An examination of the relationship between visual capture and prism adaptation

The phenomena of prismatically induced “visual capture” and adaptation of the hand were compared. In Experiment 1, it was demonstrated that when the subject’s hand was transported for him by the experimenter (passive movement) immediately preceding the measure of visual capture, the magnitude of the immediate shift in felt limb position (visual capture) was enhanced relative to when the subject moved the hand himself (active movement). In Experiment 2, where the dependent measure was adaptation of the prism-exposed hand, the opposite effect was produced by the active/passive manipulation. It appears, then, that different processes operate to produce visual capture and adaptation. It was speculated that visual capture represents an immediate weighting of visual over proprioceptive input as a result of the greater precision of vision and/or the subject’s tendency to direct his attention more heavily to this modality. In contrast, prism adaptation is probably a recalibration of felt limb position in the direction of vision, induced by the presence of a registered discordance between visual and proprioceptive inputs.     

The probability-matching decision rule in the visual discrimination of order

In three experiments, human Ss were required to decide, on each trial, which of two spatially proximate, nearly simultaneous, lights was illuminated first. The right light preceded the left on either .33 or .83 of the trials. When Ss were frequently informed of these values, then, regardless of the accuracy of performance, Ss adjusted the rate at which they made “right” responses to approximate the rate at which the right-first pattern was presented. These results are in clear agreement with an adaptation of Atkinson’s three-state detection model.     

The relationship between cognitive,motor-kinesthetic,and oculomotor adaptation

The literature concerning adaptation to prism indicates that several adaptive mechanisms may be important. The particular mechanism or mechanisms involved depends (at least in part) upon the type of adaptive exposure. In the present study. three adaptive mechanisms (cognitive. oculomotor, and motor-kinesthetic) were investigated. Ss were asked to point in the dark at an illuminated target. The target was seen displaced from its veridical position due to a wedge prism placed before S’s right eye. The left eye was occluded. Ss then viewed their visual target pointing errors through the displacing prism without seeing any part of their bodies. One group of Ss was instructed to ignore these prism-induced errors and to continue pointing at the target’s visual position. A second group of Ss was instructed to compensate fully for their errors and to at tempt to eliminate them on all future trials. For the latter group errors were completely eliminated, while for Ss instructed to ignore their errors, relatively small improvement in visual target settings occurred. This improvement was called cognitive adaptation, since it depended on the S’s conscious control. In addition. for both conditions. evidence was found that allowing Ss to view their prism-induced pointing errors resulted in some form of motor-kinesthetic adaptation. This adaptation was hypothesized to represent a change in the judged position of the pointing hand relative to its felt position. It was concluded that this motor-kinesthetic adaptation was dependent, in part, upon cognitive information concerning the effects of the prism and that it serves to reduce conflict between cognitive and visual cues, i.e., between what S believes and what he sees.     

Effects of temporal uncertainty on watchkeeping performance

Two experiments were conducted to assess the relative effects of signal density and regularity on watchkeeping performance. In Experiment I, three levels of density (6, 24, and 96 signals/hr.) were combined factorially with three levels of variability (coefficients of variation of 0.01, 0.l0, and 1.00), and I0 Ss were assigned at random to each of the nine conditions. In Experiment II, five leveIs of density (6, 12, 24, 48, and 96 signals/hr.) were combined with the same three levels of variability, and 13 Ss were assigned to each condition. Each S monitored a visual “blinking-lights” display for an hour under instructions to detect and report the occurrence of certain “critical signals,” i.e., arrests of alternation of the lights. Response times (RT’s) to correctly detected signals in both experiments decreased as a linear function of logarithmic increases in signal density. An uncertainty metric, the signal surprisal due to density, was derived, and the watchkeeper’s RT was expressed as an increasing linear function of this measure of temporal uncertainty. Interpretation of these and 0 ther data support a functional, psychophysical approach to the study of watchkeeping behavior.     

Discriminative conditioning of prism adaptation

Two experiments were used to demonstrate that adaptation to ll-deg prism displacement can be conditioned to the stimuli associated with the goggles in which the prisms are housed. In Experiment 1 it was found that repeated alternation between a series of target-pointing responses while wearing prism goggles and a series of responses without prism goggles led to larger adaptive shift when S was tested with nondisplacing goggles than when tested without goggles. The results of Experiment 2 indicated that the adaptation revealed in the first experiment was primarily proprioceptive, rather than visual. Surprisingly, most Ss reported greater difficulty during the exposure period in overcoming the negative aftereffect than they did the prism-induced error.     

SDT analysis of binary decisions and sensory intensity ratings to noxious thermal stimuli

During three sessions, each of 24 Ss responded to noxious thermal stimuli, using the following judgments: binary decision, S responded “high” or “low”; sensory intensity rating, S rated his sensory experience along a thermal intensity continuum; and concurrent report, S’s binary decision was followed by an intensity rating. The binary-decision d’ was significantly higher than the rating d′, suggesting that Ss could not maintain multiple thermal criteria in a consistent fashion. The criteria for pain obtained with single and concurrent intensity rating judgments did not differ. These results suggest that the most efficacious and valid method for the study of experimental pain is to obtain concurrent responses, and to use binary decisions to compute d’ and sensory intensity ratings to locate S’s criterion for reporting pain.     

Perception of two-dimensional Markov constraints within visual displays

A method is described for constructing visual displays in which statistical constraints are encoded within two spatial dimensions without introducing one-dimensional linear constraints. Within each local group of four elements, the state of one element was determined with a given probability by the previously generated states of the other three. Ss rated such displays on a scale from “lumpy” (or crude texture) to “lacy” (or even texture). The consistency of classification obtained for displays with strong aggregated (“lumpy”) properties was substantially higher than that obtained for displays with strong distributed (“lacy”) properties. An incidental feature of the Ss’ behavior was their deliberate degrading of the visual quality of the displays. Comparison is made with one-dimensional displays concatenated in two dimensions.     

The elusive tradeoff: Speed vs accuracy in visual discrimination tasks

Theoretical models for choice reaction time and discrimination under time pressure must account for Ss’ ability to trade accuracy for increased speed. The fast guess model views these tradeoffs as different mixtures of “all-or-none” strategies, while incremental models assume they reflect different degrees of thoroughness in processing the stimulus. Three experiments sought tradeoffs for difficult visual discriminations, using explicit payoffs to control and manipulate pressures for speed and accuracy. Although guessing was pervasive, the simple fast guess model could be rejected; Experiments II and III obtained tradeoffs even when fast guesses were purged from Ss’ data. Tradeoff functions fit by several formulations revealed: (1) slower rates of increase in accuracy for more similar stimuli, and (2) substantial “dead times” (80–100 msec slower than detection times) before discrimination responses could exceed chance accuracy. Errors were sometimes faster and sometimes slower than correct responses (depending on S’s speed-accuracy trade); the latter effect may reflect a ceiling on S’s achievable accuracy. A final discussion examines implications of the results for models of discrimination under time pressure; it suggests modifications in present models, focusing on the random walk model, and describes an alternative “deadline” model.     

What is the “front” of a simple geometric form?

A total of 670 undergraduate Ss were tested in three studies conducted in an attempt to define a set of cues that minimally specify perceived “frontness” and “backness” of objects. In Experiment I, Ss were instructed to identify the “front” and “back” of printed squares to which no, one, or two circles were attached. In Experiment II, different Ss made the same kind of judgment to a wider range of geometric forms. In Experiment III, different Ss judged the direction of “imagined” movement of forms from Experiment I. The results indicated that the “front” and “back” are asymmetric opposite sides, with “front” the side most different from the rest and the side toward which the form is imagined to be moving.     

Visual search under conditions of very rapid sequential Input rates

The purposes of the present experiment were to provide information on rate of information processing in visual perception and to determine the degree to which the “sequential blanking” effect found by Mayzner. Tresselt, and Cohen (1966) constituted a limitation on rapid sequential input rates. A 10-channel tachisto scope was employed that permitted controlled durations of each of the 10 channels and the 9 inter channel intervals. The S’s task was one of visual search or detection in which he searched for a target letter among noise letters. A temporal interval forced-choice procedure was used. In addition to varying the rate at which letters were sequentially presented, various irregular temporal spatial orders of presentation of the letter sequences were employed and the direction and orientation of the display in the visual field was varied as was also the spacing between adjacent stimuli. No evidence of “sequential blanking” was found either in terms of the detection criterion or in the Ss’ phenomenal reports. Detection performance was as good at a rate of 2 1/2 msec per letter as it was at a rate of 30 msec per letter.     

Confidence ratings in speech perception research: Evaluation of an efficient technique for discrimination testing

Discriminability of voice onset time was determined for four naive Ss in order to evaluate the relative efficiency of a testing procedure which utilized confidence ratings along with the conventional oddity task. Ss rated their judgments on oddity trials as “very very sure,” “somewhat sure,” or “just guessing.” Each S’s discrimination scores were given weights according to his ratings, yielding functions that were compared with those computed using unweighted percent correct scores. The confidence-rating technique produced readily interpretable results with about one-third as many judgments as are needed when the conventional procedure is used. Possible problems with the interpretation of the functions and the generalizability of the technique are discussed.     

Effects of temporal uncertainty on watchkeeping performance

Two experiments were conducted to assess the relative effects of signal density and regularity on watchkeeping performance. In Experiment I, three levels of density (6, 24, and 96 signals/hr.) were combined factorially with three levels of variability (coefficients of variation of 0.01, 0.10, and 1.00), and 10 Ss were assigned at random to each of the nine conditions. In Experiment II, five levels of density (6, 12, 24, 48, and 96 signals/hr.) were combined with the same three levels of variability, and 13 Ss were assigned to each condition. Each 5 monitored a visual “blinking-lights” display for an hour under instructions to detect and report the occurrence of certain “critical signals,” i.e., arrests of alternation of the lights. Response times (RT’s) to correctly detected signals in both experiments decreased as a linear function of logarithmic increases in signal density. An uncertainty metric, the signal surprisal due to density, was derived, and the watchkeeper’sRT was expressed as an increasing linear function of this measure of temporal uncertainty. Interpretation of these and other data support a functional, psychophysical approach to the study of watchkeeping behavior.     

Effect of direction of sequential presentation and redundancy on short-term recognition memory

Short-term recognition memory was tested by presenting six letters, one after the other, followed by a target letter and having S indicate whether or not the target matched one of the six letters. Recognition memory for a letter was better when it was embedded in a six-letter word, rather than a nonword, and when it was included in a sequence presented left-to-right, rather than right-to-left (Experiment 1). Reducing the presentation rate from 4/sec to 2.5/sec largely eliminated the left-to-right effect (Experiment 2). The effect of direction of presentation was greater for redundant (Experiment 1) than for nonredundant sequences (Experiment 3) and was greater for Ss who more frequently formed a word out of the sequence (Experiments 1 and 2), but was no greater for words than nonwords (Experiments 1 and 2) and no greater for letter than for line-figure sequences (Experiment 3). These findings suggest that the left-to-right effect depends as much, or more, on “peripheral” processes (e.g., eye movements) as on “central” processes (e.g., reading).     

Adaptation to displaced vision: Variations on the “prismatic-shaping” technique

Adaptation to displaced vision was measured, using three variations on Howard’s (1968) “prismatic shaping technique.” Over a series of 40 trials, a lateral displacement of 11.3 deg was introduced either gradually or suddenly. Both the amount of adaptation (negative aftereffect) and the accuracy of target localization at the completion of 40 trials were found to be directly related to the “suddenness” with which the displacement was introduced.     

What does a person in a “TOT” state know that a person in a “don’t know” state doesn’t know

The purpose of this study was to examine the significance of Brown and McNeill’s (1966) findings regarding the “tip of the tongue” (TOT) phenomenon, A modified version of their procedure was used with 56 Ss. Although their findings that Ss in a TOT state can detect parts and properties of the missing word were generally replicated, a division of the TOT state into a variety of substates showed correct detection rate to vary greatly, depending on the substate involved. In addition, correct detection of partial information was demonstrated even when S declared he had no knowledge of the selected word (don’t know). It was suggested that a distinction be made between information detection based on knowledge of the characteristics common to the class of items of which the target is a member (“class detection”) and detection based on knowledge of characteristics specific to the target in question (“differential detection”). Both class and differential detection were found to obtain in TOT states as well as in the don’t know state. Some theoretical and methodological implications were suggested     

Evidence for all-or-none preperceptual processing in perceptual set

“Set” is known to improve the accuracy of report of the stimulus attributes for which Ss are set to respond. The set may produce this effect by acting on either preperceptual or postperceptual processes, or both. To elucidate the manner by which set produces its effect, this paper explores the consequences of two assumptions concerning set (1) On any given trial, a S is either “set” or “not set”: (2) if “set” by the stimulus information. S’s perception of the stimulus actually improves, whereas, if “not set” by the stimulus reformation, the S’s report correctness is improved by an independent interaction of stimulus and set information on a response process. Evidence is provided for both these assumptions. In addition. It is argued that only set given before stimulation can affect a perceptual process.     

Retro- and prospection for mental time travel: Emergence of episodic remembering and mental rotation in 5- to 8-year old children

We investigate the common development of children’s ability to “look back in time” (retrospection, episodic remembering) and to “look into the future” (prospection). Experiment 1 with 59 children 5 to 8.5 years old showed mental rotation, as a measure of prospection, explaining specific variance of free recall, as a measure of episodic remembering (retrospection) when controlled for cued recall. Experiment 2 with 31 children from 5 to 6.5 years measured episodic remembering with recall of visually experienced events (seeing which picture was placed inside a box) when controlling for recall of indirectly conveyed events (being informed about the pictures placed inside the box by showing the pictures on a monitor). Quite unexpectedly rotators were markedly worse on indirect items than non-rotators. We speculate that with the ability to rotate children switch from knowledge retrieval to episodic remembering, which maintains success for experienced events but has detrimental effects for indirect information.     

Meaning above the head: combinatorial constraints on the visual vocabulary of comics

“Upfixes” are “visual morphemes” originating in comics where an element floats above a character’s head (ex. lightbulbs or gears). We posited that, similar to constructional lexical schemas in language, upfixes use an abstract schema stored in memory, which constrains upfixes to locations above the head and requires them to “agree” with their accompanying facial expressions. We asked participants to rate and interpret both conventional and unconventional upfixes that either matched or mismatched their facial expression (Experiment 1) and/or were placed either above or beside the head (Experiment 2). Interpretations and ratings of conventionality and face–upfix matching (Experiment 1) along with overall comprehensibility (Experiment 2) suggested that both constraints operated on upfix understanding. Because these constraints modulated both conventional and unconventional upfixes, these findings support that an abstract schema stored in long-term memory allows for generalisations beyond memorised individual items.