Use of the pigmentometer,a new device for measuring skin albedo: Relating skin color with a series of physiological measures

Use of the Pigmentometer, a new device for measuring skin albedo: Relating skin color with a series of physiological measures. An apparatus has been described for the indirect measurement of skin albedo in human subjects. This device operates on the principle of the reflectance of light as influenced by the lightness or darkness of the skin. This new equipment was used to examine the relationship between lightness or darkness of the skin and the basal level and responsivity of some autonomic nerovus system physiological variables in a series of 46 black and 47 white male and female subjects. It was observed that blacks had significantly lower (darker) skin albedo (PI), a significantly higher skin resistance (SR) and amplitude of the galvanic skin response (GSR), and an insignificant higher basal heart rate (HR). Pearson Product-Movement correlations between all measures from the total population showed significant relationships between PI and SR, SR and GSR and HR and HRR (heart rate response). The further separation of the total population into subgroups of blacks, whites, males, females, and black and white male and female groups, respectively, altered some of these differences and relationships previously observed. These results appeared to support the premise that race is more responsible for influencing the measured physiological responses, particularly SR, than is the lightness or darkness of the skin.     

Alcoholism and memory: broadening the scope of alcohol-expectancy research

Current biopsychosocial research on the etiology of alcoholism has begun to focus on memory processes as a possible common pathway for drinking decisions. The alcohol-expectancy construct is rooted both in cognitive psychology and alcohol research and can serve as a vehicle for this study. Reexamination of one recent review of issues in alcohol-expectancy research provides an opportunity to broaden the scope of this research with theoretical and methodological alternatives to those suggested in that review. Most importantly, this article shows that expectancy findings, discussed by Leigh (1989a) as reflecting "psychometric" limitations, are instead quite consistent with recent network models of memory structure. Such models can provide an informative guide to future research activities. It is also recommended that alcohol-expectancy research remain open to inputs from expectancy theories already developed in several psychological domains, as well as to theories of social cognition and attitude structure in addition to those advanced by Leigh.     

Decomposition can harm the accuracy of behavioural frequency reports

In survey research, the use of decomposition can lead to pronounced reporting errors as seen by overreporting and overall reporting error. A total of 87 subjects answered either decomposed or undecomposed questions concerning telephone calls made by them while at work. The questionnaire conditions varied the length of the reference period (1 week or 6 months), and the type of call (local or long‐distance). Decomposition conditions introduced either spatial or temporal cues. In all comparisons, decomposed questions increased overreporting bias relative to undecomposed questions. In addition, undecomposed questions with a 1‐week reference period led to increased overreporting bias in comparison to undecomposed/6‐month questions. Results are consistent with a category split estimation model in which smaller categories are predicted to lead to overreporting, and larger categories to underreporting. Decomposition is not recommended for gaining retrospective reports of non‐distinctive, frequent events. Copyright © 2000 John Wiley & Sons, Ltd.     

Decoding human brain activity during real-world experiences

The human brain evolved to function and survive in a highly stimulating, complex and fast-changing world. Attempting to ascertain the neural substrates of operating in naturalistic contexts represents a huge challenge. Recently, however, researchers have begun to use several innovative analysis methods to interrogate functional magnetic resonance imaging (fMRI) data collected during dynamic naturalistic tasks. Central to these new developments is the inventive approach taken to segregating neural activity linked to specific events within the overall continuous stream of complex stimulation. In this review, we discuss the recent literature, detailing the key studies and their methods. These analytical techniques can be applied in a wide range of cognitive domains and, thus, offer exciting new opportunities for gaining insights into the brain bases of thoughts and behaviours in the real-world setting where they normally occur.     

Deconstructing episodic memory with construction

It has recently been observed that the brain network supporting recall of episodic memories shares much in common with other cognitive functions such as episodic future thinking, navigation and theory of mind. It has been speculated that 'self-projection' is the key common process. However, in this Opinion article, we note that other functions (e.g. imagining fictitious experiences) not explicitly connected to either the self or a subjective sense of time, activate a similar brain network. Hence, we argue that the process of 'scene construction' is better able to account for the commonalities in the brain areas engaged by an extended range of disparate functions. In light of this, we re-evaluate our understanding of episodic memory, the processes underpinning it and other related cognitive functions.     

The effect of visual threat on spatial attention to touch

Viewing a threatening stimulus can bias visual attention toward that location. Such effects have typically been investigated only in the visual modality, despite the fact that many threatening stimuli are most dangerous when close to or in contact with the body. Recent multisensory research indicates that a neutral visual stimulus, such as a light flash, can lead to a tactile attention shift towards a nearby body part. Here, we investigated whether the threat value of a visual stimulus modulates its effect on attention to touch. Participants made speeded discrimination responses about tactile stimuli presented to one or other hand, preceded by a picture cue (snake, spider, flower or mushroom) presented close to the same or the opposite hand. Pictures of snakes led to a significantly greater tactile attentional facilitation effect than did non-threatening pictures of flowers and mushrooms. Furthermore, there was a correlation between self-reported fear of snakes and spiders and the magnitude of early facilitation following cues of that type. These findings demonstrate that the attentional bias towards threat extends to the tactile modality and indicate that perceived threat value can modulate the cross-modal effect that a visual cue has on attention to touch.