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Performance on two multiple-choice testing procedures was examined during unit tests and a final examination. The Immediate Feedback Assessment Technique provided immediate response feedback in an answer-until-correct style of responding. The testing format which served as a point of comparison was the Scantron form. One format was completed by students in introductory psychology courses during unit tests whereas all students used the Scantron form on the final examination. Students tested with Immediate Feedback forms on the unit tests correctly answered more of the final examination questions which were repeated from earlier unit tests than did students tested with Scantron forms. Also, students tested with Immediate Feedback forms correctly answered more final examination questions previously answered incorrectly on the unit tests than did students tested previously with Scantron forms.

The purpose of this study was to determine the influence of the D1-selective partial agonist SKF 38393 on the odor detection performance of rats using high precision olfactometry and a go/no-go operant task. Previous studies have found that the D2 receptor partial agonist quinpirole decreases such performance, but the influences of D1 receptor activation are unknown. In experiment 1, such detection performance to the odorant ethyl acetate was enhanced by SKF 38393, relative to saline, in male rats at 7.5 and 10.0 mg/kg i.p. dose levels, but not at the lower doses of 1.0, 2.5, and 5.0 mg/kg. In experiment 2, this enhancement was replicated at the 7.5 and 10.0 mg/kg doses and was shown to occur at the 12.5 mg/kg dose as well. In experiment 3, similar enhancement was shown for the odorant eugenol in female rats at the 7.5, 10.0 and 12.5 mg/kg doses, suggesting this effect is neither sex-specific nor confined to the odorant ethyl acetate. In experiment 4, a 0.025 mg/kg dose of the D1 receptor antagonist SCH 23390 depressed the enhancement produced to ethyl acetate by 7.5 mg/kg SKF 38393 to control levels. Overall, these data demonstrate that, in contrast to quinpirole, SKF 38393 improves odor detection performance in the rat and that this phenomenon can be attenuated by the D1 receptor blocker SCH 23390.

Illusion decrement for the Müller-Lyer and Horizontal-Vertical illusions was examined. The experiment consisted of an initial adjustment of an illusion followed by 20 test trials, each with an intervening 60-sec. intertrial interval during which a comparator line and a standard line set to equality were visually inspected for 0, 20, 40, or 60 sec. After each intertrial interval the length of the comparator line was reset by the experimenter to either 0 or 90 cm, and subjects then adjusted its length to perceived equality with the standard line (42 cm). Illusion decrement was inversely related to the duration of inspection for each illusion, with significant reductions in magnitude of illusion observed for all groups. These results support prior demonstrations that perceptual learning mechanisms are operative during brief periods of visual inspection, especially when these periods are followed by the opportunity to make repeated adjustments.

The acquisition and extinction of a conditioned taste aversion in Egyptian spiny mice and Long-Evans rats was compared during 20 posttest sessions using a cross-over design and double-blind control procedures. Spiny mice preexposed to a sucrose CS demonstrated more latent inhibition and a faster rate of extinction than did Long-Evans rats preexposed to the same CS. Preference indices did not differ between control animals or as a function of gender. The present results are the first report of the effects of latent inhibition on learning taste aversion in Egyptian spiny mice.

The effects of accurate and erroneous feedback on magnitude of illusion for the Müller-Lyer illusion were examined. The provision of accurate feedback substantially reduced the magnitude of the Müller-Lyer illusion whereas the influences of inaccurate feedback were dependent upon whether subjects were prompted to overestimate or to underestimate the length of the comparison line.

Perceptual error in the Müller-Lyer and the Horizontal-Vertical illusions was quantified using nonparametric signal-detection measures of sensitivity and response bias. Sensitivity scores were positively related to signal strength with the greatest values observed for the strongest signals. Sensitivity at each signal strength did not differ between the two illusions. Response-bias scores were inversely related to signal strength, with the most conservative biases observed for the strongest signals. Response biases for each signal strength were significantly more conservative for the Horizontal-Vertical than for the Müller-Lyer illusion.

The effectiveness of an early intervention program to remediate developmental delays in children age birth to 3 years was examined in part- and full-time groups (Study 1). Significant improvements on age-appropriate measures of developmental standing were observed for both groups, with the greatest gains observed for the full-time group. In Study 2, the stress of parents with developmentally delayed children was measured on the Parental Stress Inventory. Reductions in stress related to children's characteristics and dysfunctional parenting skills were observed on some subscales, supporting prior research which indicated extension of the outcomes of early intervention beyond the child was desirable.

The influences of hypothyroidism on behavioral measures of the taste function in male and female Long-Evans rats were determined. Experimental rats' preferences for and ability to detect NaCl, HCl, sucrose, and quinine sulfate were examined before, during, and after 9 weeks of maintenance on 0.1% propylthiouracil (PTU), an agent that produces marked hypothyroidism, with similar determinations made for control animals. Despite significant decreases in PTU-treated rats' serum triiodothyronine (T3) and thyroxin (T4), there were no changes in sensitivity or responsivity to the target tastants. However, altered preferences for NaCl, HCl, and quinine sulfate were observed for PTU-treated rats; elevated consumption of HCl and quinine sulfate was present at the end of the study when serum T3 and T4 had returned to near-baseline levels. The data confirm observations that PTU-induced hypothyroidism alters rats' taste preference behavior.

NaCl thresholds and ability to discriminate between NaCl and sucrose were assessed in rats using an operant discrimination conditioning procedure before and during moderate and severe zinc deprivation and during zinc supplementation. NaCl thresholds were approximately 1 mM before dietary zinc manipulation. They increased in all zinc-deprived rats tested 10 and 17 days after initiation of deprivation but did not change in pair-fed controls maintained on supplemental zinc. Threshold changes were greater for those rats severely zinc deprived than for those only moderately deprived and were greater as the period of deprivation lengthened. Plasma zinc concentrations decreased significantly in deprived rats from values obtained at baseline, values in severely deprived rats being significantly lower than in those only moderately deprived. Although zinc-deprived rats discriminated NaCl from sucrose, they made more discrimination errors than controls. Following 24 days of zinc supplementation, previously deprived rats exhibited no significant improvement in gustatory performance, although their body weight increased and plasma zinc concentrations increased; but these later changes were not significant. These results demonstrate that zinc deprivation induces decreased gustatory sensitivity and confirm a role for zinc in taste.

The influences of three methyl xanthines (MX) on human taste responsivity, caffeine, theophylline, and theobromine, were examined using blind control procedures. Taste responsivity in the same subjects was determined using the matching procedure described by Schiffman (Study 1) and the whole-mouth procedure described by Sheperd (Study 2). In each study, the duration of MX pretreatment necessary to enhance taste responsivity was examined. No potentiation of overall- and taste-quality specific intensity ratings was observed for any tastant, independent of test procedure, type, and concentration of MX pretreatment, or length of MX pretreatment. Taste intensity ratings, especially for NaCl, were higher following pretreatment with water than methyl xanthine or adenosine combined with caffeine. Adenosine, added at several concentrations to caffeine pretreatments, influenced neither taste responsivity nor taste intensity ratings.

Taste detection performance for representatives of the four taste qualities as a function of stimulus volume (5 x 10(-4) to 1 x 1(-1) ml) was examined in rats using high-precision gustometry, computer-controlled operant procedures, nonparametric signal detection measures of sensitivity and responsivity, and blind control procedures. The overall sensitivity index was positively related to stimulus volume (rs = .60), with optimal detection performance attained with a 5 x 10(-3) ml stimulus volume for salty tastants and a 1 x 10(-2) ml stimulus volume for the other taste qualities. The overall responsivity index was inversely related to stimulus volume (rs = -.47), especially for sour and bitter tastants. These results are consistent with prior observations and demonstrate that operant methods using small tastant samples produce sensitive estimates of the rat's taste detection performance and response bias.

The influence of adrenalectomy (ADX) on the odor detection performance of male Long-Evans rats was assessed using high-precision olfactometry and a go/no-go operant signal detection task. Nonparametric signal detection measures of sensitivity and responsivity, as well as measures of S+ response latency, the number of aborted trials, and session time, were obtained in daily 250-trial test sessions prior to and after adrenalectomy. Four ADX animals were tested using the odorant pyridine, three using the odorant eugenol, and two using the odorant ethyl acetate. Nine other rats served as sham-operated controls. Neither odor detection nor related nonsensory performance measures were influenced by adrenalectomy or sham-operation procedures. These results imply that adrenalectomy has little or no influence on the odor detection performance of the rat.

The present study examined procedure-specific differences in the acquisition and retention of perceptual learning using four forms of the Horizontal-Vertical illusion. Training to criterion was conducted using intertrial feedback, continued visual inspection, or yoked-control procedures. Retention of perceptual learning was assessed at posttraining intervals ranging from 1 minute to 1 month. Subjects trained with feedback achieved criterion in fewer trials and showed greater accuracy and short-term retention of perceptual learning on the inverted-T figure and the 1-in. vertical line-production task. The present results show that the correction of inaccurate strategic factors most likely represents the temporary acquisition of compensatory strategies that facilitate performance on simple perceptual-motor skills tasks.

The influences of early crawling experience on motor skill development were examined in children identified by parents as crawlers or noncrawlers during early infancy. Relative to the performance of crawlers, noncrawlers showed lower average and subtest-specific performance on selected measures of the Miller Assessment for Preschoolers. These results, interpreted through Ayres' sensory integration theory and applied to current occupational therapy practice, support Farber's hypothesized importance of early crawling experience in the development of sensory and motor systems of the body and general motor skill development.

Taste sensitivity and responsivity, two-tastant and taste-mixture discrimination performance, and taste preferences were examined prior to and after the selective desalivation of 48 male Long-Evans rats. Altered preference behavior was observed in rats after removal of the major salivary glands, as well as after removal of only the submandibular-sublingual complexes. In 9 of 12 desalivated rats, decreased sensitivity and increased responsivity to near-threshold sodium chloride solutions were observed, although these changes were less than one-half an order of magnitude. No between-group differences in performance on two-tastant and taste-mixture discrimination tasks were observed. These results suggest that decrements in absolute sensitivity do not result in concomitant deficits in the discrimination of taste qualities.

The influence of 33 days of combined dietary sodium and water deprivation on the taste sensitivity and responsivity of the rat to a wide range of NaCl solutions and discrimination tasks was examined using double-blind procedures, high-precision gustometry, and an automated operant go/no-go task. Sodium concentration in urine and saliva but not plasma decreased significantly only in the sodium-deficient rats. The same measures remained unchanged in control animals. Nonparametric measures of taste sensitivity and responsivity to NaCl did not differ between sodium-deficient and control animals and performance on taste discrimination, reversal learning, and lick-rate tasks remained the same between the groups as well. The present results support and extend previous findings that dietary-induced sodium deficiency increases NaCl and water consumption, but alters neither the sodium-deficient rat's taste sensitivity and responsivity nor performance on simple and complex tasks in which tastants serve as cues for discriminative responding.

The present study examined potential differences in structural and strategic factor estimates involved in the Horizontal-Vertical (HV) illusion. Performance on adjustment and production-task forms of the illusion was examined under the conditions of intertrial feedback, continued visual inspection, combined feedback and visual inspection, as well as control procedures. Estimates of structural and strategic factors were procedure-specific and, for each task, the correction of inaccurate strategic factors was significantly greater for the feedback than the visual-inspection and control groups. There were no significant additive effects when feedback was combined with visual inspection. The illusion results from an overestimation of the length of vertical lines, seems to be predominantly cognitive in nature, and exists in the absence of line bisection and a comparison line.

An operant conditioning procedure is described for assessing taste detection and discrimination in rats. Rats were trained to lick at a 10-barrel stimulus delivery tube for a 0.005-ml sample of a positive (S+) or negative (S-) stimulus and to switch to a water delivery tube after presentation of S+. The system is computer controlled and selection of stimuli can be made interactive with performance. After preliminary training, absolute and intensity-difference thresholds can be determined in 1-2 sessions. Mean absolute thresholds in 10 rats for NaCl, sodium-saccharin, and sucrose were 0.0049%, 0.0012%, and 0.035%, respectively. Intensity-difference thresholds (not reported previously in the rat) for NaCl and saccharin were 16.1% and 12.3%, respectively. With these procedures rats also rapidly acquired 2-tastant discriminations, including those involving taste mixtures.

The Horizontal-Vertical (HV) Illusion was examined in two studies in which subjects adjusted the vertical line in L-shaped and inverted-T figures or produced lines in the vertical and horizontal planes. On the adjustment tasks, vertical lines were made significantly shorter than horizontal comparison lines, especially for the inverted-T figure. On the production tasks, lines drawn in the vertical plane were significantly shorter than lines drawn in the horizontal plane. The adjusted and created lines of subjects receiving intertrial feedback on illusion magnitude were significantly more accurate and less variable than the estimations of control subjects. Performance on either task or figure type did not differ as a function of sex of subject. The present results show that the HV illusion exists in the absence of line bisection or a comparison line and results from the overestimation of vertical lines. These findings further clarify the relative contributions of the structural and strategy mechanisms in the formation of the Horizontal-Vertical Illusion.

The effects of dietary copper and Vitamin B-6 deficiency on NaCl sensitivity in adult male rats were assessed in separate studies using a double-blind protocol, high-precision gustometry, computer-controlled go/no-go operant procedures and signal detection measures of sensitivity and responsivity. The dietary manipulations reduced plasma copper ion content to 40% of baseline levels in the copper deficient group and plasma 5'-pyridoxalphosphate content to 5% of baseline levels in the Vitamin B-6 deficient group and, as expected, altered hematocrit and hemoglobin levels in both groups. These metabolic changes resulted in increased NaCl preference in the Vitamin B-6 deficient group but did not alter sensitivity or responsivity to NaCl, and similar results were obtained in simple and complex taste discrimination tests. The present results demonstrate that dietary copper and Vitamin B-6 deficiencies do not result in altered taste sensitivity in the adult male rat.

Taste detection thresholds for sodium chloride, sucrose, citric acid and quinine sulfate were determined with the Henkin three drop forced-choice method at stimulus volumes 0.05 ml, 0.50 ml, and 0.90 ml, with and without water rinses. Taste thresholds were inversely related to stimulus volume (median rs = -.68 and, within each volume, thresholds did not differ as function of water rinsing. The detection thresholds for sodium chloride (range: 15.06 mM to 6.7 mM), sucrose (range: 24.22 mM to 14.13 mM), citric acid (range: 1.47 mM to 0.5 mM) and quinine sulfate (range: 0.35 mM to 0.12 mM) were similar to those of other investigators using considerably larger stimulus volumes and different psychophysical procedures. The present results demonstrate that the Henkin three drop method provides a more optimal measure of changes in taste sensitivity when stimulus volumes of approximately 1 ml are used in place of the standard 0.05 ml stimulus volume.

The influence of adrenalectomy on the taste sensitivity and responsivity of Long-Evans rats to sodium chloride and sucrose tastants presented separately and in mixtures was examined using high precision gustometry, computer-controlled go/no-go operant procedures, and nonparametric signal detection measures. Relative to baseline levels, adrenalectomized rats' plasma corticosterone levels decreased by 328% while sodium chloride and water consumption increased by 548% and 165%, respectively. The same measures remained unchanged in sham-operated animals. Taste sensitivity and responsivity to sodium chloride and sucrose did not differ between adrenalectomized and sham-operated animals and discrimination performance remained the same between the groups as well. The present results support and extend previous findings that adrenalectomy and the resultant corticosteroid deficiency does not influence taste sensitivity or responsivity in the rat.