The relationship between self-reported vividness and latency during mental size scaling of everyday items: phenomenological evidence of different types of imagery

We examined how the relationship between ratings of vividness (or image strength) and image latency might reflect the concerted action of two visual imagery pathways hypothesized by Kosslyn (1994): the ventral pathway, processing object properties, and the dorsal pathway, processing locative properties of mental images. Participants formed their images at small or large angular display sizes, varying the amount of size scaling needed. In Experiment 1, display size varied between participants, and images were trial unique. The higher the vividness, the faster the generation of small images (requiring size scaling of less than 10 degrees), which would recruit mainly the ventral pathway. This vivid-is-fast relationship changed for large images (requiring size scaling of 10 degrees or more), which would recruit mainly the dorsal pathway. The size-dependent alteration of the vivid-is-fast relationship was replicated in the first block of Experiment 2. However, when repeated over 3 consecutive blocks, image generation sped up, and gradually the vivid-is-fast relationship tended to occur for all display sizes until complete automatization of image generation occurred. The findings suggest that differential patterns of vividness-latency relationship can reflect the types of images involved, their relative ventral and dorsal contributions, and the involvement of working memory.     

Mental image generation and the contrast sensitivity function

In one experiment, observers were instructed to generate small and large visual mental images in a light-adapted or a dark-adapted viewing condition, and to rate the vividness of each image. In light-adapted viewing, small images were generated faster than large images. However, the pattern of results was reversed in dark-adapted viewing. Furthermore, the dark-adapted images were more vivid than the light-adapted images. The results show that mental images can be mapped onto some regions of the contrast sensitivity function (CSF), so that the latency (and vividness) of a particular image can be predicted. Since the CSF reflects visual processes occurring mainly in V1, the results agree with functional magnetic resonance imaging data in indicating that early visual pathways participate in imagery. Nonetheless, imagery and perception may involve different processes hosted by the same neural structures as indicated by the direct relationship between image latency and contrast sensitivity.     

Relationships among measures of visual imagery

As a step toward the development of an objective measure of visualization ability, five tasks which yielded seven separate measures were administered to 74 Ss and intercorrelated. The tasks were: paired associate recall improvement (RI), recognition memory (RM), the Bett's Questionnaire on Mental Imagery (QMI) as revised by Sheehan (1967a, b), a task calling for the production of visual images (PVI) where rated vividness and latency of image attainment were measured, and a task requiring the imagining of emotional scenes (ES) where rated vividness and rated anxiety were measured. The results indicated that although paired associate learning scores per se were related to RM, neither of the memory measures of visualization (RI and RM) were related to any of the other visualization measures. A cluster of intercorrelations was obtained among self-ratings of image vividness on the QMI, PVI and ES tasks. This cluster also included a measure of latency of report of “best image” attainable derived from the PVI task. None of the measures correlated with anxiety ratings on the ES task. These findings were discussed in relation to previous studies and the potential value of the latency measure as an adjunct measure of visualization ability was noted.     

执行控制资源损耗对自传体记忆生动性和情绪的影响

旨在探究健康个体执行控制资源损耗对自传体记忆生动性及情绪的影响。实验一采用Stroop任务探讨了一般执行控制资源损耗的影响,结果发现损耗组自传体记忆生动性和情绪强度显著低于控制组。实验二进一步探讨不同的执行控制资源损耗的影响,结果显示中央执行的资源损耗对生动性和情绪强度影响最大,而视空间模板与语音环之间没有显著差异。实验结果支持了自传体记忆的执行控制资源受损理论和资源有限理论,并对临床治疗具有实际应用价值。     

Evaluating the mind's eye: the metacognition of visual imagery

Can people evaluate phenomenal qualities of internally generated experiences, such as whether a mental image is vivid or detailed? This question exemplifies a problem of metacognition: How well do people know their own thoughts? In the study reported here, participants were instructed to imagine a specific visual pattern and rate its vividness, after which they were presented with an ambiguous rivalry display that consisted of the previously imagined pattern plus an orthogonal pattern. On individual trials, higher ratings of vividness predicted a greater likelihood that the imagined pattern would appear dominant when the participant was subsequently presented with the binocular rivalry display. Off-line self-report questionnaires measuring imagery vividness also predicted individual differences in the strength of imagery bias over the entire study. Perceptual bias due to mental imagery could not be attributed to demand characteristics, as no bias was observed on catch-trial presentations of mock rivalry displays. Our findings provide novel evidence that people have a good metacognitive understanding of their own mental imagery and can reliably evaluate the vividness of single episodes of imagination.     

Eye movements reduce vividness and emotionality of “flashforwards”

Earlier studies have shown that eye movements during retrieval of disturbing images about past events reduce their vividness and emotionality, which may be due to both tasks competing for working memory resources. This study examined whether eye movements reduce vividness and emotionality of visual distressing images about feared future events: “flashforwards”. A non-clinical sample was asked to select two images of feared future events, which were self-rated for vividness and emotionality. These images were retrieved while making eye movements or without a concurrent secondary task, and then vividness and emotionality were rated again. Relative to the no-dual task condition, eye movements while thinking of future-oriented images resulted in decreased ratings of image vividness and emotional intensity. Apparently, eye movements reduce vividness and emotionality of visual images about past and future feared events. This is in line with a working memory account of the beneficial effects of eye movements, which predicts that any task that taxes working memory during retrieval of disturbing mental images will be beneficial.     

The importance of the keyword-generation method in keyword mnemonics

Keyword mnemonics is under certain conditions an effective approach for learning foreign-language vocabulary. It appears to be effective for words with high image vividness but not for words with low image vividness. In this study, two experiments were performed to assess the efficacy of a new keyword-generation procedure (peer generation). In Experiment 1, a sample of 363 high-school students was randomly into four groups. The subjects were required to learn L1 equivalents of a list of 16 Latin words (8 with high image vividness, 8 with low image vividness), using a) the rote method, or the keyword method with b) keywords and images generated and supplied by the experimenter, c) keywords and images generated by themselves, or d) keywords and images previously generated by peers (i.e., subjects with similar sociodemographic characteristics). Recall was tested immediately and one week later. For high-vivideness words, recall was significantly better in the keyword groups than the rote method group. For low-vividness words, learning method had no significant effect. Experiment 2 was basically identical, except that the word lists comprised 32 words (16 high-vividness, 16 low-vividness). In this experiment, the peer-generated-keyword group showed significantly better recall of high-vividness words than the rote method groups and the subject generated keyword group; again, however, learning method had no significant effect on recall of low-vividness words.     

Working memory and the vividness of imagery

The working memory framework was used to investigate the factors determining the phenomenological vividness of images. Participants rated the vividness of visual or auditory images under control conditions or while performing tasks that differentially disrupted the visuospatial sketchpad and phonological loop subsystems of working memory. In Experiments 1, 2, and 6, participants imaged recently presented novel visual patterns and sequences of tones; ratings of vividness showed the predicted interaction between stimulus modality and concurrent task. The images in experiments 3, 4, 5, and 6 were based on long-term memory (LTM). They also showed an image modality by task interaction, with a clear effect of LTM variables (meaningfulness, activity, bizarreness, and stimulus familiarity), implicating both working memory and LTM in the experience of vividness.     

Detection of a change in photorealism1

The perceived degree of photorealism is interpreted as reflecting the artificialness or naturalness of images. Natural images (real‐scene photographs) are images with high degrees of naturalness, while artificial images (e.g., paintings) are images with low degrees of naturalness. Alternatively, natural images are images with low degrees of artificialness, while artificial images are images with high degrees of artificialness. We attempted to disambiguate these two interpretations of the perception of photorealism by using a change‐blindness paradigm. Participants observed an image sequence showing a gradual transformation from a natural image to an artificial image or vice versa, and reported changes they noticed. More participants reported noticing changes in photorealism for the natural‐to‐artificial transformations than for the opposite transformations. This asymmetry indicates that disappearing naturalness was detected more readily than emerging naturalness, or alternatively, emerging artificialness was detected more readily than disappearing artificialness. The results for the control conditions showed that the emergence of visual information was detected more readily than the disappearance. These results suggest that the perception of photorealism should be considered as the perception of artificialness.     

Perceptual integration of motion and form information: evidence of parallel-continuous processing

In three visual search experiments, the processes involved in the efficient detection of motion-form conjunction targets were investigated. Experiment 1 was designed to estimate the relative contributions of stationary and moving nontargets to the search rate. Search rates were primarily determined by the number of moving nontargets; stationary nontargets sharing the target form also exerted a significant effect, but this was only about half as strong as that of moving nontargets; stationary nontargets not sharing the target form had little influence. In Experiments 2 and 3, the effects of display factors influencing the visual (form) quality of moving items (movement speed and item size) were examined. Increasing the speed of the moving items (> 1.5 degrees/sec) facilitated target detection when the task required segregation of the moving from the stationary items. When no segregation was necessary, increasing the movement speed impaired performance: With large display items, motion speed had little effect on target detection, but with small items, search efficiency declined when items moved faster than 1.5 degrees/sec. This pattern indicates that moving nontargets exert a strong effect on the search rate (Experiment 1) because of the loss of visual quality for moving items above a certain movement speed. A parallel-continuous processing account of motion-form conjunction search is proposed, which combines aspects of Guided Search (Wolfe, 1994) and attentional engagement theory (Duncan & Humphreys, 1989).     

Measuring the size of mental images

Mental images seem to have a size; the experimental problem was to map that image size onto a scale of physical measurement. To this end, two experiments were conducted to measure the size of mental images in degrees of visual angle. In Experiment 1, college students employed light pointers to indicate the horizontal extent of projected mental images of words (the letter string, not the referent). Imagined words covered about 1.0 degress of visual angle per letter. In Experiment 2, a more objective eye-movement response was used to measure the visual angle size of imagined letter strings. Visual angle of eye movement was found to increase regularly as the letter distance between the fixation point and a probed letter position increased. Each letter occupied about 2.5 degrees of visual angle for the four-letter strings in the control/default size condition. Possible relations between eye movements and images are discussed.     

Reducing the vividness and emotional impact of distressing autobiographical memories: the importance of modality-specific interference

Experimental analogues of post-traumatic stress disorder suggest that loading the visuospatial sketchpad of working memory with a concurrent task reduces the vividness and associated distress of predominantly visual images. The present experiments explicitly tested the hypothesis that interfering with the phonological loop could analogously reduce the vividness and emotional impact of auditory images. In Experiment 1, 30 undergraduates formed non-specific images of emotive autobiographical memories while performing a concurrent task designed to load either the visuospatial sketchpad (eye movements) or phonological loop (articulatory suppression). Participants reported their images to be primarily visual, corresponding to the greater dual-task disruption observed for eye movements. Experiment 2 instructed participants to form specifically visual or auditory images. As predicted, concurrent articulation reduced vividness and emotional intensity ratings of auditory images to a greater extent than did eye movements, whereas concurrent eye movements reduced ratings of visual images much more than did articulatory suppression. Such modality-specific dual-task interference could usefully contribute to the treatment and management of intrusive distressing images in both clinical and non-clinical settings.     

Prospective and positive mental imagery deficits in dysphoria

We know less about positive mental imagery than we do about negative mental imagery in depression. This study examined the relationship between depressed mood and the subjective experience of emotion in imagined events; specifically, prospective imagery, and imagery in response to emotionally ambiguous stimuli. One hundred and twenty-six undergraduates completed measures of depression, imagery vividness for future events, and a homograph interpretation task in which they generated images and subsequently rated image pleasantness and vividness. As predicted, compared to low dysphoria, high dysphoria was associated with poorer ability to vividly imagine positive (but not negative) future events. These findings were augmented by the observation that high dysphorics provided lower pleasantness ratings of images generated in response to homographs they interpreted as positive. We suggest that an imbalance in the inability to vividly imagine positive but not negative future events may curtail the ability of high dysphorics to be optimistic. High dysphoric individuals are further disadvantaged: even when they interpret ambiguity positively, the resulting images they generate are associated with less positive affect. Therapeutic strategies that address both such positive-specific imagery biases hold promise for depression treatment innovation.     

Effects of eye movements on the rate of discovery and the vividness of visual images

Two studies investigated the effects of eye movements on the rate of discovery and the vividness of visual images. Eye movements were manipulated by having three conditions: (1) The Ss were instructed to make eye movements while generating images to noun pairs; (2) the Ss were instructed not to make eye movements, but to think about making eye movements while generating images to noun pairs; (3) the Ss were instructed not to make eye movements and not to think about making eye movements while generating images to noun pairs. In addition, the ease of generating images was manipulated by using noun pairs that differed in their image-evoking capacity; five of the noun pairs consisted of high imagery-evoking nouns and five consisted of low imagery-evoking nouns. The two experiments were similar, with the exception that a between-groups design was used in Experiment 1, whereas Experiment 2 employed a within-Ss design. The results of both experiments showed highly significant effects of noun-pair type on both the rate of discovery and the vividness of images, with the fastest and most vivid images occuring to the high-imagery noun pairs. The effects of the eye-movement conditions on the rate of discovery and the vividness of the images were not significant in either experiment, and these findings are discussed in terms of the relationship of ocular activity to imagery.     

Surface cues reduce the latency to name rotated images of objects.

Jolicoeur (1985, Memory & Cognition 13 289-303) found a linear increase in the latency to name line drawings of objects rotated (0 degrees to 120 degrees) from the upright (0 degrees) in the initial trial block. This effect was much shallower in later blocks. He proposed that the initial effect may indicate that mental rotation is the default process for recognising rotated objects, and that the decrease in this effect, seen with practice, may reflect the increased use of learned orientation-invariant features. Initially, we were interested in whether object-colour associations that may be learned during the initial block, could account for the reduced latency to name rotated objects, seen in later blocks. In experiment 1 we used full-cue colour images of objects that depicted colour and other surface cues. Surprisingly, given that Jolicoeur's findings were replicated several times with line drawings, we found that even the initial linear trend in naming latency was shallow. We replicated this result in follow-up experiments. In contrast, when we used less-realistic depictions of the same objects that had fewer visual cues (ie line drawings, coloured drawings, greyscale images), the results were comparable to those of Jolicoeur. Also, the initial linear trends were steeper for these depictions than for full-cue colour images. The results suggest that, when multiple surface cues are available in the image, mental rotation may not be the default recognition process.     

Measure of the ability to rotate mental images

The aim of this study was to design an innovative test to measure the ability to rotate mental images. An unfolded cube was designed, which participants had to reassemble mentally, prior to mentally rotating the image, and answering 23 questions concerning the cube. The Measure of the Ability to Rotate Mental Images (MARMI) test was administered to 354 participants. Cronbach alpha was .90, and high correlations between this test and other image rotation and spatial image tests were found. However, poor correlations were observed between test scores and the responses to the visual imagery vividness questionnaire. Both test reliability and validity underscore that it is a good instrument for measuring the ability to rotate mental images.     

Sensory features of mental images in the framework of human actions

What determines the sensory impression of a self-generated motor image? Motor imagery is a process in which subjects imagine executing a body movement with a strong kinesthetic and/or visual component from a first-person perspective. Both sensory modalities can be combined flexibly to form a motor image. 90 participants of varying ages had to freely generate motor images from a large set of movements. They were asked to rate their kinesthetic as well as their visual impression, the perceived vividness, and their personal experience with the imagined movement. Data were subjected to correlational analyses, linear regressions, and representation similarity analyses. Results showed that both action characteristics and experience drove the sensory impression of motor images with a strong individual component. We conclude that imagining actions that impose varying demands can be considered as reexperiencing actions by using one’s own sensorimotor representations that represent not only individual experience but also action demands.     

Effect of display size on visual attention

Attention plays an important role in the design of human-machine interfaces. However, current knowledge about attention is largely based on data obtained when using devices of moderate display size. With advancement in display technology comes the need for understanding attention behavior over a wider range of viewing sizes. The effect of display size on test participants' visual search performance was studied. The participants (N = 12) performed two types of visual search tasks, that is, parallel and serial search, under three display-size conditions (16 degrees, 32 degrees, and 60 degrees). Serial, but not parallel, search was affected by display size. In the serial task, mean reaction time for detecting a target increased with the display size.     

视觉表象产生的大脑半球专门化效应

采用Kosslyn单侧视野速示技术, 以英文字母图片为学习材料, 通过三个实验考察了视觉表象产生的大脑半球专门化效应。实验一提出在两种类型的视觉表象产生任务中, 有两种截然不同的加工起作用, 但却不能直接证实这两种不同加工机制的存在。实验二和实验三则进一步证实了两种表象产生任务具有不同的认知加工机制, 并表现出不同的大脑半球专门化效应。上述研究表明: 大脑两半球均参与产生视觉心理表象, 但分工不同, 并表现出不同的单侧化效应: 大脑左半球通过运用类别空间关系产生表象更有效, 大脑右半球运用数量空间关系产生表象更有效。结果进一步拓展了Kosslyn关于视觉空间关系加工的大脑半球专门化观点。     

Effects of spatial separation between stimuli in whole report from brief visual displays

Direct measurements of the effects of spatial separation between stimuli in whole report from brief visual displays are reported. The stimuli were presented on the periphery of an imaginary circle centered on fixation. In Experiment 1, each display showed two capital letters (letter height approximately equal 1.3 degrees, width approximately equal 0.9 degree, eccentricity approximately equal 5.5 degrees). The proportion of correctly reported letters was a strictly increasing, decelerating function of the spatial separation between the letters for center-to-center separations ranging from less than 2 degrees to more than 10 degrees of visual angle. Experiment 2 yielded similar results with triples of letters. Experiment 3 showed that accuracy increased with spatial separation for report of two short words, and Experiment 4 showed the same result for words presented upside down. The results are explained by a model of lateral masking (crowding) based on competitive interactions within receptive fields of cortical neurons.