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.     

Both perceptual and conceptual factors influence taste-odor and taste-taste interactions

Observers are often asked to make intensity judgments for a sensory attribute of a stimulus that is embedded in a background of “irrelevant” stimulusdimensions. Under some circumstances, these background dimensions of the stimulus can influence intensity judgments for the target attribute. For example, judgments of sweetness can be influenced by the other taste or-odor qualities of a solution (Frank & Byram, 1988; Kamen et al., 1961). Experiments 1 and 2 assessed the influence of stimulus context, instructional set, and reference stimuli on cross-quality interactions in mixtures of chemosensory stimuli. Experiment 1 demonstrated that odor-induced changes in sweetness judgments were dramatically influenced when subjects rated multiple attributes of the stimulus as compared with when they judged sweetness alone. Several odorants enhanced sweetness when sweetness alone was judged, while sweetness was suppressed for these same stimuli when total-intensity ratings were broken down into ratings for the sweetness, saltiness, sourness, bitterness, and fruitiness of each solution. Experiment 2 demonstrated a similar pattern of results when bitterness was the target taste. In addition, Experiment 2 showed that the instructional effects applied to both taste-odorand taste-taste mixtures. It was concluded that the taste enhancement and suppression observed for taste-odor and taste-taste mixtures are influenced by (1) instructional sets which influence subjects’ concepts of attribute categories, and (2) the perceptual similarities among the quality dimensions of the stimulus.     

Effects of discriminability and irrelevant information on absolute judgments’

The effects of irrelevant information (0, 1, 2, or 3 bits stimulus) on absolute judgments of size were measured at different levels of discrimination difficulty. The stimuli were 7 small circular spots of light of different sizes, selected from an eaual-discriminability scole, and arranged into 6 pairs that represented different levels of stimulus dissimilarity. Three of the pairs comprised a low-dissimilarity (LD) subgrouping in which different lepels of dissimilarity and discriminability were confounded, whereas the remaining three pairs comprised a high-dissimilarity (HD) subgrouping in which different levels of dissimilarity occurred at a single high level of discriminability. Different colors were used to provide the four levels of irrelevant information; 240 Ss (10 in each of the 24 experimental conditions) made absolute judgments of size under the classical procedure for the method of single stimuli. Separate analyses of errors, reaction times, and rates of information transmission indicated that irrelevant information had an increasingly detrimental effect on absolute judgments as discrimination difficulty was increased (in the LD subgroup), but essentially no effect where discriminations were easily modefin the HD subgroup).     

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.     

Range effects of an irrelevant dimension on classification

In univariate classification tasks, subjects sort stimuli on the basis of the only attribute that varies. In orthogonal classification tasks, often called filtering tasks, there additionally are trial-to-trial variations in irrelevant attributes that the subjects are instructed to ignore. Performance is generally slower in filtering tasks than in univariate control tasks. We investigated this slowing in experiments of how the range of irrelevant trial-to-trial variation affects responses in pitch/loudness classification tasks. Using two levels of pitch and of loudness as stimuli, Experiment 1 replicated prior work showing that responses are slowed more when the range of the irrelevant dimension is made larger. Also in Experiment 1, sequential analyses showed that response time depends both on sequence and on the stimulus set independent of sequence. Experiments 2 and 3 used several levels on the irrelevant dimension and showed that responses to categorize loudness are slowed more by larger trial-to-trial pitch differences, but only on trials when the response repeats. When the response changes, performance is essentially unaffected by trial-to-trial irrelevant variation. This interaction supports the conclusion that slowed average performance in orthogonal classification tasks, which is known as Garner interference, is not due to difficulties that subjects have in filtering stimulus attributes. It is due to how subjects process successive stimulus differences. We call for more frequent reports of sequential analyses, because these can reveal information that is not available from data averages.     

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.     

The influence of irrelevant information on speeded classification tasks

Multidimensional stimuli, which could vary on one, two, or all three dimensions within a particular series, were presented to Ss who were required to classify each stimulus on the basis of its value on a specified dimension. The prior relevance of the irrelevant dimensions and the difficulty of the task were varied. Latency and error data indicated that Ss were unable to gate the irrelevant information effectively. It was further concluded that this lack of perfect gating cannot be simply attributed to competing responses learned during the experiment.     

Stimulus discriminability in the magnitude estimation and category rating of loudness

Thirty-three Ss made category ratings and magnitude estimations of 10 auditory stimuli differing in loudness. The results from each task were examined in terms of the response uncertainty conditional upon each stimulus. The results did not support the suggestion that category judgments are influenced by the relative discriminability of stimuli in a way which is not characteristic of magnitude estimates, but were found to be consistent with the subjective Standard hypothesis. It is argued that the observed quasi-logarithmic relationship between category scale and ratio scale values reflects the constraints placed upon responses in category rating tasks.     

Disconfirmed hedonic expectations produce perceptual contrast, not assimilation

In studies of hedonic ratings, contrast is the usual result when expectations about test stimuli are produced through the presentation of context stimuli, whereas assimilation is the usual result when expectations about test stimuli are produced through labeling, advertising, or the relaying of information to the subject about the test stimuli. Both procedures produce expectations that are subsequently violated, but the outcomes are different. The present studies demonstrate that both assimilation and contrast can occur even when expectations are produced by verbal labels and the degree of violation of the expectation is held constant. One factor determining whether assimilation or contrast occurs appears to be the certainty of the expectation. Expectations that convey certainty are produced by methods that lead to social influence on subjects' ratings, producing assimilation. When social influence is not a factor and subjects give judgments influenced only by the perceived hedonic value of the stimulus, contrast is the result.     

Directed attention and perception of temporal order.

The present research examined the effects of directed attention on speed of information transmission in the visual system. Ss judged the temporal order of 2 stimuli while directing attention toward 1 of the stimuli or away from both stimuli. Perception of temporal order was influenced by directed attention: Given equal onset times, the attended stimulus appeared to occur before the unattended stimulus. Direction of attention also influenced the perception of simultaneity. The findings support the notion that attention affects the speed of transmission of information in the visual system. To account for the pattern of temporal order and simultaneity judgments, a model is proposed in which the temporal profile of visual responses is affected by directed attention.     

An eye fixation analysis of choice and judgment with multiattribute stimuli

The present paper examined the selection of processing heuristics for choice and judgment across a range of stimuli. Eye fixations were monitored while six subjects made choices or judgments of pairs of gambles, vacations, or gifts. Each stimulus was represented by three attributes that varied in the amount of dimensional interdependency. The two heuristics of interest were dimensional and holistic evaluation. Each manifested a characteristic pattern of eye fixations. Dimensional evaluation required alternating fixations from a single attribute of one stimulus to the same attribute of the other stimulus. Holistic evaluation was characterized by transitions from attribute to attribute within a single stimulus. The results demonstrated that when the stimulus attributes were either interdependent (gambles) or dissimilar (gifts), the processing heuristic was determined by stimulus characteristics. When the stimulus dimensions were neither interdependent nor dissimilar (vacations), the selection of a processing strategy was determined by the prescribed task. This study suggests that any global theory of choice or judgment must be validated over a wide range of stimuli.     

Effects of stimulus–stimulus short-term memory associations in a Simon-like task

The Simon effect refers to faster responding when an irrelevant stimulus location corresponds with the response to a relevant stimulus attribute than when it does not. We investigated whether a memory-based Simon-like effect would occur when the irrelevant spatial attribute was associated with the stimulus during a prior task. In a first task, an association between colour and location was formed by requiring participants to count the occurrences of two colour stimuli, each of which was always presented in a left or right location. In a second task, the colour stimuli were presented centrally and mapped to left and right keypresses, with the mapping being inconsistent or consistent with the prior colour-location associations. A Simon-like effect was evident at the start of the second task, with performance being better when the established colour–position associations were consistent with the colour–response mapping than when they were not. This result indicates that stimulus–stimulus short-term memory associations formed during the first task transferred to the second task. For the remainder of the second task, the data showed a more conservative speed–accuracy criterion for the inconsistent condition than for the consistent condition, though a processing efficiency measure suggested that the prior stimulus–stimulus short-term associations may also continue to directly influence performance. Results suggest that simple declarative knowledge, as represented by stimulus–stimulus STM links, exerts less persistent transfer effects than procedural knowledge as provided by stimulus–response STM links.     

A Comparison of Different Methods for the Elicitation of Attribute Weights: Structural Modeling,Process Tracing,and Self-Reports

This study investigates whether structural modeling, process tracing, and self-reports are able to provide similar information about attribute weights in multiattribute evaluation processes. In three experiments subjects had to evaluate a large number of profiles of fictitious persons described on a number of attributes. The experiments differed in type of judgment task, type of subjects, and number of attributes. Subject attribute weights were derived in all cases by fitting a statistical model (statistical weights), by analyzing verbal protocols (verbal protocol weights), and by directly asking the subject how important the attributes are for the judgments (subjective weights). Correspondence between the three sets of weights is examined in two ways: by computing the correlation between three sets of weights and by calculating how adequately the different sets of weights, applied in a linear model, can predict the subject′s judgments. The first method appears to be inappropriate for investigating correspondence. The correlations are rather unstable because of the small number of attributes, and apart from that, they tend to underestimate real correspondence when the weights in the respective sets are approximately equal. The second method shows that the three sets of weights are about equally adequate in predicting the actual subject judgments. It is concluded that this method convincingly demonstrates that the three different ways of eliciting attribute weights yield similar results.     

Exogenous influences on task set activation in task switching

To explore the effect of exogenous processes on cognitive control, we used a cueing task-switching paradigm with two spatial judgement tasks and added an irrelevant colour attribute to the task-relevant spatial attribute of the target. The colour was not related to any specific Stimulus-Response relation in the tasks. A correlation was created between stimulus colour and task identity. This correlation was strong but imperfect in Experiment 1 and perfect in Experiment 2. As a result of the colour-task correlation, stimuli contained redundant information about task identity. By changing the correlation pattern every few blocks we caused this information to be sometimes invalid. In both experiments, performance was worse when the information carried by the target was invalid than when it was valid. However, this effect was exclusive to conditions with short task preparation time. By comparing performance with a control group, which had no colour-task correlation (in Experiment 2) we established that the colour manipulation did not cause a qualitative change in preparation strategy, and that the exogenous effect was stronger in switch trials than in repetition trials. We conclude that exogenous processes that are related to task set affect performance primarily if they are presented before endogenous processes of task set preparation have been launched.     

The interaction between specific and general information in category learning and representation: unitization and parallel interactive processing

We investigated the effects of specific stimulus information on the use of rule information in a category learning task in 2 experiments, one presented here and an intercategory transfer task reported in an earlier article. In the present experiment photograph--name combinations, called identifiers, were associated with 4 demographic attributes. The same attribute information was shown to all participants. However, for one group of participants, half of the identifiers were paired with attribute values repeated over presentation blocks. For the other group the identifier information was new for each presentation block. The first group performed less well than the second group on stimuli with nonrepeated identifiers, indicating a negative effect of specific stimulus information on processing rule information. Application of a network model to the 2 experiments, which provided for the growth of connections between attribute values in learning, indicated that repetition of identifiers produced a unitizing effect on stimuli. Results suggested that unitization produced interference through connections between irrelevant attribute values.     

Exogenous influences on task set activation in task switching

To explore the effect of exogenous processes on cognitive control, we used a cueing task-switching paradigm with two spatial judgement tasks and added an irrelevant colour attribute to the task-relevant spatial attribute of the target. The colour was not related to any specific Stimulus–Response relation in the tasks. A correlation was created between stimulus colour and task identity. This correlation was strong but imperfect in Experiment 1 and perfect in Experiment 2. As a result of the colour–task correlation, stimuli contained redundant information about task identity. By changing the correlation pattern every few blocks we caused this information to be sometimes invalid. In both experiments, performance was worse when the information carried by the target was invalid than when it was valid. However, this effect was exclusive to conditions with short task preparation time. By comparing performance with a control group, which had no colour–task correlation (in Experiment 2) we established that the colour manipulation did not cause a qualitative change in preparation strategy, and that the exogenous effect was stronger in switch trials than in repetition trials. We conclude that exogenous processes that are related to task set affect performance primarily if they are presented before endogenous processes of task set preparation have been launched.     

The "euphoria" effect of music videos--a study of the reception of music with visual images

An attempt is made to study the impact of visual information on the perception of music by employing (rock) music videos as stimuli. Forty music videos were presented to judges, who either saw the video or only heard the respective pieces of music. They had to judge the emotions conveyed via the piece of music/video on scales and their overall impression on semantic differential scales. Results indicate that visual information as presented in music videos has considerable effects on impressions: When pieces of music are presented as music videos, more positive emotions are attributed, while presentation of the pieces of music alone resulted in more negative emotion attributions. Thus, music videos seem to "euphorize" the recipient. Furthermore, video presentation compared to presentation of music alone evoked more intense "complexity/interest" as well as "activity" judgments, while "evaluation" judgments were not influenced by the medium of presentation. In addition, a number of presentation factors (like the speed of the music or the number of cuts in the videos) do influence impressions. This leads to the conclusion that researchers should pay more attention to such microcharacteristics of stimuli. In general, the effects found to be due to the medium of presentation are independent of the effects on judgments due to content (i.e., presentation factors).     

Stimulus context and absolute magnitude estimation: a study of individual differences

The effect of stimulus context on absolute-magnitude-estimation (AME) judgments was examined by determining whether the loudness judgment of a tone is influenced by the intensities of other tones presented within the session. A group of 18 subjects was tested in separate sessions in which they judged stimuli within either a low (10-60 dB SL) or a high (40-90 dB SL) range of intensities. Examination of the results of individual subjects revealed that judgments of stimuli common to the two ranges were, in most subjects, unaffected or only slightly affected by the position of the range. The judgments of 2 subjects who failed to follow the instructions, however, showed very large context effects due to changing the stimulus range. The results of a second experiment, in which 22 subjects judged the loudness of tones within either a narrow (35-65 dB SL) or a wide (20-80 dB SL) range, revealed that, in all but 1 subject, the width of the range had no systematic effect on the loudness judgments of stimuli common to both ranges. This was also true 1 month later when 16 of the subjects returned to the laboratory to judge the loudness of tones within an even wider range of 10-90 dB SL. It was concluded that AME judgments are relatively insensitive to the potential biasing influences of stimulus context.     

Response requirements and the contrast effect in loudness judgments

Ss responded to a series of soft tones via category judgments, reaction time responses, or simple nonquantitative discrimination judgments. An evaluation was then made of the contrast effects obtained in the category judgments of these same soft tones when subsequently presented along with a series of loud tones. A control group was also used which did not receive the initial trials with the soft tones. The results indicated: (1) equivalent contrast effects for all four groups for the soft tones and (2) significantly greater judgments of the loud tones in the group that had used category judgments on the initial trials with soft tones. These results, alonR with a trend analysis, were used to argue for a joint semantic shift and equalization of category usage process underlying the contrast effect when Ss are required to denote the stimuli initially by means of category judgments.