Papers by Alejandro Lleras
Psychonomic Bulletin & Review, Oct 1, 2007
The negative compatibility effect (NCE) is the surprising result that low-visibility prime arrows... more The negative compatibility effect (NCE) is the surprising result that low-visibility prime arrows facilitate responses to opposite-direction target arrows. Here we compare the priming obtained with simple arrows to the priming of emotions when categorizing human faces, which represents a more naturalistic set of stimuli and for which there are no preexisting response biases. When inverted faces with neutral expressions were presented alongside emotional prime and target faces, only strong positive priming occurred. However, when the neutral faces were made to resemble the target faces in geometry (upright orientation), time (flashing briefly), and space (appearing in the same location), positive priming gradually weakened and became negative priming. Implications for theories of the NCE are discussed.
Psychonomic Bulletin & Review, 2017
Extant theories of the attentional blink propose that the most critical factor in determining sec... more Extant theories of the attentional blink propose that the most critical factor in determining second target accuracy is the time that elapses between the first and second targets. We report that this conclusion has overlooked an equally important determinant, namely, the frequency of the entraining stream in which these targets are embedded. Specifically, we show in two experiments that the signature of the attentional blink-second target accuracy that increases with intertarget lag-is significantly larger for entraining streams that are in the alpha-beta frequency range, relative to streams that are slower (theta) or faster (gamma). This finding ties the attentional blink critically, for the first time, to these two prominent oscillation frequencies that are known to be involved in the control of human attention and consciousness.
Journal of Experimental Psychology: General, 2005
Journal of experimental psychology. General, 2004
The negative compatibility effect (NCE) is the surprising result that visual targets that follow ... more The negative compatibility effect (NCE) is the surprising result that visual targets that follow a brief prime stimulus and a mask can be identified more rapidly when they are opposite rather than identical to the prime. In a recent article in this journal, S. T. Klapp and L. B. Hinkley (2002) proposed that this reflected a competition between inhibitory unconscious processes and excitatory conscious processes. The authors of the current article report 7 experiments with results countering this theory and propose an alternative account within the framework of object substitution masking. In this account, the NCE reflects the updating of perceptual objects, including their links to responses closely associated with those objects.
Journal of Vision, 2010
Abstract Humans are exceptionally good at resuming a search that has been momentarily interrupted... more Abstract Humans are exceptionally good at resuming a search that has been momentarily interrupted; making accurate detections in far less than the half second normally needed to begin a search (Lleras et al., 2005). It is proposed that rapid resumption depends on an ...
Journal of Vision, 2010
The negative compatibility effect (NCE) is the surprising result that low-visibility prime arrows... more The negative compatibility effect (NCE) is the surprising result that low-visibility prime arrows facilitate responses to opposite-direction target arrows. Here we compare the priming obtained with simple arrows to the priming of emotions when categorizing human faces, which represents a more naturalistic set of stimuli and for which there are no preexisting response biases. When inverted faces with neutral expressions were presented alongside emotional prime and target faces, only strong positive priming occurred. However, when the neutral faces were made to resemble the target faces in geometry (upright orientation), time (flashing briefly), and space (appearing in the same location), positive priming gradually weakened and became negative priming. Implications for theories of the NCE are discussed.
Journal of Experimental Child Psychology, 2011
In this study, 7-19-year-olds performed an interrupted visual search task in two experiments. Our... more In this study, 7-19-year-olds performed an interrupted visual search task in two experiments. Our question was whether the tendency to respond within 500 ms after a second glimpse of a display (the rapid resumption effect [Psychological Science, 16 (2005) 684-688]) would increase with age in the same way as overall search efficiency. The results indicated no correlation of rapid resumption with search speed either across age groups (7, 9, 11, and 19 years) or at the level of individual participants. Moreover, relocating the target randomly between looks reduced the rate of rapid resumption in a very similar way at each age. These results imply that implicit perceptual prediction during search is invariant across this age range and is distinct from other critical processes such as feature integration and control over spatial attention.
In three experiments, we examine whether drivers can accurately judge whether or not they could a... more In three experiments, we examine whether drivers can accurately judge whether or not they could avoid a potential collision. Using a driving simulator, we compare drivers' actual avoidance performance with their judgments about whether they could have maneuvered successfully to avoid the collision. At a slow speed (48 kph), drivers underestimated their ability to avoid collisions, judging that more space
These 6 experiments explored the ability of moving random dot patterns to attract attention, as m... more These 6 experiments explored the ability of moving random dot patterns to attract attention, as measured by a simple probe-detection task. Each trial began with random motion (i.e., dots linearly moved in random directions). After 1 s motion in 1 hemifield became gradually coherent (i.e., all dots moved up-, down-, left-, or rightwards, or either towards or away from a vanishing point). The results show that only looming motion attracted attention, even when the task became a more demanding discrimination task. This effect is not due to an apparent magnification of stimuli presented in the focus of expansion. When the coherent motion started abruptly, all types of motion attracted attention at a short stimulus onset asynchrony. The looming motion effect only disappeared when attention was drawn to the target location by an arrow. These results suggest that looming motion plays a unique role in guiding spatial attention.
Journal of Vision, 2015
Feature singleton search tasks have been characterized as being independent of the number of non-... more Feature singleton search tasks have been characterized as being independent of the number of non-target elements in the display (Treisman and Gelade, 1980; Wolfe, 1994). Previous work from our lab has shown that reaction times on feature singleton search tasks in fact increase logarithmically with the number of non-target (lure) elements in the display and that the steepness of the logarithmic function is modulated by lure-target similarity (Madison, Buetti & Lleras, 2014). Duncan and Humphreys (1989) proposed an effect of distractor heterogeneity on search performance such that distractor-distractor similarity modulates search efficiency, and that distractor rejection is facilitated by the repetition of identical distractors (a mechanism called spreading suppression). Here we challenge those claims and demonstrate that in parallel search, we find no evidence for distractor-distractor effects, nor for spreading suppression (grouping of distractors). We tested search performance in displays containing multiple types of lures simultaneously (e.g., a red target amongst yellow, blue and orange lures). To evaluate performance on these mixed displays, we first computed estimates of logarithmic processing costs for each type of lure (obtained from a different set of subjects) when the target was presented amongst uniform fields of each type of lure (e.g., a red target amongst only orange distractors). We then used those estimates to predict what reaction times in mixed displays ought to be if (a) each item in the display was processed independently from one another and (b) the processing of all items was performed in unlimited capacity parallel fashion. In two separate experiments, with different combinations of lures, this model (a simple linear addition of logarithmic processing costs), was able to account for 95.67% and 94.41% of the variance of reaction times in mixed displays. These results argue strongly against both distractor-distractor interactions as well as spreading suppression effects in parallel search. Meeting abstract presented at VSS 2015.
Visual Cognition, 2008
The consensus view among students of face perception is that faces are processed holistically/con... more The consensus view among students of face perception is that faces are processed holistically/configurally. However, the exact nature of these processes is still under dispute. The holistic approach (eg, Tanaka & Farah, 2003 5. Tanaka, JW and Farah, MJ 2003.���The holistic representations of faces���. In Perception of faces, objects, and scenes, Edited by: Peterson, MA and Rhodes, G. 53���74. New York: Oxford University Press.
Journal of Vision, 2010
Recent studies of visual short-term memory have revealed surprising limitations on the capacity a... more Recent studies of visual short-term memory have revealed surprising limitations on the capacity and detail of its object representations. Several studies have demonstrated our ability to integrate features across dimensions in memory tasks, but few have examined whether or not task-...
Attention, Perception, & Psychophysics, 2013
It is well known that observers can implicitly learn the spatial context of complex visual search... more It is well known that observers can implicitly learn the spatial context of complex visual searches, such that future searches through repeated contexts are completed faster than those through novel contexts, even though observers remain at chance at discriminating repeated from new contexts. This contextual-cueing effect arises quickly (within less than five exposures) and asymptotes within 30 exposures to repeated contexts. In spite of being a robust effect (its magnitude is over 100 ms at the asymptotic level), the effect is implicit: Participants are usually at chance at discriminating old from new contexts at the end of an experiment, in spite of having seen each repeated context more than 30 times throughout a 50-min experiment. Here, we demonstrate that the speed at which the contextual-cueing effect arises can be modulated by external rewards associated with the search contexts (not with the performance itself). Following each visual search trial (and irrespective of a participant's search speed on the trial), we provided a reward, a penalty, or no feedback to the participant. Crucially, the type of feedback obtained was associated with the specific contexts, such that some repeated contexts were always associated with reward, and others were always associated with penalties. Implicit learning occurred fastest for contexts associated with positive feedback, though penalizing contexts also showed a learning benefit. Consistent feedback also produced faster learning than did variable feedback, though unexpected penalties produced the largest immediate effects on search performance.
Uploads
Papers by Alejandro Lleras