Illusory causal crescents: misperceived spatial relations due to perceived causality

When an object A moves toward an object B until they are adjacent, at which point A stops and B starts moving, we often see a collision--ie we see A as the cause of B's motion. The spatiotemporal parameters which mediate the perception of causality have been explored in many studies, but this work is seldom related to other aspects of perception. Here we report a novel illusion, wherein the perception of causality affects the perceived spatial relations among two objects involved in a collision event: observers systematically underestimate the amount of overlap between two items in an event which is seen as a causal collision. This occurs even when the causal nature of the event is induced by a surrounding context, such that estimates of the amount of overlap in the very same event are much improved when the event is displayed in isolation, without a 'causal' interpretation. This illusion implies that the perception of causality does not proceed completely independently of other visual processes, but can affect the perception of other spatial properties.     

Seeing the Fisher<Emphasis Type="Italic">Z</Emphasis>-transformation

Since 1915, statisticians have been applying Fisher'sZ-transformation to Pearson product-moment correlation coefficients. We offer new geometric interpretations of this transformation.     

Long-term memory survives nerve injury and the subsequent regeneration process

A three-neuron network (a central pattern generator [CPG]) is both sufficient and necessary to generate aerial respiratory behavior in the pond snail, Lymnaea stagnalis. Aerial respiratory behavior is abolished following a specific nerve crush that results in axotomy to one of the three CPG neurons, RPeD1. Functional regeneration of the crushed neurite occurs within 10 days, allowing aerial respiratory behavior to be restored. Functional regeneration does not occur if the connective is cut rather than crushed. In unaxotomized snails, aerial respiratory behavior can be operantly conditioned, and following memory consolidation, long-term memory (LTM) persists for at least 2 weeks. We used the Lymnaea model system to determine (1) If in naive animals axotomy and the subsequent regeneration result in a nervous system that is competent to mediate associative learning and LTM, and (2) if LTM survives RPeD1 axotomy and the subsequent regenerative process. We show here that (1) A regenerated nervous system is competent to mediate associative memory and LTM, and (2) LTM survives axotomy and the subsequent regenerative process.     

Landmark-based spatial search in honeybees. I.

Honeybees were trained to find sugar water in the middle of an array of two landmarks of different colours. Unrewarded tests compared searching on the training array with searching on rotated arrays. On rotated tests, a system using the angles between landmarks would continue to search in the middle. A system using vectors to individual elements would search at locations outside the rotated array at which the distances and compass directions to a subset of landmarks matched. Results indicated that bees used both elements and interlandmark angles, but they relied most on one favourite landmark element. Results support the template model of landmark use in honeybees, with the minor parametric modification that weights given to different elements may be unequal. Received:6 July 1998 / Accepted after revision:7 December 1998     

Children’s Acceptance of Others with Disability: The Influence of a Disability-Simulation Program

Elementary school is a transitional and impressionable period for any child. In inclusive classroom settings, children with disabilities may experience the challenges of acceptance and integration into peer relationships. The experience of children with disabilities in such classrooms can be positive if their classmates are accepting and open. One way to encourage these attitudes is by increasing awareness through disability-simulation. This study evaluates an existing school program, whose goal is to increase acceptance of others with disability. We surveyed students to assess the influence of the program. An adapted acceptance scale was distributed to students before and after participation in the program. Our hypothesis was that student acceptance would increase after participating in the program. Additionally, we hypothesized that physical, visual, and auditory disabilities would be easier for students to understand, making acceptance scores for these disabilities higher than those for a learning disability. We report changes in acceptance using group means. Our results reveal that post-survey responses showed higher acceptance than pre-survey responses, especially for auditory disabilities. Other significant findings include differences in attitudes between the two schools and differences based on prior experience with someone with a disability. By evaluating the effectiveness of this type of program (whose efficacy has been controversial in the literature), this study can provide teachers, administrators, genetic counselors, and parents with a better idea of how to address children’s attitudes towards peers. In our study, the effectiveness of promoting understanding through disability-simulation has proven its worth to improve children’s acceptance.     

Racial and Ethnic Differences in Direct-to-Consumer Genetic Tests Awareness in HINTS 2007: Sociodemographic and Numeracy Correlates

To examine the association of 1) race/ethnicity and 2) numeracy with awareness of DTC genetic tests. Secondary analysis of 6,754 Hispanic, black, and white adult respondents to the National Cancer Institute’s 2007 Health Information National Trends Survey (HINTS). Logistic regression was used to examine sociodemographic predictors of DTC genetic tests awareness including race/ethnicity, income, education, and gender. Next, two numeracy variables were added to the model. After controlling for sociodemographic variables, black respondents were significantly less likely to have heard of DTC genetic tests compared to white respondents (OR = 0.79; CI: 0.65–0.97). When numeracy variables were added to the model, the effect of black race was no longer significant (OR = 0.84; CI: 0.69–1.04). Hispanic respondents did not significantly differ from white respondents in awareness of DTC genetic tests. Other significant correlates of DTC genetic tests awareness in the full model included education, income, age, and numeracy variables including degree to which people use medical statistics and numbers to make health decisions, and preference for words or numbers when discussing “the chance of something happening.” Although black respondents were generally less aware of DTC genetic tests than white respondents, this relationship appears to be partially mediated by numeracy.     

Differences in neuronal activity explain differences in memory forming abilities of different populations of Lymnaea stagnalis

The ability to learn and form long-term memory (LTM) can enhance an animal's fitness, for example, by allowing them to remember predators, food sources or conspecific interactions. Here we use the pond snail, Lymnaea stagnalis, to assess whether variability between natural populations (i.e., strains) in memory forming capabilities correlates with electrophysiological properties at the level of a single neuron, RPeD1. RPeD1 is a necessary site of LTM formation of aerial respiratory behaviour following operant conditioning. We used strains from two small, separate permanent ponds (TC1 and TC2). A comparison of the two populations showed that the TC1 strain had enhanced memory forming capabilities. Further, the behavioural phenotype of enhanced memory strain was explained, in part, by differences in the electrophysiology of RPeD1. Compared to RPeD1 from the naive TC2 strain, RPeD1 from the TC1 strain has both a decreased resistance and decreased excitability. Moreover, 24h after a single 0.5h training session, those membrane properties, as well as the firing and bursting rate, decrease further in the TC1 strain but not in the TC2 strain. The initial differences in RPeD1 properties in the TC1 strain coupled with their ability to further change these properties with a single training session suggests that RPeD1 neurons from the TC1 strain are "primed" to rapidly form memory.     

Assuming too much from 'familiar' brain potentials

Familiarity is sometimes associated with midfrontal old/new (FN400) signals, but investigators assume too much by inferring familiarity whenever they identify these signals. We describe how Rosburg and colleagues (2011) made this assumption, yielding potentially faulty conclusions about the recognition heuristic. We provide an alternative interpretation emphasizing implicit processing that can underlie decision-making.     

Alternate behavioural measurements following a single operant training regime demonstrate differences in memory retention

Frequently studies of learning and memory measure a single focal behaviour; however it is likely that any learning paradigm will alter multiple behavioural traits in the same animal. We used video footage of the great pond snail (Lymnaea stagnalis), collected immediately prior to both training and testing for memory in response to operant conditioning to reduce aerial respiration, to measure two additional alternate behavioural traits: reducing the size of the pneumostome (breathing orifice) opening and shell tilt to cover the pneumostome. Typically, the training regime used here results in memory to reduce the number of breathing attempts lasting 24?h but not 72?h. However, memory duration when measured using the two additional behavioural traits differed significantly; shell tilt was short-lived lasting less than 1?h following training, whereas the reduction in pneumostome size was still apparent 72?h following training. Therefore, conclusions about the ability of L. stagnalis to retain memory in response to a single type of training regime will differ significantly depending on the focal behavioural trait measured. A significant correlation between the reduction in opening attempts and visible pneumostome area indicated that these behavioural traits are co-specialised, whereas pneumostome opening and shell tilt behaviour varied independently.