Effect of simultaneous auditory stimulation on vibrotactile thresholds

Vibrotactile thresholds were determined at 250 and 400 Hz in the presence of (1) the sounds emitted by the vibrator, (2) continuous tonal or narrow-band masking noise, or (3) a pulsed tone synchronized with the vibrator signal. The measure of a cross-modality effect was the threshold shift occurring between each condition and the control condition, in which earmuff silencers eliminated the vibrator sounds. Continuous tones or noise had no effect upon vibrotactile thresholds. However, auditory signals synchronized with the vibrator signals did significantly elevate vibrotactile thresholds.     

Effects of the menstrual cycle on vibrotactile sensitivity

Psychophysical thresholds for the detection of vibration delivered to the thenar eminence of the right hands of young males and females were measured every other day for 30–34 days. The frequency of the vibratory stimulus was either 15 or 250 Hz. The sinusoidal stimuli applied through a 3.0-cm² contactor were 700 msec in duration and had rise-fall times of 25 msec. Stimulus amplitude was measured with a calibrated accelerometer mounted on the moving element of the vibrator. Data were plotted as a function of successive days in the menstrual cycle. Thresholds for detecting the 15-Hz stimulus did not change significantly, whereas thresholds for detecting the 250-Hz stimulus varied significantly over the menstrual cycle. The 250-Hz threshold became progressively lower as subjects approached the onset of menstruation. After the onset of menstruation, the 250-Hz threshold gradually increased, reaching a maximum value approximately 12 or 13 days later. Soon after the 12th or 13th day of the cycle, the threshold again began to decline and continued to decline until the onset of the next menstrual cycle. The thresholds of women taking birth control pills did not change systematically over the testing period.     

Vibrotactile loudness addition

Os adjusted the intensity of vibration at a single locus on the right hand to a value equal in vibratory loudness to various patterns of vibration on the left hand. The patterns were created by 1 to 5 equated vibration generators, varied with respect to sensation level and distances among the vibrators. The results were: (a) increasing from 1 to 5 vibrators produced a doubling in vibratory loudness, (b) neither loudness level of the components nor distance among vibrators had any effect on the slope of the overall loudness growth function. as also adjusted the intensity of a white noise to equal in magnitude the patterns of vibration presented (a) to the left hand as before and (b) to loci distributed over the surface of the body. The results were the same as those obtained using a single vibrator as standard. The specific loci stimulated did not appear to have any effect on vibrotactile loudness addition.     

Vibrotactile loudness addition

Os adjusted the intensity of vibration at a single locus on the right hand to a value equal in vibratory loudness to various patterns of vibration on the left hand. The patterns were created by 1 to 5 equated vibration generators, varied with respect to sensation level and distances among the vibrators. The results were: (a) increasing from 1 to 5 vibrators produced a doubling in vibratory loudness, (b) neither loudness level of the components nor distance among vibrators had any effect on the slope of the overall loudness growth function. Os also adjusted the intensity of a white noise to equal in magnitude the patterns of vibration presented (a) to the left hand as before and(b) to loci distributed over the surface of the body. The results were the same as those obtained using a single vibrator as standard. The specific loci stimulated did not appear to have any effect on vibrotactile loudness addition.     

Adventures with the “Plastic Man”: Sex Toys, Compulsory Heterosexuality, and the Politics of Women’s Sexual Pleasure

While previous studies have addressed symbolic implications of lesbian dildo usage and quantitative findings about women’s vibrator use, little research has assessed women’s subjective feelings about using sex toys. This study draws upon qualitative interviews with twenty women from diverse ages and backgrounds to illuminate six themes in women’s narratives about sex toys: (1) emphasis on non-penetrative use of phallic sex toys; (2) embarrassment about disclosing use to partner(s); (3) personifying vibrators and dildos as male; (4) coercion and lack of power when using sex toys; (5) embracing sex toys as campy, fun, and subversive; and (6) resistance to sex toys as impersonal or artificial. Emerging patterns revealed that queer women more often constructed sex toys as subversive, fun, and free of shame while heterosexual women more often believed most women self-penetrate with sex toys, that sex toys threatened male partners, and they described more coercion involving sex toys. This article explores implications for sexual identity and sex toys, along with women’s negotiation of the “masculine” presence of sex toys in their narratives about using sex toys.     

On the locus of visual dominance

A series of six experiments explored the dominance of vision over audition reported by Colavita (1974). We first confirmed the existence of visual dominance in a paradigm somewhat different from Colavita’s: Mean reaction time (RT) to a light was found to be faster than to a simultaneously presented tone, even though the stimuli were equated in subjective intensity and even though RT to the tone presented alone was faster than to the light presented alone. Additional experiments showed that when subjects did not have to respond to light, tone RT was equal or faster (intersensory facilitation) when a light was present than when it was not. These findings suggest that sensory or perceptual processing of the tone is not affected by the light, i.e., that visual dominance is nonsensory in locus and depends on the relevance of the light stimulus. This interpretation was reinforced by other findings which showed that the degree of visual dominance was sensitive to the probability of light, tone, and light-plus-tone trials and to instructions to attend to a specific modality, but was not sensitive to the intensity of the light.     

Vibrotactile spatial summation

By means of a two-interval, forced-choice technique, absolute thresholds were obtained at several sites on the skin for short bursts of mechanical vibration. The difference between the energy required for a single vibrator, in dB, to reach threshold and the energy required for two vibrators presented successively to reach threshold was taken as the measure of probability summation. Spatial summation was computed as the difference between the energies required for threshold for the two vibrators presented successively and simultaneously. Both probability summation, 0.52 dB lowering in threshold, and spatial summation, 1.94 dB lowering in threshold, remained constant as a function of the distance between the two vibrators on the thigh. Similar amounts of summation were obtained unilaterally and bilaterally on the fingers. When the frequency of vibration was lowered to 9 Hz, no spatial summation was found. When the frequencies of vibration at the two test sites were different, 160 Hz at one locus, 360 Hz at the other locus, there was no spatial summation.     

Short-term memory for simultaneously presented visual and auditory signals in the pigeon

A series of divided-attention experiments in which matching to the visual or auditory component of a tone-light compound was compared with matching to visual or auditory elements as sample stimuli were carried out. In 0-s delayed and simultaneous matching procedures, pigeons were able to match visual signals equally well when presented alone or with a tone; tones were matched at a substantially lower level of accuracy when presented with light signals than when presented as elements. In further experiments, it was demonstrated that the interfering effect of a signal light on tone matching was not related to the signaling value of the light, and that the prior presentation of light proactively interfered with auditory delayed matching. These findings indicate a divided attention process in which auditory processing is strongly inhibited in the presence of visual signals.     

Appetitive-aversive interactions: Superconditioning of fear by an appetitive cs

Four groups of rats received conditioned suppression training in which a tone and light compound was reinforced with shock. If the light had been previously paired with free food, enhanced fear conditioning accrued to the tone during compound training relative to control groups pre-exposed to the light alone, the light semi-randomly associated with food, or the light unpaired with food. The second experiment replicated the difference in aversive conditioning for the groups receiving the light either paired or unpaired with food. The results are discussed in terms of the functional similarity of a conditioned excitor for food and a conditioned inhibitor for shock.     

Background illumination effects upon in vitro conditioning in Hermissenda

In the marine snail Hermissenda, associative learning can be accomplished by paired presentations of light and vestibular stimulation. It is generally assumed that associative learning depends upon the intensity or salience of the conditioned or unconditioned stimulus (CS and US, respectively). Accordingly, during Hermissenda conditioning a stronger dark adaptation is expected to render the CS (the light) more salient and hence facilitate association. We studied the influence of background illumination level using an in vitro pairing procedure in Hermissenda. This procedure allows one to assess the effect of conditioning upon a single cell, the B photoreceptor, which is implicated in this learning process. After 15 min of adaptation to a dim background light, B photoreceptors maintained a basal rate of firing, while after adaptation to complete darkness, they stopped firing. Paired and unpaired groups received 10 training trials in either a completely dark or a dim light environment. Although a trial to trial cumulative increase in excitability was found in the paired group trained in darkness, only the paired group trained under dim background light showed a higher input resistance and cell excitability 10 min after training. These results suggest that the background dim illumination was not needed for the induction but played a role in the maintenance of the pairing effect. Possible mechanisms for such a modulatory effect are discussed.     

The depiction of car light beams in a child born completely blind

A 12-year-old child (DI) who was completely blind from birth, made a series of tactual (raised-lines) drawings of cars. Among them, there was the depiction of a 'fast car at night' in which DI drew beams of light projecting out of the car. We analyse this drawing, and the preceding ones. We argue that the way in which cars and light beams were depicted by DI cannot be fully and solely explained by graphic imprecision, executive or motor deficiencies, or by rote or verbal learning. Instead, we propose that the most plausible explanation is that DI's depiction of light in a fast car at night reflects the child's na?ve knowledge of light propagation, and that this knowledge was gained through perceiving light as radiant heat.     

Timing multimodal events in pigeons

The peak procedure was used in two experiments to study pigeons' ability to time multimodal events. In the first experiment, birds were trained to time a single event consisting of a 9-s tone or light followed by a 21-s fixed interval associated with a signal of light or tone (signal of the other modality). On occasional empty trials, different lengths of the first signal were followed by a long period of the second signal. Peak response times as a function of the duration of the first signal were linear and had a slope of close to one in all birds. This indicates that the birds were timing only the second signal. In a second experiment, two complex events were used in training. One consisted of a 9-s tone or light followed by a 21-s fixed interval associated with a light or tone. The other consisted of a 21-s tone or light followed by a 9-s fixed interval associated with a light or tone. Different durations of the first signal were again used on empty trials. Peak response times as a function of the duration of the first signal were again linear in all birds. The slope of the function was less than one but greater than zero for 3 birds. This indicates that these birds were partly timing the entire complex event of 30-s duration and partly timing only the second signal of the event. A model is proposed in which the bird takes as a criterion for timing a weighted average of different target criteria. Comparisons with the performance of rats are made.     

Differential effects of red and blue coloured lighting on gambling behaviour

Gambling at a modified version of three-card brag was observed for 28 volunteers, subjected to red or blue light conditions. It is concluded that subjects within a red light environment gambled more money more often and selected riskier odds than did subjects gambling under blue light. Furthermore, riskier bets were generally associated with later trials and red light again enhanced such an effect as compared with blue light. The results are discussed in terms of psychoanalytical theory, psychophysiology and choice shifts within group situations for various gambling activities.     

Additive and suppressive response summation with a chain schedule

Rats responded in a two-segment (variable-interval variable-interval) chain schedule. In one experiment, three subjects had either clicker, light, or clicker plus light as terminal-segment stimuli. All three responded at the highest rate when clicker plus light were present, thus showing additive summation. For three other subjects, initial-segment stimuli were either clicker, light, or clicker plus light. Two subjects responded at the lowest rate when clicker plus light were present, thus showing suppressive summation. In a second experiment, three subjects had either clicker, light, or neither clicker nor light as terminal-segment stimuli. None of these subjects showed reliable additive summation. Three other subjects had clicker, light, or neither as the initial-segment stimulus, and all three showed suppressive summation. Additive and suppressive summation both can be demonstrated with chain schedules, but stimulus parameters may be major variables in producing the effect.     

A Light Theory of Color

Traditional theories locate color in primary qualities of objects, indispositional properties of objects, in visual fields, or nowhere. Incontrast, we argue that color is located in properties of light. Morespecifically, light is red iff there is a property P of the lightthat typically interacts with normal human perceivers to give thesensation of red. This is an error theory, because objects and visualfields that appear red are not really red, since they lack theproperties that make light red. We show how this light theory solvesor avoids problems that afflict its competitors.     

Colour changes as a function of luminance contrast.

When spectral light increases in luminance, the hues change. Normally, long-wavelength light becomes increasingly yellow, and short-wavelength light turns blue or blue-green. This is known as the Bezold-Brücke hue shift. Less notice has been paid to the change in relative chromatic content (saturation or chromatic strength) that accompanies these shifts in hue. As luminance contrast increases from zero, chromatic strength increases to reach a maximum at a luminance that is wavelength dependent. Short-wavelength blueish light reaches this maximum at low relative luminances, whereas midspectral yellowish stimuli need several log units higher luminance. Red and green are somewhere in between. For luminances above this maximum, the chromatic content usually diminishes, and most light becomes more whitish in appearance. In this study it is demonstrated how the combined chromatic appearance of hue and chromatic strength change with intensity. Both phenomena find a common physiological interpretation in the nonlinear and nonmonotonic responses of colour-opponent P cells in the retina and lateral geniculate nucleus of the primate. A model that combines the outputs of six P-cell types accounts for observers' estimates of hue and chromatic strength.     

The influence of generalization decrement on the outcome of a feature-positive discrimination

In a feature-positive discrimination subjects receive training in which reinforced presentations of a compound, AB⁺, are intermixed among non-reinforced presentations of one element, A^o. The three reported experiments compared the results of this procedure when using a light or a tone as the feature-positive stimulus, B. In all three experiments, the tone elicited a stronger conditioned response than the light when it was presented alone. The main concern of Experiments 2 and 3 was to examine whether this effect was due to training being incomplete for subjects receiving the light as the B element. In Experiment 2 it was found that extended discrimination training did not diminish the difference between the properties of the light and the tone. Experiment 3 revealed that this effect was not due to differences in the asymptotic associative strength of either A or the compound. It is argued that these results are not readily compatible with contemporary theories of learning, and an alternative account is presented.     

Lights and lattices and where they are seen

The article discusses characteristics of internal visual images and is based on personal observations of lucid dream and hypnopompic phenomena. In the context of lucid dreaming there sometimes occur persisting bright lights that do not behave like ordinary dream images. These phenomena appear as areas of light, peripheral light, disks of light, sun-like concentrations of light, and fullness of light. These luminous phenomena remain in a fixed location in my view in spite of any dreamed body movement, may appear in different dreams in the same locations, are not truly representational, and appear to be unrelated to other dream images, visual or otherwise. These stable intense lights remain in a fixed location in relation to an area defined by keeping the head still and moving the eyes. This area is the space that is filled at times by scannable hypnopompic geometrical patterns or scannable hypnagogic complex images. Although space-filling patterns look like they extend like a dome over the eyes, a close examination shows that they have a two-dimensional flatness that reaches over the entire scannable area. The observation of these patterns as flat becomes understandable when we think of the internal image as having no distance or separation from the seeing of the image, that is, as being experienced face on at every point. The flatness of the hypnopompic pattern implies the flatness of all internal images. The experiences translates the flat image to external positions around the eyes. This translation is explained.     

Auditory-visual conflicts in the perceived duration of lights, tones and gaps

The perceived duration of a short tone (1,000 or 1,500 msec) was longer than that of a separately presented light of equal length. Thus, when light and tone were presented simultaneously, there was a conflict in perceived duration. In that case, the perceived duration of an interval filled with both light and tone was close to that of an interval filled with tone alone. A silent gap in otherwise continuous tone was perceived as longer than a gap in otherwise continuous light, and the perceived duration of a gap occurring simultaneously in both light and tone was close to that of a gap in tone alone. Thus, auditory dominance occurred under the preceding conditions-that is, auditory-visual conflicts in perceived duration, whether occurring between filled intervals or gaps, were resolved in favor of the auditory modality. Visual dominance occurred only under one condition, in which the intensity of tone was reduced, and in which the perceived duration of a 500-msec light was longer than that of a 500-msec tone. The finding of auditory dominance in the perception of time runs counter to the results of studies of sensory conflicts in spatial perception, where vision typically dominates audition and touch.     

Increasing conspicuity on night-time roads: Perspectives from cyclists and runners

Pedestrians and cyclists are at significant risk of being killed as a result of a collision with a vehicle at night-time because of their poor conspicuity. Retroreflective strips positioned on the moveable joints, in a biological motion configuration (biomotion), greatly enhance the night-time conspicuity of pedestrians and cyclists, but it is not clear how widely this strategy is adopted among those running and cycling under low light levels (dawn and dusk or at night). This study explored runners’ and cyclists’ beliefs about their own conspicuity, and the strategies they use to increase their conspicuity and safety under low light levels.Nine focus groups involving 50 participants (mean age = 39.5 ± 13.9 years) were held with individuals who ran and/or cycled under low light conditions or at night-time. The strategies that participants used to increase their conspicuity and enhance their personal safety, and the importance they placed on increased conspicuity to other road users at night was explored. Data were analysed thematically, with two main themes identified. Strategies describes the different approaches used to increase conspicuity when running or cycling in low light, some of which are ineffective. Importance describes how conspicuity relates to other considerations that influence cyclists and runners. While they may believe that conspicuity is essential for their safety, they may compromise their own conspicuity by prioritising style or comfort, or because they believe that being more conspicuous is of limited value because it cannot compensate for the behaviour of other road users.In summary, cyclists and runners are largely unaware of effective strategies to increase their night-time conspicuity, particularly the use of biomotion reflective strips. Garment manufacturers should ensure that conspicuity features (with supporting educative product information on labels) are incorporated into cyclists’ and runners’ clothing or accessories to improve wearer conspicuity and hence safety in low light conditions.