Expression of flavor preference depends on type of test and on recent drinking history.

The persistence of a conditioned flavor preference was examined in 3 experiments. All contained an initial acquisition phase in which half the rats were given almond odor mixed with sucrose (AS) in some sessions and water (W) only in other sessions, whereas the other half (controls) were given explicitly unpaired exposures to almond (A) and sucrose (S) in separate sessions. Subsequent 2-bottle choice tests revealed a persistent preference for A, despite extinction exposure to A or S, but this depended on the choice offered on test: Exposure to A did not extinguish the preference for A over W but did reduce the preference for AS over S; conversely, exposure to S did not extinguish the preference for AS over S but did reduce the preference for A over W. These results indicate that flavor preferences can be resistant to extinction procedures but suggest that the expression of such preferences in choice tests depends on an adaptation-level process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tracking with a differential brightness display: I. Acquisition and transfer.

An experiment was conducted that investigated the comparative tracking performances using a differential brightness display (DBD) and a conventional positional display. The results indicated superior tracking performance with the positional display. When the percentage reduction of system error at the completion of training was computed, the differences between display groups was minimal. The inability of S to maintain precisely the same level of performance with the brightness display as with the positional display was attributed to an "area-of-uncertainty" around the reference brightness. Distinctions were made regarding performance between "early learning" and "late learning" for both displays. It was suggested that, during early learning, S established control-display relationships and learned the nature of the forcing function. During late learning, S's performance consisted of finer control adjustments. These adjustments were much finer for the positional display than for the DBD because of the area-of-uncertainty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retention of three brightness discriminations by rats following posterior cortical lesions.

Trained 60 male Long-Evans hooded rats on 1 of 3 brightness discriminations. In 1 task, the discriminanda differed in both luminance and luminous flux. In the 2nd task, the discriminanda differed only in terms of luminous flux. In the 3rd task, the discriminanda differed only in terms of luminance. Following acquisition, 1/2 of the Ss on each task underwent removal of the striate cortex. Retention tests indicate that a discrimination based on flux cues was relatively undisturbed following striate cortex removal, whereas a discrimination based on luminance cues appeared to be permanently lost. Transfer discrimination tests indicate that deficits other than sensory impairments may follow striate ablation. Results are discussed in terms of sensory and attentional deficits which occur with striate cortex removal. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tests of a model of binocular brightness.

Tested a model of binocular brightness mixing which describes binocular brightness as the vector sum of the 2 monocular brightnesses where each monocular brightness is weighted according to an autocorrelation function that measures the relative amounts of contour and contrast in the 2 monocular views. 3 experiments were carried out with 2 Os, and show that binocular brightness interactions depend on the size and shape of the monocular stimuli in ways predicted by the model. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acute alcohol intoxication disrupts brightness but not olfactory conditioning in preweanling rats.

The present experiments tested the effect of acute alcohol administration on Pavlovian conditioning of 21-day-old rats using conditioned stimuli of two different sensory modalities—olfaction, an early developing sensory capacity functional at birth, and vision, a later developing sensory system not becoming functional until approximately 15 days of age. Conditioning and testing were conducted between 30 and 60 min following gastric intubation with either physiological saline or a mildly intoxicating alcohol dose (1.5 g/kg body weight). Brain alcohol levels were observed to remain at a peak and stable concentration during this period (Experiment 1). Alcohol impaired acquisition or expression of conditioned aversions to a visual cue paired with footshock when presented either as a single-element conditioned stimulus or as part of an odor/visual compound stimulus (Experiment 2), but it had no discernible effect on conditioned aversions to an olfactory stimulus that had similarly been paired with footshock (Experiments 2 and 3). The results suggest that alcohol may impair some aspects of learning but spare others, depending perhaps on the particular sensory modality to be conditioned. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioned preferences in the rat with an unnatural need state: Morphine withdrawal.

Placed 30 morphine addicted and 15 nonaddicted female albino rats on a 21-day conditioning regimen which involved the daily alternation of access to either water, sucrose-octa-acetate (SOA), or no liquid for 1 hr. The addicted Ss received injections of morphine after either the SOA sessions or the no-liquid sessions. Nonaddicted Ss were injected with morphine after the SOA sessions. Following the last injection, Ss were given a 2-bottle preference test between SOA and water. Results show that the addicted Ss that received morphine-SOA pairings had an increased preference for SOA, whereas the nonaddicted Ss showed a decrease in SOA preference after the same conditioning treatments. Addicted Ss that received the morphine injections on the no-liquid days showed no change in SOA preference. (21 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory stimulation induces filial preferences for huddling in rat pups.

Rat pups of all ages huddle with conspecifics, but the sensory control of contact behavior changes ontogenetically. Thermal cues control huddling until about Day 15, at which time species' odors become the dominant stimulus. The present 2 experiments with 150 Sprague-Dawley rat pups indicate that the filial response to conspecifics is dependent on olfactory experience. A synthetic chemical scent was added to the smells of the dam from Day 1 to Day 20 postpartum. Standardized videographic tests were used to assess the development of huddling preference. Preferences for nest-typical smells emerged by Day 15 in Ss from both scented and nonscented litters. Ss from scented nests preferred to huddle with a scented stimulus rat, whereas control Ss preferred a nonadulterated rat stimulus. Additional testing indicated that the affirmative preferences were specific to rearing odor and were not based on decreased aversion to test scents or on disrupted olfactory discrimination. The ontogeny of species-typical contact behavior is discussed in terms of the induction of a perceptual preference that is based on early odor stimulation. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Binocular brightness: A suppression-summation trade off.

Two experiments with 22 undergraduates estimated binocular brightness of targets of large visual extent. On each trial one eye was presented with a fairly intense luminance of 800 cd/m–2, and the other eye with 1 of 12 luminances ranging from zero to 800 cd/m–2. Exp 1, using ganzfeld stimuli, produced a large amount of binocular brightness summation and very little Fechner's paradox, a decrease in binocular brightness that occurs when the luminances to the 2 eyes differ greatly. Exp 2, using a smaller target with very low spatial frequencies, produced greater Fechner's paradox than the ganzfelder, but more binocular summation and less Fechner's paradox than what is usually reported for small targets with abrupt contours. Results suggest a trade-off between suppressive and summative mechanisms involving binocular cells that are spatially tuned. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of immediately preceding task brightness on visual performance.

To determine how visual performance at low photopic brightness levels is affected by the brightness of an immediately preceding visual task, Ss were required to read photographs of banks of instrument dials (a near-vision task) and banks of Landolt rings (a far-vision task) after adaptation to the brightness level of the first task, under speed and accuracy instructions. The Ss performed both the near and far tasks. Within the brightness ranges used, performance was related to the brightness of the task but not to the brightness of the immediately preceding task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coefficients of brightness of sintered alloys

Summary The author measured the coefficients of brightness of several sintered copper-nickel alloys at various stages of homogenization. The brightness coefficient always increases at the beginning of homogenization. For comparison, coefficients of brightness were calculated on the basis of relationships between the latter and concentration, as well as computed concentration distributions. Definite agreement was found between the experimental and calculated data.Translated from Poroshkovaya Metallurgiya, No. 11(47), pp. 39–42, November, 1966.The author is indebted to L. O. Zhenin-Maiskaya for assistance in this investigation.     

Tracking with a differential brightness display: II. Peripheral tracking.

Tracking performances were compared using a differential brightness display (DBD) and a conventional positional display when both displays were moved to the periphery. Results of a previous study and the present study have shown that performance with the positional display was superior to performance with the DBD when the S looked directly at them. As the displays were moved to the peripheral visual areas (15°, 30°, and 45° eccentricity) the reverse of this was true, performances with the DBD were superior. This was reflected both in the actual performance scores and the amount of time S spent looking toward the displays. These results were interpreted in terms of the underlying physiology of the retina and control movements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prenatal experience and postnatal perceptual preferences: Evidence for attentional-bias in bobwhite quail embryos ( Colinus virginianus).

Previous studies have indicated that concurrent multimodal sensory stimulation can interfere with prenatal perceptual learning. This study further examined this issue by exposing 3 groups of bobwhite quail embryos (Colinus virginianus) to (a) no supplemental stimulation, (b) a bobwhite maternal call, or (c) a maternal call paired with a pulsating light in the period prior to hatching. Experiments differed in terms of the types of stimuli presented during postnatal preference tests. Embryos receiving no supplemental stimulation showed no preference between stimulus events in all testing conditions. Embryos receiving exposure to the unimodal maternal call preferred the familiar call over an unfamiliar call regardless of the presence or absence of pulsating light during testing. Embryos exposed to the call-light compound preferred the familiar call only when it was paired with the light during testing. These results suggest that concurrent multimodal stimulation does not interfere with prenatal perceptual learning by overwhelming the young organism's limited attentional capacities. Rather, multimodal stimulation biases what information is attended to during exposure and subsequent testing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On cross-modal similarity: Auditory–visual interactions in speeded discrimination.

A series of four experiments explored how cross-modal similarities between sensory attributes in vision and hearing reveal themselves in speeded, two-stimulus discrimination. When subjects responded differentially to stimuli on one modality, speed and accuracy of response were greater on trials accompanied by informationally irrelevant "matching" versus "mismatching" stimuli from the other modality. Cross-modal interactions appeared in (a) responses to dim/bright lights and to dark/light colors accompanied by low-pitched/high-pitched tones; (b) responses to low-pitched/high-pitched tones accompanied by dim/bright lights or by dark/light colors; (c) responses to dim/bright lights, but not to dark/light colors, accompanied by soft/loud sounds; and (d) responses to rounded/sharp forms accompanied by low-pitched/high-pitched tones. These results concur with findings on cross-modal perception, synesthesia, and synesthetic metaphor, which reveal similarities between pitch and brightness, pitch and lightness, loudness and brightness, and pitch and form. The cross-modal interactions in response speed and accuracy may take place at a sensory/perceptual level of processing or after sensory stimuli are encoded semantically. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of the Stevens exponential function for brightness perception

Study of the brightness scaling function within the range from 2.10(-2) to 3.5.10(3) lk revealed that the total curve of brightness estimation was not exactly Stevens power function within this range: the exponent's value and its deviation was variable in different light regions. Presumably, the luminance's region with minimal value of exponent is the most information for brightness perception. There seems to exist a certain interrelationship between both Veber--Fechner's and Stevens' laws.     

Hand preferences for simple reaching in juvenile chimpanzees (Pan troglodytes): Continuity in development.

Hand preferences were assessed in 51 chimpanzees (Pan troglodytes; 28 male and 23 female) ranging from 2 to 5 years of age. Simple reaching served as the measure of lateral bias in hand preference during 2 assessments separated by 1 year. A significant sex by hand preference interaction was found with a greater prevalence of right-handed males than females. No significant differences were found between age and either strength or direction of hand preference. A significant interaction was found between rearing and strength of hand preference. Mother-reared chimpanzees showed significantly greater strength in hand preference than nursery-reared chimpanzees. Finally, a significant positive correlation was found between tests of hand preference conducted over a 1-year interval. These data suggest that in chimpanzees hand preferences are established by 2 years of age and are stable throughout the juvenile developmental period. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lightness, brightness, and brightness contrast: 1. Illuminance variation

Changes of annulus luminance in traditional disk-and-annulus patterns are perceptually ambiguous; they could be either reflectance or illuminance changes. In more complicated patterns, apparent reflectances are less ambiguous, letting us place test and standard patches on surrounds perceived to be different grays. Our subjects matched the apparent amounts of light coming from the patches (brightnesses), their apparent reflectances (lightnesses), or the brightness differences between the patches and their surrounds (brightness contrasts). The three criteria produced quantitatively different results. Brightness contrasts matched when the patch/surround luminance ratio of the test was approximately equal to that of the standard. Lightness matches were illumination invariant but were not exact reflectance matches; the different surrounds of test and standard produced a small illumination-invariant error. This constant error was negligible for increments, but, for decrements, it was approximately 1.5 Munsell value steps. Brightness matches covaried substantially with illuminance.     

Behavioral measurement of thermal pain sensitivity in humans: Effects of stimulus intensity and instructions.

This study validated a human behavioral model of thermal nociception analogous to the rodent tail-flick assay. Effects of instructions and stimulus intensity on behavior (i.e., finger withdrawal latency) were evaluated. Using a repeated measures randomized crossover design, the authors exposed 10 volunteers to varying radiant heat intensities (from 42.2 to 52.2 degrees Celsius) during each of 4 sessions. In the different sessions, participants were told to remove their finger when they felt heat, felt unpleasant, felt pain, or could no longer tolerate pain. Withdrawal latencies significantly decreased as stimulus intensity increased and significantly increased for sensory, affective, pain, and intolerance instructions. Instruction set differences were significantly larger at higher stimulus intensities. this technique may be useful in human psychopharmacological research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of attachment in differentially reared infant monkeys (Macaca radiata): Response to separation and a novel environment.

Observed infants from 2 environments, either low foraging demand or variable foraging demand for their mothers, to assess the developmental consequences of rearing environments for 12 infant bonnet macaques under 2 test conditions after the completion of the differential rearing treatment. One of the test conditions involved introduction of the rearing cohorts to a novel room; this was done in 2 series of 4 1-hr sessions: a series before and a series after completion of the 2nd test condition. The 2nd test condition involved a 20.5-hr removal of each mother from the rearing cohort; this was repeated once a week for 3 wks. Results of the novel room tests effectively differentiated rearing treatments in this study and suggested group differences in attachment security. In contrast, the maternal separations failed to differentiate treatments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of pencil-and-paper and tactile-board forms of the Self-Directed Search.

Compared the equivalence of scores and preference for 2 forms of the Self-Directed Search (SDS). During the 1st testing session, 48 undergraduates were alternately assigned to complete the pencil-and-paper or tactile-board forms of the SDS. One week later, each S completed the other form of the SDS and a questionnaire designed to assess their preference for 1 of the 2 forms. Results indicate that the 2 forms were equivalent. There was no difference between Ss' overall preference for one form or the other; however, differential preferences did emerge when S sex and GPA were taken into account. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Species-specific auditory preference of bobwhite quail chicks (Colinus virginianus) is altered by social interaction with siblings.

The study examined whether reinstating specific aspects of the normally occurring postnatal setting (ongoing social interaction with siblings during rearing and/or testing) would influence bobwhite quail chicks' attraction to their species-typical maternal call. Results revealed that incubator-reared chicks exhibit a strong preference for the species-typical bobwhite maternal call over a group of the same-aged siblings in simultaneous choice tests at 24 hr and 48 hr after hatching, but only if the birds are kept in relative social isolation. No preference for the maternal call was found at 24 hr or at 48 hr if chicks were reared in a group of same-aged chicks from hatching and tested to the maternal call vs. siblings or the maternal call paired with a live adult bobwhite hen vs. siblings. These results raise doubts about the appropriateness of the usual methods of isolation rearing in the study of species-typical perceptual preferences and underscore the importance of considering features of the natural social context in the analysis of early perceptual and social behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)