Three-dimensional spatial representation in freely swimming fish

Research on spatial cognition has focused on how animals encode the horizontal component of space. However, most animals travel vertically within their environments, particularly those that fly or swim. Pelagic fish move with six degrees of freedom and must integrate these components to navigate accurately--how do they do this? Using an assay based on associative learning of the vertical and horizontal components of space within a rotating Y-maze, we found that fish (Astyanax fasciatus) learned and remembered information from both horizontal and vertical axes when they were presented either separately or as an integrated three-dimensional unit. When information from the two components conflicted, the fish used the previously learned vertical information in preference to the horizontal. This not only demonstrates that the horizontal and vertical components are stored separately in the fishes' representation of space (simplifying the problem of 3D navigation), but also suggests that the vertical axis contains particularly salient spatial cues--presumably including hydrostatic pressure. To explore this latter possibility, we developed a physical theoretical model that shows how fish could determine their absolute depth using pressure. We next considered full volumetric spatial cognition. Astyanax were trained to swim towards a reward in a Y-maze that could be rotated, before the arms were removed during probe trials. The subjects were tracked in three dimensions as they swam freely through the surrounding cubic tank. The results revealed that fish are able to accurately encode metric information in a volume, and that the error accrued in the horizontal and vertical axes whilst swimming in probe trials was similar. Together, these experiments demonstrate that unlike in surface-bound rats, the vertical component of the representation of space is vitally important to fishes. We hypothesise that the representation of space in the brain of vertebrates could ultimately be shaped by the number of the degrees of freedom of movement that binds the navigating animal.     

When up-words meet down-sentences: evidence for word- or sentence-based compatibility effects?

Participants were presented with sentences mentioning an entity with a typical location in the upper or lower vertical space (e.g., roof vs. root). Sentences supported or reversed the typical location of the target entity. Sensibility judgments requiring upwards or downwards responses were faster when the response matched rather than mismatched the target entity's typical location. This compatibility effect was independent of whether the sentence context supported or reversed the target entity's typical location. The results, therefore, provide clear evidence for word-based but no evidence for sentence-based simulation processes.     

Additional weight influences the reaching behavior of low-risk preterm infants

The authors investigated the influence of additional weight in the reaching behavior of preterm infants. Nine low-risk preterm and 10 full-term infants age 5-7 months participated. A toy was presented in two procedures: (a) baseline and (b) additional weight (bracelet with weight of 20% of the infant's upper limb mass). The additional weight reduced the straightness index at 5 months, increased the mean velocity and decreased the movement units at all months, and increased unsuccessful grasps at 5 and 7 months in preterm infants. Preterm infants showed less movement units at all months and less unsuccessful grasps at 6 months compared with full-term infants. Weight disturbance seems to change the intrinsic dynamics involved in reaching movements of 5-7-month-old preterm infants.     

The interaction of temporal generalization gradients predicts the context effect

In a temporal double bisection task, animals learn two discriminations. In the presence of Red and Green keys, responses to Red are reinforced after 1-s samples and responses to Green are reinforced after 4-s samples; in the presence of Blue and Yellow keys, responses to Blue are reinforced after 4-s samples and responses to Yellow are reinforced after 16-s samples. Subsequently, given a choice between Green and Blue, the probability of choosing Green increases with the sample duration-the context effect. In the present study we asked whether this effect could be predicted from the stimulus generalization gradients induced by the two basic discriminations. Six pigeons learned to peck Green following 4-s samples (S(+)) but not following 1-s samples (S(-)) and to peck Red following 4-s samples (S(+)) but not following 16-s samples (S(-)). Temporal generalization gradients for Green and Red were then obtained. Finally, the pigeons were given a choice between Green and Red following sample durations ranging from 1 to 16 s. Results showed that a) the two generalization gradients had the minimum at the S(-) duration, an intermediate value between the S(-) and the S(+) durations, and the maximum at the S(+) as well as more extreme durations; b) on choice trials, preference for Green over Red increased with sample duration, the context effect; and c) the two generalization gradients predicted the average context effect well. The Learning-to-Time model accounts for the major trends in the data.     

License to sin: Self‐licensing as a mechanism underlying hedonic consumption

Hedonic overconsumption is often considered to be caused by impulsive factors. The current paper investigates whether self‐licensing, relying on reasons to justify subsequent gratification, can also be included as a significant contributor to hedonic consumption. Two studies were conducted to investigate whether self‐licensing can account for an increase in hedonic consumption while ruling out impulsive factors such as resource depletion, negative affect, and visceral state as alternative explanations. A pilot study indicated that perceiving oneself as having invested greater effort and thus having a self‐licensing cue did not lead to a decline in self‐control capacity compared with not having a self‐licensing cue. The main study employed the same procedure and established that having a licensing cue did lead to increased snack intake while controlling for impulsive factors. Together, these studies support the notion that self‐licensing is a separate mechanism leading to hedonic gratification independent of impulsive factors. Copyright © 2011 John Wiley & Sons, Ltd.     

Intrinsic religiosity reduces intergroup hostility under mortality salience

Results of three studies indicate that intrinsic religiosity and mortality salience interact to predict intergroup hostility. Study 1, conducted among 200 American Christians and Jews, reveals that under mortality salience, intrinsic (but not extrinsic or quest) religiosity is related to decreased support for aggressive counterterrorism. Study 2, conducted among 148 Muslims in Iran, demonstrates that intrinsic religiosity predicts decreased out‐group derogation under mortality salience. Study 3, conducted among 131 Polish Christians, shows that under mortality salience, priming of intrinsic religious concepts decreases support for aggressive counterterrorism. Copyright © 2012 John Wiley & Sons, Ltd.     

Are the pathogens of out-groups really more dangerous?

We question the plausibility of Fincher & Thornhill's (F&T's) argument that localised pathogen-host coevolution leads to out-groups having pathogens more damaging than those infecting one's own family or religious group.     

Arm adductor with arm abduction in rotator cuff tear patients vs. healthy--design of a new measuring instrument

The incidence of (a)symptomatic rotator cuff tears is high, but etiologic mechanisms are unclear and treatment outcomes vary. A practical tool providing objective outcome measures and insight into etiology and potential patient subgroups is desirable. Symptomatic cuff tears coincide with humerus cranialization. Adductor co-activation during active arm abduction has been reported to reduce subacromial narrowing and pain in cuff patients. We present an easy-to-use method to evaluate adductor co-activation. Twenty healthy controls and twenty full-thickness cuff tear patients exerted EMG-recorded isometric arm abduction and adduction tasks. Ab- and adductor EMG's were expressed using the "Activation Ratio (AR)" (-1 ≤ AR ≤ 1), where lower values express more co-activation. Mean control AR's ranged from .7 to .9 with moderate to good test-retest reliability (ICC: .60-.74). Patients showed significantly more adductor co-activation during abduction, with adductor AR's ranging between .3 (teres major) and .5 (latissimus dorsi). In conclusion, the introduced method discriminates symptomatic cuff tear patients from healthy controls, quantifies adductor co-activation in an interpretable measure, and provides the opportunity to study correlations between muscle activation and humerus cranialization in a straightforward manner. It has potential as an objective outcome measure, for distinguishing symptomatic from asymptomatic cuff tears and as a tool for surgical or therapeutic decision-making.     

Identity construction and career development interventions with emerging adults

Today's wealthy societies are more fluid, varied and complex than they were just a few decades ago. As a consequence, what were “vocational choices” at the beginning of the 20th century now appear as “life designing issues”. In this context, contemporary research stresses the plurality and relative malleability of human subjects as well as their ability to take reflexive stances on their current and past experiences. Fitting in such an epistemology, a self-constructing model is proposed as a basis for a life designing counseling interview. This model describes self-identity as a dynamic system of (past, present and expected) subjective identity forms (SIF), the synthesis and dynamism of which originate in a tension between two kinds of reflexivity. Counseling interviews with emerging adults show that the elicitation of some expected SIF allows them to re-read their current and past experiences from such a perspective and constitutes a compelling incentive to act.