Chromatic rod vision VIII. Simultaneous contrast

Stabell, U. & Stabell, B. Chromatic rod vision. VIII. Simultaneous contrast. Scand. J. Psychol., 1973, 14, 1619.-Compared with the curve of additive opponent hue, the curve of scotopic hue of simultaneous contrast was found to be displaced toward blue in the orange and green-yellow regions of inducing field. The results are explained on the assumptions that (a) change of disposition for scotopic hue reflects variation in ratio of primary hue-related processes of inducing field, and (b) the chromatic-related opponent processes, in a dark-adapted and chromatically neutral eye, are of equal magnitude within the photochromatic interval.     

Manipulations of vasopressin alter aggression differently across testing conditions in monogamous and non‐monogamous Peromyscus mice

Differences in the distribution of arginine vasopressin (AVP) and a subtype of AVP receptors, the V_1a receptor, may explain dissimilarities in social behavior of monogamous and non‐monogamous rodents. Intracerebroventricular infusions of AVP and a V_1a antagonist were used in sexually naive males of two mouse species, the monogamous and highly aggressive California mouse (Peromyscus californicus) and the non‐monogamous and less aggressive white‐footed mouse (P. leucopus), to begin testing the interaction between the social system of a species and the effects of AVP on aggression. Two testing conditions, the resident‐intruder aggression test (R‐I) and the neutral arena aggression test, were used because they may differ in function and underlying biological mechanisms. In the R‐I test, administration of the antagonist lengthened attack latencies in California mice. In contrast, blocking V_1a receptors did not alter attack latencies in the R‐I test in white‐footed mice or in the neutral arena aggression test in both species. AVP also did not alter aggression in either species in either behavioral test. Overall, these results suggest that AVP may be more likely to be associated with offensive aggression as measured in the R‐I test than with neutral arena aggression and that the effects of AVP manipulations may differ between monogamous and non‐monogamous rodents. Aggress. Behav. 31:000–000, 2005. © 2005 Wiley‐Liss, Inc.     

Children's face recognition in different contexts: the role of encoding strategies

In this study, the relationship between face recognition and different facial encoding strategies was investigated. Children (6-8 years, N= 134) participated in both a face recognition task and an encoding task. During the recognition task, they saw 7 target faces in an eyewitness context (video) or in a neutral context (static black and white slides) which they later had to recognize from a set of 21 faces. On the encoding task, the same children had to categorize new faces (schematic and photorealistic) into two categories. The construction of the categories allowed participants to encode the faces either analytically (by focusing on a single attribute) or holistically (in terms of overall similarity). The results showed that face recognition was better in the social than in the neutral context. In the neutral context, only holistic encoding was connected to better face recognition. In the social context, children seemed to use not only information about the faces but also information about the persons.     

Photopic visual phantom illusion: its common and unique characteristics as a completion effect

An illusion similar to the stationary visual phantom illusion presented earlier by Gyoba (1983, Vision Research 23 205-211) is reported. This illusion is visible in photopic vision and we have tentatively named it the 'photopic phantom illusion'. A typical example of this illusion is a white and light-gray square-wave grating occluded by a black region. In this figure, a phantom grating running across the occluder with clear contours but less contrast, is seen. The critical spatial frequencies of photopic phantoms have been measured and compared with those of scotopic phantoms that have been reported previously, revealing a great resemblance between them. We discuss the characteristics of this illusion in terms of transparency, stereoscopic viewing, and perceptual completion.     

Minimizing Intergroup Contact: An Urban Field Study

This study examines the effects of observing the negative or neutral behavior of a black or a white couple on white subjects' subsequent social interactions with either a black or a white person. Subjects encountered either a black or a white couple having an argument or a neutral interaction. Shortly thereafter the subjects were approached by either a black or white male confederate who asked for directions. A 2 (Couple's Race) × 2 (Couple's Behavior) × 2 (Confederate's Race) analysis of variance revealed that white subjects interacted with a black confederate for a shorter period of time after having observed a black couple's argument.     

CHROMATIC ROD VISION

S tabell B. & S tabell U. Chromatic rod vision. IV. Time between pre-and test-stimulation varied. Scand. J. Psychol ., 1972, 13 , 141–144.—The scotopic contrast hue was determined as a function of time between pre-and test-stimulation. As the interval increased, the scotopic hue was found to change from orange toward yellow in the 440–475 nm region of pre-stimulation and from violet-blue toward violet in the 550–595 nm region. It is concluded that (1) depending on wavelength of pre-stimulation, the processes in the red-green substance may revert to the mid-valued state faster or slower than the processes in the yellow-blue substance, and (2) the red/blue ratio of the violet hue which has to be added to the additive opponent hue to produce the scotopic contrast hue, may change as a function of time between pre- and test-stimulation.     

Social Influences on Judgments of Rape Victims: The Role of the Negative and Positive Social Reactions of Others

An experimental study examined whether judgments about a rape victim can be influenced by the social reactions of others, and whether this effect would be moderated by the type of rape (stranger or date rape) or by the gender of the participants. One hundred and ten U.S. college students (90% white; 59% female) responded to rape vignettes in which the type of rape and the social reactions received by the victim (negative, positive, or neutral) were manipulated. People exposed to negative social reactions made less positive judgments. Men and people who read about a date rape also made less positive judgments, but neither variable interacted with type of reactions to impact judgments.     

DURATION OF SCOTOPIC CONTRAST HUES

STABELL, U. & STABELL, B. Duration of scotopic contrast hues. Scand. J. Psychol. , 1971, 12, 106–112.–It is generally accepted that following intense and prolonged bleaching, regeneration of cone pigments in man takes a few minutes to reach completion. The results show that the scotopic hue may remain visible for more than one hour. Hence, it is suggested that light signals and not bleaching signals produce the scotopic contrast hues.     

CHROMATIC ROD VISION III. Duration of pre-stimulation varied

S tabell B. & S tabell U. Chromatic rod vision. III. Duration of pre-stimulation varied. Scand. J. Psychol ., 1972, 13 , 136–140.—The scotopic contrast hue was determined as a function of duration of pre-stimulation, together with the additive opponent hue. It is concluded that the red/blue ratio which has to be added to the additive opponent hue to produce the scotopic contrast hue, may change as a function of both wavelength and duration of pre-stimulation.     

The role of target gender and race in children's encoding of category‐neutral person information

Two studies are reported that examine whether children encode category‐neutral information about target persons with respect to gender and race categories. In Study 1, using a semi‐naturalistic adaptation of the ‘who said what?’ technique (Taylor, Fiske, Etcoff, & Ruderman, 1978), children of 5, 8 and 11 years were asked to recall peers' choices in a preference task. For all three age groups, significantly more within‐sex than between‐sex confusions were found, indicating that children had encoded neutral information about targets with respect to their sex. In Study 2, 5‐, 8‐ and 11‐year‐old children were presented with a conventional ‘who said what?’ task in which they were shown four photographs, two of black children and two of white children, along with 16 statements attributed to the target children (i.e. four statements to each child). Following this, 16 statement cards had to be assigned to photographs of the four target persons to indicate ‘who said what’. Across all age groups there were significantly more within‐ than between‐race confusions. The evidence from these two studies indicates that even for category‐neutral information, gender and race play an important role in children's initial encoding of others' behaviour.     

CHROMATIC ROD VISION

STABELL, B. & STABELL, U. Chromatic rod vision. I. Wavelength of test-stimulation varied. Scand. J. Psychol. , 1971, 12, 175–178.–The ability to distinguish one type of radiation from another by its hue disappears in scotopic vision. Accordingly, scotopic hues are found to be invariant of variation of wavelength. It is concluded, on the basis of the Principle of Univariance, that hues may be triggered by light signals initiated in one type of receptor.     

On bad mood and white bears: The effects of mood state on ability to suppress unwanted thoughts

Does temporary mood influence people's ability to engage in effective thought suppression? Based on past research on mental control and recent work on affective influences on social cognition, this experiment predicted and found that negative mood improved and positive mood impaired people's ability to suppress their thoughts when instructed not to think of a neutral concept, white bears. We also found clear evidence for ironic rebound effects: on a subsequent generative task, intrusions of the suppressed thought were greater in the negative than in the positive mood group. Participants received positive or negative feedback about performance on a supposed creativity task to induce positive or negative moods, and then engaged in two consecutive generative writing tasks, the first accompanied by instructions to suppress thoughts of white bears. Those in a negative group reported fewer “white bear” intrusions when attempting to suppress, but more “white bear” intrusions (an ironic rebound effect) in the subsequent task when the suppression instruction was lifted. The implications of these results for everyday tasks of mental control, and for recent affect–cognition theories are discussed.     

Likelihood of attending to the color word modulates Stroop interference

Three experiments investigated whether the Stroop color-naming effect is modulated by the likelihood of a color word capturing visual attention. In Experiment 1, a bar or a neutral word was presented at fixation as a color carrier, along with a color word randomly appearing in either an achromatic color (white in the main experiment, gray in a follow-up) or purple. Reduction of the Stroop effect (known as Stroop dilution) occurred when the color word was achromatic but not (or to a lesser extent) when it was in purple. In Experiment 2, the color of the color word remained constant throughout trial blocks, and Stroop dilution was equally evident when the word was always in purple and when it was always in white. In Experiment 3, a color bar was presented as the color carrier with both a color word and a neutral word. In this case, the Stroop effect was larger when the color word appeared in purple, and smaller when the neutral word appeared in purple, than when neither word did. These results imply that the extent to which processing of a color word occurs is determined by the likelihood of the word capturing attention.     

Developing conceptions of racism among young white adults in the context of cultural diversity coursework

Despite substantial research on racial attitudes and racial identity development among young white adults, little is known about the development of their conceptions about racism. The present study assessed a five-step, empirically based contextualist model of the development of conceptions about racism in young white adults, adapted from the research of Perry (1970), Kitchener and Fischer (1990), and others. A total of 55 young white adults participating in cultural diversity coursework responded to questionnaires about the nature and causes of racism and responses were classified according to the five-step model. Results indicated that many first-year white college students think about racism in dualistic terms, comparable to those described by Perry (1970) in some first-year students' epistemological concepts. Over a semester, many students showed transitions to higher steps, conceptually integrating more dimensions of the problem. Such developmental transitions may be highly context-specific. Implications for educational interventions are discussed.     

African Art in Deep Time: De‐race‐ing Aesthetics and De‐racializing Visual Art

In two essays in the ART/Artifact (1988) exhibition catalog, white American museum curator Susan Vogel and white American philosopher Arthur Danto pronounce that Africans do not distinguish between art and nonart. Although seemingly objective empirical statements, their assertions about Africa and its art are racially based ruminations of a white supremacist worldview. I argue that in theorizing within the category of race they produced racialized aesthetics that commit the Eurocentric fallacy of upholding systemic racist objectives. I argue that (1) their assertions fail to be about African art, but about hegemony and power; (2) as the longest enduring artistic activity of humanity, African art is an important check to racialized aesthetics; (3) art is produced outside the category of race and from a critically conscious awareness of the world; and (4) art bespeaks creativity and presupposes the artistic and moral values of a culture in the manipulation and transformation of physical reality.     

Affective valence and P300 when stimulus arousal level is controlled

Visual stimuli from the International Affective Picture System (IAPS) were employed in a modified oddball paradigm to elicit the P300 event-related brain potential (ERP) in young adult females (N=12). The pictures varied on valence (negative, neutral, positive) ratings but had the same medium arousal level ratings. The images were presented as targets with a standard stimulus composed of red/white triangles designed to mimic the spatial frequency of the pictures. P300 amplitude from negative relative to neutral stimuli was smaller over frontal areas, whereas amplitude from positive relative to neutral stimuli did not differ. P300 amplitude differences among valence categories were consistent across the midline electrodes, and did not change over the parietal area where arousal effects are typically observed. The findings suggest that valence affects P300 frontal amplitude, and arousal level should be controlled when using emotional stimuli to elicit ERPs. Theoretical implications are discussed.     

Thought suppression failures in combat PTSD: A cognitive load hypothesis

The present study investigated the relation between thought suppression of emotionally neutral content [i.e., Wegner's (1994) “white bear”], incidental traumatic thought intrusion, and skin conductance responses in combat-related Posttraumatic Stress Disorder (PTSD). Participants included service members who either: a) had PTSD following an Operation Iraqi Freedom deployment; b) were free of psychiatric diagnosis following deployment (Combat Equivalent), or c) were pre-deployed and without psychiatric diagnosis (Pre-Deployed). PTSD Service Members reported the greatest intrusion of combat thoughts during the suppression task and demonstrated a post-suppression rebound effect with a neutral thought. Non-specific skin conductance responses indicated that the suppression task was related to similar levels of increased sympathetic activity for both the PTSD and Pre-Deployed groups, whereas the Combat Equivalent group showed no increased activation during thought suppression. Intrusive traumatic thoughts combined with failures in neutral thought suppression may be a consequence of increased cognitive load in PTSD.     

Scotopic and photopic afterimages

Stabell, U. & Stabell, B. Scotopic and photopic afterimages. Scand. J. Psychol., 1973, 14, 210–212.MdashThe curves of photopic and scotopic afterimages were found to coincide, confirming the suggestion that disposition for scotopic contrast hue is controlled basically by the ratio of hue-related processes initiated upon chromatic prestimulation of cones, while the achromatic test-stimulation is a constant stimulus, regardless of test variables.     

Effects of a stimulus associated with a victim's pain on later aggression.

Male college students participated in an experiment designed to associate a neutral stimulus with a victim's pain and then to assess the impact of the paired stimulus on their aggression. The subjects were either provoked or not provoked by a confederate's shock evaluation. They then observed a flashing white light that was associated with either their former evaluator's pain or an irrelevant, affectively neutral event. The subjects then administered electric shocks to a different confederate, with whom they had not interacted previously, at the flash of both the familiar white light (the conditioned stimulus) and a novel blue light. Results supported the prediction that provoked subjects would give more intense shocks to the conditioned stimulus when it had been associated with their evaluator's pain. Unprovoked subjects were found to give less intense shocks to the light that had been associated with their evaluator's pain.