Hi David Carpenter.
These few articles may help your student with some biblio. for her study.
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A vigilance task sensitive to the effects of stimulants, hypnotics, and
environmental stress: The Scanning Visual Vigilance Test
Lieberman_HR, Coffey_B, Kobrick_J
BEHAVIOR RESEARCH METHODS INSTRUMENTS & COMPUTERS, 1998,
Vol.30, No.3, pp.416-422
The Scanning Visual Vigilance Test is a variable-length detection test designed to
assess the ability of individuals to maintain visual alertness for sustained periods
of time. The test was designed to be sensitive to changes in vigilance produced
by subtle variations in performance, such as those produced by low doses of
centrally acting food constituents, drugs, or environmental stress. The test has
been shown to be sensitive to the effects of stimulants and sedatives, as well as
cold stress and sleep loss. It requires the subject to continuously scan a video
monitor to detect the occurrence of infrequent stimuli that are difficult to detect.
The number of stimuli correctly detected, false alarms, and reaction times are
recorded. The stimulus is a small rectangle displayed for 2 sec at random
locations on a darker region of a video monitor at random or pseudo-random
times. The brightness of the stimulus can be adjusted for each subject individually
on an automated threshold detection test. Training and test session length are
defined by the experimenter. Hardware requirements are an IBM-compatible
personal computer (286 or higher) with a color or grayscale VGA monitor.
A comparison of the ability of 8-9-year-old children and adults to detect taste
stimuli
James_CE, Laing_DG, Oram_N
PHYSIOLOGY & BEHAVIOR, 1997, Vol.62, No.1, pp.193-197
Conflicting data exist in the literature regarding the maturity of the human sense
of taste during childhood and if gender influences gustatory development. To
investigate these 2 questions, taste detection thresholds for the 4 common
tastants sucrose, sodium chloride, citric acid, and caffeine were established for
61 young adults and 68 children aged 8-9 years old, using a paired-comparison
forced-choice procedure. No significant differences were found between the mean
thresholds of women and men, or between those of female children and adults. In
contrast, male children had significantly higher thresholds for all 4 tastants than
adult females, for all tastants except caffeine than adult men, and for sucrose and
sodium chloride than female children. It is concluded that the taste sensitivity of 8-
9-year-old males, although well developed, has not fully matured, and that taste
sensitivity is not affected by gender in young adults.
AGING, CAFFEINE, AND INFORMATION-PROCESSING - AN EVENT-RELATED
POTENTIAL ANALYSIS
LORIST_MM, SNEL_J, MULDER_G, KOK_A
EVOKED POTENTIALS-ELECTROENCEPHALOGRAPHY AND CLINICAL
NEUROPHYSIOLOGY, 1995, Vol.96, No.5, pp.453-467
Structural and energetic processes in information processing were studied in
young and elderly subjects. A visually focussed selective search task was used,
in which subjects had to select relevant information, followed by controlled
memory search processes to locate a target item. Caffeine was used to
manipulate the energetic state of the subjects. During task performance event-
related potentials (ERPs) and reaction time (RT) were recorded. Subjects were 15
young and 15 elderly healthy, non-smoking, moderate caffeine consumers (250-
600 mg/day). Before the experimental sessions they abstained from caffeine for
greater than or equal to 12 h. In the experiment subjects received 250 mg caffeine
or placebo dissolved in decaffeinated coffee. RT data seem to indicate that aging
effects are at least partly due to a shift in the speed-accuracy trade-off. ERP
results provide evidence for decreased levels of energy resources in the elderly.
The identification of relevant information and stimulus evaluation processes were
delayed in the elderly, suggesting an additional effect of aging on structural
processes. Caffeine improved performance and increased the amplitude of the N1,
N2b, and P3b, in both young and old subjects. These results suggest that
caffeine makes more energy resources available for task performance. The effects
of aging on P3b latency were counteracted by caffeine. Other caffeine effects did
not differ significantly between young and elderly subjects.
INFLUENCE OF CAFFEINE ON SELECTIVE ATTENTION IN WELL-RESTED
AND FATIGUED SUBJECTS
LORIST_MM, SNEL_J, KOK_A, MULDER_G
PSYCHOPHYSIOLOGY, 1994, Vol.31, No.6, pp.525-534 Effects of caffeine were
studied in a visual focused selective search task in well-rested and fatigued
subjects. A dose of 200 + 50 mg caffeine or placebo, dissolved in decaffeinated
coffee, was administered in a double-blind and deceptive fashion. The task was to
detect a target letter on one diagonal of a visual display designated as relevant
and ignore stimuli presented on the irrelevant diagonal. Behavioral measures were
supplemented by event-related potential (ERP) measures. Subjects reacted faster
in the caffeine condition. Caffeine enhanced the N1 and the N2b components.
Selection of relevant information apparently was more adequate in this condition.
Search negativity was not affected by caffeine. Caffeine effects on the P3 elicited
by target letters were more pronounced in the fatigued than in the well-rested
subjects, indicating that the effects of caffeine are dependent on the state of the
subject. The results suggest that caffeine has specific rather than general effects
on information processing.
THE EFFECT OF SWEETENERS ON BITTER TASTE IN YOUNG AND
ELDERLY SUBJECTS
SCHIFFMAN_SS, GATLIN_LA, SATTELYMILLER_EA, GRAHAM_BG,
HEIMAN_SA, STAGNER_WC, ERICKSON_RP
BRAIN RESEARCH BULLETIN, 1994, Vol.35, No.3, pp.189-204
The purpose of this study was to quantify the degree of reduction in perceived
bitterness by sweeteners at both threshold and suprathreshold concentrations of
bitter compounds. Detection and recognition thresholds were determined for six
bitter compounds (caffeine, denatonium benzoate, magnesium chloride, quinine
hydrochloride, sucrose octaacetate, and urea) in the absence and presence of
several suprathreshold concentrations of five sweeteners. The sweeteners were:
sucrose, aspartame, sodium saccharin, mannitol, and sorbitol. Polycose was
also tested along with the sweeteners. The degree to which bitter thresholds were
affected by the addition of sweeteners was dependent on the chemical
classification of the sweeteners and their concentrations. In general, the natural
sweeteners, sucrose, mannitol, and sorbitol, were more effective than the
noncaloric sweeteners, aspartame and sodium saccharin, in elevating the
detection and recognition thresholds of the bitter compounds. A sweetness
intensity approximating that of 6% sucrose (0.175 M sucrose) or greater was
required to elevate thresholds. For elderly subjects, sweeteners did not
significantly elevate thresholds for denatonium benzoate and sucrose
octaacetate. The degree to which sorbitol and sucrose can decrease the
perceived bitterness intensity of suprathreshold concentrations of the six bitter
compounds was also determined. The concentrations of sweeteners and bitter
compounds were selected to be of moderate to high subjective intensity. The
levels of sweeteners used in the mixtures were: sucrose (none, 0.946 M, and 2.13
M) and sorbitol (none, 2.1 M, and 3.68 M). Both sweeteners significantly reduced
the bitterness ratings of almost every concentration of the six bitter compounds.
The greatest reductions in bitterness were 87.0% for 0.192 mu M denatonium
benzoate mixed with 2.13 M sucrose and 84.7% for 1.8 M urea mixed with 3.68
M sorbitol.
SMELL AND TASTE FUNCTION IN THE VISUALLY-IMPAIRED
SMITH_RS, DOTY_RL, BURLINGAME_GK, MCKEOWN_DA
PERCEPTION & PSYCHOPHYSICS, 1993, Vol.54, No.5, pp.649-655
Surprisingly few quantitative studies have addressed the question of whether
visually impaired individuals evidence, perhaps in compensation for their loss of
vision, increased acuteness in their other senses. In this experiment we sought to
determine whether blind subjects outperform sighted subjects on a number of
basic tests of chemosensory function. Over 50 blind and 75 sighted subjects were
administered the following olfactory and gustatory tests: the University of
Pennsylvania Smell Identification Test (UPSIT); a 16-item odor discrimination test;
and a suprathreshold taste test in which measures of taste-quality identification
and ratings of the perceived intensity and pleasantness of sucrose, citric acid,
sodium chloride, and caffeine were obtained. In addition, 39 blind subjects and 77
sighted subjects were administered a single staircase phenyl ethyl alcohol (PEA)
odor detection threshold test. Twenty-three of the sighted subjects were
employed by the Philadelphia Water Department and trained to serve on its water
quality evaluation panel. The primary findings of the study were that (a) the blind
subjects did not outperform sighted subjects on any test of chemosensory
function and (b) the trained subjects significantly outperformed the other two
groups on the odor detection, odor discrimination, and taste identification tests,
and nearly outperformed the blind subjects on the UPSIT. The citric acid
concentrations received larger pleasantness ratings from the trained panel
members than from the blind subjects, whose ratings did not differ significantly
from those of the untrained sighted subjects. Overall, the data imply that
blindness, per se, has little influence on chemosensory function and add further
support to the notion that specialized training enhances performance on a number
of chemosensory tasks.
THE EFFECTS OF CAFFEINE AND AUTOMATICITY ON A VISUAL
INFORMATION-PROCESSING TASK
LOKE_WH
HUMAN PSYCHOPHARMACOLOGY-CLINICAL AND EXPERIMENTAL, 1992,
Vol.7, No.6, pp.379-388
The present study examined caffeine's effect on mental performance in contrast to
a recent study (Loke and Goh, 1992) which examined the effects of caffeine user-
effect on mental performance. Taken together, the studies would provide a
detailed understanding of the effects of caffeine and automaticity on the visual
search/detection domain of information processing. Analyses of the baseline
measures of the visual search/detection task showed significant differences
between low and high levels of automaticity and levels of task difficulty.
Performance on the low difficulty level was higher than the high difficulty level, and
performance on automatic task was higher than on non-automatic task. Caffeine,
however, did not interact with automaticity and task difficulty. Therefore, given that
the present study used unpractised (novice) subjects with similar levels of caffeine
consumptions and personality characteristics, the visual search/detection domain
of information processing is shown to be insensitive to the effects of caffeine. This
supports the general view that caffeine does not affect cognition, learning, and
memory performance. Also, the non-significant three-way interaction of drug,
automaticity, and task difficulty would therefore suggest that caffeine does not
affect resource capacity. Of note is that knowledge of drug administration
assessments (drug guessing) was sensitive to the effects of caffeine in the
automatic condition and not in the non-automatic condition, suggesting that the
effects of caffeine are task-dependent. In contrast, the expected sensitivity of
mood assessments to caffeine's effects was not shown. Since caffeine is shown
to be a 'weak' stimulant, given its commonly known non-significant effects on
mental performance, caffeine-administered subjects may lack sufficient external
cues to allow them to perceive and report correctly that they were given caffeine.
THE EFFECT OF CAFFEINE USE ON A VISUAL INFORMATION-PROCESSING
TASK
LOKE_WH, GOH_WD
HUMAN PSYCHOPHARMACOLOGY-CLINICAL AND EXPERIMENTAL, 1992,
Vol.7, No.3, pp.175-181
Past caffeine studies have shown that differences in task performance may be
due to differences in habitual caffeine consumption levels of individuals. No study
has yet investigated this caffeine user effect alone without confounding it with the
administration of caffeine. The present study used a visual search/detection task
to test whether high caffeine users have an enhanced resource capacity and
therefore show higher baseline performance than low and moderate caffeine
users. A three-way interaction between caffeine user (low, moderate, and high
caffeine user), automaticity (automatic and non-automatic), and task difficulty (low
and high) was predicted, with user effect significant for the non-automatic portion
of the task. The three-way interaction was not significant, suggesting that user
effect is not dependent on resource capacity. Several interpretations, based on
theoretical, empirical, methodological, and statistical viewpoints, are discussed
as to the non-significant caffeine user effect.
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> I have a student who is looking for research on the effects of caffine.
> SHe is particularly interested in what effects it might have in signal
> detection tasks, but is having trouble finding existing research. CAn
> anybody help her (us), with some references?
All the best
Bye for now.
Jorge Alvoeiro.
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Doutor Jorge Alvoeiro
(Ph.D., Hull, UK)
Instituto Piaget-Viseu,
Estrada do Alto do Gaio,
Lordosa,
3510-651 Viseu,
Portugal.
