Reasoning and the weighting of attributes in attitude judgments.

Two experiments examined processes by which analyzing reasons may influence attitude judgments. Participants made multiple liking judgments on sets of stimuli that varied along 6 a priori dimensions. In Study 1, the stimulus set consisted of 64 cartoon faces with 6 binary-valued attributes (e.g., a straight vs a crooked nose). In Study 2, the stimuli were 60 digitized photographs from a college yearbook that varied along 6 dimensions uncovered through multidimensional scaling. In each experiment, half of the participants were instructed to think about the reasons why they liked each face before making their liking rating. Participants' multiple liking ratings were then regressed on the dimension values to determine how they weighted each dimension in their liking judgments. The results support a process whereby reasoning leads to increased variability and inconsistency in the weighting of stimulus information. Wilson's model of the disruptive effects of reasoning on attitude judgments ( e.g., T. D. Wilson, D. S. Dunn, D. Kraft, & D. J. Lisle, 1989 ) is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Signal detection and threshold measures for chronic back pain patients, chronic illness patients, and cohort controls to radiant heat stimuli.

15 chronic low back pain patients, 11 chronic respiratory patients, and 11 nonpatient controls (mean ages 47–56 yrs) were studied using a standard radiant heat signal detection methodology. Following determination by ascending limits of each S's stimulus detection and faint pain thresholds, 26 randomized trials at each of 5 stimulus levels were administered. Ss rated each stimulus on a 6-point subjective rating scale ranging from no pain to severe pain. Results indicate that the back pain Ss and respiratory Ss had higher radiant heat pain thresholds than the controls, and the back pain Ss had a discrimination deficit for mildly painful stimuli. Results fit the predictions of an adaptation model of pain perception in chronic pain patients as opposed to a hypochondriasis model. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Body site variation of cool perception thresholds, with observations on paradoxical heat

Thresholds for the perception of coolness and heat pain were determined in sessions that randomly intermixed temperature increases and decreases. Four body sites were tested bilaterally: thenar eminence of the hand, plantar surface of the foot, dorsolateral forearm, and lateral calf. Coolness thresholds were lowest for the hand, intermediate for the forearm, and highest for the leg and foot. Laterality differences were not statistically significant. In 34% of the sessions, subjects did not consistently report cool or cold sensations with detectable temperature decreases. When they did not report cool or cold, they most often reported heat or pain, thus exhibiting the phenomenon of "paradoxical heat." There were significantly more paradoxical heat responses when cooling stimuli were intermixed with painfully hot stimuli than when they were intermixed with only warm stimuli. There was no significant correlation observed between thresholds for coolness and heat pain, either across body sites or across subjects at any single body site. This result implies that the various factors relevant to thermal sensitivity (i.e., thermal properties of the epidermis, innervation density) are differentially important for cool versus heat pain perception.     

Attention, exposure duration, and gaze shifting in naming performance.

Two experiments are reported in which the role of attribute exposure duration in naming performance was examined by tracking eye movements. Participants were presented with color-word Stroop stimuli and left- or right-pointing arrows on different sides of a computer screen. They named the color attribute and shifted their gaze to the arrow to manually indicate its direction. The color attribute (Experiment 1) or the complete color-word stimulus (Experiment 2) was removed from the screen 100 ms after stimulus onset. Compared with presentation until trial offset, removing the color attribute diminished Stroop interference, as well as facilitation effects in color naming latencies, whereas removing the complete stimulus diminished interference only. Attribute and stimulus removal reduced the latency of gaze shifting, which suggests decreased rather than increased attentional demand. These results provide evidence that limiting exposure duration contributes to attribute naming performance by diminishing the extent to which irrelevant attributes are processed, which reduces attentional demand. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Perception of cliff swallow calls by birds (Hirundo pyrrhonota and Sturnus vulgaris) and humans (Homo sapiens).

Tested for species differences in the perception of the cliff swallow chick begging call. One cliff swallow, 3 European starling, and 3 human Ss were trained on go–no-go or repeating background tasks to discriminate between all possible stimulus pairs, measured by percentage of correct response and latency. Multidimensional scaling was used to convert the similarity measures into a 2-dimensional map for each S. Most of the maps were significantly correlated in Dimension 1 but not in Dimension 2. A cluster analysis separated bird and human maps. To identify the most important acoustic cues for each S, the coordinates of each dimension were regressed on acoustic variables measured from the stimuli. For all Ss, center frequency was Dimension 1. Different acoustic cues were associated with Dimension 2, with agreement only on bandwidth, by the cliff swallow and 1 starling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cytogenetic and molecular analysis of dynamic mutation associated with fragile X syndrome

The gate control theory of pain (Melzack and Wall, 1965) suggests that tactile stimuli can decrease the perception of pain. We have found the reverse effect: Heat at levels that induce pain can substantially suppress tactile sensitivity, independently of shifts in attention or arousal. Ten human observers were stimulated by a tonic, pain-producing heat stimulus and vibrotactile stimuli (1, 10, and 100 Hz) coincidentally presented to the right thenar eminence. Vibrotactile thresholds were assessed with the skin at a normative temperature of 31 degrees C and at higher temperatures producing pain. Increases in vibrotactile thresholds (mean change = 7.3 dB) occurred at skin temperatures just below and above those that induced pain. Furthermore, absolute-magnitude estimates of suprathreshold vibrotactile stimuli determined during the same experiments showed decreased sensitivity and psychophysical recruitment. The changes are not attributable to attentional or arousal shifts, since they were not associated with changes in auditory thresholds. Furthermore, the changes occurred just below the subjects' pain thresholds (where nociceptors are presumably activated). This over-twofold diminution of vibrotactile sensitivity suggests that heat stimuli capable of inducing pain can significantly diminish taction, perhaps through a "touch gate" in a manner similar to the gate control theory proposed for pain.     

Quantitative modeling of visual attention processes in patients with Parkinson's disease: Effects of stimulus integrality on selective attention and dimensional integration.

Parkinson's disease (PD) patients and normal controls (NCs) were administered a series of visual attention tasks. The dimensional integration task required integration of information from 2 stimulus dimensions. The selective attention task required selective attention to 1 stimulus dimension while ignoring the other stimulus dimension. Both integral- and separable-dimension stimuli were examined. A series of quantitative models of attentional processing was applied to each participant's data. The results suggest that (a) PD patients were not impaired in integrating information from 2 stimulus dimensions, (b) PD patients were impaired in selective attention, (c) selective attention deficits in PD patients were not due to perceptual interference, and (d) PD patients were affected by manipulations of stimulus integrality and separability in much the same way as were NCs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integration of health care economics for addiction treatment in clinic care

Visceral pain is a substantial, clinical problem but unfortunately few experimental models are available to study this phenomenon in man. In the present study we inserted a stimulation catheter 5-10 cm into the ileo-sigmoidostomy of nine patients. The catheter contained six small, flexible electrodes separated by 4 mm. The gut was stimulated by single burst, repeated burst (five stimuli delivered at 2 Hz), or continuous burst stimuli (4 Hz for 30, 60, 90, and 120 s). The sensation (ST), pain detection (PDT), and pain tolerance (PTT) thresholds to single/repeated burst stimuli were determined. The location/size/sensitivity of referred pain after repeated/continuous stimulation were characterized. The brain potentials to single burst stimuli and to increasing stimulus intensity were measured. ST to single burst stimuli was easy to determine (8 mA) and to reproduce. The patients found it difficult to determine the PDT and PTT to single burst stimuli, however both thresholds were easily determined for repeated burst stimuli. The pain thresholds to single burst stimuli were twice as high as the thresholds to repeated burst stimuli, indicating the importance of central temporal summation for visceral pain. Minor changes in the stimulus location resulted in changes of the referred pain projection site. The words most frequently selected (78%) from the McGill Pain Questionnaire to describe repeated burst stimulations were shooting, pricking, flashing, and boring. The amplitude of the brain potentials increased at increasing stimulus intensity. A stimulus intensity giving an initial pain rating of around 5 on a 0-10 visual analog scale (VAS) was used for continuous stimulation. A general increase of the pain intensity and the area of referred pain was found during this stimulation. It was concluded that electrical stimulation of the human gut provokes pain and especially long sequences of visceral stimuli are adequate to evoke referred pain mimicking pain profiles of pathologic origin.     

Dual temporal pitch percepts from acoustic and electric amplitude-modulated pulse trains

Two experiments examined the perception of unmodulated and amplitude-modulated pulse trains by normally hearing listeners and cochlear implantees. Four normally hearing subjects listened to acoustic pulse trains, which were band-pass filtered between 3.9 and 5.3 kHz. Four cochlear implantees, all postlinguistically deaf users of the Mini System 22 implant, listened to current pulse trains produced at a single electrode position. In the first experiment, a set of nine loudness-balanced unmodulated stimuli with rates between 60 and 300 Hz were presented in a multidimensional scaling task. The resultant stimulus spaces for both subject groups showed a single dimension associated with the rate of the stimuli. In the second experiment, a set of ten loudness-balanced modulated stimuli was constructed, with carrier rates between 140 and 300 Hz, and modulation rates between 60 and 150 Hz. The modulation rates were integer submultiples of the carrier rates, and each modulation period consisted of one higher-intensity pulse and one or more identical lower-intensity pulses. The modulation depth of each stimulus was adjusted so that its pitch was judged to be higher or lower 50% of the time than that of an unmodulated pulse train having a rate equal to the geometric mean of the carrier and modulation rates. A multidimensional scaling task with these ten stimuli resulted in two-dimensional stimulus spaces, with dimensions corresponding to carrier and modulation rates. A further investigation with one normally hearing subject showed that the perceptual weighting of the two dimensions varied systematically with modulation depth. It was concluded that, when filtered appropriately, acoustic pulse trains can be used to produce percepts in normal listeners that share common features with those experienced by subjects listening through one channel of a cochlear implant, and that the central auditory system can extract two temporal patterns arising from the same cochlear location.     

Experimental manipulation of therapeutic conditions.

The authors explore the heretofore vague "something more" attributed to the therapeutic relationship by experimentally demonstrating the effect of just 2 almost universally posited therapist-offered conditions which make for a "meaningful" interpersonal relationship, warmth and empathic understanding, upon 1 critical aspect of patient behavior in therapy, patient intrapersonal exploration. The authors characterize the therapeutic relationship as a stimulus complex within which the relearning process takes place most deeply and most efficaciously. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of geometric image distortions at various eccentricities

PURPOSE: Human ability to perceive spatial stimuli declines with increasing eccentricity. To study this phenomenon with natural images, the authors applied the spatial scaling method by measuring the smallest detectable amount of geometric change in a human face at several eccentricities for a series of stimulus magnifications to find out whether performance could be made equal across the visual field simply by an appropriate enlargement. METHODS: The authors used a novel method to produce subtle changes to an image of a face. The smallest change recognized was determined using a two-alternative forced-choice method and expressed in terms of correlation sensitivity, the inverse of the correlation between the images that just could be discriminated. RESULTS: The detection of changes in the facial features, presumably a spatially complex task, became equal across the visual field simply by an appropriate change of scale. The E2 value represents the eccentricity at which the foveal stimulus size must double to maintain performance at the foveal level. The E2 values, found to be 1.73 degrees to 2.45 degrees, were similar to our previously measured values for vernier acuity, orientation discrimination, and curvature detection and discrimination, obtained with the same method of spatial scaling. CONCLUSIONS: The authors' results indicate that with adequate stimulus magnification, one is capable of detecting geometric changes in complex images such as face equally at the fovea and in the periphery. In this task, there seems to be no qualitative difference between the accuracy of foveal and peripheral processing.     

The object-based Simon effect: Grasping affordance or relative location of the graspable part?

Reaction time is often shorter when the irrelevant graspable handle of an object corresponds with the location of a keypress response to the relevant attribute than when it does not. This object-based Simon effect has been attributed to an affordance for grasping the handle with the hand to the same side. Because a grasping affordance should differentially affect keypress responses only when they are made with different hands, we conducted three experiments that measured the object-based Simon effect for frying pan stimuli using between- and within-hand response sets. When the relevant stimulus dimension was color, neither the object-based Simon effect nor the location-based Simon effect varied across response sets. When upright-inverted orientation judgments were made for the frying pan and for nongraspable stimuli derived from it, there again was no significant difference in size of the between- and within-hand Simon effects for any of the stimuli. The results provide evidence that the Simon effect for graspable frying pan stimuli is because of relative location of the handle and not to a grasping affordance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorization of sounds.

The authors conducted 4 experiments to test the decision-bound, prototype, and distribution theories for the categorization of sounds. They used as stimuli sounds varying in either resonance frequency or duration. They created different experimental conditions by varying the variance and overlap of 2 stimulus distributions used in a training phase and varying the size of the stimulus continuum used in the subsequent test phase. When resonance frequency was the stimulus dimension, the pattern of categorization-function slopes was in accordance with the decision-bound theory. When duration was the stimulus dimension, however, the slope pattern gave partial support for the decision-bound and distribution theories. The authors introduce a new categorization model combining aspects of decision-bound and distribution theories that gives a superior account of the slope patterns across the 2 stimulus dimensions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effects of CO2 laser in treatment of cervical dentinal hypersensitivity

The effectiveness of CO2 laser therapy in the reduction and elimination of dentinal hypersensitivity in vivo and its thermal effects on tooth surfaces in vitro were investigated. Twenty-three patients with 91 sensitive teeth participated in this study and were followed for 3 months. The parameters used with CO2 laser were 1 W in a continuous wave mode and irradiation time ranging from 5 to 10 s. Hypersensitivity was assessed by thermal stimulus (a blast of air from a dental syringe). Thermal effects were measured by thermography using 10 extracted human teeth. After laser treatment, all patients were immediately free from sensitive pain. Over 3 months, the CO2 laser treatment reduced dentinal hypersensitivity to air stimulus by 50%. All teeth remained vital with no adverse effects. Thermography revealed no temperature increase on irradiated tooth surfaces subjected to water coolant. These results show that the CO2 laser is useful in the treatment of cervical dentinal hypersensitivity without thermal damage to pulp.     

Discrimination of Multidimensional Visual Stimuli by Mice: Intra- and Extradimensional Shifts.

A visual discrimination protocol similar to that used with monkeys was adapted to measure attentional set-shifting in mice. An automated touchscreen procedure with compound visual stimuli was used to train mice to attend to 1 of 2 stimulus dimensions (lines or shapes). On a 2nd problem with new stimuli, the mice were required to attend to the same dimension (intradimensional [ID] shift) or switch to the previously irrelevant dimension (extradimensional [ED] shift). Mice readily learned the initial compound discrimination and following shift problem, but there was no ID-ED difference. The fact that mice can be tested with stimuli and task sequences similar to those used with primates suggests that this method can be used to directly compare higher cognitive functions in diverse species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emerging attributes in monkey short-term memory.

Conducted 2 experiments to examine the role of recency information and stimulus novelty and familiarity in delayed-matching-to-sample (DMTS) performance. Five female 5–8 yr old macaques (one of which was not included in Exp II) were tested on DMTS problems in which the correct and incorrect choice stimuli were both familiar, both relatively novel, or different in familiarity. Initially, novelty and familiarity exerted their influence as preferences (familiar stimuli were preferred). As more training was given, however, novelty and familiarity began to act as discriminative attributes. For example, Ss came to use the fact that the to-be-remembered stimulus was relatively novel to reject alternative choice stimuli that were more familiar. Theories of animal memory based on a single memory attribute cannot address these results. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interaction between drug discriminative stimuli and exteroceptive, sensory signals.

Interactions between drug discriminative stimuli based on 5.6 and 10 mg/kg sodium pentobarbital (ip) and exteroceptive stimuli (visual and auditory) were studied in 27 male Sprague-Dawley rats in a T-maze. In 3 groups, visual stimuli (light vs dark) were differentially paired with drug stimuli; the 4th group discriminated combinations of tonal frequencies (1 kHz or 10 kHz) and the presence or absence of pentobarbital (10 mg/kg). In general, visual stimuli controlled choice behavior (left or right turn) to a greater extent than did the drug training stimuli, whereas the auditory stimuli exerted no apparent control over the pentobarbital stimulus in Group 4. Tests with higher doses (13.75 and 17.5 mg/kg) indicated augmented stimulus control by the drug dimension in 2 groups (Group 1, 10 mg/kg pentobarbital vs saline; Group 2, 5.6 mg/kg vs 10 mg/kg pentobarbital) but not in the 3rd group (5.6 mg/kg pentobarbital vs saline) in the "conflict" situation, in which the exteroceptive conditions signaled one response whereas the drug stimulus signaled the opposite response. Discrimination training with only one of the stimulus dimensions resulted in stimulus control in the following order: 10 mg/kg vs saline?>?5.6 mg/kg vs saline?>?1 kHz vs 10 kHz. This indicates that the auditory stimuli were of marginal significance. It is concluded drugs can compete with exteroceptive, visual stimuli for associative strength. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pavlovian second-order conditioned analgesia.

Three experiments, with 118 Sprague-Dawley rats, assessed conditioned analgesia in a Pavlovian 2nd-order conditioning procedure by using inhibition of responding to thermal stimulation as an index of pain sensitivity. In Exp I, Ss receiving 2nd-order conditioning showed longer response latencies during a test of pain sensitivity in the presence of the 2nd-order conditioned stimulus (CS) than Ss receiving appropriate control procedures. Exp II found that extinction of the 1st-order CS had no effect on established 2nd-order conditioned analgesia. Exp III evaluated the effects of post 2nd-order conditioning pairings of subcutaneous morphine sulfate (10–20 mg/kg) and the shock unconditioned stimulus/stimuli (UCS). Ss receiving paired morphine–shock presentations showed significantly shorter response latencies during a hot-plate test of pain sensitivity in the presence of the 2nd-order CS than did Ss receiving various control procedures; 2nd-order analgesia was attenuated. Data extend the associative account of conditioned analgesia to 2nd-order conditioning situations and are discussed in terms of the mediation of both 1st- and 2nd-order analgesia by an association between the CS and a representation or expectancy of the UCS, which may directly activate endogenous pain inhibition systems. (52 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Asymmetry of inference in the dishabituation paradigm.

The habituation paradigm is frequently used to assess cognitive development in infants. Habituation to a stimulus by repeated presentation, followed by dishabituation (increased attention to a novel stimulus) is taken to imply discriminability of the novel stimulus. However, infants do not always dishabituate, even when the old and new stimuli are known to be discriminable. It is postulated that failure of dishabituation could be due either to a lack of discriminability of the new stimulus or to failure to relate it to the schema elaborated during habituation. Support for this postulate was obtained in 4 experiments with a total of 200 infants ranging in age from 5.5 to 29 mo. The materials varied from geometric forms through auditory stimuli to conceptual categories. In some cases dishabituation did not occur despite the known discriminability of familiar and novel stimuli. The degree of attention directed toward the new stimulus might better be understood in terms of the degree of discrepancy between the unfamiliar stimulus and the schema for the familiar (the curvilinear discrepancy hypothesis) rather than the ease of discriminability between old and new stimuli. (French abstract) (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structures in two-choice reaction-time data.

This study served (a) to illustrate a maximum likelihood estimation procedure for metric multidimensional scaling applied to speeded same–different judgments, (b) to compare the spatial representations of various stimulus sets derived from dissimilarity data obtained in conditions of data- and resource-limitations with the spatial representations of the same stimulus sets derived from dissimilarity measures collected in conditions of unlimited viewing and/or responding, and (c) to examine the concepts of integrality and separability as they apply to the dimensional decomposability of stimuli. The results showed that although the same spatial metrics best represented perceived dissimilarities for each subject within each stimulus set, individual differences and divergence with results obtained on similar stimulus sets in different conditions were apparent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)