What wild primates know about resources: opening up the black box

We present the theoretical and practical difficulties of inferring the cognitive processes involved in spatial movement decisions of primates and other animals based on studies of their foraging behavior in the wild. Because the possible cognitive processes involved in foraging are not known a priori for a given species, some observed spatial movements could be consistent with a large number of processes ranging from simple undirected search processes to strategic goal-oriented travel. Two basic approaches can help to reveal the cognitive processes: (1) experiments designed to test specific mechanisms; (2) comparison of observed movements with predicted ones based on models of hypothesized foraging modes (ideally, quantitative ones). We describe how these two approaches have been applied to evidence for spatial knowledge of resources in primates, and for various hypothesized goals of spatial decisions in primates, reviewing what is now established. We conclude with a synthesis emphasizing what kinds of spatial movement data on unmanipulated primate populations in the wild are most useful in deciphering goal-oriented processes from random processes. Basic to all of these is an estimate of the animal’s ability to detect resources during search. Given knowledge of the animal’s detection ability, there are several observable patterns of resource use incompatible with a pure search process. These patterns include increasing movement speed when approaching versus leaving a resource, increasingly directed movement toward more valuable resources, and directed travel to distant resources from many starting locations. Thus, it should be possible to assess and compare spatial cognition across a variety of primate species and thus trace its ecological and evolutionary correlates. This contribution is part of the special issue “A Socioecological Perspective on Primate Cognition” (Cunningham and Janson 2007b)     

Chronic Noise Exposure and Physiological Response: A Prospective Study of Children Living under Environmental Stress

Chronic exposure to aircraft noise elevated psychophysiological stress (resting blood pressure and overnight epinephrine and nonepinephrine) and depressed quality-of-life indicators over a 2-year period among 9- to 11-year-old children. Data collected before and after the inauguration of a major new international airport in noise-impacted and comparison communities show that noise significantly elevates stress among children at ambient levels far below those necessary to produce hearing damage.     

Achieving what cannot be done: coping with the time constants in a dynamic decision task by doing something else

This study examines how people handle the time constants in dynamic decision tasks, using a microworld called NEWFIRE which simulates forest fire fighting. The results showed that the participants did not adapt to the time constants, as shown by the fact that they did not discriminate between fires requiring different number of fire fighting units when varying the number of fire fighting units was a means of compensating for the time constants. If they were allowed to move units before the fire started their performance improved, suggesting that they could compensate for their problems with the time constants by restructuring the task in such a way that they did not need to consider them. It is suggested that such restructuring may well be how people handle dynamic tasks also in other circumstances, and that more effort should be put into studying what people actually do in dynamic tasks, rather than into only assessing whether or not they perform optimally.     

Externalising behaviour from infancy to mid-adolescence: Latent profiles and early predictors

The overall aim of the current study was to identify typical trajectory classes of externalising behaviour, and to identify predictors present already in infancy that discriminate the trajectory classes. 921 children from a community sample were followed over 13 years from the age of 18 months. In a simultaneously estimated model, latent class analyses and multinomial logit regression analyses suggested a five-class solution for developmental patterns of externalising problem behaviours: High stable (18% of the children), High childhood limited (5%), Medium childhood limited (31%), Adolescent onset (30%), and Low stable (16%). Six risk factors measured at 18 months significantly discriminated among the classes. Family stress and maternal age discriminated the High stable class from all the other classes. The results suggest that focusing on enduring problems in the relationship with the partner and partners' health may be important in preventive and early intervention efforts.     

Wild capuchin monkeys anticipate the amount of ripe fruit in natural trees

Tropical forests have a high diversity of tree species which have very low densities and vary across time in their seasons of peak fruiting and maturation rates. As evidence of the ability of primates to track or anticipate changes in fruit production at individual trees, researchers have used the increased speed of primate groups toward more rewarding food patches. We analyzed the speed of approach to natural trees of wild capuchin monkeys under the effect of scramble competition, after excluding any plausible visual, olfactory and auditory cues. We conducted all-day group follows of three habituated capuchin groups at Iguazú National Park, Argentina, collecting data on ranging behavior and patterns of visits to fruit trees in relation with their location and fruit availability. Travel speed varied according to the expected reward at a feeding tree, increasing as rewards increased from low values, but decreasing again at very high values. Also, travel speed varied with time of day, decreasing from the time of first activity as the monkeys became less hungry, and increasing again toward late afternoon. Measures of unripe fruit cover did not explain variation in travel speed at any distance from a focal tree. Our data imply that, after excluding sensory cues, capuchins appear to anticipate time-varying ripe fruit quantity of natural resources, suggesting that they use memory of tree location and anticipation of fruit maturation. We also confirm that speed is a good measure about expectations of resources, as has been shown in previous studies.     

Second language vocabulary level is related to benefits for second language listening comprehension under lower reverberation time conditions

The acoustic qualities of a room can have a deleterious effect on the quality of speech signals. The acoustic measurement of reverberation time (RT) has shown to impact second language (L2) speech comprehension positively when lower due to release from spectral and temporal masking effects as well as top-down processing factors. This auralization experiment investigated the benefits of better L2 vocabulary and executive function (updating) skills during L2 listening comprehension tests under shorter versus longer RT conditions (0.3 and 0.9?s). 57 bilingual university students undertook L2 vocabulary, number updating and L2 listening comprehension tests. After splitting groups into high/low vocabulary and updating groups, a mixed ANOVA was conducted. The high number updating group showed no significant differences or interactions in L2 listening comprehension than the lower number updating group across RT conditions. The high vocabulary group had 22% better L2 listening comprehension than the low vocabulary group in long RT, and 9% better in short RT. A significant benefit in L2 listening comprehension due to release from reverberation was only evident in the high vocabulary group. Results indicate that the benefit of good room acoustics for listening comprehension is greatest for those with better language (vocabulary) ability.     

Multimedia learning trumps retrieval practice in psychology teaching

It is well established that studying with (vs. without) visual illustrations as well as taking tests (vs. restudying) is beneficial for learning, but on which strategy should one put the efforts, or should they be combined for best learning? Eighty‐eight upper secondary school students were given a brief lecture presented verbally (6 classes) or with the aid of a visual illustration (visuoverbal, 6 classes). The information was processed again by taking a memory test or by restudying. Recall and transfer tests were conducted after some few minutes and again after one week. The visuoverbal lecture resulted in better learning than verbal presentation only. A significant study strategy by retention interval interaction was found. However, this interaction was not qualified by a testing effect. Hence, taking tests (retrieval practice) did not lead to better learning than restudying. It was concluded that it is worthwhile to use visual illustrations in teaching. However, the present study did not reveal any synergistic effects from the combination of visuoverbal presentation and retrieval practice.     

Persistent effects of subliminal stimulation: sex differences and the effectiveness of debriefing

Persistent and non-trivial effects of unconscious stimuli have been reported (Sohlberg & Birgegard, 2003). This raises the ethical question of whether informing participants about such stimuli effectively returns them to a normal state. Two experiments (sex-mixed, N = 70 and 118) tested two kinds of debriefing to participants following subliminal (tachistoscopic) attachment-related or control stimulation. Measures were the Beck Depression Inventory, Structural Analysis of Social Behavior, and Retrospective Attachment. Results showed persistent effects. Simple debriefing about the stimulus was effective in preventing these, while more elaborate debriefing also describing the effects and mechanisms for them was less effective. Persistent effects were also strongly related to participant sex, but debriefing effects were similar in men and women with regard to the purpose of debriefing. The findings have implications for ethical recommendations for subliminal research, and suggest that this unexplored area requires more attention.