The purpose of the present study was to examine the influence of task set on the spatial and temporal characteristics of eye movements during scene perception. In previous work, when strong control was exerted over the viewing task via specification of a target object (as in visual search), task set biased spatial, rather than temporal, parameters of eye movements. Here, we find that more participant-directed tasks (in which the task establishes general goals of viewing rather than specific objects to fixate) affect not only spatial (e.g., saccade amplitude) but also temporal parameters (e.g. fixation duration). Further, task set influenced the rate of change in fixation duration over the course of viewing but not saccade amplitude, suggesting independent mechanisms for control of these parameters.

The purpose of the present study was to examine the influence of task set on the spatial and temporal characteristics of eye movements during scene perception. In previous work, when strong control was exerted over the viewing task via specification of a target object (as in visual search), task set biased spatial, rather than temporal, parameters of eye movements. Here, we find that more participant-directed tasks (in which the task establishes general goals of viewing rather than specific objects to fixate) affect not only spatial (e.g., saccade amplitude) but also temporal parameters (e.g., fixation duration). Further, task set influenced the rate of change in fixation duration over the course of viewing but not saccade amplitude, suggesting independent mechanisms for control of these parameters.

Variation in political ideology has been linked to differences in attention to and processing of emotional stimuli, with stronger responses to negative versus positive stimuli (negativity bias) the more politically conservative one is. As memory is enhanced by attention, such findings predict that memory for negative versus positive stimuli should similarly be enhanced the more conservative one is. The present study tests this prediction by having participants study 120 positive, negative, and neutral scenes in preparation for a subsequent memory test. On the memory test, the same 120 scenes were presented along with 120 new scenes and participants were to respond whether a scene was old or new. Results on the memory test showed that negative scenes were more likely to be remembered than positive scenes, though, this was true only for political conservatives. That is, a larger negativity bias was found the more conservative one was. The effect was sizeable, explaining 45% of the variance across subjects in the effect of emotion. These findings demonstrate that the relationship between political ideology and asymmetries in emotion processing extend to memory and, furthermore, suggest that exploring the extent to which subject variation in interactions among emotion, attention, and memory is predicted by conservatism may provide new insights into theories of political ideology.

A new method combining spatial-cueing and compound-stimulus paradigms draws on involuntary attentional orienting elicited by a spatially uninformative central arrow cue to investigate global/local processing under incidental processing conditions, wherein global/local levels were uninformative (do not aid performance) and task-irrelevant (need not be processed to perform the task). The task was peripheral target detection. Cues were compound arrows, which were either consistent (global/local arrows oriented in same direction) or inconsistent (global/local arrows oriented in opposite directions). Global/local processing was measured by spatial-cueing effects (response time [RT] difference between target locations validly cued by an arrow and targets at different locations), with the test of global/local advantage represented by the effect of cue-level for inconsistent cues (RT difference between global-valid and local-valid cues). Cue-target interval (stimulus-onset-asynchrony [SOA]) was manipulated to test whether global/local advantage varied with relative stimulus availability. Experiment 1 observed a Cue-Level × SOA interaction such that an early, large global cueing effect was followed by a later, smaller local cueing effect, indicative of a global-to-local shift in advantage. This occurred despite knowledge that global/local arrows were uninformative and task-irrelevant and could therefore be ignored, thus displaying key properties of an involuntary process. Experiment 2 added neutral cues (arrow at one level, rectangle at the other) and determined that the reversal was not due to inhibition of the globally cued location or to attenuation of global information but rather to the presence of conflicting spatial information. Experiments 3 and 4 ruled out alternative accounts for these results. These data indicate global precedence in attended but incidentally processed objects.

Computer classifiers have been successful at classifying various tasks using eye movement statistics. However, the question of human classification of task from eye movements has rarely been studied. Across two experiments, we examined whether humans could classify task based solely on the eye movements of other individuals. In Experiment 1, human classifiers were shown one of three sets of eye movements: Fixations, which were displayed as blue circles, with larger circles meaning longer fixation durations; Scanpaths, which were displayed as yellow arrows; and Videos, in which a neon green dot moved around the screen. There was an additional Scene manipulation in which eye movement properties were displayed either on the original scene where the task (Search, Memory, or Rating) was performed or on a black background in which no scene information was available. Experiment 2 used similar methods but only displayed Fixations and Videos with the same Scene manipulation. The results of both experiments showed successful classification of Search. Interestingly, Search was best classified in the absence of the original scene, particularly in the Fixation condition. Memory also was classified above chance with the strongest classification occurring with Videos in the presence of the scene. Additional analyses on the pattern of correct responses in these two conditions demonstrated which eye movement properties successful classifiers were using. These findings demonstrate conditions under which humans can extract information from eye movement characteristics in addition to providing insight into the relative success/failure of previous computer classifiers.

No abstract

In stimulus identification tasks, stimulus and response, and location and response information, is thought to become integrated into a common event representation following a response. Evidence for this feature integration comes from paradigms requiring keypress responses to pairs of sequentially presented stimuli. In such paradigms, there is a robust cost when a target event only partially matches the preceding event representation. This is known as the partial repetition cost. Notably, however, these experiments rely on discrimination responses. Recent evidence has suggested that changing the responses to localization or detection responses eliminates partial repetition costs. If changing the response type can eliminate partial repetition costs it becomes necessary to question whether partial repetition costs reflect feature integration or some other mechanism. In the current study, we look to answer this question by using a design that as closely as possible matched typical partial repetition cost experiments in overall stimulus processing and response requirements. Unlike typical experiments where participants make a cued response to a first stimulus before making a discrimination response to a second stimulus, here we reversed that sequence such that participants made a discrimination response to the first stimulus before making a cued response to the second. In Experiment 1, this small change eliminated or substantially reduced the typically large partial repetition costs. In Experiment 2 we returned to the typical sequence and restored the large partial repetition costs. Experiment 3 confirmed these findings, which have implications for interpreting partial repetition costs and for feature integration theories in general.

Recent work indicates that the more conservative one is, the faster one is to fixate on negative stimuli, whereas the less conservative one is, the faster one is to fixate on positive stimuli. The present series of experiments used the face-in-the-crowd paradigm to examine whether variability in the efficiency with which positive and negative stimuli are detected underlies such speed differences. Participants searched for a discrepant facial expression (happy or angry) amid a varying number of neutral distractors (Experiments 1 and 4). A combination of response time and eye movement analyses indicated that variability in search efficiency explained speed differences for happy expressions, whereas variability in post-selectional processes explained speed differences for angry expressions. These results appear to be emotionally mediated as search performance did not vary with political temperament when displays were inverted (Experiment 2) or when controlled processing was required for successful task performance (Experiment 3). Taken together, the present results suggest political temperament is at least partially instantiated by attentional biases for emotional material.