Does social environment influence learning ability in a family-living lizard?

Early developmental environment can have profound effects on individual physiology, behaviour, and learning. In birds and mammals, social isolation during development is known to negatively affect learning ability; yet in other taxa, like reptiles, the effect of social isolation during development on learning ability is unknown. We investigated how social environment affects learning ability in the family-living tree skink (Egernia striolata). We hypothesized that early social environment shapes cognitive development in skinks and predicted that skinks raised in social isolation would have reduced learning ability compared to skinks raised socially. Offspring were separated at birth into two rearing treatments: (1) raised alone or (2) in a pair. After 1 year, we quantified spatial learning ability of skinks in these rearing treatments (N = 14 solitary, 14 social). We found no effect of rearing treatment on learning ability. The number of skinks to successfully learn the task, the number of trials taken to learn the task, the latency to perform the task, and the number of errors in each trial did not differ between isolated and socially reared skinks. Our results were unexpected, yet the facultative nature of this species’ social system may result in a reduced effect of social isolation on behaviour when compared to species with obligate sociality. Overall, our findings do not provide evidence that social environment affects development of spatial learning ability in this family-living lizard.     

Surrogates and Empty Intentions: Husserl’s “On the Logic of Signs” as the Blueprint for his First Logical Investigation

This paper accomplishes two tasks. First, I examine in detail Edmund Husserl’s earliest philosophy of surrogates, as it is found in his 1890 “On the Logic of Signs (Semiotic)”. I analyze his psychological and logical investigations of surrogates, where the former is concerned with explaining how these signs function and the latter with how they do so reliably. His differentiation of surrogates on the basis of their genetic origins and degrees of necessity is discussed. Second, the historical importance of this text is disclosed by showing how Semiotic serves as both the inspiration for, and the foil to, Husserl’s 1901 First Logical Investigation. Husserl not only adopts the idea that linguistic signs can function via association, but also maintains that such signs can motivate me to execute one of two experiences. The key difference between the texts is that Husserl abandons his theory of surrogates in 1901, instead holding that I can experience absent objects by means of empty intentions. The reasons why Husserl found it necessary to transform this tenet of his philosophy are discussed at length.     

Overconcern with weight and shape is not the same as body dissatisfaction: evidence from a prospective study of pre-adolescent boys and girls

Overconcern with weight and shape and body dissatisfaction have both emerged as significant predictors of disordered eating. However, it is unclear how these constructs relate to each other, and if each has different antecedents and consequences. This study aimed to identify prospective predictors of each construct and to determine their relative importance in predicting dietary restraint and binge eating. Eight- to 13-year-old boys and girls (N = 259) were assessed at baseline and one-year follow-up, using a range of measures that included the Child Eating Disorder Examination. Psychosocial variables predicted overconcern with weight and shape whilst objective weight predicted body dissatisfaction. Body dissatisfaction and weight and shape concern predicted restraint, and weight and shape concern and restraint predicted binge eating. Findings provide support for the theoretical differences between body dissatisfaction and overconcern with weight and shape, and highlight the importance of focusing on specific body image variables.     

Different Media for Organizational Communication: Perceptions of Quality and Satisfaction

We examined the satisfaction in and perceived quality of information about one’s job, business unit, and company, as well as perceived quality of urgent news (i.e., news about changes in business and generally considered legally sensitive material), communicated via different media. Results from 598 fulltime employees revealed that rich media (e.g., face-to-face) was most related to satisfaction in information about one’s job and business unit and in perceived quality of information from the supervisor; lean media (e.g., company newsletter) was most related to satisfaction in and quality of information from top management, while moderate media (e.g., e-mail) was only significantly related to perceived quality of urgent news. Trust in top management was positively related to satisfaction in and quality of information shared by management. Lean media most strongly related to quality of urgent news, over and above rich communication.The authors would like to thank Monica Moloney for her support on this project.     

Why opening a door is as easy as eating an apple: A reply to Thompson-Schill and Botvinick (2006)

Martin and Cheng (2006) present evidence suggesting that difficulty in verb generation is related to the strength of associative links between nouns and verbs and not to competition from alternative verb responses. Specifically, they show that latencies for verb generation are related to the associative strength of the most frequently produced verb and not to the ratio of the strength of the first to the second most frequently produced verb. Thompson-Schill and Botvinick (2006) have provided modeling results indicating how the findings of Martin and Cheng might be accommodated in a competitive model. Here we discuss how two noncompetitive models account for the findings and why such models should be preferred.     

Influences of grasp selection in typically developing children

When reaching towards an object, adults favour grasps which, following the intended action, end in a comfortable position even when this requires them to start in an uncomfortable position (the end-state-comfort effect). However, this strategy is not consistently used by children who instead seem to favour a minimal pre-contact rotation of the hand, even when this results in an uncomfortable end position. In terms of multiple movements, the strategies used for grip selection are unclear; adults may still grasp for end-state-comfort given their propensity to plan to the end of a movement; however, children who are less able to concatenate movement may tend to start-state-comfort movements. The current study considered grip selection in children ranging from 4 to 12 years and in a group of adults. Participants were asked to rotate a disc so that an arrow pointed towards a specific target(s), the number of sequences in a movement was increased from one to three. Planning for end-state-comfort was seen in all participants and a clear developmental trajectory was identified whereby the relative comfort of an end position could be directly predicted by age in months. Adults and 10–12-year-olds favoured an end-state-comfort strategy whereas the younger children gave equal weighting to end-state-comfort, start-state-comfort and no initial rotation strategies. All groups were able to end a movement comfortably when it was composed of three steps; however, the proportion of movements relying on an end-state-comfort strategy decreased as sequence length increase whereas the proportion of start-state-comfort and no initial rotation strategies increased. The current data support the concept that a mechanism for planning grasps may be based on motor experience.     

Soames on Quine and Davidson

A discussion of Quine and Davidson, as interpreted and criticized in Scott Soames’ Philosophical Analysis in the Twentieth Century, Volume II.