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.     

On the orienting value of attitudes: attitude accessibility as a determinant of an object's attraction of visual attention.

Four experiments tested the hypothesis that objects toward which individuals hold attitudes that are highly accessible from memory (i.e., attitude-evoking objects) are more likely to attract attention when presented in a visual display than objects involving less accessible attitudes. In Experiments 1 and 2, Ss were more likely to notice and report such attitude-evoking objects. Experiment 3 yielded evidence of incidental attention; Ss noticed attitude-evoking objects even when the task made it beneficial to ignore the objects. Experiment 4 demonstrated that inclusion of attitude-evoking objects as distractor items interfered with Ss' performance of a visual search task. Apparently, attitude-evoking stimuli attract attention automatically. Thus, accessible attitudes provide the functional benefit of orienting an individual's visual attention toward objects with potential hedonic consequences.     

Testing visual short-term memory: Simultaneous versus sequential presentations

Two experiments testing immediate ordered recall are presented; in these experiments, subjects engaged in repetitive speech (“articulatory suppression”) during a visual presentation in order to prevent auditory recoding of the stimuli. In both experiments, a simultaneous presentation produced results that suggested the use of visual short-term memory, whereas a sequential presentation did not. In Experiment 1, visual confusion errors occurred more often than would be expected by chance for a simultaneous presentation but not for a sequential presentation. In Experiment 2, recall from visual short-term memory was expected to suffer more when subjects wrote a prefix than when they spoke a prefix; this effect occurred for a simultaneous presentation but not for a sequential presentation. These results suggest that existence of a visual short term store that retains a simultaneous presentation but not a sequential presentation.     

Influence of short-term memory codes on visual image processing: evidence from image transformation tasks.

Three experiments showed that phonological recording of visual stimuli in short-term memory (STM) affects coding in long-term memory (LTM) and therefore performance on tasks involving generation and manipulation of visual images of the stimuli. An image transformation task was devised. It consists of mentally subtracting a part of an image to discover in the remainder another object. In Experiment 1, Ss were required to learn a set of easily nameable visual stimuli and then perform the subtraction task on images retrieved from LTM. Performance was significantly better when initial learning was accompanied by articulatory suppression (AS). Experiment 2 confirmed that AS had no effect when the task was performed on an image of a just-presented stimulus. In Experiment 3, the nameability of the stimuli was manipulated. The results replicated the effect of AS for items that were easy to name but showed no effect of AS for stimuli that were difficult to name.     

Confidence ill stimulus predictions and choice reaction time

In two choice reaction time (RT) experiments, a stimulus prediction and a confidence judgment in the prediction preceded each occurrence of one of two stimulus alternatives. Ss identified each stimulus presentation by pressing a left-hand or right-hand telegraph key. In Experiment I the source of the stimulus predictions and confidence estimates was varied between groups of 20 Ss. For each condition, RT to correctly predicted stimuli was an inverse function of prediction confidence. Following incorrectly predicted stimuli, RT was not reliably influenced by confidence when S gave both predictions and confidence judgments; but RT to incorrectly predicted stimuli was an increasing function of confidence when E verbalized the predictions and confidence estimates or when S predicted and E indicated confidence. In Experiment II Ss made predictions and the validity of Es confidence estimate was manipulated between Ss. When Es confidence was perfectly related to the probability of a correct prediction, choice RT to nonpredicted stimuli was inversely related to confidence. However, choice RT to nonpredicted stimuli was not affected by prediction confidence when Es judgments were random.     

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.     

The integration of habits maintained by food and water reinforcement through stimulus compounding.

In Experiment 1, a light and a tone were correlated independently with water reinforcement of bar pressing by rats. With different naive subjects in Experiment 2, one of these stimuli was correlated with food and the other with water reinforcement (counterbalanced). In both experiments the absence of tone and light signaled extinction. Tests of stimulus-reinforcer independence in Experiment 2 indicated that tone and light controlled behavior whose rate was specifically affected by deprivation state. In the stimulus-compounding tests of both experiments, response rates were higher to tone-plus-light than to tone or light presented alone (additive summation). This is the first report of additive summation produced through compounding stimuli paired with different reinforcers. The results are discussed in the context of the effects of incentive motivation on operant performance.     

Learning the structure of event sequences

How is complex sequential material acquired, processed, and represented when there is no intention to learn? Two experiments exploring a choice reaction time task are reported. Unknown to Ss, successive stimuli followed a sequence derived from a "noisy" finite-state grammar. After considerable practice (60,000 exposures) with Experiment 1, Ss acquired a complex body of procedural knowledge about the sequential structure of the material. Experiment 2 was an attempt to identify limits on Ss ability to encode the temporal context by using more distant contingencies that spanned irrelevant material. Taken together, the results indicate that Ss become increasingly sensitive to the temporal context set by previous elements of the sequence, up to 3 elements. Responses are also affected by priming effects from recent trials. A connectionist model that incorporates sensitivity to the sequential structure and to priming effects is shown to capture key aspects of both acquisition and processing and to account for the interaction between attention and sequence structure reported by Cohen, Ivry, and Keele (1990).     

Size-distance paradox with accommodative micropsia

Two experiments tested the hypothesis that the paradoxical relative distance judgment associated with the size-distance paradox is due to the visual system’s assuming equal linear size and perceiving a smaller angular size for the closer stimulus equal in visual angle. In Experiment I, two different sized coins were presented successively, and 16 Ss were asked to give ordinal judgments of apparent distance and apparent size. When the two coins depicted the same figures, the closer stimulus was judged to be farther and smaller, more frequently, than when two coins depicted different figures. In Experiment II, 48 Ss were asked to give ratio judgments of apparent distance, apparent linear size, and apparent angular size for two stimuli which were presented successively. When the stimuli were of equal shape, the mean ratios of the far stimulus to the near stimulus were smaller for the apparent distance but larger for the apparent linear size and angular size than when the stimuli were of different shape. The obtained distance judgments were consistent with the hypothesis but the obtained judgments of linear size and angular size were not.     

编码时间对序列视觉信息整合的影响

本研究采用空白单元格定位任务,探讨序列刺激整合的时间特性。实验1重复前人的实验,验证了时间间隔对整合绩效的影响;实验2系统操纵了对先前刺激的编码时间与时间间隔,结果发现,编码时间越长,记忆的效果越好,虽然会妨碍对随后刺激的知觉,但整合绩效越高;而随着时间间隔的延长,延长编码时间带来的优势逐渐减弱。结论提示,人们能够整合视觉短时记忆和视知觉的信息,而且这种整合的时间特性不同于知觉整合。     

Laterality effects in perceptual matching

Two experiments are reported in which Ss had to indicate whether pairs of simple geometric forms were “same” or “different.” In Experiment I the two forms were either both in the left visual hemifield or both in the right hemifield. Reaction times were unaffected by the locus of the stimuli. In Experiment 2, in addition to left and right pairs, there were pairs in which one of the stimuli was on the left and the other was on the right. Under these conditions, reaction times were faster for pairs totally on the left than for pairs totally on the right. The data support the notion that implicit scanning patterns are important in determining laterality differences. When such scanning is not involved and when simple nonverbal stimuli and responses are employed, laterality differences are eliminated.     

Response selection in choice reaction time: Test of a buffer model

Two experiments were conducted to test a buffer model of response selection. Subjects reacted to the onset of one of six possible visual stimuli by pressing either a left- or a right-hand key. Two stimuli were assigned to one key Itwo-item set) and four stimuli were assigned to the other key flour-item set). An irrelevant monaural tone accompanied the visual stimulus in Experiment 1 but not in Experiment 2. Results of Experiment 1 showed that reactions were faster when the location of the tone corresponded with the response than when it did not, and the difference between these corresponding and noncorresponding conditions was greater for the two-item set than for the four-item set. Results supported the notion that the response selection process involved a serial self-terminating search of response buffers and that the tone determined the buffer searched first. In both experiments, reactions were faster to stimuli from the twoitem set than to stimuli from the four-item set     

A constant error in the perception of brief temporal intervals

Ss were presented two stimuli of equal duration separated in time. The parrs of stimuli were vibrotactile, auditory, or visual. The Ss adjusted the time between the two stimuli to be equal to the duration of the first stimulus. The results show that for stimulus durations ranging from 100 to 1,200 msec, Ss set the tune between the two stimuli too long and by a constant amount. For vibrotactfle stimuli, the constant was 596 msec; for auditory stimuli, 657 msec; and for visual stimuli, 436 msec. Changing the intensity of the vibrotactile stimuli did not change the size of the constant error. When Ss were presented two tones with a burst of white noise between the tones and adjusted the duration of the white noise to be equal to the duration of the first tone, the white noise was not adjusted too long by a constant amount. The results suggest that there is a constant error in the perception of unfilled relative to filled temporal intervals.     

An informational analysis of absolute judgments of torque

Five male Ss participated in seven experiments involving absolute judgments of stimuli selected from a continuum of torque. Experiment 1 required Ss to make judgments on the intensity of 16 stimuli separated by equal intervals. These results were used in the construction of individual scales of equal discriminability. These scales were then used to select the stimuli for the remaining six experiments, in which 6, 8, 10, 12, 14, or 16 stimuli, separated by subjectively equal intervals, were used. An informational analysis was performed to determine the capacity of the kinesthetic system to transmit information derived from the inducement of torque. Maximum values of 1.680, 2.050, and 2.524 bits of information transmitted were obtained when the response was considered the output, and the input variables were, respectively: the stimulus; the stimulus and the S; the stimulus, the S, and the previous stimulus. These results were discussed in relation to information theory and the use of torque information in closed-loop control of movement.     

Visual evoked potentials elicited by subjective contour figures

In order to investigate the relationship between the appearance of illusory figures and the wave form of visual evoked potentials (VEPs), 8 different visual pattern stimuli were presented to 8 normal subjects. Four of the stimuli (experimental stimuli) produced subjective figures and contours (squares and discs). The 4 other stimuli (reference stimuli), although equal to the experimental stimuli in the amount of physical energy, did not produce the illusion of squares or discs. Electrodes were placed on the scalp at central and occipital locations. Three prominent peaks in the occipital record were observed in all subjects. An amplitude difference of VEP N180 (N2) between the subjective figures and the reference stimuli was found in the values for each subject. Enhancement of the VEP of the illusory figure stimuli was observed for a specific component (N2), whereas the amplitude values at the central components and the occipital P120 (P2) and P280 (P3) were almost the same as the reference values. The VEP (N2 component) amplitude enhancement at the occipital area for subjective figure stimuli suggests that illusory contour formation takes place at higher levels in the visual system. This was known from experiments using dichoptic presentation.     

Asymmetry of automatic change detection shown by the visual mismatch negativity: An additional feature is identified faster than missing features

In two experiments, we demonstrated that an asymmetric effect of the brain electric activity that is elicited by nonattended visual stimuli is similar to the one found in responses observed in the performance of visual search tasks. The automatic detection of violated sequential regularities was investigated by measuring the visual mismatch negativity (vMMN) component of event-related brain potentials (ERPs). In Experiment 1, within a sequence of stimulus displays with O characters, infrequently presented Q characters elicited an earlier vMMN than did infrequent O characters within a sequence of Q characters. In Experiment 2, similar asymmetric results emerged if only 16 % of the characters were different within an infrequent display. In both experiments, these stimuli were irrelevant; during the stimulus sequences, participants performed a demanding videogame. We suggest that the underlying match/mismatch and decision processes are similar in the vMMN and in the attention-related visual search paradigm, at least in the case of the stimuli in the present experiments.     

Detection and identification of words and letters in simulated visual search of word lists

Ss were shown a rapid sequence of words and had to (a) make a speeded response to the presentation of a predefined target and (b) report a "response word" which they thought immediately followed the target in the sequence. In Experiment I presentation rate was varied orthogonally with the number of alternative targets. Detection errors and latency increased with target set size, as did the distance of the response word from the target in the list sequence. Increases in presentation rate produced greater target-response distance without affecting detection time. In Experiment II Ss were in some conditions given only the initial letter of the targets; the response could be either the whole word following the target or only its initial letter. The results indicated that Ss could, within limits, concurrently detect initial letters and identify words. Alternatives to hierarchical-type models of stimulus processing in visual search were discussed.     

Memory for modality of presentation: Within-modality discrimination

Two experiments demonstrated that Ss are capable of making within-modality memory discriminations in both visual and auditory modalities. In Experiment I Ss studied mixed lists of pictures and labels representing common objects and were subsequently required to judge whether the original presentation was pictorial or verbal The high level of performance achieved on this task was unaffected by degree of categorical relatedness of items within method of presentation or by instructions to produce visual images when items were presented verbally. In Experiment II Ss demonstrated the ability to remember whether a sentence was originally presented by a male or a female speaker. Some strategies by which within-modality discrimination in memory might be accomplished are discussed.     

Investigating the effect of stimulus range on attribute weight

Classic economic theories of choice assume that trade-offs are made consistently and are not swayed by irrelevant contextual variables. One possible source of trade-off inconsistency is investigated by asking whether attribute weights are affected by variations in the range of the stimuli presented. Ss should be influenced by the range of the stimuli only when distributional characteristics provide information about the value of the stimuli. In six experiments, Ss made judgments when the range (a) did not provide information about the value of the scores on the scales, (b) might provide such information, and (c) certainly provided this information. In Experiments 1-5, Ss were not influenced by the range of the stimuli. The only exception was Experiment 6, which required Ss to judge hypothetical job candidates on the basis of stimulus scales with which the Ss had no previous experience. In this experiment the meaning of the scales was determined entirely by the location of each stimulus within the presented distribution. In general, the results support the classical view of decision making: that attribute weights exist independent of situational demands, and that Ss' judgments are not influenced by irrelevant stimuli.     

Intensity and reverberation as factors in the auditory perception of egocentric distance

Both auditory intensity and reverberation have previously been shown to be sufficient to produce systematically varying judgments of perceived distance when several values of the variable are presented repeatedly to the same observer. Such studies do not, however, indicate clearly whether these cues are functioning in an absolute or in a relative manner. An absolute cue to auditory distance would require that two groups presented with different values of the variable in question should report different values of perceived distance. Two experiments are reported in which intensity variation and reverberation are examined. The results showed that auditory intensity differences over a range of 20 dB did not serve as an absolute cue to auditory distance, but could serve as a strong cue to changes in such distance. A comparison of data obtained in a normally reverberatory setting (Experiment 1) and an anechoic chamber (Experiment 2) indicated that the state of reverberation could serve as an absolute cue, with greater reverberation being associated with greater perceived distances. Some of the results were discussed in terms of the possibility that the specific distance tendency (a concept developed to handle some phenomena in visual space perception) might have applicability to the study of auditory perceived distance as well.