Libet-style experiments,neuroscience, and libertarian free will

People have disagreed on the significance of Libet-style experiments for discussions about free will. In what specifically concerns free will in a libertarian sense, some argue that Libet-style experiments pose a threat to its existence by providing support to the claim that decisions are determined by unconscious brain events. Others disagree by claiming that determinism, in a sense that conflicts with libertarian free will, cannot be established by sciences other than fundamental physics. This paper rejects both positions. First, it is argued that neuroscience and psychology could in principle provide support for milder deterministic claims that would also conflict with libertarian free will. Second, it is argued that Libet-style experiments—due to some of their peculiar features, ones that need not be shared by neuroscience as a whole—currently do not (but possibly could) support such less demanding deterministic claims. The general result is that neuroscience and psychology could in principle undermine libertarian free will, but that Libet-style experiments have not done that so far.     

RSVP in orbit: Identification of single and dual targets in motion

Three experiments using rapid serial visual presentation (RSVP) tested participants' ability to detect targets in streams that are in motion. These experiments compared the ability to identify moving versus stationary RSVP targets and examined the attentional blink with pairs of targets that were moving or stationary. One condition presented RSVP streams in the center of the screen; a second condition used an RSVP that was orbiting in a circle, with participants instructed to follow the stream with their eyes; and a third condition had participants fixate in the middle while observing a circling RSVP stream. Relative to performance in stationary RSVP streams, participants were not markedly impaired in detecting single targets in RSVP streams that were moving, either with or without instructions to pursue the motion. In streams with two targets, a normal attentional blink effect was observed when participants were instructed to pursue the moving stream. When participants had to maintain central fixation as the RSVP stream moved, the attentional blink was nearly absent even when a trailing mask was added. We suggest that the reduction of the attentional blink for moving RSVP streams may reflect a reduced ability to perceive the temporal boundaries of the individual items.     

Comparison of force, power, and striking efficiency for a Kung Fu strike performed by novice and experienced practitioners: preliminary analysis

This paper presents a comparison of force, power, and efficiency values calculated from Kung Fu Yau-Man palm strikes, when performed by 7 experienced and 6 novice men. They performed 5 palm strikes to a freestanding basketball, recorded by high-speed camera at 1000 Hz. Nonparametric comparisons and correlations showed experienced practitioners presented larger values of mean muscle force, mean impact force, mean muscle power, mean impact power, and mean striking efficiency, as is noted in evidence obtained for other martial arts. Also, an interesting result was that for experienced Kung Fu practitioners, muscle power was linearly correlated with impact power (p = .98) but not for the novice practitioners (p = .46).     

Quality of Life (QoL) in a Brazilian Sample of Older Adults: The Role of Sociodemographic Variables and Depression Symptoms

The aim of the present study was to identify relevant variables associated with Quality of Life (QoL) in older adults. Older adults, up to 60 years old, were interviewed. Subjects were recruited through convenience sampling. 339 paticipants, who were stratified by gender, age, and subjective perception of health and illness, answered questions on sociodemographic issues, QoL (WHOQOL-100) and depressive symptomathology (Beck Depression Inventory—BDI). The multiple linear regression analysis showed associations of overall perception of QoL with depression levels, subjective perception of health status and gender. The individual analysis of each domain concluded that depression levels are correlated to all QoL domains, while health status was associated with physical, psychological, independence level and social relationship domains. Other variables were also assessed. The assessment of older adults concerning their QoL perceptions is associated with gender, age, marital status, social class, literacy rate, perception of health, and more substantially associated with depressive symptoms levels. Nevertheless, some limitations of this study and further ones are suggested.     

Four studies on how past and current suicidality relate even when "everything but the kitchen sink" is covaried

T. E. Joiner's (2004, in press) theory of suicidal behavior suggests that past suicidal behavior plays an important role in future suicidality. However, the mechanism by which this risk is transferred and the causal implications have not been well studied. The current study provides evaluation of the nature and limits of this relationship across 4 populations, with varying degrees of suicidal behavior. Across settings, age groups, and impairment levels, the association between past suicidal behavior and current suicidal symptoms held, even when controlling for strong covariates like hopelessness and symptoms of various Axis I and II syndromes. Results provide additional support for the importance of past suicidality as a substantive risk factor for later suicidal behavior.