Is visual information integrated across saccades?

After subjects established fixation on a target cross, 12 dots were presented parafoveally. When the dots were presented, the subjects made an eye movement to the location of the dots, and during the saccade the 12 initially presented dots were replaced by 12 other dots. The 24 dots were part of a 5 × 5 matrix, and the task of the subject was to report which dot was missing. The data were consistent with other recent studies: subjects could successfully report the location of the missing dot far above chance (54%), whereas performance in a control condition (in which the two sets of dots were presented to different spatial and retinal locations) was almost at chance level (10%). However, a number of control conditions demonstrated that the effect was due primarily to persistence from the phosphor of the cathode ray tube used for stimulus presentation and that little of the visual information integrated was across two fixations. Implications of the results for a theory of integration across saccades are discussed.     

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.     

Causal attributions as a function of locus of control, initial confidence, and performance outcomes.

Causal attributions and body movements indicative of tension were recorded while subjects completed an anagrams task that was more extensive than most similar tasks used in attribution studies. Nine trials each containing 10 anagrams were presented such that most subjects succeeded on three sets of relatively simple anagrams, failed on three sets of difficult anagrams, and either succeeded or failed on three sets of intermediately difficult anagrams. Attributions and body movements were predicted by a combination of locus of control, initial confidence, and type of outcome. High-confident internals attributed responsibility for outcomes to themselves more than did low-confident externals, and this difference was most prominent when subjects failed. Tension-indicating body movements were also less common among the former than the latter subjects and were in greater evidence with failure than with success. The data indicate that there is consistency between locus of control and causal attributions obtained during performances. The data also correspond to the findings on helplessness in which aversive agents prove to be more deleterious when individuals perceive themselves as unable to alter their negative circumstances.     

Perceptual identification thresholds for 150 fragmented pictures from the Snodgrass and Vanderwart picture set

This paper reports perceptual identification thresholds for 150 pictures from the 1980 Snodgrass and Vanderwart picture set. These pictures were fragmented and presented on the Apple Macintosh microcomputer in a picture-fragment completion task in which identification thresholds were obtained at three phases of learning: Train (initial presentation), New (initial presentation after training on a different set), and Old (repeated presentation of the Train set). Pictures were divided into five sets of two subsets of 15 pictures each, which served alternately as the Train and New sets. A total of 100 subjects participated in the task, with 10 subjects assigned to each subset. Individual thresholds for each picture at each phase of learning are presented, along with the fragmented pictures identified by 35% of the subjects across the Train and New learning phases. This set of fragmented pictures is provided for use in experiments in which a single level of fragmented image is presented for identification after a priming phase. Correlations between the Snodgrass and Vanderwart norms and identification thresholds at the three phases of learning are also reported.     

Implicit processing in the cued recall of young and old adults.

Two cued recall experiments were reported in which younger and older subjects studied target words varying in number of preexperimental associates. In Experiment 1, targets were studied in either the absence or presence of meaning-related context cues, with recall always prompted by the cues. In the absence of context, words with smaller sets of associates were easier to recall than those with larger sets, but this effect was reduced for older subjects. The presence of a study context cue facilitated recall and eliminated the effect of associative set size for both ages. In Experiment 2, targets were studied and tested in the presence of unrelated words. In this situation, words with smaller sets of associates were less likely to be recalled than words with larger sets; again the effect was reduced for older subjects. The results are interpreted as an age decrement in processing implicitly activated information.     

Interactive versus passive dynamics and the exploratory analysis of multivariate data

In two experiments, we examined subjects’ ability to infer structure from three-dimensional data presented dynamically in interactive versus passive mode and in static scatterplots. Accuracy of estimating the number of clusters in three-dimensional data sets was measured for each of these conditions, as a function of cluster discriminability.     

Anagram solution speed as a joint function of manifest anxiety and number of category sets

Anagrams constructed from words in 1,2,3, or 4 conceptual categories were administered in random sequences to subjects scoring at the extremes of the Taylor Manifest Anxiety Scale. Scince explicit instructions were given to the subjects concerning the nature of the categories involved, it is assumed that sets for responding with words from these categories were present from the start. The results demonstrate a negative relation of solution rate to number of category sets and an interaction of this variable with manifest anxiety. Anxiety facilitates performance in the presence of a single category set but inhibits performance when multiple sets are concurrently operative. The latter finding is consistent with the drive interpretation of manifest anxiety by Taylor and Spence.     

Relative quantity judgments in South American sea lions (<Emphasis Type="Italic">Otaria flavescens</Emphasis>)

There is accumulating evidence that a variety of species possess quantitative abilities although their cognitive substrate is still unclear. This study is the first to investigate whether sea lions (Otaria flavescens), in the absence of training, are able to assess and select the larger of two sets of quantities. In Experiment 1, the two sets of quantities were presented simultaneously as whole sets, that is, the subjects could compare them directly. In Experiment 2, the two sets of quantities were presented item-by-item, and the totality of items was never visually available at the time of choice. For each type of presentation, we analysed the effect of the ratio between quantities, the difference between quantities and the total number of items presented. The results showed that (1) sea lions can make relative quantity judgments successfully and (2) there is a predominant influence of the ratio between quantities on the subjects’ performance. The latter supports the idea that an analogue representational mechanism is responsible for sea lions’ relative quantities judgments. These findings are consistent with previous reports of relative quantities judgments in other species such as monkeys and apes and suggest that sea lions might share a similar mechanism to compare and represent quantities.     

Context effects in judging taste intensity: A comparison of variable line and category rating methods

The effect of stimulus range and stimulus spacing was examinedwhen subjects registered the perceived intensity of sweet liquids using either a matching procedure (Experiment 1) or category rating (Experiment 2). The matching procedure is conceptually similar to absolute magnitude estimation, whereby subjects match their impression of number size to their impression of the subjective magnitude of a stimulus. In Experiment 1, subjects matched their impression of the stimulus to their impression of the magnitude of the length of a continuously variable line under their control. In Experiment 2, subjects rated perceived sweetness on a vertical 13-point scale with five equally spaced verbal labels. In both experiments, three sets of four sucrose concentrations were employed. In two of these sets, a set of weaker solutions and a set of stronger solutions, concentrations were separated by 0.25 log units. In a third set, which spanned the range of concentrations used in the other two sets (0.87 to 27.36% w/v), solutions were separated by 0.5 log units. An examination ofboth individual and group data showed the matching procedure to be less susceptible to a range bias than the rating procedure. In particular, a single intensity function accommodated data from individual ranges better when the matching procedure was used than when the rating procedure was used. No effect of stimulus spacing was evident in the data from either procedure.     

Components of attentional set-switching

A series of distinct event-related potentials (ERPs) have been recorded from the scalp of human subjects as they switch from one task to another. It is possible that task switching may depend on different mechanisms depending on whether the switch requires a change in attentional set, in other words the redirecting of attention to different aspects of a sensory stimulus, or whether it requires a change in intentional set, in others words a change in the way that responses are selected. To address this issue, the current study recorded ERPs while subjects switched between attentional sets and the results were compared with those of a previous investigation in which subjects switched between intentional sets. Subjects selected stimuli according to two conflicting attentional sets, each emphasizing one visual stimulus dimension (colour, shape). Pairs of stimuli, only one of which was to be attended, were presented for between eight and seventeen trials then either a switch or a stay cue was shown. The switch cue instructed subjects to switch from the current attentional set to the other set, while the stay cue instructed subjects to maintain the current set. Comparing ERPs time-locked to the switch and stay cues revealed neural correlates of the initiation of a task switch. Comparing the ERPs time locked to the first stimuli after either stay or switch cues identified neural correlates of the implementation of a task switch. A similar modulation over parietal electrodes was seen when subjects were switching between either attentional or intentional sets. While an intentional set switch began with a medial frontal modulation, attentional set switching began with a lateral frontal modulation. Implementing a new attentional set was associated with modulation of relatively early visual potentials, while implementing a new intentional set was associated with modulation of later response-related potentials. The results confirm that task switching consists of a number of constituent processes which may be taxed to different degrees depending on whether a task-switch paradigm requires subjects to change the way in which they select stimuli or responses.     

‘Attentional Bias’ in correlation judgments? Smedslund (1963) revisited

Smedslund (1963) reports one of the first studies that investigated human judgments of correlation. Smedslund's conclusion, that people reason about correlation mostly from a consideration of the number of times two variables co-occur, has become textbook wisdom (e.g. Baron's "attentional bias", 1994). Yet the data reported in Smedslund's paper fall short of endorsing such a conclusion. After reviewing the original paper, we present the method with which we replicated Smedslund's main experiment. In Experiment 1 subjects were presented with symptom-disease correlation data through a simulated medical diagnosis task. Subjects clearly discriminated between data sets which shared an equal number of symptom-disease co-occurrences but which otherwise showed different levels of correlation. Subjects' diagnoses showed a propensity to predict the disease in the presence of the symptom, and symptom-disease co-occurrences were overestimated in two of the five data sets presented to the subjects. Experiment 2 used a novel abstract scenario with a symmetric predictor variable. Judgments again indicated good discrimination, and biases in prediction responses and case recall were eliminated. In both experiments, judgments of zero correlation were a function of the outcome base rate. We evaluate and contrast the extent to which Cheng's (1997) model of causal induction and two associative models, Rescorla and Wagner (1972) and Pearce (1987) can anticipate the observed pattern in the mean judgments.     

Parallel scanning of auditory and visual information

Two experiments involving memory retrieval of auditorilv and visually presented materials were performed. In Experiment I, subjects were presented with memory sets of 1, 2, or 4 stimuli and then with a test item to be classified as belonging or not belonging to the memory set. In Condition 1, each memory stimulus was a single, auditorily presented letter. In Condition 2, each memory stimulus was a visually presented letter. In Conditions 3 and 4, each memory stimulus was a pair of letters, one presented visually and the other auditorily. Mean reaction time (RT) for the classification task increased as a function of number of memory stimuli at equal rates for all four conditions. This was interpreted as evidence for a parallel scanning process in Conditions 3 and 4 where the auditory item and visual item of each memory stimulus pair can be scanned simultaneously. Experiment II compared memory retrieval for a simultaneous condition in which auditory and visual memory items were presented as pairs with a sequential condition in which mixed auditory-visual memory sets were presented one item at a time. RTs were shorter for the simultaneous condition. This was interpreted as evidence that parallel scanning may depend upon memory input parameters.     

Numerical judgments by chimpanzees (Pan troglodytes) in a token economy

We presented four chimpanzees with a series of tasks that involved comparing two token sets or comparing a token set to a quantity of food. Selected tokens could be exchanged for food items on a one-to-one basis. Chimpanzees successfully selected the larger numerical set for comparisons of 1 to 5 items when both sets were visible and when sets were presented through one-by-one addition of tokens into two opaque containers. Two of four chimpanzees used the number of tokens and food items to guide responding in all conditions, rather than relying on token color, size, total amount, or duration of set presentation. These results demonstrate that judgments of simultaneous and sequential sets of stimuli are made by some chimpanzees on the basis of the numerousness of sets rather than other non-numerical dimensions. The tokens were treated as equivalent to food items on the basis of their numerousness, and the chimpanzees maximized reward by choosing the larger number of items in all situations.     

Pre-employment honesty testing: Fakability,reactions of test takers,and company image

Two common employer concerns about pre-employment honesty testing were addressed: fakability and the test taker's reaction to such tests. Students, 84% with work experience in industries where honesty tests are common, took an honesty test under one of three instructional sets: respond honestly, fake good, and respond as if applying for a job. While subjects instructed to fake good could easily do so, the scores of subjects responding as job applicants more closely resembled those of subjects instructed to respond honestly. Strong negative reactions to honesty tests were not found; rather, most subjects felt that such tests were appropriate. The use of pre-employment honesty tests was not found to have a large impact on test taker perceptions of employers using such tests.     

Parallel non-verbal enumeration is constrained by a set-based limit

Adults can represent approximate numbers of items independently of language. This approximate number system can discriminate and compare entities as varied as dots, sounds, or actions. But can multiple different types of entities be enumerated in parallel and stored as independent numerosities? Subjects who were prevented from verbally counting watched an experimenter hide sequences of objects in two locations. The number of object types, which contrasted in category membership, color, shape, and texture, varied from 1 to 5, and object types were completely temporally intermixed. Subjects were then asked how many objects of each type were in each location. In three experiments, subjects successfully enumerated the objects of each type in each location when 1-3 types were presented, but failed with 4 or 5 types, regardless of the total number of objects seen. Thus, adults can perform simultaneous enumeration of multiple sets that unfold in temporally intermixed fashion, but are limited to 3 such sets at a time. Furthermore, they perform these parallel enumerations in the absence of training or instruction, and can do so for sets of objects that are hidden in distinct locations. The convergence of this 3-set capacity limit with the 3-item capacity limit widely observed in studies of working memory suggests that each enumeration requires a single slot in memory, and that storage in memory is required before enumeration can occur.     

Comparing Data Sets: Implicit Summaries of the Statistical Properties of Number Sets

Comparing datasets, that is, sets of numbers in context, is a critical skill in higher order cognition. Although much is known about how people compare single numbers, little is known about how number sets are represented and compared. We investigated how subjects compared datasets that varied in their statistical properties, including ratio of means, coefficient of variation, and number of observations, by measuring eye fixations, accuracy, and confidence when assessing differences between number sets. Results indicated that participants implicitly create and compare approximate summary values that include information about mean and variance, with no evidence of explicit calculation. Accuracy and confidence increased, while the number of fixations decreased as sets became more distinct (i.e., as mean ratios increase and variance decreases), demonstrating that the statistical properties of datasets were highly related to comparisons. The discussion includes a model proposing how reasoners summarize and compare datasets within the architecture for approximate number representation.     

Associative false consumer memory: effects of need for cognition and encoding task

Two experiments investigated the effects of product–attribute associations on false consumer memory. In both experiments, subjects were presented with sets of related product attributes under incidental encoding conditions. Later, recognition memory was tested with studied attributes, non-studied but associated attributes (critical lures) and non-studied unrelated attributes. In Experiment 1, the effect of Need for Cognition (NFC) was assessed. It was found that individuals high in NFC recognised more presented attributes and falsely recognised more associative critical lures. The increase in both true and associative false memory was accompanied by a greater number of responses that index the retrieval of detailed episodic-like information. Experiment 2, replicated the main findings through an experimental manipulation of the encoding task that required subjects to consider purchase likelihood. Explanations for these findings are considered from the perspective of activation processes and knowledge structures in the form of gist-based representations.     

The elimination of visible behaviour from social interactions: Effects on verbal,nonverbal and interpersonal variables

The study intended to test a number of implications of the alleged communicative functions of nonverbal behaviours. Four sets of specific hypotheses were defined under the general expectation of important effects of the suppression of visible behaviours from a channel of communication. Pairs of subjects were requested to interact either face-to-face or through a wooden screen depriving them of reciprocal visibility. Dependent variables comprised nonverbal behaviours, indices of paralinguistic, syntactic, grammatical and content aspects of the speech, and ratings of the partner and of the interpersonal situation. In spite of the number and variety of measurements, differences in line with the predictions were extremely rare. It is concluded that, better than the communicative ones, other functions such as assistance to the speech encoding processes, probably account for the abundance of nonverbal behaviours among speaking subjects.     

Ego development, authoritarianism, and social status: an investigation of the incremental validity of Loevinger's sentence completion test (short form)

This study presents two sets of analyses designed to evaluate the relation between a 12-item form of the Washington University Sentence Completion Test of ego development (Short Form; SCT-S) and socioeconomic status (SES). The subjects were a large national random sample of adolescent and young adult men and women who were stratified into three artificial age cohorts. The first set of hierarchical multiple regression analyses indicated that SES accounted for 8% to 13% of the variance in SCT-S scores. Incremental validity of the SCT-S in predicting social attitudes, beyond that predicted by SES, was generally supported for authoritarian aggression and partially supported in predicting masculine sex role expectations. Findings suggest that research on ego development with subjects over age 18 might use level of education as a rough index of SES. For younger subjects, parental factors and education are both important. This study also provides revised age-specific national norms for the SCT-S.