Dichoptic induction of movement aftereffects contingent on color and on orientation

Some comparative experiments on the dichoptic induction of the movement aftereffect (MAE) contingent on color and the MAE contingent on orientation are reported. Colorcontingent movement aftereffects could be evoked only when the eye which had viewed color during adaptation also viewed color during test sessions. When the apparent color of the test field was changed by binocular color rivalry, contingent movement aftereffects (CMAEs) appropriate to the suppressed color were reported. After dichoptic induction of the orientation-contingent MAE, aftereffects could be obtained whether the eliciting gratings and stationary test fields were presented together to either eye alone or were dichoptically viewed.     

Dichoptic and dichotic micropattern discrimination

Ss compared two rapidly successive, brief, discriminably different stimulus elements, called a micropattern, with a second micropattern composed of the same two stimulus elements presented in reverse temporal order. Discriminations could be made between two such micropatterns in the monaural (monocular) as well as in the dichotic (dichoptic) modes of presentation. Discrimination between micropatterns was based on the perceptual dominance of the temporally trailing stimulus element in both modalities and in both modes of presentation. While monaural (monocular) micropattern discrimination is significantly superior to dichotic (dichoptic) discrimination, the existence of dichotic (dichoptic) discrimination demonstrates that no essential peripheral process is required for micropattern discrimination.     

Dichoptic interaction of visual structure and light flashes

Perceptual interaction between monocular flashes and different amounts of continuously visible target structure shown to the other eye was investigated. A response variable called dominance of the flashes is defined and found to be a direct function of flash intensity and an inverse function of contraocular target structure. The dominance variable is distinguished from subjective brightness of the flashes and subjective complexity of the targets. The observed effects are attributed to limited central processing capacity with increased informational load.     

Dichoptic reading: The role of meaning in binocular rivalry

These experiments sought to determine whether meaning influences the predominance of one eye during binocular rivalry. In Experiment 1, observers tried to read meaningful text under conditions in which different text streams were viewed by the two eyes, a situation mimicking the classic dichotic listening paradigm. Dichoptic reading proved impossible even when the text streams were printed in different fonts or when one eye received a 5-sec advantage. Under non-rivalry conditions, the observers were able to read text presented at twice the rate used for dichoptic testing, indicating that cognitive overload does not limit performance under conditions of rivalry. In Experiment 2, observers were required to detect repeated presentations of a probe target within a string of characters presented to one eye. Although this task was easily performed under monocular viewing conditions, it proved difficult when the two eyes received dissimilar character strings. This was true regardless of whether the probed eye viewed nonsense strings, real words, or meaningful text. In a condition designed to encourage semantic processing of one eye’s view, the observers were required to detect animal names as well as to detect the probe target. Performance remained inferior to that measured under monocular conditions. Even the observer’s own name proved insufficient to influence the predominance of one eye under conditions of dichoptic stimulation. When two text strings were physically superimposed and viewed monocularly, essentially no probes were detected, indicating that the failure to see some probes during rivalry reflects a limitation unique to dichoptic viewing. These results contradict theories attributing binocular rivalry to an attentional process that operates on monocular inputs that have received refined analysis. This conclusion may be limited to rival stimuli whose meaning is defined linguistically, not structurally.     

Generalization in the effects of a mood induction procedure

Mood Induction Procedures (MIP's) requiring subjects to read depressing self-referent statements have recently been employed in laboratory analogues of depression. Although these procedures have been shown to effect mood, their effectiveness in producing more general changes in behaviour has been less consistent. An alternative MIP was used in this study. Thirty-two male and female students listened either to a depressing or an affectively neutral tape. The MIP produced significant mood disturbance and significant decrease in self-rated activation. However, during the test phase, the MIP group showed greater behavioural activation in a counting speed measure, and facilitated performance on a shuttlebox noise-escape task. Evidence is presented which suggests that this represented a characteristic initial response by depressed and helpless subjects on laboratory tasks.     

Subjective and reinforcing effects of smoking during negative mood induction

Two notions strongly held by many smokers are that negative mood increases smoking behavior and that this increase is due to the ability of smoking to alleviate negative affect. This study used a modified mood induction procedure to examine both the impact of smoking on induced mood, as well as the effect of induced mood on actual smoking behavior. Forty-eight smokers were randomly assigned to a smoking or a water-drinking comparison group. Each participant attended 3 sessions during which 1 of 3 mood states (positive, negative, or neutral) was induced. Contrary to expectation, smoking did not attenuate negative affect. However, negative mood induction subsequently quickened latency to smoke and increased number of puffs consumed ad lib.     

Chromatic induction effects in the Hermann grid illusion.

The chromatic Hermann grid illusion was investigated in sixteen subjects, with variation of the lightness contrast between the chromatic inducing squares and the background, and the saturation and hue of the inducing squares. Subjects made magnitude estimates of the sharpness and clarity of perceived dots at the intersections of the grid, and matched the appearances of the dots with Munsell chips. A chromatic induction effect was found to occur in the absence of lightness contrast, but the sharpness of the illusory dots increased with increasing lightness contrast (p less than 0.001). The saturation of the perceived dots increased with increases in the saturation of the inducing squares (p less than 0.05), and was higher for the longer wavelengths than for the shorter wavelengths (p less than 0.005). Neural units with center-surround arrangements responding differentially to light of the same color in the center and the surround, e.g. red off-centers and red on-surrounds, could account for the chromatic induction effect.     

A multiscale filtering explanation of gradient induction and remote brightness induction effects: a reply to Logvinenko (2003)

Grating induction is a brightness effect in which a counterphase spatial brightness variation (a grating) is induced in a homogeneous test strip that is surrounded by an inducing luminance grating (McCourt, 1982 Vision Research 22 119-134). Moulden and Kingdom (1991 Vision Research 31 1999-2008) introduced an interesting variant of grating induction (sometimes referred to as gradient induction) in which multiple strips of either a linear luminance ramp or a sine-wave grating were interlaced with strips of homogeneous luminance. We (Blakeslee and McCourt, 1999 Vision Research 39 4361-4377) demonstrated that a simple multiscale filtering explanation could account for grating induction. Recently, however, Logvinenko (2003 Perception 32 621-626) presented several arguments impugning the adequacy of spatial filtering approaches to understanding brightness induction in gradient induction stimuli. We propose that Logvinenko's arguments apply only to a limited class of filtering models, specifically those which employ only a single spatial filter. To test this hypothesis we modeled gradient induction stimuli as a function of inducing contrast, as well as Logvinenko's (2003) remote induction stimulus, using our multiscale oriented difference-of-Gaussians (ODOG) model (Blakeslee and McCourt 1999). The ODOG model successfully predicts the appearance of the inducing strips and the homogeneous test strips in the gradient induction stimuli and the appearance of the test patches in the remote induction stimuli. These results refute Logvinenko's (2003) claims, and we interpret them as providing strong evidence for a multiscale filtering approach to understanding both gradient induction and remote brightness induction effects.     

Mood induction effects upon goal setting and performance in young children

The purpose of the present investigation was to demonstrate that goal setting varies with happy/sad mood-induced states in young children. In turn, on the basis of current Goal Setting Theory, it was predicted that goal level mediates the child's subsequent performance. Young children were assigned randomly to either happy or sad mood induction states, were asked to set their own goals, and then performed the task. In light of the findings, mood state was manipulated effectively in the children, with the following result: A happy mood state produced a significantly higher goal and superior performance than a sad mood state. However, no strong evidence was provided for the notion that goal setting mediated the impact of mood induction upon performance. The developmental implication of these findings are discussed.     

Bayes and blickets: effects of knowledge on causal induction in children and adults

People are adept at inferring novel causal relations, even from only a few observations. Prior knowledge about the probability of encountering causal relations of various types and the nature of the mechanisms relating causes and effects plays a crucial role in these inferences. We test a formal account of how this knowledge can be used and acquired, based on analyzing causal induction as Bayesian inference. Five studies explored the predictions of this account with adults and 4-year-olds, using tasks in which participants learned about the causal properties of a set of objects. The studies varied the two factors that our Bayesian approach predicted should be relevant to causal induction: the prior probability with which causal relations exist, and the assumption of a deterministic or a probabilistic relation between cause and effect. Adults' judgments (Experiments 1, 2, and 4) were in close correspondence with the quantitative predictions of the model, and children's judgments (Experiments 3 and 5) agreed qualitatively with this account.     

The effects of indirect induction hypnosis and practice imagery on tertiary student goal achievement

The effects of hypnosis and Practice Imagery (PI) on 51 tertiary students' achievement of goals were examined. PI involved directing participants through two imageries (succeeding with the goal and continuing without success) and further directing participants to practice moving back and forth between the two imageries to instill a sense of power over the goal and to provide practice in goal success. Seventeen hypnotized and 17 non-hypnotized subjects received identical imagery training by listening to an audio tape recording while 17 control subjects received no training. Hypnosis subjects received indirect induction hypnosis prior to hearing the tape. Goal Attainment Scaling was used to determine level of goal achievement. Hypnotized participants who received the PI treatment showed significantly greater goal achievement than control subjects. Implications for use of hypnosis combined with PI in tertiary school counselling centres are discussed.     

Negating the effects of binaural cues: competition between auditory streaming and contralateral induction

When a pair of monaural pure tones, A and B, are repeatedly alternated in one ear, with noise bursts presented in synchrony with B in the other ear, the noise sometimes delateralizes B. This is presumably a case of Warren and Bashford's (1976) contralateral induction effect. However, the present experiment shows that the degree of contralateral induction is proportional to the separation in frequency between A and B. It was also found that the degree to which the noise bursts influenced B's timbre was proportional to the separation in frequency between A and B. The combined results suggest that cues that govern the sequential organization of sounds influence the use of binaural cues not only during the assignment of position to auditory events but during the assignment of timbre.     

The effects of anxious mood induction on suggestibility to misleading post‐event information

Little research has been carried out into the effects of anxious mood at the time of either the encoding of misleading post‐event information or the time of its possible retrieval, on subsequent suggestibility. Participants comprised 160 first‐year undergraduates. Using a standard suggestibility paradigm, half of all participants were exposed to misleading information while half were non‐misinformed controls. In addition there were four state anxiety conditions, dependent on the timing of the anxious mood induction: at the time of encoding misleading information; at retrieval only; at both encoding and retrieval; or at neither encoding nor retrieval (controls). Results showed memory accuracy for non‐suggestible items was unaffected by the anxious mood induction. With respect to suggestibility, there was a strong effect of misleading information. In addition, within the misinformed group, all three groups who experienced the anxious mood induction were significantly less suggestible than controls. These findings are discussed both in terms of theories of anxiety and cognition and the applied implications for the increasing use by the police of video‐recorded witness interviews. Copyright © 2004 John Wiley & Sons, Ltd.     

Playing with fire: effects of negative mood induction and working memory on vocabulary acquisition

We investigated the impact of emotions on learning vocabulary in an unfamiliar language to better understand affective influences in foreign language acquisition. Seventy native English speakers learned new vocabulary in either a negative or a neutral emotional state. Participants also completed two sets of working memory tasks to examine the potential mediating role of working memory. Results revealed that participants exposed to negative stimuli exhibited difficulty in retrieving and correctly pairing English words with Indonesian words, as reflected in a lower performance on the prompted recall tests and the free recall measure. Emotional induction did not change working memory scores from pre to post manipulation. This suggests working memory could not explain the reduced vocabulary learning in the negative group. We argue that negative mood can adversely affect language learning by suppressing aspects of native-language processing and impeding form-meaning mapping with second language words.     

Self-esteem differences in the effects of hypocrisy induction on behavioral intentions in the health domain

Two studies investigated whether individuals with varying levels of self-esteem respond differently in the hypocrisy paradigm. In the first study, all participants were regular smokers. Those in the hypocrisy condition delivered a speech in front of a camera on the dangers of smoking. The principal dependent measure was the intention to stop smoking. In the second study, participants in the hypocrisy condition wrote a public (personally identifiable) passage about the importance of a healthy lifestyle. The principal dependent measure was the intention to improve one's health behaviors. In both studies, self-esteem scores were positively related to intentions to change behavior in the hypocrisy condition but not in a control condition. The implications of these findings for conceptions of self-esteem and for dissonance theory are discussed.     

Pain as a motivator of smoking: effects of pain induction on smoking urge and behavior

Tobacco smoking has been associated with the development and exacerbation of chronically painful conditions. Conversely, there is reason to believe that smokers may be motivated to use tobacco as a means of coping with their pain. To date, no controlled, experimental studies have tested for a causal relationship between pain and smoking motivation. The primary aim of the current study was to test the hypothesis that laboratory-induced cold pressor pain would enhance smoking motivation, as measured by self-reported urge to smoke and observation of immediate smoking behavior. Smokers (N=132) were randomly assigned to either pain or no pain conditions. Results indicated that situational pain increased urge ratings and produced shorter latencies to smoke. The relationship between pain and increased urge to smoke was partially mediated by pain-induced negative affect. The relationship between pain and shorter latency to smoke was fully mediated by pain-induced urge to smoke. This study provides the 1st experimental evidence that situational pain can be a potent motivator of smoking.     

Causal knowledge and categories: the effects of causal beliefs on categorization, induction, and similarity

Despite the recent interest in the theoretical knowledge embedded in human representations of categories, little research has systematically manipulated the structure of such knowledge. Across four experiments this study assessed the effects of interattribute causal laws on a number of category-based judgments. The authors found that (a) any attribute occupying a central position in a network of causal relationships comes to dominate category membership, (b) combinations of attribute values are important to category membership to the extent they jointly confirm or violate the causal laws, and (c) the presence of causal knowledge affects the induction of new properties to the category. These effects were a result of the causal laws, rather than the empirical correlations produced by those laws. Implications for the doctrine of psychological essentialism, similarity-based models of categorization, and the representation of causal knowledge are discussed.