities. Although these results may provide some theoretical insight into the underlying nature of symmetry in gait, their overall magnitude does not seem to invalidate the current widespread use of symmetry assumptions in clinical and research settings today.     

Predicting Child Restraint Device Use: A Comparison of Two Models1

This study's first objective was to apply Ajzen's theory of planned behavior (TPB) in the context of automobile child restraint device use to identify determinants of that behavior. A second objective was to test two specific hypotheses regarding the predictive role of perceived behavioral control: (a) Its inclusion should increase the proportion of variance already explained in intention by the attitudinal and normative components included in the theory of reasoned action; and (b) given the behavior under study, a model in which perception of behavioral control's influence on behavior is entirely mediated by intention, should fit the data. Subjects (N= 590) were parents driving with their 3- to 5-year-old children intercepted while entering or leaving parking lots of different public settings. The behavior of interest, child restraint device use, was rated by two independent observers. A self-report questionnaire assessing all constructs of Ajzen's model was given to the parent, who was instructed to return it by mail. Data were analyzed using LISREL VII. Results showed that perceived behavioral control and, to a lesser extent, attitude, emerged as the main determinants of behavioral intention which was itself predictive of child restraint device use. In addition, both hypotheses regarding the relation between perceived behavioral control on the one hand and intention and behavior, on the other, were supported. Discussion centered first on the mechanism through which perceived behavioral control exerts its influence, and second on the implications of the present results for the theory of reasoned action as well as for the theory of planned behavior.     

Adolescents' expectancies of success,self-evaluations,and attributions about performance on spatial and verbal tasks

The present study examined the expectancies of success, evaluations of performance, and achievement-related attributions that high school students made about verbal and spatial tasks that typically show sex differences. Although no sex differences were found in task performance, boys expected to do better than girls on both the spatial and verbal tasks. After completing the task, the girls continued to evaluate their performance more negatively than did boys on the spatial tasks. On spatial tasks girls also attributed to themselves less ability and saw the tasks as being more difficult than did boys. The results suggest that there are generalized, rather than task-specific, sex differences in achievement expectancies, evaluations, and attributions. These findings are discussed in terms of their implications for sex-related differences in cognitive functioning and subsequent achievement behaviors.The authors gratefully acknowledge support from the Judith Offer Fund and from the Spencer Foundation.     

Neural and behavioural effects of domoic acid, an amnesic shellfish toxin, in the rat.

To examine the neurotoxic effects of domoic acid, an amnesic shellfish toxin, electroencephalographic and behavioural experiments were conducted on 38 rats. Injection of domoic acid (0.5-1.0 mg/kg intravenously, or 0.04-0.08 microgram intraventricularly) caused seizure discharges in the hippocampus, tonic-clonic convulsions, and death within a few days. Convulsions and ensuing death were prevented by diazepam. Animals pretreated with diazepam (5 mg/kg, ip) tolerated intraventricular dose of domoic acid 0.4 microgram, but showed a loss of pyramidal neurons mainly in the CA3, CA4, and a part of CA1 areas of the dorsal hippocampus. Learning of a radial maze task was severely impaired in naive rats after intraventricular injection of domoic acid (and diazepam, ip). In the animals previously trained on the maze task, domoic acid interfered with relearning of the same task. These effects appear similar to those of kainic acid and are analogous to the symptoms observed in humans who ingested mussels tainted with domoic acid.