Use of slope and feature cues in pigeon (Columba livia) goal-searching behavior

Terrain slope provides a directional frame of reference for reorientation and navigation, similar to cardinal directions. Previous studies have shown that, in a goal location task, slope is a very salient cue and that pigeons tend to rely on it even if it is not the most informative cue. Such a strong dependence on one type of information, when there are more effective predictors of reward, is a key premise for a modular view of information processing. Here we tested the provocative hypothesis of a "slope module" for reorientation in slanted environments. Pigeons had to solve a goal location task using slope or another, theoretically salient cue: a beacon feature. Overall, searching behavior was controlled almost equally by the two cues. The fact that, for the first time, slope failed to capture most of the associative strength allows us to reject a strong modularity view and suggests instead that there is competition between cues based on salience. As an interesting additional finding, the reliance on slope and the feature was affected by training location (uphill vs. downhill), suggesting the possibility of a modulatory role of effort on the cue-weighting mechanism of reorientation.     

A Modeling Study of Potential Sources of Curvature in Human Reaching Movements

The authors of this article suggest that the slight but consistent posture-dependent curvature of the spatial paths in the kinematic transformation between intrinsic and extrinsic coordinates may result in a systematic curvature of movements initially planned as straight-line trajectories toward the target. A kinematic planning model is presented that takes into account the anisotropy of the intrinsic and extrinsic transformation and tends to avoid movements that require excessive joint rotations by introducing slight deviations from a straight-line trajectory. Preliminary simulations showed reasonably good agreement with experimental data, especially considering that the current model is strictly based on kinematics. A quantitative analysis showed that the strategy used in the model achieves a favorable compromise between straight-line movements and angular joint changes: By slightly increasing the spatial length of the movement (i.e., by introducing curvature), an individual can greatly reduce the total amount of joint rotation required to produce the movement.     

Reorienting with terrain slope and landmarks

Orientation (or reorientation) is the first step in navigation, because establishing a spatial frame of reference is essential for a sense of location and heading direction. Recent research on nonhuman animals has revealed that the vertical component of an environment provides an important source of spatial information, in both terrestrial and aquatic settings. Nonetheless, humans show large individual and sex differences in the ability to use terrain slope for reorientation. To understand why some participants—mainly women—exhibit a difficulty with slope, we tested reorientation in a richer environment than had been used previously, including both a tilted floor and a set of distinct objects that could be used as landmarks. This environment allowed for the use of two different strategies for solving the task, one based on directional cues (slope gradient) and one based on positional cues (landmarks). Overall, rather than using both cues, participants tended to focus on just one. Although men and women did not differ significantly in their encoding of or reliance on the two strategies, men showed greater confidence in solving the reorientation task. These facts suggest that one possible cause of the female difficulty with slope might be a generally lower spatial confidence during reorientation.     

Consequence and Interpolation in ?ukasiewicz Logic

Building on Wójcicki??s work on infinite-valued ?ukasiewicz logic ?_??, we give a self-contained proof of the deductive interpolation theorem for ?_??. This paper aims at introducing the reader to the geometry of ?ukasiewicz logic.     

Matching therapeutic interventions to drug and alcohol abusers’ stage of motivation: The clients’ perspective

The present study aims to explore the issue of matching the appropriate therapeutic intervention according to the stage of readiness for change in addictive clients, following the model proposed by Prochaska and DiClemente in the 1980s. The study focuses solely on the perspectives of people with drug and alcohol problems, in contrast to previous ones which have been concerned with the researchers’ understandings and postulations of the issue under exploration. One of the most important findings of this study is that participants in the “early” stages of their readiness to change their addictive behaviour, irrespective of their gender or whether they had seen a therapist significantly prefer non-action-oriented therapeutic interventions than action-oriented interventions. Similarly, participants in the “later” stages, showed a significant preference to action-oriented than non-action interventions, irrespective of their gender or previous experience of counselling. It is suggested then that careful assessment of the stage of motivation and individual-tailored intervention should be an essential element of any treatment program for drug and alcohol addicted clients.     

The ‘If’ in the ‘What If’

In this paper, I defend the view that any good account of the logical form of thought experiments should contain a conditional. Moreover, there are some reasons to think it should be a counterfactual conditional. First, I defend Williamson’s account of the logical form of thought experiments against a competing account offered by Ichikawa and Jarvis. The two accounts have a similar structure, but Williamson’s posits a counterfactual conditional where Ichikawa and Jarvis’ posits a strict conditional. Williamson’s motivation is related to the problem of deviant realizations, and Ichikawa and Jarvis propose to take care of this problem by enriching the content of the thought experiment in the way we enrich the content of a text of fiction. However, this sort of enrichment is also compatible with Williamson’s account. I then consider a different view, defended by Malmgren, on which a complex possibility claim exhausts our reasoning on typical thought experiments. I argue that this account, leaving out a conditional, fails to represent an important part of our reasoning with thought experiments. This is brought out by reflection on the relationship between thought experiments and similar actual cases and by reflection on the requirement, formulated by Malmgren herself, that our reasoning should have an adequate level of generality.

     

Songs as an aid for language acquisition

In previous research, Saffran and colleagues [Saffran, J. R., Aslin, R. N., & Newport, E. L. (1996). Statistical learning by 8-month-old infants. Science, 274, 1926-1928; Saffran, J. R., Newport, E. L., & Aslin, R. N. (1996). Word segmentation: The role of distributional cues. Journal of Memory and Language, 35, 606-621.] have shown that adults and infants can use the statistical properties of syllable sequences to extract words from continuous speech. They also showed that a similar learning mechanism operates with musical stimuli [Saffran, J. R., Johnson, R. E. K., Aslin, N., & Newport, E. L. (1999). Abstract Statistical learning of tone sequences by human infants and adults. Cognition, 70, 27-52.]. In this work we combined linguistic and musical information and we compared language learning based on speech sequences to language learning based on sung sequences. We hypothesized that, compared to speech sequences, a consistent mapping of linguistic and musical information would enhance learning. Results confirmed the hypothesis showing a strong learning facilitation of song compared to speech. Most importantly, the present results show that learning a new language, especially in the first learning phase wherein one needs to segment new words, may largely benefit of the motivational and structuring properties of music in song.     

Lifetime and 12‐Month Nonsuicidal Self‐Injury and Academic Performance in College Freshmen

We examined whether nonsuicidal self‐injury (NSSI) is associated with academic performance in college freshmen, using census‐based web surveys (N = 7,527; response = 65.4%). NSSI was assessed with items from the Self‐Injurious Thoughts and Behaviors Interview and subsequently linked with the administratively recorded academic year percentage (AYP). Freshmen with lifetime and 12‐month NSSI showed a reduction in AYP of 3.4% and 5.9%, respectively. The college environment was found to moderate the effect of 12‐month NSSI, with more strongly reduced AYPs in departments with higher‐than‐average mean departmental AYPs. The findings suggest that overall stress and test anxiety are underlying processes between NSSI membership and academic performance.