Motion by nearby players biases perception but not action in judgments of baseball destination

In this research, the influence of irrelevant reference frames on estimates of ball destination was examined. In 3 experiments, confederate base runners and fielders served as distractor stimuli while balls were rolled from home plate to random locations along a barrier hidden under an elevated tarp between first and second base. Stationary participants estimated the position that the ball would exit from under the tarp if there were no barrier, whereas running participants ran along the back edge of the barrier and touched the top of the tarp above where they believed the ball would exit. Estimates of ball destination were significantly biased in the direction opposite to the confederates' motion for stationary participants, but were accurate for running participants. These findings are consistent with other perception-action dissociations, and show that relative motion effects can occur in a naturalistic setting.     

Potentiation, overshadowing, and blocking of spatial learning based on the shape of the environment

Rats were trained in Experiment 1 to find a submerged platform in 1 corner of either a rectangular or a kite-shaped pool. When the walls creating this corner were a different color than the opposite walls, then learning about the shape of the pool was potentiated in the kite but not in the rectangle. Experiments 2-4 revealed that learning about the rectangle can be overshadowed and blocked when information about the wall color indicates the location of the platform. The results mimic findings that have been obtained with Pavlovian conditioning, and they challenge the claim that learning about the shape of the environment takes places in a dedicated geometric module.     

Spatial learning based on the shape of the environment is influenced by properties of the objects forming the shape

In 3 experiments rats had to find a submerged platform that was located in a corner of a kite-shaped pool. The color of the walls creating this corner provided an additional cue for finding the platform in the shape + color condition but not the shape-only condition. During tests in a pool with walls of a uniform color but no platform, more time was spent in the corner where the platform was originally located after training in the shape + color than in the shape-only condition. The results challenge theories that assume either that learning about the shape of the environment takes place in a dedicated module or that cues compete for the control they acquire over behavior.     

Adolescents' energy cost in marching band

The primary purpose of this study was to examine adolescents' energy cost in a marching band. High school marching band participants (N=15) completed five 3-min. stages of treadmill marching, using a 57.2-cm stride length (typical standard of eight steps per five yards) as follows: without instruments at 75 m x min.(-1) and 132 steps x min.(-1) (Stage 1): without instruments at 91 m x min.(-1) and 160 steps x min.(-1) (Stage 2); carrying instruments at 75 m x min.(-1) and 132 steps x min.(-1) (Stage 3); carrying instruments at 91 m x min.(-1) and 160 steps x min.(-1) (Stage 4); and playing instruments at 75 m x min.(-1) and 132 steps x min.(-1) (Stage 5). Mean heart-rate response to an actual parade performance was similar to the mean Stage 5 treadmill heart rate (n=6). With regard to a high school marching band, these results suggest that energy demand for marching cadences approximates 4.5 and 6.0 metabolic equivalents for moderate and fast paces, respectively.     

Frankensteins and cyborgs: visions of the global future in an age of technology

This paper draws attention to the role of representation in the depiction of scientific and technological innovation as a means of understanding the narratives that circulate concerning the shape of things to come. It considers how metaphors play an important part in the conduct of scientific explanation, and how they do more than describe the world in helping also to shape expectations, normalise particular choices, establish priorities and create needs. In surveying the range of metaphorical responses to the digital and biotechnological age, we will see how technologies are regarded both as 'endangerment' and 'promise.' What we believe 'technology' is doing to 'us' reflects important implicit philosophies of technology and its relationship to human agency and political choice; yet we also need to be alert to the assumptions about 'human nature' itself which inform such reactions. The paper argues that embedded in the various representations implicit in the new technologies are crucial issues of identity, community and justice: what it means to be (post)human, who is (and who is not) entitled to the rewards of technological advancement, what priorities (and whose interests) will inform the shape of global humanity into the next century.     

Observing a fictitious stressful event: haematological changes,including circulating leukocyte activation

The aim of this study was to assess the effect of watching a psychological stressful event on the activation of leukocytes in healthy human volunteers. Blood samples were obtained from 32 healthy male and female subjects aged between 20 and 26 years before, during and after either watching an 83-minute horror film that none of the subjects had previously seen (The Texas Chainsaw Massacre, 1974) or by sitting quietly in a room (control group). Total differential cell counts, leukocyte activation as measured by the nitroblue tetrazolium (NBT) test, heart rate and blood pressure (BP) measurements were taken at defined time points. There were significant increases in peripheral circulating leukocytes, the number of activated circulating leukocytes, haemoglobin (Hb) concentration and haematocrit (Hct) in response to the stressor. These were accompanied by significant increases in heart rate, systolic and diastolic BP (P<0.05 from baseline). This is the first reported study on the effects of observing a psychologically stressful, albeit fictitious event on circulating leukocyte numbers and the state of leukocyte activation as determined by the nitrotetrazolium test.     

A Meta-Analysis of Structural and Functional Brain Imaging in Dementia of the Alzheimer's Type: A Neuroimaging Profile

We conducted a quantitative review of the imaging literature using meta-analytic methodology to characterize further the magnitude of hippocampal deficit in probable Alzheimer's disease (AD) and to determine whether other neuroanatomic structures in AD can better discriminate the disease from normal aging. Additionally, we parceled the discriminability of neuroanatomic structures by duration of disease to determine those structures most sensitive to AD in its early and late stages. One hundred twenty-one studies published between 1984 and 2000 met criteria for inclusion in the present analysis. In total, structural (i.e., CT and MRI) and functional (i.e., SPECT and PET) neuroimaging results from 3511 patients with AD, and 1632 normal healthy controls were recorded across meta-analyses. Our results include neuroimaging profiles for both early onset and longer duration patients with AD. In sum, these profiles yield a signature of diagnostic markers in both cortical and subcortical neuroanatomic areas. This signature is consistent with the clinical phenomenology of Alzheimer's dementia and should aid in the positive identification of AD.     

Measuring the speed of the conscious components of recognition memory: remembering is faster than knowing

Three experiments investigated response times (RTs) for remember and know responses in recognition memory. RTs to remember responses were faster than RTs to know responses, regardless of whether the remember-know decision was preceded by an old/new decision (two-step procedure) or was made without a preceding old/new decision (one-step procedure). The finding of faster RTs for R responses was also found when remember-know decisions were made retrospectively. These findings are inconsistent with dual-process models of recognition memory, which predict that recollection is slower and more effortful than familiarity. Word frequency did not influence RTs, but remember responses were faster for words than for nonwords. We argue that the difference in RTs to remember and know responses reflects the time taken to make old/new decisions on the basis of the type of information activated at test.     

Cognitions and depressive symptoms among ethnic minority adolescents

Cognitive models have guided effective intervention strategies in the treatment of depression. However, little is known about the cognitive model's relevance in different cultural ethnic groups in the United States. This study examines the cross-sectional and longitudinal associations among cognitive variables and depressive symptoms among African American, Caucasian, and Hispanic adolescents in the United States. Community adolescents (N = 450) ages 14-18 years (African American n = 79; Caucasian n = 273; Hispanic n = 98) provided information regarding their depressive symptoms and cognitions at two surveys, 6 months apart. Self-efficacy, cognitive errors, and hopelessness were associated with concurrent depressive symptoms at baseline. In addition, cognitive errors at baseline, controlling for baseline depressive symptoms and the occurrence of stressful events, predicted depressive symptoms at follow-up. Ethnic differences disappeared when parent education level was controlled. Our findings demonstrate support for the cognitive model of depression across ethnic groups. The importance of controlling for social class when examining ethnic differences in psychological variables is highlighted by our findings.     

It looks easy! Heuristics for combinatorial optimization problems

Human performance on instances of computationally intractable optimization problems, such as the travelling salesperson problem (TSP), can be excellent. We have proposed a boundary-following heuristic to account for this finding. We report three experiments with TSPs where the capacity to employ this heuristic was varied. In Experiment 1, participants free to use the heuristic produced solutions significantly closer to optimal than did those prevented from doing so. Experiments 2 and 3 together replicated this finding in larger problems and demonstrated that a potential confound had no effect. In all three experiments, performance was closely matched by a boundary-following model. The results implicate global rather than purely local processes. Humans may have access to simple, perceptually based, heuristics that are suited to some combinatorial optimization tasks.