Reliable Decrements Research Articles

A Developmental Investigation of Prospective Memory: Effects of Interruption

The effects of interrupting an event-based prospective memory (PM) task and its associated ongoing task were compared for two groups of children: 8- to 9-year-olds (n = 35) and 12- to 13-year-olds (n = 28). Additionally, PM performance was examined as a function of attainment on a battery of tests of executive functioning (viz., Controlled Oral Word Association Test, Letter Number Sequencing Test, Stroop Color and Word Test, and Trail Making Test). A significant main effect of age indicated that the older children correctly carried out intended actions more often than the younger children. Consistent with the prefrontal model of PM, interruption had no impact on PM accuracy in the older group but produced reliable decrements to the accuracy of the younger group. Whereas IQ showed no association with PM performance, reliable relations between PM skills and aspects of their executive functioning were found.

Sensorimotor Dysfunction in HIV/AIDS: Effects of Antiretroviral Treatment and Comorbid Psychiatric Disorders

Balance and gait problems have repeatedly been mentioned in case descriptions of patients infected with Human Immunodeficiency Virus (HIV-1). Objective evidence of these problems has rarely been reported, however. Furthermore, the extent to which balance and gait are influenced by antiretroviral medications or comorbid psychiatric disorders has rarely been examined. The study compared 78 HIV-1 seronegative volunteers to 28 HIV/AIDS patients receiving no antiretroviral therapy, 25 patients receiving only nucleoside analogue therapy, and 37 patients receiving Highly Active Antiretroviral Therapy (HAART). The dependent measures included Equilibrium Quotient scores recorded during 3 subtests of the Sensory Organization Test (SOT), the number of falls during each subtest, the functional base of support, gait speed and cadence, single leg balance time, proximal strength, and vibrotactile threshold of the foot. The analysis employed the number of alcohol and drug abuse problems, depression severity, and body mass index as covariates. ANCOVAs revealed significant decrements in the 3 HIV-1 seropositive groups relative to the control group on Equilibrium Quotient scores during the most difficult of the SOT subtests (sway-referenced support surface with eyes-closed). HIV/AIDS patients also exhibited a smaller functional base of support and greater vibrotactile thresholds. Antiretroviral treatment did not affect balance; but, it did alter sensory threshold in a complex manner. HIV/AIDS is associated with reliable decrements in balance and peripheral sensory function which are variably sensitive to antiretroviral treatment. The implications of these findings for mobility, and workplace or operator safety, should be contemplated.

Recognition of emotion from inverted schematic drawings of faces.

The present study investigated whether facial expressions of emotion are recognized holistically, i.e., all at once as an entire unit, as faces are or featurally as other nonface stimuli. Evidence for holistic processing of faces comes from a reliable decrement in recognition performance when faces are presented inverted rather than upright. If emotion is recognized holistically, then recognition of facial expressions of emotion should be impaired by inversion. To test this, participants were shown schematic drawings of faces showing one of six emotions (surprise, sadness, anger, happiness, disgust, and fear) in either an upright or inverted orientation and were asked to indicate the emotion depicted. Participants were more accurate in the upright than in the inverted orientation, providing evidence in support of holistic recognition of facial emotion. Because recognition of facial expressions of emotion is important in social relationships, this research may have implications for treatment of some social disorders.

RECOGNITION OF EMOTION FROM INVERTED SCHEMATIC DRAWINGS OF FACES

The present study investigated whether facial expressions of emotion are recognized holistically, i.e., all at once as an entire unit, as faces are or featurally as other nonface stimuli. Evidence for holistic processing of faces comes from a reliable decrement in recognition performance when faces are presented inverted rather than upright. If emotion is recognized holistically, then recognition of facial expressions of emotion should be impaired by inversion. To test this, participants were shown schematic drawings of faces showing one of six emotions (surprise, sadness, anger, happiness, disgust, and fear) in either an upright or inverted orientation and were asked to indicate the emotion depicted. Participants were more accurate in the upright than in the inverted orientation, providing evidence in support of holistic recognition of facial emotion. Because recognition of facial expressions of emotion is important in social relationships, this research may have implications for treatment of some social disorders.

Cognitive functioning in children with sickle cell disease: a meta-analysis.

To establish whether sickle cell disease (SCD) affects cognitive functioning in children with no evidence of cerebral infarction. We conducted a meta-analysis of studies of cognition in SCD to determine the size of any statistical difference between children with SCD and controls. Methodological factors were evaluated according to the size and frequency of group differences. There were small but reliable decrements in cognitive functioning on IQ measures (4.3-point difference overall). The most methodologically rigorous studies showed a highly similar pattern. Sampling issues associated with the effect size for IQ were identified. Measures of specific abilities appear more sensitive than IQ scores to cognitive decrements in SCD. SCD is associated with cognitive effects even in the absence of cerebral infarction. The causes of this cognitive decrement may include direct effects of SCD on brain function or indirect effects of chronic illness.

Environmental context and recognition: the role of recollection and familiarity.

Evidence for effects of changed environmental context on recognition has been equivocal. Using 3 experiments, the author investigated the role of environmental context from a dual-processing approach. Experiment 1 showed that testing word recognition in a novel context led to a reliable decrement but only for recognition accompanied by conscious recollection, with familiarity-based recognition judgments being unaffected. This was replicated in Experiment 2 using stimuli that were novel to the participants (nonwords). Experiment 3 showed that the decrement in recollection also occurred when the changed-context condition involved presenting items in a different but familiar context. The results suggest that effects of environmental context will only be found when recognition is accompanied by conscious recollection and that this effect is due to a specific item-context association.

Change in affective state assessed by impaired color-naming of threat-related words

This study investigated the effects of mood induction on Stroop color-naming times for threat-related words. The subjects’ task was to color-name sets of threat-related words and affectively neutral matched control words both before and after mood-induction. Subjects were shown a short film about the medical effects of nuclear war (negative affect manipulation), a humorous cartoon, or no film. A significant and highly reliable color-naming decrement of the threat-related words was observed only after the negative affect manipulation. This indicates that the attentional bias towards the processing of threat-related material observed in clinically anxious or high Trait-Anxious subjects can be induced in initially nonanxious subjects. An incidental recall task included in the procedure provided no evidence of mood state dependent recall.

Reduced Text Structure at Two Text Levels: Impacts on the Performance of Technical Readers

Cues to text structure have been proposed to operate a number of different levels and it has been suggested that lower-level factors (e.g., word decoding) are more critical to reader performance than are higher-level factors (e.g., paragraph and text structure). The current study involved presenting texts in their base form and with cues to coherence at two levels—at the word and paragraph level—removed. These manipulations were performed on technical texts at two levels of familiarity and were presented to technical readers. Tests of recall, recognition, and problem-solving revealed that while removal of cues to local coherence did produce reliable decrements in reader performance, more dramatic effects occurred when both types of cues were removed. Results are discussed in terms of their relevance to questions of information design.

Perceptual bisection in rats: The effects of physostigmine, scopolamine and pirenzepine

The effects of cholinergic drugs on three different perceptual bisection tasks were studied in rats. Physostigmine (0.056–0.56 mg/kg), a reversible anticholinesterase, produced dose-dependent decrements in discriminability (A′), but did not affect the bisection point (BP) in visual duration, auditory duration, and auditory intensity bisection tasks. This finding is consistent with results previously obtained in an auditory duration bisection task with an irreversible anticholinesterase, diisopropyl phosphorfluoridate. Scopolamine (0.075–0.422 mg/kg), a muscarinic cholinergic-receptor antagonist, produced dose-dependent decrements in both A′ and BP in visual and auditory duration bisection tasks. The behavioral antagonism between physostigmine (0.56 mg/kg) and scopolamine (0.075–0.237 mg/kg) was studied in the visual and auditory duration bisection tasks. The BP was not affected by physostigmine alone or in combination with scopolamine, except at the largest dose of scopolamine, which produced a reliable decrement in the BP. A′, however, was equally decreased by physostigmine alone and all combinations of physostigmine and scopolamine. Pirenzepine (1, 3 and 10 mg/kg), a selective high-affinity M 1 muscarinic antagonist, had no effect on A′ or the BP in the duration bisection tasks, suggesting changes in perception produced by muscarinic antagonists do not involve the M 1 receptor subtype. The similar drug effects in different sensory modalities (visual and auditory) and perceptual systems (subjective duration and loudness) suggest that cholinergic drugs may affect perceptual mechanisms responsible for sensory coding, such as the output of a neural generator.

Distributed processing of sensory information in the leech. II. Identification of interneurons contributing to the local bending reflex

Isolated midbody ganglia of the leech Hirudo medicinalis were surveyed for interneurons contributing to the dorsal component of the local bending reflex, i.e., to the excitation of dorsal excitatory motor neurons that follows stimulation of dorsal mechanoreceptors responsive to pressure (P cells). Nine types of local bending interneuron could be distinguished on physiological and morphological grounds--8 paired and 1 unpaired cell per ganglion. Synaptic latencies from sensory neurons to interneurons were consistent with a direct or possibly disynaptic pathway. Connections between interneurons appeared to be rare and hyperpolarization of individual interneurons during local bending produced small but reliable decrements in motor neuron response, suggesting that multiple parallel pathways contribute to the behavior. Paradoxically, most interneurons received substantial inputs from ventral as well as dorsal mechanoreceptors, indicating that interneurons that were distinguished by their contribution to dorsal local bending were, in fact, active in ventral and lateral bends as well. The capacity to detect a particular stimulus and produce the appropriate response cannot be localized to particular types of interneuron; rather, it appears to be a distributed property of the entire local bending network.

Effects of Background Music on Phonological Short-Term Memory

Immediate memory for visually presented verbal material is disrupted by concurrent speech, even when the speech is unattended and in a foreign language. Unattended noise does not produce a reliable decrement. These results have been interpreted in terms of a phonological short-term store that excludes non-speechlike sounds. The characteristics of this exclusion process were explored by studying the effects of music on the serial recall of sequences of nine digits presented visually. Experiment 1 compared the effects of unattended vocal or instrumental music with quiet and showed that both types of music disrupted STM performance, with vocal music being more disruptive than instrumental music. Experiment 2 attempted to replicate this result using more highly trained subjects. Vocal music caused significantly more disruption than instrumental music, which was not significantly worse than the silent control condition. Experiment 3 compared instrumental music with unattended speech and with noise modulated in amplitude, the degree of modulation being the same as in speech. The results showed that the noise condition did not differ from silence; both of these proved less disruptive than instrumental music, which was in turn less disruptive than the unattended speech condition. Theoretical interpretation of these results and their potential practical implications for the disruption of cognitive performance by background music are discussed.

Pattern perception in infants: Effects of structure and transformation

Four experiments on pattern perception in 4-month-old infants are reported. The first two experiments examined the perception of pattern structure as defined by Garner (1974). Although the infants did not show an immediate preference for well-structure patterns (Experiment 1), during habituation they showed a reliable decrement in looking only to well-structured patterns (Experiment 2). On recovery trials in Experiment 2 infants were presented with two types of pattern change: a new configuration of the habituation pattern and a change in the orientation of the habituation pattern. The infants recovered looking to the orientation change, but generally not to the changes in configuration. It is argued that the results of Experiment 2 highlight the role of symmetry, especially vertical symmetry, in infant pattern perception. Recovery of looking to changes in the orientation, size, and position of the habituation pattern was examined in Experiments 3 and 4 where it was demonstrated that such changes are salient to the infant, arguably because of the presence of a surrounding, external frame.

Fluprazine hydrochloride does not decrease defensive behaviors of wild and septal syndrome rats

Recent studies indicate that fluprazine hydrochloride reduces offensive attack in laboratory rats and mice without decreasing defensive behavior during conspecific encounters. Since wild rats and rats displaying the “septal lesion syndrome” show much more pronounced defensive reactions than do normal laboratory rats, these animals were used to provide a more critical test of fluprazine's effectiveness on defense. When a dose of fluprazine hydrochloride (8 mg/kg), previously shown to be highly effective in reducing or eliminating offense, was given to wild and septal syndrome rats these animals showed no reliable decrement in a wide range of defensive reactions including biting attack (defensive attack) to human handling and other stimulation. These findings support the view that fluprazine does not appreciably affect defensive attack or other defensive behaviors even though it strongly inhibits offensive attack.

Changes in Maze-Solving Errors Due to Stress

Maze-solving was examined as a candidate performance measurement tool for assessing the effect of stress. Stress was induced by limiting the amount of time available for subject input. The usefulness of this task as a measurement tool was evaluated in a series of three experiments. The first experiment sought to isolate a particular maze configuration (size and difficulty level) which would show reliable and sensitive differences among a range of dot speeds. The second experiment assessed the effect of repeated presentation on performance. The final experiment in this series investigated the effect of dot speed on maze performance using a within-subject design and the maze configuration chosen in the first experiment. Results from these experiments were consistent: increases in dot speed produced reliable decrements in performance. The strategies used in solving these mazes were examined qualitatively as well as quantitatively. The number of incorrect paths chosen increased as the dot speed increased, and errors that did occur were not as readily corrected. Furthermore, the errors that occured with increased dot speed were typically errors of commission, rather than simple failures of motor coordination. These tendencies indicated that the decrement in performance scores with increased dot speed was due to shortened planning horizon.

Effects of acute or chronic administration of low doses of a dopamine agonist on drinking and locomotor activity in the rat.

Low doses of piribedil (0.25-5.0 mg/kg) administered acutely produced reliable decrements in locomotor activity in thirsty and non-thirsty animals, the greatest effect occurring at the highest dose. A sequence of ten daily injections of piribedil produced indications of the development of tolerance, at the two highest doses (2.5 and 5.0 mg/kg) in thirsty animals. The smallest doses used, given either acutely or chronically, produced a weak enhancement of drinking behaviour within the first 15 min of a drinking test, as shown by a reduction in latency to drink and an increase in the amount of water consumption. Tolerance did develop with respect to drinking behaviour; animals treated chronically with piribedil displayed higher levels of drinking at several dose levels when compared with acutely treated subjects. The tolerance displayed at the two highest doses could have a close affinity with that shown with regard to locomotor activity.

The influence of ship motion on manual control skills

The effects of ship motion on a range of typical manual control skills were examined on the Warren Spring ship motion simulator driven in heave, pitch and roll by signals taken from the frigate H MS Avenger at 13m/s(25 knots) into a force 4 wind. The motion produced a vertical r.m.s. acceleration of 0024g, mostly between 01 and 0-3 Hz, with comparatively little pitch or roll. A task involving unsupported arm movements was seriously affected by the motion; a pursuit tracking task showed a reliable decrement although it was still performed reasonably well (pressure and free-moving tracking controls were affected equally by the motion); a digit keying task requiring ballistic hand movements was unaffected. There was no evidence that these effects were caused by sea-sickness. The differing response to motion of the different tasks, from virtual destruction to no effect, suggests that a major benefit could come from an attempt to design the man/control interface on board ship around motion resistant tasks.

Development of the Letter-Shape Keyboard: A New Approach to the Design of Data Entry Devices

Development of a four key typewriter for Hebrew characters is described. It capitalizes on the visual imagery capabilities of human operators. Parallel and sequential key strokes are employed as graphic elements to reproduce the shape of printed letters. Preliminary experiments show that letter-shape code is acquired with little training and is highly resistant to forgetting. Single hand blind typing at a relatively fast rate is achieved after few hours of training. No difference is revealed between right and left hand operation. Only small and non reliable decrements in data entry rates were observed when system was operated during a simulated flight mission in a F-4 simulator.

Effects of oral and intramuscular carbaryl administrations on repeated chain acquisition in monkeys.

A type of learning task was utilized to determine the effective dose of carbaryl on Macaca fascicularis for both oral and in routes of administration. Monkeys were required to press four buttons in a set order; the order was changed daily. A baseline reversal design was utilized to test all animals several times at each concentration. The im carbaryl injections resulted in consistent, statistically reliable decrements in total session time and increases in errors at 5 and 10 mg/kg for the 4 animals in this section of the experiment, but produced no change in performance at 1 mg/kg. Errors increased in 3 of 4 monkeys after 3 mg/kg injections. Oral doses as high as 50 mg/kg were not consistently effective in changing performance on the task in any of 5 animals included in this section of the experiment. Some support was given to the suggestion that monkeys are more tolerant of carbaryl than are rats. These are the first reported effects (other than the LD50) of carbaryl in monkeys.

Duration of Tonic Immobility In Lizards (Anolis Carolinensis) as a Function of Repeated Immobilization, Frequent Handling, and Laboratory Maintenance

Research has shown that chickens given repeated elicitations of the tonic immobility reaction, an habituation procedure, show larger decrements in duration of tonic immobility on a subsequent test trial than do either birds given simple handling or naive animals. The present study attempted to replicate this finding with another animal commonly used in studies of tonic immobility, the anole lizard (Anolis carolinensis). Experiment 1 employed the between-groups design used in previous studies and failed to detect differences among the three treatments (habituated, handled, and naive) in duration of immobility. A second experiment used a within-subjects measure of immobility duration to demonstrate that the habituation procedure and simple handling produce similar decrements in duration of immobility. The final experiment demonstrated that anoles maintained in a group-living situation, with some daily exposure to humans, also show reliable decrements in duration of immobility. These results are congruent with those obtained by Boice and Williams (1971) with frogs (Rana pipiens).

Texture size specificity in the slant aftereffect

Transfer of the median plane slant aftereffect was assessed across changes in stimulus texture size (sine-wave grating frequency). Under binocular viewing, reliable decrements in aftereffect magnitude were observed when texture size was changed, compared with no-change control conditions. Under monocular viewing conditions, no significant aftereffects were found. The results indicate a spatial-frequency-specific component of binocular slant aftereffects.