An investigation into hemisphere differences in adaptation to contrast

Attention, Perception, & Psychophysics - Suggestions that the cerebral hemispheres differ in their ability to adapt to high-contrast visual stimuli were investigated using vertical sinusoidal...     

An investigation of several parameters of the horizontal-vertical illusion

Length of standard line, degrees of lateral separation of H and V stimuli, and which line served as standard or comparison stimulus were systematically varied in a 4 by 3 by 2 factorial design on the horizontal-vertical illusion. When illusion affects were averaged under H- and V-standard conditions, a negative relationship obtained between magnitude of illusion and length of line. With. vertical as standard, the illusion increased as a function of lateral separation of stimuli, but decreased with horizontal as standard. These differential trends for H- and V-standard conditions contributed to the unsystematic relationship between the size of the illusion and progressive displacement of H and V lines. The illusion curves for three lengths of standard line across degrees of lateral separation were similar. The findings are viewed as incompatible with explanations of the H-V illusion involving the so-called “error of the standard.”     

Ipsilateral loudness adaptation over multiple intensity levels

Could monaural loudness adaptation be a simple artifact of psychophysical contrast? From adaptation data based on the Ipsilateral Comparison Paradigm (ICP), A. J. Dange, J. S. Warm, E. M. Weiler, and W. N. Dember (1993) concluded that loudness adaptation was not an artifact of psychophysical contrast, but their conclusion was dependent on results from one intensity. This study, involving multiple intensities, re-examined the issue of contrast versus adaptation and generally supported the conclusions of Dange et al. The results also showed an unexpected asymmetry of adaptation based on the direction of the referent modulation used with the ICP technique. Some implications are discussed.     

Dissociating conflict adaptation from feature integration: a multiple regression approach

Congruency effects are typically smaller after incongruent than after congruent trials. One explanation is in terms of higher levels of cognitive control after detection of conflict (conflict adaptation; e.g., M. M. Botvinick, T. S. Braver, D. M. Barch, C. S. Carter, & J. D. Cohen, 2001). An alternative explanation for these results is based on feature repetition and/or integration effects (e.g., B. Hommel, R. W. Proctor, & K.-P. Vu, 2004; U. Mayr, E. Awh, & P. Laurey, 2003). Previous attempts to dissociate feature integration from conflict adaptation focused on a particular subset of the data in which feature transitions were held constant (J. G. Kerns et al., 2004) or in which congruency transitions were held constant (C. Akcay & E. Hazeltine, in press), but this has a number of disadvantages. In this article, the authors present a multiple regression solution for this problem and discuss its possibilities and pitfalls.     

Understanding prism adaptation: An individual differences approach

Attention, Perception, & Psychophysics - Adaptation of college students to wedge prisms was studied in terminal exposure and continuous exposure conditions. The adaptation experience was...     

Meditation and psychosocial adaptation: An exploratory study

The current study examined differential patterns of interrelationships between meditators and nonmeditators on issues pertaining to psychosocial adaptation. Subjects (N=66) were randomly selected from mailing lists provided by theAssociation of Transpersonal Psychology or were solicited via classified advertising in theChicago Tribune and theDallas Morning News. The findings of the current study indicate that there are no differences between meditators and nonmeditators on level of psychosocial adaptation. However examination of the zero-order correlations between dependent measures revealed differential patterns of interrelationships within the meditator and nonmeditator groups. The findings suggest that further research is needed which expands upon the influence of meditation on psychosocial adaptation by addressing topics specific to meditative practice. The implications for the development of qualitative research methods designed to investigate psychosocial parameters in transpersonal psychology are discussed.     

Using nonlinear regression to estimate parameters of dark adaptation

An objective technique for estimating the kinetics of dark adaptation is presented, with which one can evaluate models with multiple parameters, evaluate several models of dark adaptation simultaneously, and rapidly analyze large data sets. Another advantage is the ability to simultaneously estimate transition times and rates of sensitivity recovery. Finally, this nonlinear regression technique does not require that the distributional properties of the data be transformed, and thus, parameter estimates are in meaningful units and reflect the actual rate of recovery of sensitivity.     

Perceiving vocal age and gender: An adaptation approach

Aftereffects of adaptation have revealed both independent and interactive coding of facial signals including identity and expression or gender and age. By contrast, interactive processing of non-linguistic features in voices has rarely been investigated. Here we studied bidirectional cross-categorical aftereffects of adaptation to vocal age and gender. Prolonged exposure to young (~ 20 yrs) or old (~ 70 yrs) male or female voices biased perception of subsequent test voices away from the adapting age (Exp. 1) and the adapting gender (Exp. 2). Relative to gender-congruent adaptor-test pairings, vocal age aftereffects (VAAEs) were reduced but remained significant when voice gender changed between adaptation and test. This suggests that the VAAE relies on both gender-specific and gender-independent age representations for male and female voices. By contrast, voice gender aftereffects (VGAEs) were not modulated by age-congruency of adaptor and test voices (Exp. 2). Instead, young voice adaptors generally induced larger VGAEs than old voice adaptors. This suggests that young voices are particularly efficient gender adaptors, likely reflecting more pronounced sexual dimorphism in these voices. In sum, our findings demonstrate how high-level processing of vocal age and gender is partially intertwined.     

Psychophysiological components of imagery

McGuigan’s neuromuscular model of information processing (1978a, 1978b, and 1989) was investigated by electrically recording eye movements (electro-oculograms), covert lip and preferred arm responses (electromyograms), and electroencephalograms. This model predicts that codes are generated as the lips are uniquely activated when processing words beginning with bilabial sounds like “p” or “b,” as is the right arm to words like “pencil” that refer to its use. Twelve adult female participants selected for their high imagery ratings were asked to form images to three orally presented linguistic stimuli: the letter “p,” the words “pencil” and “pasture,” and to a control stimulus, the words “go blank.” The following findings were significant beyond the 0.05 level: an increased covert lip response only to the letter “p,” increased vertical eye activity to “p” and to the word “pencil,” right arm response only to the word “pencil,” and a decreased percentage of alpha waves from the right 02 lead only to the word “pasture.” Since these covert responses uniquely occurred during specific imagery processes, it is inferred that they are components of neuromuscular circuits that function in accord with the model of information processing tested.     

Subjective phrase structure: An empirical investigation

The present study represents an attempt to investigate the basis of subjective groupings of words in sentences, employing Edwin Martin's subjective phrase structure technique. Results indicate that subjects base their judgments not only on grammatical structure but also on constituent length and on stress and intonation patterns.A shorter version of this paper was presented to the Annual Meeting of the Canadian Linguistic Association at McGill University, Montreal, May 1972.     

Face processing as a brain adaptation at multiple timescales

I consider face processing as the brain's adaptive response to phylogenetic, ontogenetic, and task-specific factors. Focusing on wide-ranging evidence from both my own laboratory and others, evidence for a primitive "quick and dirty" route for face processing that exists prior to postnatal experience is reviewed. Next, I trace the emergence of cortical specialization for face processing influenced by individual developmental experience (ontogenetic adaptation) and suggest that this ontogenetic adaptation is also heavily constrained by the phylogenetic system. Finally, I turn to recent evidence on task-specific modulation of activity in the core face network that illustrates brain adaptation at a finer timescale than that for the other systems. Current evidence indicates that task-specific modulation of the cortical face network does not emerge until the teenage years. As previously proposed for other components of cognition, I propose that these systems are complementary to each other, each compensating for the others' weaknesses. Different face-related systems are adapted to respond to survival pressures at different timescales, from millennia, to months, to microseconds.     

An investigation of the role of some person and situation variables in multiple cue probability learning

Making decisions using judgements of multiple non-deterministic indicators is an important task, both in everyday and professional life. Learning of such decision making has often been studied as the mapping of stimuli (cues) to an environmental variable (criterion); however, little attention has been paid to the effects of situation-by-person interactions on this learning. Accordingly, we manipulated cue and feedback presentation mode (graphic or numeric) and task difficulty, and measured individual differences in working memory capacity (WMC). We predicted that graphic presentation, fewer cues, and elevated WMC would facilitate learning, and that person and task characteristics would interact such that presentation mode compatible with the decision maker's cognitive capability (enhanced visual or verbal WMC) would assist learning, particularly for more difficult tasks. We found our predicted main effects, but no significant interactions, except that those with greater WMC benefited to a larger extent with graphic than with numeric presentation, regardless of which type of working memory was enhanced or number of cues. Our findings suggest that the conclusions of past research based predominantly on tasks using numeric presentation need to be reevaluated and cast light on how working memory helps us learn multiple cue–criterion relationships, with implications for dual-process theories of cognition.