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121.
The effects of varying interaural time delay (ITD) and interaural intensity difference (IID) were measured in normal-hearing sighted and congenitally blind subjects as a function of eleven frequencies and at sound pressure levels of 70 and 90 dB, and at a sensation level of 25 dB (sensation level refers to the pressure level of the sound above its threshold for the individual subject). Using an 'acoustic' pointing paradigm, the subject varied the IID of a 500 Hz narrow-band (100 Hz) noise (the 'pointer') to coincide with the apparent lateral position of a 'target' ITD stimulus. ITDs of 0, +/-200, and +/-400 micros were obtained through total waveform delays of narrow-band noise, including envelope and fine structure. For both groups, the results of this experiment confirm the traditional view of binaural hearing for like stimuli: non-zero ITDs produce little perceived lateral displacement away from 0 IID at frequencies above 1250 Hz. To the extent that greater magnitude of lateralization for a given ITD, presentation level, and center frequency can be equated with superior localization abilities, blind listeners appear at least comparable and even somewhat better than sighted subjects, especially when attending to signals in the periphery. The present findings suggest that blind listeners are fully able to utilize the cues for spatial hearing, and that vision is not a mandatory prerequisite for the calibration of human spatial hearing. 相似文献
122.
Simon TR Anderso M Thompson MP Crosby A Sacks JJ 《Suicide & life-threatening behavior》2002,32(1):42-50
Data from a nationally representative sample of 5,238 U.S. adults were used to examine the extent to which physical assault victimization was associated with suicidal ideation or behavior (SIB). The results from multivariable logistic regression analyses indicate that physical assault victimization was positively associated with SIB after adjusting for sociodemographic characteristics and alcohol use (OR = 3.6; 95% CI = 2.4-5.5). Those who were injured during the most recent physical assault (OR = 2.7; 95% CI = 1.2-6.0) and those who were assaulted by a relative (OR = 3.4; 95% CI= 1.0-11.0) or intimate partner (OR = 7.7; 95% CI = 2.7-22.5) were significantly more like to report SIB than victims who were not injured or were assaulted by a stranger. Also, those who were victimized but not injured (OR = 5.6; 95% CI = 3.8-8.2) and those who were victimized by a stranger (OR = 2.9; 95% CI = 1.4-6.0) were more likely to report SIB than non-victims. These results highlight the need for legal, medical, mental health, and social service providers to address the co-occurrence of violent victimization and suicidal ideation, particularly, but not exclusively, victimization by family members and intimates. 相似文献
123.
In the first part of this paper we review evidence suggesting that there exists a mechanism that selects input on the basis of its similarity to the required action. This response-based input selection differs from the more established space- and object-based input selection in that it is not constrained by the structure of the input. Our evidence suggests that the two-choice Stroop effect is caused by this response-based selection mechanism. By contrast, it is known that the flanker effect is determined by the space- and object- based selection mechanisms. We explore whether the conflict resolution of the Stroop and flanker tasks is different as well by embedding these two tasks in a PRP (Psychological Refractory Period) paradigm. We show that the Stroop and the PRP effects are additive whereas the flanker and the PRP effects are underadditive, suggesting that the processes in charge of the conflict resolution in the Stroop and the flanker tasks are indeed different. We discuss possible reasons for this difference, and discuss possible ways in which the response-based mechanism can be implemented in information processing models. 相似文献
124.
Hofer SM Christensen H Mackinnon AJ Korten AE Jorm AF Henderson AS Easteal S 《Psychology and aging》2002,17(2):194-208
The influence of a genetic risk factor, apolipoprotein E (apoE) epsilon4 variant, was assessed in older adults aged 70 to 94 on 3 occasions over 7 years. The results of latent growth curve analyses are reported for individuals genotyped for apoE at the 2nd measurement occasion (n = 601) and for a subsample of individuals without probable or definite dementia during the 1st or 2nd occasion (n = 434). ApoE-epsilon4 status was a significant predictor of level and change in memory performance and change in speed performance in the full sample, and of initial level and change in memory performance in the nondemented subsample. These results support previous findings that apoE-epsilon4 is associated with accelerated memory deterioration in individuals without clinical dementia. 相似文献
125.
Women with disabilities have low employment rates and about one-third live in poverty. They represent half of the population using either services of the vocational rehabilitation (VR) system or the welfare system, and many use both. Although both systems have made gains in improving their employment status, neither comprehensively addresses the needs of this population. Welfare policy has encouraged state level innovation and moved large numbers of people into employment in as little as five years. State welfare agencies offer a range of services specifically addressing the needs of families with children. VR agencies have decades of specific experience assisting people with disabilities gain employment. Welfare reform has been the cruise ship moving large numbers of people across an ocean. VR agencies have been the kayak builders designing specialized small craft to move specific people along tributaries. What can they learn from each other? Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
126.
The single-trial passive avoidance task is a useful procedure for examining learning and memory in the young chick. However, it has recently been suggested that discrepant results reported by different laboratories are due to differences in training procedure. The present study investigated a number of parameters surrounding the passive avoidance task, using day-old White Leghorn, Black Australorp cockerels. The results suggested that presentation of a water-dipped bead immediately after the aversive bead significantly altered retention levels. In addition, when the water-dipped bead was presented after the aversive bead, chicks failed to discriminate between beads for a period of 10 min following exposure to the aversant experience. A novel variant of the passive avoidance procedure, involving pretraining with a water-dipped red bead, training with an aversant-coated red bead, and testing with a dry red bead, was evaluated. A measure of avoidance was calculated using all three trials. It is suggested that the use of a single bead, measured both before and after the training experience and using both aversant- and water-trained controls, results in the most concise characterization of memory-related phenomena in the chick which is not contaminated by a carryover effect from the aversive training experience to the nonaversive bead. 相似文献
127.
Posttraining glucocorticoid receptor agonist enhances memory in appetitive and aversive Pavlovian discrete-cue conditioning paradigms 总被引:1,自引:0,他引:1
Glucocorticoid modulation of emotional memory has repeatedly been shown in aversive learning paradigms, but has received little attention in appetitive tasks. It has also been suggested that it may be selective for contextual cues. In order to investigate if glucocorticoids can modulate memory in discrete-cue conditioning of both appetitive and aversive tasks, two experiments were carried out. Male Lister-Hooded rats received pairings of an auditory cue and either food-reward (experiment 1) or footshock (experiment 2), followed immediately by posttraining injections of the glucocorticoid receptor agonist dexamethasone (0.3, 0.6, and 1.2 mg/kg) or vehicle. Dexamethasone (1.2 mg/kg) led to significantly enhanced learning. These results give support to the notion that glucocorticoids play a role in the modulation of both appetitive and aversive emotional memories and show that their role in learning goes beyond the construction of context representations. The modulation of appetitive and aversive discrete-cue learning may be subserved by a common mechanism. 相似文献
128.
Numerous previous investigators have explained species differences in spatial memory performance in terms of differences
in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial
memory performance of echidnas (or "spiny anteaters") can be understood in terms of the spatio-temporal distribution of their
prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas
were better able to learn to avoid a previously rewarding location (to "win-shift") than to learn to return to a previously
rewarding location (to "win-stay"), at short retention intervals, but were unable to learn either of these strategies at retention
intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval
results do not.
Electronic Publication 相似文献
129.
Little is known about how a prey species' cognitive limitations might shape a predator's prey-capture strategy. A specific
hypothesis is investigated: predators take advantage of times when the prey's attention is focussed on its own prey. Portia fimbriata, an araneophagic jumping spider (Salticidae) from Queensland, is shown in a series of 11 experiments to exploit opportunistically
a situation in which a web-building spider on which it preys, Zosis genicularis (Uloboridae), is preoccupied with wrapping up its own prey. Experimental evidence supports three conclusions: (1) while relying
on optical cues alone, P. fimbriata perceives when Z. genicularis is wrapping up prey; (2) when busy wrapping up prey, the responsiveness of Z. genicularis to cues from potential predators is diminished; and (3) P. fimbriata moves primarily during intervals when Z. genicularis is busy wrapping up prey. P. fimbriata's strategy is effective partly because the wrapping behaviour of Z. genicularis masks the web signals generated by the advancing P. fimbriata's footsteps and also because, while wrapping, Z. genicularis' attention is diverted away from predator-revealing cues.
Electronic Publication 相似文献
130.
Current theoretical thinking about dual processes in recognition relies heavily on the measurement operations embodied within the process dissociation procedure. We critically evaluate the ability of this procedure to support this theoretical enterprise. We show that there are alternative processes that would produce a rough invariance in familiarity (a key prediction of the dual-processing approach) and that the process dissociation procedure does not have the power to differentiate between these alternative possibilities. We also show that attempts to relate parameters estimated by the process dissociation procedure to subjective reports (remember-know judgments) cannot differentiate between alternative dual-processing models and that there are problems with some of the historical evidence and with obtaining converging evidence. Our conclusion is that more specific theories incorporating ideas about representation and process are required. 相似文献