Color naming, lens aging, and grue: what the optics of the aging eye can teach us about color language

Many languages without separate terms for green and blue are or were spoken in locations receiving above-average exposure to ultraviolet-B (UV-B) radiation. It has been proposed that this correlation is caused by premature lens aging. This conclusion was supported by an experiment in which younger observers used the term "blue" less often when they described simulated paint chips filtered through the equivalent of an older observer's lens-removing much short-wavelength light-than when they described the unfiltered versions of the same paint chips. Some stimuli that were called "blue" without simulated aging were called "green" when filtered. However, in the experiment reported here, we found that the proportion of "blue" color-name responses did not differ between younger subjects and older observers with known ocular media optical densities. Color naming for stimuli that were nominally green, blue-green, or blue was virtually identical for older and younger observers who viewed the same (unfiltered) stimuli. Our results are inconsistent with the lens-brunescence hypothesis.     

Comparing Knowledge of β-Thalassemia in Samples of Italians,Italian-Americans,and Non-Italian-Americans

The purpose of this study was to determine the level of β-thalassemia awareness among Italians living on the eastern side of Sicily (Bronte, Catania, and Tortorici, Messina), Italian-Americans, and Americans of other ethnic backgrounds (Other-Americans). A questionnaire was developed which asked respondents knowledge questions about both β-thalassemia and Down Syndrome. Five hundred questionnaires were distributed, and 456 were ultimately returned and analyzed (150 Italians, 156 Italian-Americans, 150 Other-Americans). Italians answered an average of 55% of the β-thalassemia correctly compared to scores of 17 and 24% for the Italian-Americans and Other-Americans, respectively. The groups did not differ in their knowledge of Down Syndrome (all answered between 58 and 60% of the questions correctly on average). Over 80% of the Italian respondents had heard of β-thalassemia compared to only 19% of the Italian-Americans. β-Thalassemia education programs in Italy appear to have dramatically increased awareness of the disorder. Similar programs need to be developed for at-risk populations in the United States.     

Experiencing nearby locations together in time: the role of spatiotemporal contiguity in children's memory for location

Three studies investigated how experiencing nearby locations together in time influences memory for location. Seven-, 9-, and 11-year-old children and adults learned 20 object locations in a small-scale space. The space was divided into regions by lines or walls. In Study 1, participants learned the locations either region by region or in a random order. Following learning, participants replaced the objects without the aid of the dots marking the locations and the boundaries subdividing the space. They replaced the objects in any order they chose. After experiencing the locations in random orders during learning, only adults underestimated distances between locations belonging to the same group (i.e., region). Conversely, 9- and 11-year-old children and adults who had experienced the locations region by region during learning underestimated these distances. These findings suggest that experiencing nearby locations together in time increases the weight children assign to categorical information in their estimates of location. Results from Studies 2 and 3 in which participants learned the locations region by region and then replaced the objects region by region (Study 2) or in a random order (Study 3) were similar, highlighting the importance of spatiotemporal cues in memory for location. (c) 2002 Elsevier Science (USA).     

Color-based motion processing is stronger in infants than in adults

One hallmark of vision in adults is the dichotomy between color and motion processing. Specifically, areas of the brain that encode an object's direction of motion are thought to receive little information about object color. We investigated the development of this dichotomy by conducting psychophysical experiments with human subjects (2-, 3-, and 4-month-olds and adults), using a novel red-green stimulus that isolates color-based input to motion processing. When performance on this red-green motion stimulus was quantified with respect to performance on a luminance (yellow-black) standard, we found stronger color-based motion processing in infants than in adults. These results suggest that color input to motion areas is greater early in life, and that motion areas then specialize to the adultlike state by reweighting or selectively pruning their inputs over the course of development.     

Reasoning counterfactually: Combining and rending

Counterfactual reasoning occurs when people are asked to assume for the sake of argument that a fact they previously thought was true is now false and to draw a conclusion on that basis. To accomplish this sort of reasoning requires a revising of one's beliefs, which was simulated in the present study. Students were shown a set of statements that they were to assure themselves was consistent. They were then asked to accept a counterfactual assumption as true and reconcile resulting inconsistencies among the set of statements. In these problems, one statement is a generality (e.g., All trees on the plaza are elms), another is a particular (e.g., This tree is a pine), and one is a counterfactual (e.g., Assume this tree is on the plaza). Students preferred to reconcile the inconsistency by identifying the generality as "true" and the particular as "false." They did this more often when the assumption combined categories than when it dislodged categories and when real beliefs were at stake rather than arbitrary generalities. This study tested current models of inference for their ability to account for counterfactual reasoning and found the results to be consistent with natural deduction system, mental models, and conceptual-integration network approaches to everyday reasoning.     

Effect of localized muscle fatigue on vertical ground reaction forces and ankle joint motion during running

The purpose of this study was to examine the changes in the vertical ground reaction force (VGRF) and ankle joint motion during the first 50% of the stance phase of running following fatiguing exercise of either the dorsiflexors or the invertors of the foot. VGRFs, sagittal and rearfoot kinematic data were collected from 11 female recreational runners running at 2.9 m/second on a treadmill prior to and following localized muscle fatigue of either the invertors or dorsiflexors of the right foot. Loading rate of the impact peak force significantly increased following fatiguing exercise of the dorsiflexors, while the peak magnitudes of the impact and push-off forces remained unchanged. There were significant decreases in dorsiflexion at heel contact, but no significant difference in any rearfoot motion parameters tested following dorsiflexor fatigue. Following fatiguing exercise of the invertors, impact peak magnitude, push-off peak magnitude and the rate of decline of the impact peak force significantly decreased; there was no change in the loading rate of the impact peak force. Invertor fatigue also resulted in a less inverted foot position at heel contact, but there were no significant differences in any other kinematic parameters tested. The results demonstrate that localized muscle fatigue of either the invertors or dorsiflexors can have a significant effect on the loading rates, peak magnitudes and ankle joint motion seen during running. These changes, due to localized muscle fatigue, may play a role in many common lower extremity running injuries.     

Time is of the essence

Timing is essential to human behaviour, but the neural mechanisms underlying time perception are still unclear. New findings from a brain-imaging study by Coull et al. show that activity in a network of motor-related areas varies parametrically with attention to time. Given that a system in which timing is important (but not the primary function) is recruited when temporal judgements are required, we should perhaps reassess the notion of a dedicated timing system in the brain.     

An experimental investigation of daytime monitoring for sleep-related threat in primary insomnia

An experimental manipulation was conducted to test the hypothesis that monitoring for sleep-related threat during the day triggers a cycle of cognitive processes that includes increased negative thinking, increased use of safety behaviours, increased perceived impairment in functioning, and increased self-reported sleepiness. Forty-seven individuals with primary insomnia were randomly assigned to a monitoring group (instructed to monitor their body sensations), a no-monitoring group (instructed to distract from their body sensations), or a no-instruction group. The manipulations to monitor or not monitor were administered immediately on waking and participants were asked to continue the manipulation throughout the experimental day. The monitoring group reported more negative thoughts, the use of more safety behaviours, and more sleepiness during the day relative to the no-instruction group. These findings offer support to a recent cognitive model, which identifies daytime monitoring for sleep-related threat as a key factor in the maintenance of the daytime distress and difficulty functioning in chronic insomnia.