Motor activation without conscious discrimination in metacontrast masking.

Nine experiments investigated motor responses to geometric stimuli (a target and a distractor) preceded by masked primes. In congruent trials, the target was preceded by a smaller target-like shape and the distractor by a smaller distractor-like shape. In incongruent trials this arrangement was reversed. In neutral trials both primes were distractor-like shapes. Highly significant effects of these priming conditions on reaction time and error rate were found, although there was no conscious discrimination of primes, as assessed by a discrimination index (d′ or ds) not different from 0. This result subsisted under conditions of time pressure, feedback, practice, and financial incentive in the discrimination task. It remained unchanged under conditions in which the reaction time and discrimination tasks were blocked, alternated, randomly mixed, or combined on each trial. It is concluded that motor activation without conscious discrimination was demonstrated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the relation between metacontrast masking and suppression of visible persistence.

Does the introduction of additional contours in a display sequence (an operation known to reduce the strength of suppression in metacontrast) also reduce suppression of visible persistence? In three experiments, duration of visible persistence was estimated by a method in which successful performance depends on the temporal integration of a pattern whose elements are displayed in two successive frames. In this procedure, the arrival of the trailing frame is known to exert a suppressive influence on the visible persistence of the leading frame. Embedding the elements of the leading frame within additional contours (a line grid) reduced the degree of suppression exerted by the trailing frame. This did not occur when the grid was part of the trailing display. We conclude that suppression of visible persistence and metacontrast masking belong to the same class of events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Backward pattern masking can vary as a nonmonotonic function of target duration: on the influence of intratraget metacontrast

The magnitude of backward masking is usually found to vary inversely with the amount of information about a target that is made available to the visual system. Contrary to these findings, we report a nonmonotonic relation between the magnitude of backward pattern masking and target duration. Specifically, masking decreased as target duration was increased to about 8 msec and, then, became more severe as target duration was further increased to a value of at least 40 msec. The occurrence of the nonmonotonic function depended on (a) the degree of definition of the target's edges, (b) the luminance levels within the target stimulus, and (c) the state of adaptation of the eye. It is hypothesized that the source of the nonmonotonic function was metacontrast interference that originated from within the target stimulus configuration. This hypothesis was supported by data that indicated that in the absence of any mask presentations, the apparent contrast between the target and its immediate background varied as a nonmonotonic function of target duration.     

Backward masking.

In backward masking, perception of a test stimulus is suppressed by masking stimulation that is presented subsequently. Psychophysical studies of this phenomenon have utilized visual, auditory, and cutaneous stimuli. These masking studies are reviewed and their results discussed in terms of possible neural mediating mechanisms. (88 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective forward masking.

Assessed the effects of masking on recall accuracy in 2 experiments with a total of 28 male undergraduates. When a patterned masking stimulus was presented immediately before a centrally-fixated, tachistoscopically-presented 7-letter row (forward masking), a selective effect on recall accuracy was found, as measured by a partial-report technique. There was greater masking of the end letters than of the center letters in the displays. When the masking stimulus was presented immediately after the presentation of a letter row (backward masking), the results confirmed previous findings of greater masking of the center letters than the end letters. These different selective effects of forward and backward masking are consistent with the assumption that the processing of multiletter displays begins at the ends of the letter rows. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metacontrast masking in amblyopia.

Measured the time course of visual signals arising from each eye of 4 strabismic and/or anisometropic amblyopes and 2 visually normal Ss using monoptic metacontrast masking. The amblyope Ss had 1 nonamblyopic eye, clear ocular media, and normal fundi. The method involved the brightness estimation of a high-contrast disk target whose visibility varied as a function of the stimulus onset asynchrony (SOA) of a subsequent annular mask. Results indicate that the SOA of optimal masking was delayed in the amblyopic eye compared to that of the fellow nonamblyopic eye or with normal eyes. The smaller the target, the greater was this SOA difference and the broader was the amblyopic U-shaped masking function. This finding is discussed in terms of the current model of metacontrast and represents the differential effect of the amblyopic process on human sustained and transient neurons. (French abstract) (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Asymmetric object substitution masking.

Object substitution masking occurs when a lateral mask persists beyond the duration of a target, reflecting reentrant processes in vision (V. Di Lollo, J. Enns, & R. Rensink, 2000). The authors studied whether substitution masking is location specific and whether it is symmetric around the target. A brief circular display of letters was presented along with a mask that designated the target. The mask was centered on the target or 1.1° to the central or to the peripheral side. Substitution masking was found even when the target and the mask were at different locations. It was asymmetric and stronger when the mask was to the peripheral side of the target than to the central side. Asymmetric substitution was observed using various masks. It could not be explained by retina acuity gradients and was not attenuated by focused attention. The authors propose that target selection triggers an asymmetric inhibitory surround that is stronger toward the central side of the target. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual masking by homonyms.

Words masked by their own homophones are more disrupted than words masked by unrelated control words. Conversely, words masked by their own associates are less disrupted than unrelated control words. This indicates that the association effect in masking cannot be due to response bias. A model to account for these results is proposed and was tested on 15 undergraduates. Results suggest that the facilitatory effect of masking by associates occurs in the perception of the target word, but the inhibitory effect of masking by homophones occurs in the attempted response or vocalization of the target words by the Ss. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tiny theories.

Describes the experiences of a graduate student who introduced manipulations into his research on dissonance with undergraduate Ss and found that Ss were experienced (not naive) and highly suspicious. Perhaps certain psychological theories are so dependent on the type of naiveté a person possesses that these theories have limited generality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chemical theories.

The chemical theories of the visual process advanced by Wald, Dartnall, and others are compared. Their adequacy for scotopic vision is substantial, while incomplete. Almost no theory successfully explains photopic vision. Evidence that rhodopsin is a light-sensitive enzyme is discussed, and it is conjectured that present extraction techniques do not permit comparison of in situ and in vitro data, particularly in the photopic case. (42 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Practice effects in backward masking.

In two experiments we demonstrate that much larger practice effects occur in a backward masking paradigm where patterned masks are used than in similar visual processing paradigms, such as lateral masking and whole report. In additional experiments we examine four possible explanations for the large practice effects: increased familiarity with the paradigm in general, learning about the targets, learning about the masks, and enhanced sensory processing. Because of failure to observe similar practice effects in related paradigms not involving backward masking and because of the sustained nature of the improvement, we reject the first explanation as a source of practice effect. Experiment 3 allowed us to reject target learning as a source of improvement as well; target sets were switched at the end of training, but no decrement in performance was observed. In Experiment 4, mask sets were switched at the end of training, revealing a significant decrement in performance. Learning about the specific masks, then, does contribute to the observed improvement. However, it is responsible for only about one third of the overall improvement in performance. The final experiment provides evidence that the residual improvement is due to enhanced sensory processing. In that experiment, training on backward masking led to a lowered threshold in a two-flash paradigm but not to a significant change in whole-report performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combining simultaneous with temporal masking.

Simultaneous and temporal masking are two frequently used techniques in psychology and vision science. Although there are many studies and theories related to each masking technique, there are no systematic investigations of their mutual relationship, even though both techniques are often applied together. Here, the authors show that temporal masking can both undo and enhance the deteriorating effects of simultaneous masking depending on the stimulus onset asynchrony between the simultaneous and temporal masks. For the task and stimuli used in this study, temporal masking was largely unaffected by the properties of the simultaneous mask. In contrast, simultaneous masking seems to depend strongly on spatial grouping and was strongly affected by the properties of the temporal mask. These findings help to identify the nature of both temporal and simultaneous masking and promote understanding of the role of spatial and temporal grouping in visual perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Current concerns in visual masking.

Theories of emotion postulate that emotional input is processed independently from perceptual awareness. Although visual masking has a long tradition in studying whether emotional pictures are processed below a supposed threshold of perceptual awareness (subliminal perception), a consensus has yet to be reached. This article reviews current concerns in the use of visual masking. These include a reliable presentation method, the role of masking pictures, common definitions of awareness and their problems, current models of awareness, and neural mechanisms. A useful strategy may be the study of dose-response relationships between awareness and emotion processing that avoids a dichotomous view of awareness and allows conclusions about the relative independence of emotional processing from awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociation theories of hypnosis.

Hypnotic responses have been attributed to 2 mechanisms that are characterized as dissociative. In E. R. Hilgard's (1986) neodissociation theory, responses are hypothesized to be due to a division of consciousness into 2 or more simultaneous streams, separated by an amnesic barrier that prevents access to suggestion-related executive functions, monitoring functions, or both. In K. S. Bowers's (1992) dissociated control theory, hypnotic inductions are hypothesized to weaken frontal control of behavioral schemas, thereby allowing direct activation of behavior by the hypnotist's suggestions. The authors review the empirical base, conceptual issues, and strengths and weaknesses of both theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal integration and vibrotactile backward masking.

In 2 experiments, 12 Ss were presented with vibrotactile target patterns to their left index fingertips. The target patterns varied in the number of line segments that they contained and were presented in the presence or absence of a backward-masking stimulus. The stimulus onset asynchrony (SOA) between the target and masker was varied. In an identification task, Ss' errors indicated that at brief SOAs the masker increased the perceived number of line segments in the targets. This effect diminished with increasing SOA, and at the longest SOAs, Ss confused targets with patterns containing the same number of line segments but varying in how the line segments were related. In an estimation task, the masker increased the number of line segments estimated to be contained in the target pattern. The effect of the masker at brief SOAs is discussed in terms of an integration theory of vibrotactile backward masking. At longer SOAs, the results suggest that the masker may interfere with the extraction of relational information in the target pattern. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Low-level masking in the attentional blink.

If two targets (T1 and T2) are to be identified among other stimuli displayed in rapid serial visual presentation (RSVP), correct identification of T1 can produce an attentional blink (AB) lasting several hundred milliseconds, during which detection of T2 is impaired. Experiment 1 confirmed that omission of the item directly following T1 (the + 1 item) reduces the AB (J. E. Raymond, K. L. Shapiro, & K. M. Arnell, 1992). The next 3 experiments varied the spatial and temporal relationships between T1 and the + 1 item to study how masking of T1 affects the AB deficit. Perception of T1 was impaired by pattern masking arising from temporal integration or superimposition of T1 and the + 1 item; it was also impaired by metacontrast masking. We conclude that masking affects the AB indirectly by degrading T1 thereby increasing the duration of T1 processing. A 2-stage model proposed by M. M. Chun and M. C. Potter (1995) is supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychological theories of obesity.

Responds to S. Schacter's (see record 1971-24450-001) article on obesity and the comments generated by the article from E. R. Bauer (1971), M. S. Smart and R. S. Smart (1971), and D. I. Templer (1971). Generalizations were raised that seemed to contradict one another. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adolescents' theories of education.

315 9th graders and 272 12th graders from 2 schools were administered a questionnaire to investigate associations between views about the purposes of education and personal goals, between personal goals and perceived causes of success, and between purposes of education and perceived causes of success. Results show that Ss found a logically consistent relationship among these elements of inquiry. For example, the view that school should enable Ss to enhance their wealth and status was less likely than any other view to be associated with a commitment to learning for its own sake and more likely to be associated with academic alienation. Ss also tended to expect success to result from the types of activity they preferred and from the personal qualities they thought school should encourage. Findings raise doubts about the wisdom of the current propensity to emphasize the role of schools in the advancement of one's wealth and social status. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)