A biased-competition approach to spatial cueing: Combining empirical studies and computational modelling

We examined the effects of cue luminance on visual orienting. Experiment 1 established that the commonly-found early facilitation and late inhibition of return (IOR) effects were independent of cue luminance with single cues in terms of their amplitude, although IOR was delayed in the low compared to the high luminance cue condition. In contrast, Experiment 2 revealed that, with dual cues of mixed luminance, both facilitation and IOR effects were found only with bright cues. When cues had equal luminance, however, there were cueing effects for two cued locations but only when the cues were bright. The data were accommodated in a neural network model of biased competition in which cueing effects emerge at more than one location provided input activation is sufficient to overcome competitive damping of the selection system.     

Effects of varying target luminance and cue luminance on attentional effects of spatial cues

Attentional effects of letter cues on target processing were investigated in a bilateral spatial cueing paradigm. Luminance contrast of the cue stimuli and of the target stimuli were both manipulated. Consistent with predictions derived from theoretical models of visual attention, manipulating cue luminance and target luminance had very different effects on performance. In agreement with the dorsal stream attention hypothesis (Marrett et al., 2011) orienting effects were unaffected by changes in cue luminance; but in agreement with the work of Reynolds, Pasternak, and Desimone (2000) and Carrasco, Ling, and Read (2004) orienting effects were strongly modulated by changes in the luminance and perceptual quality of the target. Theoretical implications of the results are considered and the data are explained in terms of a sensory enhancement effect, whereby attention amplifies the neuronal responses for attended stimuli.     

The influence of visual short-term memory on size perception

We show that perceived size of visual stimuli can be altered by matches between the contents of visual short-term memory and stimuli in the scene. Observers were presented with a colour cue (to hold in working memory or to merely identify) and subsequently had to indicate which of the two different-coloured objects presented simultaneously on the screen appeared bigger (or smaller). One of the two objects for size judgements had the same colour as the cue (matching stimulus) and the other did not (mismatching stimulus). Perceived object size was decreased by the reappearance of the recently seen cue, as there were more size judgement errors on trials where the matching stimulus was physically bigger (relative to the mismatching stimulus) than on trials where the matching stimulus was physically smaller. The effect occurred regardless of whether the visual cue was actively maintained in working memory or was merely identified. The effect was unlikely generated by the allocation of attention, because shifting attention to a visual stimulus actually increased its perceived size. The findings suggest that visual short-term memory, whether explicit or implicit, can decrease the perceived size of subsequent visual stimuli.     

A taxonomy of errors in multiple-target visual search

Multiple-target visual searches are especially error prone; once one target is found, additional targets are likely to be missed. This phenomenon, often called satisfaction of search (which we refer to here as subsequent search misses; SSMs), is well known in radiology, despite no existing consensus about the underlying cause(s). Taking a cognitive laboratory approach, we propose that there are multiple causes of SSMs and present a taxonomy of SSMs based on searchers' eye movements during a multiple-target search task, including both previously identified and novel sources of SSMs. The types and distributions of SSMs revealed effects of working memory load, search strategy, and additional causal factors, suggesting that there is no single cause of SSMs. A multifaceted approach is likely needed to understand the psychological causes of SSMs and then to mitigate them in applied settings such as radiology and baggage screening.     

Attention to distinguishing features in object recognition

This study advances the hypothesis that, in the course of object recognition, attention is directed to distinguishing features: visual information that is diagnostic of object identity in a specific context. In five experiments, observers performed an object categorization task involving drawings of fish (Experiments 1–4) and photographs of natural sea animals (Experiment 5). Allocation of attention to distinguishing and non-distinguishing features was examined using primed-matching (Experiment 1) and visual probe (Experiments 2, 4, 5) methods, and manipulated by spatial precuing (Experiment 3). Converging results indicated that in performing the object categorization task, attention was allocated to the distinguishing features in a context-dependent manner, and that such allocation facilitated performance. Based on the view that object recognition, like categorization, is essentially a process of discrimination between probable alternatives, the implications of the findings for the role of attention to distinguishing features in object recognition are discussed.     

The properties of object representations constructed during visual search in natural scenes

To investigate properties of object representations constructed during a visual search task, we manipulated the proportion of trials/task within a block: In a search-frequent block, 80% of trials were search tasks; remaining trials presented a memory task; in a memory-frequent block, this proportion was reversed. In the search task, participants searched for a toy car (Experiments 1 and 2) or a T-shape object (Experiment 3). In the memory task, participants had to memorize objects in a scene. Memory performance was worse in the search-frequent block than in the memory-frequent block in Experiments 1 and 3, but not in Experiment 2 (token change in Experiment 1; type change in Experiments 2 and 3). Experiment 4 demonstrated that lower performance in the search-frequent block was not due to eye-movement behaviour. Results suggest that object representations constructed during visual search are different from those constructed during memorization and they are modulated by type of target.     

Dynamic orientation cues decrease the viewpoint cost of mental rotation

Mental rotation, as a covert simulation of motor rotation, could benefit from spatial updating of object representations. We are interested in what kind of visual cue could trigger spatial updating. Three experiments were conducted to examine the effect of dynamic and static orientation cues on mental rotation, using a sequential matching task with three-dimensional novel objects presented in different views. Experiment 1 showed that a rotating orientation cue with constant speed reduced viewpoint costs in mental rotation. Experiment 2 extended this effect with a varied-speed rotating orientation cue. However, no such benefit was observed with a static orientation cue in Experiment 3. These findings indicated that a visually continuous orientation cue is sufficient to elicit spatial updating in mental rotation. Furthermore, there may be differences in the underlying mechanisms of spatial updating on the basis of constant-speed rotating cues and varied-speed rotating cues.     

See an object,hear an object file: Object correspondence transcends sensory modality

An important task of perceptual processing is to parse incoming information into distinct units and to keep track of those units over time as the same, persisting representations. Within the study of visual perception, maintaining such persisting object representations is helped by “object files”—episodic representations that store (and update) information about objects' properties and track objects over time and motion via spatiotemporal information. Although object files are typically discussed as visual, here we demonstrate that object–file correspondence can be computed across sensory modalities. An object file can be initially formed with visual input and later accessed with corresponding auditory information, suggesting that object files may be able to operate at a multimodal level of perceptual processing.     

No templates for rejection: a failure to configure attention to ignore task-irrelevant features

ABSTRACT

Knowing the colour of an upcoming target allows one to bias attention towards objects of that colour. It is far less clear whether knowing the colour of an up-coming distractor can allow one to suppress attention to items of that colour. Arita, Carlisle, and Woodman (2012) suggest that people can create a template for rejection. However, the method used in Arita et al. may have allowed people to adopt a strategy of internally generating a positive cue for the target colour or target hemifield. Here we use a method very similar to theirs, but manipulate the display layouts and the number of un-cued colours in ways that should thwart such strategies. Across three experiments, we find a negative cuing benefit only in a very special circumstance that encourages a strategic shift to internally generating a positive cue (the same circumstance used by Arita et al.). We conclude that people are unable to use a negative feature-cue on a trial-by-trial basis to suppress attention to upcoming distractors, and attribute the finding in Arita et al. to a strategic shift rather than a template for rejection.     

Satisfaction at last: Evidence for the “satisfaction” hypothesis for multiple-target search errors

ABSTRACT

Multiple-target visual searches are susceptible to Subsequent Search Miss (SSM) errors—a reduced accuracy for target detection after a previous target has already been detected. SSM errors occur in critical searches (e.g., evaluations of radiographs and airport luggage x-rays), and have proven to be a stubborn problem. A few SSM theories have been offered, and here we investigate the “satisfaction” account: failing to completely finish a search after having found a first target. Accuracy on a multiple-target search task was compared to both how long participants spent searching after finding a first target and their target sensitivity in a separate vigilance task. Less time spent searching and poor vigilance predicted higher SSM error rates. These results suggest that observers who are more likely to miss a second target are less likely to thoroughly search after finding a first target, thus offering some of the first evidence for the “satisfaction” account.