Visual search through color displays: Effects of target-background similarity and background uniformity

The effects of target-background similarity and background uniformity were investigated in two experiments in which subjects reported the presence or absence of an achromatic target item in arrays containing irrelevant chromatic items. In Experiment 1, both “present” and “absent” decision times were an increasing function of the similarity of a predefined target item to the background, and were shortened when the interitem similarity of the background set was increased. In Experiment 2, the effects of target-background similarity on the “present” decision were replicated when subjects were not informed on each trial as to which member of the target set might appear in the array, and the “absent” decision was faster when each row of the array comprised background items of a single color than when these items were allocated randomly to array locations. The results are interpreted in terms of the role of pre-attentive grouping operations.     

Effects of target-background luminance ratios upon the autokinetic illusion

This study investigated effects of the target-background luminance ratios upon the autokinetic illusion, with special emphasis on manipulation of the background intensity. Exp. 1, in which the effects of four levels of target luminance were examined against the completely dark background, showed that the target luminance did not affect the illusion as long as the target was small enough in size (0.17 degrees in visual angle). This result confirmed the suggestion by Edwards in 1954. In Exp. II effects of the target-background luminance ratios were examined by varying the luminance of target and background independently. Dominant illusory patterns at the luminance ratio 1 were "pendulum-like" and "bobbing"; these differed from those at higher ratios ("winding"). On the other hand, latency and duration were not affected by the ratios. These findings suggest that the movement pattern is effective in specifying the autokinetic illusion, if it is appropriately categorized and represented.     

Judgments of similarity and spatial models

Ss judged the similarity between all pairs of stimulus objects under 3 conditions: when the objects were (a) Munsell 5R color patches varying in value and chroma; (b) parallelorams varying in size and tilt; and (c) circles-with-radius varying in diameter and angle of radius. For each set of judgments, the pattern of deviations from the Euclidean model was used to diagnose the most appropriate spatial model. The results confirm previous findings that the Euclidean space is appropriate for judgments of color patches, but that the city block space is appropriate for judgments of geometrie forms which vary on perceptually distinct dimensions.     

Visual search for real world targets under conditions of high target-background similarity: Exploring training and transfer in younger and older adults

Real world visual search tasks often require observers to locate a target that blends in with its surrounding environment. However, studies of the effect of target-background similarity on search processes have been relatively rare and have ignored potential age-related differences. We trained younger and older adults to search displays comprised of real world objects on either homogenous backgrounds or backgrounds that camouflaged the target. Training was followed by a transfer session in which participants searched for novel camouflaged objects. Although older adults were slower to locate the target compared to younger adults, all participants improved substantially with training. Surprisingly, camouflage-trained younger and older adults showed no performance decrements when transferred to novel camouflage displays, suggesting that observers learned age-invariant, generalizable skills relevant for searching under conditions of high target-background similarity. Camouflage training benefits at transfer for older adults appeared to be related to improvements in attentional guidance and target recognition rather than a more efficient search strategy.     

Priming in deduction: a spatial arrangement task

The mental model theory assumes that people reason by manipulating mental representations of states of the word, called "mental models." In the present study we used a new deduction task based on diagrammatic premises. We show that a premise can prime other premises that induce similar mental models in a way analogous to the case of words with related meanings, which prime one another. We present three experiments. In Experiment 1 we used an evaluation task. In Experiment 2, a construction task was used. The priming effect was obtained in both cases. In a third experiment we show that the priming effect was still present when partcipants were instructed to ignore a prime displayed before the premises. In all three experiments we compared determinate and indeterminate problems and found faster responses in the former.     

Exploring the effects of similarity on mapping spatial relations

Solving a map task requires transferring information acquired in one spatial context to another context, an ability that marks an important step in cognitive development. This study investigated how preschoolers’ mapping performance was affected by the extent of similarity between spaces. Whereas prior work examined effects of similarity in tasks involving matching individual objects, our tasks required considering spatial relations among objects. We found that the accuracy of mapping between two spaces with somewhat different perceptual features was higher than the accuracy of mapping between spaces with identical features. Yet, a further increase in differences between the two spaces had a detrimental effect on mapping. The results suggest that some degree of similarity between spaces is beneficial to children’s ability to transfer relational information. However, when the spaces have the same surface features, it may draw children’s attention to individual objects and inhibit their ability to focus on common relations across contexts.     

Contextual cuing based on spatial arrangement of color

Previous studies have demonstrated that, in visual search, repetition of a target's "context" significantly improves search performance (contextual cuing; Chun & Jiang, 1998). Context in those studies was defined as either spatial configuration or featural combination. In the present work, we demonstrate that repeating the spatial arrangement of object colors (conjunction of spatial configuration and featural combination) also leads to contextual cuing (Experiment 1). Experiments 2 and 3 rule out the possibility that the contextual cuing we find in Experiment 1 is caused only by the spatial configuration of color patches. Experiment 4 rules out the possibility that it is caused only by featural combination. Experiments 5 and 6 demonstrate that color-arrangement-based contextual cuing is an unconscious process. Experiments 7 and 8 demonstrate that contextual cuing seems to be more effective onchromatic (hue) variation than on achromatic (luminance) variation. In sum, our results demonstrate that contextual cuing is not merely associated learning in separate domains; it is a more integrated process than has perhaps been appreciated.     

Progress and paradigm shifts in spatial vision over the 20 years of ECVP

In the beginning there was light, and form, and visual mechanisms. This paper traces developments in research on spatial vision over the 20 years of ECVP, with particular emphasis on (1) hyperacuity, (2) peripheral vision, (3) amblyopia and development, and (4) learning and plasticity.     

Selection and inhibition in infancy: evidence from the spatial negative priming paradigm

We used a spatial negative priming (SNP) paradigm to examine visual selective attention in infants and adults using eye movements as the motor selection measure. In SNP, when a previously ignored location becomes the target to be selected, responses to it are impaired, providing a measure of inhibitory selection. Each trial consisted of a prime and a probe, separated by 67, 200, or 550 ms interstimulus intervals (ISIs). In the prime, a target was accompanied by a distractor. In the probe, the target appeared either in the location formerly occupied by the distractor (ignored repetition) or in another location (control). Adults exhibited the SNP effect in all three ISI conditions, producing slower saccade latencies on ignored repetition versus control trials. The SNP effect obtained for infants only under 550 and 200 ms ISI conditions. These results suggest that important developments in visual selection are rooted in emerging inhibitory mechanisms.     

基于问题解决式的类比推理的老化：表面相似性和结构相似性的作用

采用2年龄(老年/年轻)×2表面相似性(高/低)×2结构相似性(高/低)三因素混合设计, 考察表面信息和结构信息在基于问题解决范式的类比推理老化中的作用。结果发现, 老年人的类比推理成绩显著差于年轻人。源问题和靶问题的表面相似性和结构相似性的提高, 会促进个体检索源问题, 并提高推理质量。对于老年人而言, 表面相似性更重要; 对于年轻人而言, 结构相似性更重要。     

Serial processing of visual spatial patterns in a search paradigm

Previous experiments in this laboratory employing a search paradigm have found highly significant differences in the detectability of a briefly exposed target pattern as a function of the spatial location of the target when it is presented simultaneously with a number of discriminably different nontarget patterns. These detectability differences, at loci equidistant from the fovea, could not be accounted for by any known variation in retinal spatial resolution or by differential lateral masking effects of the target by nearby nontarget patterns. These observations led to the hypothesis that the target in these experiments was detected by a serial mechanism which "scanned" a persisting but rapidly degrading neural representation of the visual scene with increasing detection failures the later in time the scan processed the location occupied by the target. If this hypothesis is correct, then target detectability should vary inversely with the number of stimuli which must be examined. The present experiment confirmed this expectation. A mathematical model of such a serial scanning process also predicts other, less obvious, effects on target detectability which were observed when the number of nontarget patterns was changed.     

Genetic dissociation of acquisition and memory strength in the heat-box spatial learning paradigm in Drosophila

Memories can have different strengths, largely dependent on the intensity of reinforcers encountered. The relationship between reinforcement and memory strength is evident in asymptotic memory curves, with the level of the asymptote related to the intensity of the reinforcer. Although this is likely a fundamental property of memory formation, relatively little is known of how memory strength is determined. Memory performance at different levels in Drosophila can be measured in an operant heat-box conditioning paradigm. In this spatial learning paradigm, flies learn and remember to avoid one-half of a dark chamber associated with a temperature outside of the preferred range. The reinforcement temperature has a strong effect on the level of learning in wild-type flies, with higher temperatures inducing stronger memories. Additionally, two mutations alter memory-acquisition curves, either changing acquisition rate or asymptotic memory level. The rutabaga mutation, affecting a type-1 adenylyl cyclase, decreases the acquisition rate. In contrast, the white mutation, modifying an ABC transporter, limits asymptotic memory. The white mutation does not negatively affect classical olfactory conditioning but actually improves performance at low reinforcement levels. Thus, memory acquisition/memory strength and classical olfactory/operant spatial memories can be genetically dissociated. A conceptual model of operant conditioning and the levels at which rutabaga and white influence conditioning is proposed.     

Effects of simple- and complex-place contexts in the multiple-context paradigm

In four experiments, a total of 384 undergraduates incidentally learned a list of 24 nouns twice in the same context (same-context repetition) or different contexts (different-context repetition). Free recall was measured in a neutral context. Experiments 1, 2, and 3 used a context repetition (same- or different-context repetition) × inter-study and retention intervals (10 min or 1 day) between-participants design. Context was manipulated by the combination of place, social environment, and encoding task (Experiment 1), place and social environment (Experiment 2), or place alone (Experiment 3). Experiment 4 used a context repetition × type of context (context manipulated by place or by place, social environment, and encoding task) between-participants design, with a 10-min inter-study interval and a one-day retention interval. The present results indicate that the determinant of the superiority of same- or different-context repetition in recall is the type of context. Implications of the results were discussed.     

Combining motor and spatial affordance effects with the divided visual field paradigm

The affordance effect has been widely investigated employing various behavioral and brain-imaging techniques. Attempts to interpret the nature of the affordance effect led to two major views. Some researchers compare this kind of compatibility effect to the Simon effect, claiming abstract spatial association between the handle orientation of visually presented stimuli and the nearest response hand. Other authors advocate pure motor activation, during processing of visually presented tools without the involvement of spatial information. However, brain-imaging studies seem to agree that no action can be computed in the absence of spatial information. Taking the latter view into account, a divided visual field experiment was conducted, with the aim of crossing spatial and affordance correspondence effects. Overall, the results supported the view that motor and spatial information go hand in hand. Moreover, the data were in agreement with neuroimaging studies that show tool and affordance processing lateralization in the left hemisphere. The results are discussed in terms of neurophysiological data and brain mechanisms of perception and action.     

The effect of spatial frequency information and visual similarity in threat detection

In the current research, we sought to examine the role of spatial frequency on the detection of threat using a speeded visual search paradigm. Participants searched for threat-relevant (snakes or spiders) or non-threat-relevant (frogs or cockroaches) targets in an array of neutral (flowers or mushrooms) distracters, and we measured search performance with images filtered to contain different levels (high and low) of spatial frequency information. The results replicate previous work demonstrating more rapid detection of threatening versus non-threatening stimuli [e.g. LoBue, V. & DeLoache, J. S. (2008). Detecting the snake in the grass: Attention to fear-relevant stimuli by adults and young children. Psychological Science, 19, 284–289. doi:10.1111/j.1467-9280.2008.02081.x]. Most importantly, the results suggest that low spatial frequency or relatively coarse levels of visual information is sufficient for the rapid and accurate detection of threatening stimuli. Furthermore, the results also suggest that visual similarity between the stimuli used in the search tasks plays a significant role in speeded detection. The results are discussed in terms of the theoretical implications for the rapid detection of threat and methodological implications for properly accounting for similarity between the stimuli in visual search studies.     

Going rogue in the spatial cuing paradigm: High spatial validity is insufficient to elicit voluntary shifts of attention

Voluntary shifts of attention are often motivated in experimental contexts by using well-known symbols that accurately predict the direction of targets. The authors report 3 experiments, which showed that the presentation of predictive spatial information does not provide sufficient incentive to elicit voluntary shifts of attention. For instance, when allowed to spontaneously choose between using a 100%-valid spatial word cue versus searching without the aid of the cue, observers consistently searched for a unique target without the aid of the cue. Another experiment showed that observers' choice to use spatial word cues could be biased by providing dedicated time to process the cue before the target display appeared (i.e., nonzero, cue-target SOAs). Although this dedicated processing time has routinely been included in spatial cuing experiments, its incentive-inducing role has never been acknowledged. Implications for theories of both voluntary and involuntary control are discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

The effects of graphemic and phonemic similarity between targets and masks in a backward visual masking paradigm

Experiments using a backward visual masking technique are described, in which the second (mask) stimulus is itself masked by a third stimulus, thus rendering guessing strategies, about target/mask relationships, difficult for subjects. Word-word and word-non-word sequences are used for the first two stimuli and it is shown that when the second stimulus resembles the first, either physically or phonologically, the severity of masking of the first is reduced. However, the target is not better reported when the mask word is semantically related to it. Consideration is given to the levels at which interaction between target and mask might occur.     

Classification and perceived similarity of compound gratings that differ in relative spatial phase

Discrimination studies suggest that two, and only two, channels encode relative spatial phase shifts in compound gratings (Bennett & Banks, 1991 ; Field & Nachmias, 1984). The more sensitive channel consists of even-symmetric filters and responds best to cosine phase shifts (e.g., 0°–180°); the other consists of odd-symmetric filters and responds best to sine phase shifts (e.g., 90°–270°). The present experiments investigated whether the two-channel model generalizes to suprathreshold perceptual tasks. Experiment 1 examined classification learning of compound gratings, consisting of a fundamental (f) and second harmonic (2f), that differed in 2f contrast and relative phase. Experiments 2 and 3 measured the perceived similarity off+2f gratings. The results of Experiment 1 were broadly consistent with the predictions of the two-channel model. Specifically, the classification data were best explained by assuming that classification was based on the responses of differentially sensitive even- and odd-symmetric filters. In Experiments 2 and 3, two-dimensional multidimensional scaling solutions provided a good account for the similarity judgments. In Experiment 2, Dimension 1 was strongly correlated with cosine phase, and Dimension 2 was moderately correlated with sine phase. In Experiment 3, cosine phase was again strongly rebated to Dimension 1, whereas the absolute value of sine phase was strongly related to Dimension 2. Overall, these results suggest that the two-channel model of phase discrimination provides a useful framework for interpreting classification and similarityjudgments of compound gratings.