A re-examination of the Stratton effect: Egocentric adaptation to a rotated visual image

The question raised by Stratton, whether a disoriented image can yield upright vision. was explored by exposing Os to a prismatically rotated field. To isolate the problem ofadaptation to altered egocentric orientation, the O’s view was restricted to a horizontal plane during both prism exposure and test. Significant adaptation based on movement-derived information was obtained.     

Tau as a potential control variable for visually guided braking

D. N. Lee (1976) described a braking strategy based on optical expansion in which the driver brakes so that the target's time-to-contact declines around a constant slope in the range -0.5 < or = tau < 0. The present results from a series of braking simulations confirm and extend earlier reports (E. H. Yilmaz & W. H. Warren, 1995) that performance is broadly compatible with the tau hypothesis. However, performance was not enhanced in situations that favored the estimation of tau, and unlike in earlier reports, performance deteriorated in the absence of a ground plane that provided information about speed and target distance. This finding suggests that the tau hypothesis does not provide a complete account of braking control.     

What are the Origins of Shamanic Journeying Imagery? The Modification of a Hypnoanalytic Technique to Address an Enduring Methodological Problem

Shamanic journeying imagery arguably transcends geographical space and historical time. However, to what extent is the content of the journeying imagery a construction of the shaman's cultural cosmology, belief systems, autobiographical memories, etc? It is suggested that attempts to answer this question are hampered by a fundamental methodological obstacle: how to detect contextual influences on imagery that the shaman cannot report on because they are outside his/her present awareness and memory. A partial solution is presented: Watkins' (1971) Watkins, J. G. 1971. The affect bridge: A hypnoanalytic technique.. The International Journal of Clinical and Experimental Hypnosis, 19: 21–27. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar] Affect Bridge, a hypnoanalytic technique used to uncover the origin of an affect. A nonhypnotic version of the technique developed for inquiry into shamanic journeying imagery is then explicated. Two recent empirical studies conducted by Rock (2006) Rock, A. J. 2006. Phenomenological analysis of experimentally induced visual mental imagery associated with shamanic journeying to the lower world.. International Journal of Transpersonal Studies, 25: 45–55.  [Google Scholar] and Rock, Casey and Baynes (2006) Rock, A. J., Casey, P. J. and Baynes, P. B. 2006. Experimental study of ostensibly shamanic journeying imagery in naive participants II: Phenomenological mapping and modified affect bridge.. Anthropology of Consciousness, 17(1): 65–83. [Crossref] , [Google Scholar], illustrating the utility of the Modified Affect Bridge with regards to investigating experimentally the origin of ostensibly shamanic journeying imagery reported by naive participants, are summarized. A tentative ostensibly shamanic journeying imagery origin typology is formulated and suggestions for future research are advanced.     

Further evidence of failure of reversal of ambiguous figures by uninformed subjects.

In studying the reversal of ambiguous figures investigators understandably have always informed subjects of the reversibility of the figures and of how each version appears. However, such knowledge may be a cause of reversal and is therefore an undesirable aspect of the method used to study it. An experiment is described that is an improvement in some respects on a previously reported one in which subjects are not informed about reversal. The result was that only about a third of the subjects ever reversed. In a control condition the same subjects were informed in the traditional way and then not only did they always reverse but did so very frequently in the time period tested. Theoretical implications of these findings are discussed.     

Suicidal ideation in college students varies across semesters: the mediating role of belongingness

The interpersonal-psychological theory of suicidal behavior (Joiner, 2005) proposes that the need to belong is fundamental; when met it can prevent suicide and when thwarted it can substantially increase the risk for suicide. We investigate one source of group-wide variation in belongingness among college students--changes in the social composition of college campuses across academic semesters--as an explanation for variation in suicidal ideation across the academic year. Our results indicate that in a sample of college students at a large southern state university (n = 309), suicidal ideation varied across academic semesters, with highest levels in summer compared to both spring and fall. Differences in suicidal ideation between summer and spring were, in large part, accounted for by belongingness. Theoretical, as well as practical, implications are discussed regarding mechanisms for seasonal variation in suicidal ideation.     

Individual differences in the response to forgone payoffs: an examination of high functioning drug abusers

This study evaluates the effect of forgone payoffs in decision‐making tasks used for studying individual differences. We investigate whether the disclosure of forgone payoffs (defined as payoffs associated with un‐chosen alternatives) has selective effects for drug abusers. Evidence suggests that drug abusers are hypersensitive to signals of positive reward. Accordingly, because the forgone payoffs of risky high‐variability options include rewarding outcomes, this may create a distraction and lead drug abusers to make more risky choices. In a controlled experiment, we examined the behavior of high‐functioning drug abusers and healthy controls using the Iowa gambling task. The results showed that in a forgone payoff condition, drug abusers made more risky choices. The results demonstrate that adding information about forgone payoffs can be useful for studying individual differences, and that studying individual differences can be valuable in evaluating the effects of forgone payoffs. Copyright © 2005 John Wiley & Sons, Ltd.     

Inhibition and anticipation in visual search: evidence from effects of color foreknowledge on preview search

We present four experiments in which we examined the effects of color mixing and prior target color knowledge on preview search (Watson & Humphreys, 1997). The task was to detect a target letter (an N or a Z) that appeared along with other new letters, when old distractors remained in the visual field. In some conditions, participants were told the target's color, in others, they were not. Foreknowledge of the target's color produced large improvements in search for both baseline and preview presentations (Experiment 1). For preview presentations, the magnitude of this effect was reduced if the target shared its color with a single colored set of previewed letters (Experiment 2). Removing this similarity across the displays greatly improved search efficiency (Experiment 3). In Experiment 4, we assessed and rejected the proposal that the effects reflected the probability that the target was carried by a particular color. We discuss the results in terms of separate effects of (1) inhibitory carryover from a preview color group and (2) an anticipatory set for a known target color.