Color-naming functions for the pigeon

Six pigeons were trained to match wavelengths in a three-key matching-to-sample paradigm. Test trials were occasionally presented, where probe wavelengths appeared on the center key and choices were made to the training stimuli presented on the side keys. Color naming functions were obtained by plotting the percentage of test trials that each training stimulus wavelength was chosen for each center key probe wavelength. The wavelength where the functions intersected was interpreted as a transition point between pigeon hues. Three experiments employed different wavelengths as training stimuli. The first two experiments demonstrated that the intersection of the color-naming functions occurred in all cases at 540 nm and 595 nm. The third experiment employed 540 nm and 595 nm as two of the three training stimuli, and the relatively slow acquisition, together with the resulting color-naming functions, supported the proposition that 540 nm and 595 nm may be transition point wavelengths between pigeon hues.     

Selective Masking and The “Lamp-Phosphor” Problem

Mollon and Polden (1978) have suggested that selective backward masking, the greater masking of central than peripheral items in briefly-presented letter rows by a patterned stimulus, may be due to an advantage conveyed to the peripheral items by the more rapid onset of the short wavelengths emitted by tachistoscope lamps. This suggestion was evaluated by comparing report accuracy under mask and no mask conditions when the tachistoscope fields were viewed through yellow or red filters that eliminated all wavelengths below 510 and 590 nm, respectively. The results showed similar selective-masking effects with both filters. Since selective masking occurs even when the short wavelength emissions are eliminated, Mollon and Polden's suggested explanation for selective masking must be rejected.     

Pattern discrimination in the near-ultraviolet by pigeons

Four pigeons were tested, using an operant conditioning method with successive stimulus presentation, on a pattern discrimination task to determine whether or not they could distinguish patterns that were illuminated by near-ultraviolet (UV) light. Tests at red, green, and UV wavelengths showed that they could significantly discriminate not only the chromatic stimuli that were visible to human observers but also the UV-illuminated patterns that humans could not see. In control sessions, the birds’ performance deteriorated to chance levels when these UV wavelengths were blocked by additional filters. Their discrimination of UV patterns precludes that the pigeon’s known sensitivity to UV is mediated by a preretinal fluorescence, as is probably the case in some other animals, since such a fluorescence does not permit a focused retinal image. Possible retinal mechanisms mediating their UV detection are discussed.     

Effects of annealing temperature on structural,optical, and electrical properties of antimony-doped tin oxide thin films

Antimony-doped tin oxide (ATO) films, approximately 320 nm in thickness, have been prepared by electron beam evaporation onto glass substrates. The films were annealed at temperatures between 400°C and 550°C in air and their structure and surface morphologies were observed by X-ray diffraction (XRD) and atomic force microscopy (AFM) after the different annealing treatments. XRD patterns of the ATO thin films as-deposited and annealed at 400°C showed that they were amorphous, but annealing beyond 400°C caused the films to become polycrystalline with tetragonal structure and orientated in the (1 1 0) direction. The grain size in the annealed films, obtained from the XRD analysis, was in the range 146–256 Å and this increased with the annealing temperature. The dislocation density, cell volume and strain were found to decrease gradually with increasing annealing temperature. Photoluminescence spectra revealed an intensive blue/violet peak at 420 nm, which increased gradually in height with annealing. It is suggested that an increase in the population of Sb⁺⁵ ions might be the reason for the enhancement of the blue/violet emission. The optical properties of the films were also investigated in the UV-visible-NIR region (300–1000 nm). The optical constants, namely the refractive index n and the extinction coefficient k in the visible region were calculated. The optical energy band gap, as determined by the dependence of the absorption coefficient on the photon energy at short wavelengths, was found to increase from 3.59 to 3.76 eV with annealing temperature.     

Gender Differences in Sado-Masochistic Arousal Among College Students

This paper tests three competing explanationsfor male-female differences in sado-masochistic sexualarousal. The male arousal hypothesis posits that becauseof socialization that emphasizes sexual aggression and experimentation (and thus higher levels ofsexual arousal and activity in all areas), men will bemore aroused by both sadism and masochism than women.The female masochism hypothesis argues that because females are socialized to be passive, they willbe more aroused by masochistic (but not sadistic)activities than males. The convergence hypothesis notesthat male female socialization (and differences in most sexual attitudes and behavior) haveconverged in recent years, and hypothesizes that thesame convergence has taken place in arousal caused bysado-masochistic behavior and fantasy. Using a sample comprised of 320 undergraduate students (69%white, 27% African American, 4% other) from a largeurban university in the Southeast, we found no evidencefor the female masochism hypothesis and only weak evidence for the convergence hypothesis. Thestrongest evidence was for the male arousal hypotheses,with males scoring significantly higher than females onseven of the twelve measures of sado-masochistic arousal, and no differently from females on theremaining five.     

Effects of the discriminability of alternatives in three-alternative concurrent-schedule performance

Six pigeons were trained on two- and three-alternative concurrent schedules in which the alternatives were signaled by different wavelengths of light on the main pecking key. The schedules were arranged according to a switching-key procedure in which pecks on a white side key produced a 3-s blackout and, intermittently, a change in the variable-interval schedule of food programmed on the main (center) key after the blackout. In Part 1, a two-alternative concurrent variable-interval schedule was arranged in which the alternatives were signaled by 560 nm and 630 nm. Parts 2 and 3 arranged three-alternative concurrent variable-interval schedules with the alternatives signaled by 560 nm, 600 nm, and 630 nm (Part 2) and 560 nm, 623 nm, and 630 nm (Part 3). Within each part, the relative rate of food reinforcers available on the alternatives was varied across a wide range. In all parts of the experiment, the ratios of responses emitted between pairs of alternatives were more extreme than the ratios of reinforcers obtained on the pairs of alternatives, a result termed overmatching. In Parts 2 and 3, generalized matching sensitivities between pairs of alternatives were found to be higher when the reinforcer rate on the third alternative was low than when it was high—an apparent failure of the constant-ratio rule. The data were well described by an extension of the Davison and Jenkins (1985) model, which assumes differing discriminabilities between concurrent-schedule alternatives in combination with a punishing effect of blackout following changeovers.     

Wavelength generalization and discrimination in the pigeon

This three-part study describes wavelength generalization gradients around a series of training wavelengths ranging from 480 to 645 om. Luminance was controlled for the pigeon’s spectral sensitivity. The response measure was probability of keypecking during a 2-sec stimulus presentation. Both an extinction procedure, where stimulus wavelengths occurred in 15-nm steps, and a maintained discrimination procedure, where step size was 2 to 4 nm, were used to obtain gradients. During a portion of the maintained discrimination procedure, new luminances were introduced, so that the effect of luminance level on gradient slope could be examined. Comparison of the resulting functions across training wavelengths revealed: (1) consistent differences in gradient slope in different spectral regions and (2) an increase in slope with luminance increase. The findings are related to recent electroretinographic wavelength contrast data and to psychophysical measures of wavelength discriminability.     

The Social Psychology of Tanning and Sunscreen Use: Self-Presentational Motives as a Predictor of Health Risk1

To the extent that many people seek and maintain a suntan because they believe it makes them more attractive, people who are particularly motivated to make good impressions on others or to be seen as physically attractive are at increased risk for skin cancer. This study examined cognitive, motivational, and attitudinal predictors of two factors that are associated with increased risk for skin cancer: engaging in behaviors that increase one's exposure to UV radiation and inadequate use of sunscreen. Self-presentational motives involving a concern for one's personal appearance and the belief that being tan enhances one's attractiveness were the strongest predictors of the degree to which respondents exposed themselves to natural and artificial sources of UV radiation. Sunscreen use was best predicted by knowing someone with skin cancer. Implications for attempts to promote safe-sun practices are discussed.     

Using UV photography to reduce use of tanning booths: a test of cognitive mediation.

Two laboratory studies were conducted in which a new type of intervention was used to reduce ultraviolet radiation (UV) exposure from tanning booth use among college students (Time 1 Ns=70 and 134). The intervention uses UV photography to highlight the damage to facial skin caused by previous UV exposure. When the authors controlled for baseline measures of booth use, students in both studies who viewed their UV photographs reported less booth use at a follow-up session 3-4 weeks later than did students not shown a copy of their photograph. Also, in both studies, the decline in use was significantly mediated by a Tanning Cognition Index composed of variables suggested by the prototype-willingness (prototype) model of health risk: tanning attitudes, tanner prototypes, and willingness to engage in risky UV exposure.     

Reaction times of pigeons on a wavelength discrimination task

After extensive pretraining, three pigeons were exposed in 2-second trials to a random series of 14 light wavelengths, ranging in one nanometer (nm) steps from 575 nanometers to 589 nanometers. Responses to one of the wavelengths, 582 nanometers, were intermittently reinforced. The relative frequency of response approached 1.0 at 582 nanometers, and decreased with progressively higher and lower wavelengths. Reaction times shorter than about 0.2 second occurred with a low frequency that was largely independent of wavelength. Wavelength controlled the frequency of longer reaction times, but did not affect the distribution of these reaction times. Consequently, receiver-operating characteristic curves constructed by using reaction time as a rating measure did not conform to the signal-detection model, in contrast to such conformity when response rate is used in a similar way. The data suggest that stimulus onset as such triggers early response emission with some small probability; the probability of responses with longer latency is controlled by wavelength, but their time of emission is controlled by some independent process.     

汉语名词、动词和动名兼类词语义加工的偏侧化现象——来自ERP的研究

将ERP技术和半视野技术相结合,采用词汇判断任务,对汉语名词、动词和动名兼类词在左脑和右脑中的加工机制进行了考察。实验结果显示,名词和动词的N400仅在左视野/右脑存在差异,名词和动词的N400在左视野/右脑和右视野/左脑中都比偏（动）和偏（名）更负。不同词类的LPC在右视野/左脑中没有显著差异;偏（名）和偏（动）的LPC在左视野/右脑中比名词和动词更正。实验结果表明,在没有语境条件下,汉语名词和动词的差异主要在具体性上,动名兼类词体现出不同于名词、动词的加工机制。     

Chromatic information processing

The investigation of visual processing mediated solely by chromatic information requires conditions preventing a subject's use of the luminance differences normally accompanying a chromatic change. In Experiment 1, which involved a discriminative reaction time (RT) task, chromatic and white stimuli of the same luminance were presented on a dimmer achromatic background. Subjects were instructed to respond only to the chromatic stimuli. RT was slowest at 570 nm and somewhat faster to short wavelengths than to long wavelengths. In Experiment 2, which compared two discriminative RT tasks, RT was faster when subjects responded to color than when they responded to white. Experiments 3 and 4 demonstrated that a brighter white surround decreased the perceived brightness of chromatic stimuli as well as their perceptual similarity to white, but did not affect RT. The results are discussed in terms of the response strength of the chromatic processing channel.     

Luminance thresholds for the Bezold-Brücke hue shift

This study presents data on the luminance difference at which a hue difference is first perceived between two identical spectral lights. Thresholds were obtained for both luminance increments and decrements from a 2.00 log troland standard for wavelengths between 470 nm and 690 nm. A predicted luminance threshold for each wavelength was calculated based on wavelength discrimination data and the Purdy constant hue contours; i.e. that luminance at which the constant hue contour intersects the wavelength discrimination bound for a given wavelength. A generally good agreement was obtained between observed and predicted values.     

Experimental measures and theoretical account of hue scaling as a function of luminance

Functions relating the magnitude of chromatic response to stimulus luminance were determined at the unique green and yellow wavelengths. These measured functions were used to account for the shift from a preponderance of green at low stimulus luminances to a preponderance of yellow at higher luminances, for a stimulus wavelength of 550 nm. The two hue magnitude functions were found to have the same power-law exponents, and the hue shift was due to the difference in thresholds between the two opponent-color systems.     

Effects of relative reinforcer frequency on complex color detection

Pigeons were trained under a discrete-trials detection procedure in which one of a set of color stimuli was presented on the center key and a single response turned off the stimulus and illuminated two side keys. Single responses to one or the other side key produced occasional reinforcers depending on the value of the color stimulus. In Experiment 1, one color-stimulus set comprised 559, 564, 569, and 574 nm, and right-key pecks were occasionally reinforced following presentations of members of this set. The other stimulus set comprised 579, 584, 589, and 594 nm, and left-key pecks were occasionally reinforced following presentations of members of this set. Across seven experimental conditions, the left/(left + right) relative reinforcer frequency was varied from .1 to .9. In Experiment 2, one stimulus set contained only one member, 574 nm, and right-key responses were occasionally reinforced following its presentation. Over 12 experimental conditions, two manipulations were carried out. First, the number of stimuli comprising the other stimulus set was increased from one (579 nm) to two (579 and 584 nm) to three (579, 584, and 589 nm) and to four (579, 584, 589, and 594 nm), and left-key responses were reinforced occasionally following center-key presentations of members of this set. Second, for each stimulus combination, the left/(left + right) relative reinforcer frequency was varied from .1 to .5 to .9 across three experimental conditions. The principal finding of Experiments 1 and 2 was that reinforcers and stimuli interacted in their effects on behavior. In Experiment 3, pairs of adjacent stimuli (5 nm apart) in the range 559 to 594 nm were presented in each experimental condition, and the left/(left + right) relative reinforcer frequency was held constant at .5. The data from all three experiments were analyzed according to a detection model describing performance in multiple-stimulus two-response procedures. This model provided independent measures of stimulus discriminability, contingency discriminability, and bias. The analysis showed that (a) consistent with the color-naming function, pigeons were better able to discriminate between higher nanometer values than lower nanometer values; (b) their ability to discriminate between the stimuli was independent of the number of wavelengths comprising each stimulus set; (c) they allocated delivered reinforcers very accurately to the previously emitted response; and (d) no consistent biases emerged.     

Modification of the optical band gap of polyethylene by irradiation with electrons and gamma rays

Irradiation of polymers has become an important technique in producing special materials for electronic applications. In this study, the effects of electron and gamma irradiation on ultra-high-molecular-weight polyethylene (UHMWPE) samples have been studied using UV–Vis absorption spectroscopy. The UHMWPE samples were irradiated with electron and gamma rays with doses ranging from 25 kGy up to 500 kGy. An increase in the optical absorption and a shifting from the UV–Vis towards longer wavelengths were observed. Concomitantly, a pronounced decrease in the optical band gap was recorded as a function of dose level. The optical band gap E _g varied from 2.86 eV for a pristine sample down to ～1.98 eV and ～2 eV for samples irradiated with gamma rays and electrons at the highest doses, respectively. A correlation between E _g and the number of carbon atoms N in a formed cluster is discussed in terms of a modified Tauc equation.     

College Freshman Performance: Summer Entrants vs. Fall Entrants

Entering college students and their advisors—high school and college personnel—frequently assert that the student will do better academically by entering college during the summer term rather than during the fall term with its many extracurricular activities. Comparing the academic performances over the first two quarters of 320 summer quarter entrants with 320 fall quarter entrants at the University of Tennessee yielded no significant differences for season entered. The ACT composite score for each student was held constant by using analysis of covariance. Significant differences for year entered—1962 or 1963—were apparently a function of the lack of reliability in grading practices. The academic performance of entering students did not benefit from summer quarter entrance.     

The development of memory efficiency and value-directed remembering across the life span: a cross-sectional study of memory and selectivity

Although attentional control and memory change considerably across the life span, no research has examined how the ability to strategically remember important information (i.e., value-directed remembering) changes from childhood to old age. The present study examined this in different age groups across the life span (N = 320, 5-96 years old). A selectivity task was used in which participants were asked to study and recall items worth different point values in order to maximize their point score. This procedure allowed for measures of memory quantity/capacity (number of words recalled) and memory efficiency/selectivity (the recall of high-value items relative to low-value items). Age-related differences were found for memory capacity, as young adults recalled more words than the other groups. However, in terms of selectivity, younger and older adults were more selective than adolescents and children. The dissociation between these measures across the life span illustrates important age-related differences in terms of memory capacity and the ability to selectively remember high-value information.     

Regions of response transition of color-coded retinal units and an attempted,analogy to behavioral response transition

Electrophysiological responses obtained from single color-coded red-green ganglion ceils of the goldfish retina were analyzed in terms of the spectral region within which response transitions occur. The data showed that criteria for response transitions can be characterized by a frequency change with the stipulation that the same number of “on” and “off” spikes occur to the same wavelength(s). The overall spectral band within which response transition occurs is 570–620 nm. The physiological response ranges were compared to psychophysical unique-yellow responses and other “yellow” judgments. The former were displaced towards the longer wavelengths as predicted by the different pigment peaks. The response characteristics of sharp boundaries and relative invariance with intensity changes provided the basis of an analogy of the two response systems.