Sensory Fatigue Research Articles

A further parallel between selective adaptation and response contrast

It is generally believed that selective adaptation effects in speech perception are due to a reduction in sensitivity of auditory feature detectors. We have recently presented evidence that these effects may derive instead from response contrast. In a further test of the contrast hypothesis, we conducted both an adaptation and a contrast experiment with matching sets of stimuli. In the adaptation experiment, subjects identified two series of velar stimuli varying in VOT, [ga-kha] and [gi-khi], before and after adaptation with each of the following test stimuli: [ga], [kha], [gi], and [khi]. In the contrast experiment, subjects identified either of two ambiguous test items (drawn from near the phonetic boundaries of the [ga-kha] and the [gi-khi] series) following a single presentation of [ga], [kha], [gi], or [khi]. For both the adaptation and the contrast experiments, (1) the [Ca] test items were more greatly affected (in a contrast direction) by [Ca] than by the [Ci] adaptor/context stimuli, and (2) the [Ci] test items were not differentially affected by the [Ca] and [Ci] adaptor/context stimuli. These parallel results suggest that vowel contingent adaptation results may well be due to response contrast rather than sensory fatigue.

Habituation in Limulus abdominal ganglia.

1. Extracellular recordings were made from dorsal root units in the abdominal ganglia of Limulus. These units are activated by tactile stimulation of the gill book covers.2. The response in these units to repeated puffs of air directed on a gill book is a rapid decline in activity. The response spontaneously recovers with time when the stimulus is withheld. Stronger stimuli or different stimuli (water drops) produce an immediate recovery of the diminished responsivity; this recovery is similar to dishabituation noted in other studies and rules out fatigue as an explanation for the dorsal root response decrement. Sensory fatigue or adaptation are ruled out by the demonstration that repeated puffs of air do not produce any response decrement in the nerves (ventral roots) which carry the afferent tactile information.3. The relationship between the number of ganglia and the acquisition of habituation was examined and no differences were found. However, during retests the Intact and Isolated Ventral Cord p...

Nutrition Survey in a Semianual-Crop Farming Village in Kochi Prefecture (Part 2)

The auther studied on daily working hours, food consumption, total nitrogen and vitamin B1 excreted into urine, sensory fatigue, and grasping power. The subjects were farmers and their wives; 7 middle class families.To get higher level of health, improvement of working conditions, longer sleeping hours and better nutrition are necessary.

Sensory Testing by Triple Comparisons

In sensory test work, the number of samples a judge can assess at any one time is often limited by sensory fatigue and confusion of stimuli. This necessitates the use of incomplete block designs. Further, the difficulty of obtaininig satisfactory quantitative measures of treatment efTects usually entails assessment by ranking. Thus there is need for a rank analysis of incomplete block designs of a versatility equivalent to that available for variables satisfying the conditions of analysis of variance. In addition, any such analysis should provide the experimenter with a check as to whether he can regard the treatments concerned as lying on a linear scale of acceptability. For, with sensory assessment, cases can and do arise where the relations between calculated average scale positions disagree with individual direct comparisons. These needs have been met in the case of blocks of size two, by the various paired comparison procedures developed in recent years [2, 4-6; 13, 14, 18, 17]. Although this is undoubtedly the most important case, instances arise where blocks of size three or more are a practical proposition and hold out the possibility of increased efficiency. Unfortunately, little work seems to have been done in the general case of blocks of size k. The result published by Durbin [7] allows an overall significance test of treatment differences on balanced incomplete block ranking experiments, whilst the rankit method of Fisher [10] has been used by some workers, but no generally accepted me'thod (of adequate versatility) has been available for blocks of size other than two. The method recently published by Pendergrass and Bradley [3, 15] which offers a comprehensive treatment of the case k = 3 is therefore of immediate interest. This paper is to assist evaluation of the Bradley-Pendergrass method by contrasting results from triple comparison testing with results obtained using paired comparisons. Two sets of data are discussed. One set is from margarine cocktail stick taste tests, where sensory fatigue is knowln to be marked. The other set is from toilet soap sniff tests, where sensory fatigue is much less of a problem.