Can imagery be distinguished from other forms of internal representation? Evidence from studies of information retrieval times

This paper provides support for the notion that images, once formed, are a distinct form of internal representation, processed differently than other forms of internal representation. In two experiments, subjects decided as quickly as possible whether or not named animals had given properties. When imagery was not used, people verified properties more quickly in accordance with how strongly associated the property was with the animal in question. When images of the whole animal were consulted, in contrast, subjects were faster in accordance with increasing size of the property, and not with increasing association strength. However, if subjects imaged only the local region where a property ought to be found, and did not consult an image of the whole animal, the size of a property no longer influenced verification time. These results and their implications for the debate over imagery vs. propositional representation were discussed.     

Measuring the visual angle of the mind's eye

People in these experiments claimed to be able to imagine moving only a given distance toward some imaged object before it seemed to “overflow,” not remaining all visible at once in their mental images. In addition, the larger the imaged object, the further away it seemed at the point of overflow. Although the angle subtended by the imaged objects at the point of overflow did not vary systematically with the size of the object, it did vary with different stimuli and instructions. These disparities in the size of the angle estimated seemed partly due to differences in criterion of “overflow”: Images seem to fade off gradually toward the periphery and not to occur in a spatial medium with sharply defined edges. When subjects were given a relatively strict definition of “overflow,” similar estimates of the “visual angle of the mind's eye” were obtained with three distinct methods: (1) Asking subjects to estimate the apparent distance at which an imaged horizontal ruler began to overflow; (2) Measuring how much time subjects required to scan across each degree of an imaged line, and then inferring the maximal angle from the time required to scan an image of a longest nonoverflowing line; and, (3) Simply asking subjects to hold up their hands to indicate the subjective size of an image of the longest possible nonoverflowing line. Finally, the maximal subjective size of images seemed related to the scope of “focal” vision, and images tended to be constructed spontaneously at about the maximal size.     

Overflow, first-sight, and vanishing point distances in visual imagery

The relationship between the size of a familiar object and the distances at which it is imaged is examined in three experiments. The distance at which an imaged object overflows the visual field is linearly related to object size, a result consistent with the size-distance invariance hypothesis (Kosslyn, 1980). The distance at which an object is initially imaged, first-sight distance, is related to the object size by a power function with an exponent less than 1. In addition, time required to scan from the first-sight to the overflow distance increases as a function of the difference between the two distance estimates. The distance at which an imaged object becomes too small to be identified, vanishing point distance, is related to object size by a power function with an exponent less than 1. This result does not support predictions made from the size-distance invariance hypothesis or Kosslyn's model of visual imagery. Implications for a theory of visual imagery and memory are discussed.     

The effects of size,clutter, and complexity on vanishing-point distances in visual imagery

Summary The portrayal of vanishing-point distances in visual imagery was examined in six experiments. In all experiments, subjects formed visual images of squares, and the squares were to be oriented orthogonally to subjects' line of sight. The squares differed in their level of surface complexity, and were either undivided, divided into 4 equally sized smaller squares, or divided into 16 equally sized smaller squares. Squares also differed in stated referent size, and ranged from 3 in. to 128 ft along each side. After subjects had formed an image of a specified square, they transformed their image so that the square was portrayed to move away from them. Eventually, the imaged square was portrayed to be so far away that if it were any further away, it could not be identified. Subjects estimated the distance to the square that was portrayed in their image at that time, the vanishing-point distance, and the relationship between stated referent size and imaged vanishing-point distance was best described by a power function with an exponent less than 1. In general, there were trends for exponents (slopes on log axes) to increase slightly and for multiplicative constants (y intercepts on log axes) to decrease as surface complexity increased. No differences in exponents or in multiplicative constants were found when the vanishing-point was approached from either sub-threshold or suprathreshold directions. When clutter in the form of additional imaged objects located to either side of the primary imaged object was added to the image, the exponent of the vanishing-point function increased slightly and the multiplicative constant decreased. The success of a power function (and the failure of the size-distance invariance hypothesis) in describing the vanishing-point distance function calls into question the notions (a) that a constant grain size exists in the, imaginal visual field at a given location and (b) that grain size specifies a lower limit in the storage of information in visual images.     

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。     

Quantification abilities in angelfish (Pterophyllum scalare): the influence of continuous variables

Previous studies investigating quantity discrimination have shown that angelfish are able to select the larger of two groups of conspecifics (shoals). The discrimination limits shown by angelfish were similar to those found for other vertebrates when large (≥4) and small quantities (<4) were presented. However, in these studies, no attempt was made to control for non-numerical features of the stimulus shoals and thus the question whether numerical or some quantitative attributes of the shoals were utilized for making the choices could not be answered. Here, we investigate whether angelfish can discriminate between shoals differing in numerical size using non-numerical attributes. We systematically manipulate density, inter-fish distance, and overall space occupied by the shoals, one factor at a time, and analyse the choices angelfish made between the contrasting stimulus shoals. The stimulus shoals consisted of contrasts between large (10 vs. 5) and small (3 vs. 2) number of conspecifics. We found density to be a sufficient condition for discrimination between large shoals as the test subjects preferred the more dense shoal. Manipulation of inter-fish distance indicated that this variable is not a necessary factor in discrimination at either shoal size contrast. Likewise, we found that the size of space occupied by the contrasted shoals also did not significantly influence discrimination. Sensitivity to the density of large shoals indicates that angelfish can discriminate shoal size using this non-numerical cue. Nevertheless, the factors we examined may represent only a subset of all possible non-numerical features upon which angelfish may base their discrimination. Thus, we suggest that further research is required to clarify whether and under what circumstances angelfish may use numerical or non-numerical features when discriminating between shoals of differing size.     

The rate of “mental rotation” of images: A test of a holistic analogue hypothesis

This paper discusses the analogue-propositional distinction and argues that, given an appropriate understanding of this issue, the question of whether a particular cognitive function is analogue or not is an empirical one. As an example of how the question can be empirically investigated, the proposed analogue operation for mental rotation of images is considered. It is argued that the view that images are rotated in a holistic analogue manner should predict that rotation rate is independent of such factors as the conceptual complexity of the stimulus or of the comparison task. Two experiments are described that investigated the effects of several stimulus and task variables on the apparent rate of “mental rotation” of images in a Shepard-type task. Instead of comparing a stimulus and misoriented probe figure to determine whether they are identical (except for orientation) or mirror images, as was the case in most of previous studies, the present experiments required subjects to judge whether the misoriented probe was a subfigure of the target stimulus. The results showed that the “rotation rate” (i.e., the slope of the RT vs. angle of misorientation function) was influenced by practice, stimulus attributes, and the nature of the comparison task. In particular, when the probe was a “good” subfigure of the reference stimulus, apparent rotation rate was greater. These results are interpreted as indicating that the linear RT vs. angle relation is not due to a holistic analogue rotation of images, as had been supposed, but arises from a more articulated and piecemeal process in which analysis of the stimulus figure interacts with the comparison task.     

The effects of distributed and focused attention on rapid scene categorization

It has been argued that distributed attention facilitates the rapid extraction of summary statistics that underpins rapid scene categorization. We directly examined this hypothesis by investigating whether distributed or focused attention is more compatible with the extraction of both summary statistics (Experiment 1) and semantic scene information (Experiments 2–4). Experiment 1 replicated Chong and Treisman’s (2005a) result that mean circle size judgments are more compatible with a distributed attention task than a focused attention task. Experiment 2 investigated whether this finding extends to simple scene categorization by replacing the averaging task with an animal detection task. Consistent with Experiment 1, the ability to detect the presence of an animal was more compatible with a distributed attention task than a focused attention task. Experiments 3 and 4 addressed whether distributed attention influences scene categorization tasks. When observers were asked to classify scenes based on their basic level (e.g., beach or forest; Experiment 3), there was no statistically significant difference between focused and distributed attention task conditions; however, superordinate level categorization (e.g., natural or manmade; Experiment 4) was faster when combined with a task requiring distributed attention compared to a task requiring focused attention.     

Functional Differences Between Upright and Rotated Images

In Experiment I subjects imaged an alphanumeric character either upright or upside-down, and triggered a test display character. Their task was to decide as quickly as possible whether the test character was NORMAL or MIRRORED. On 72% of the trials the test was at the orientation imaged. Reaction time (RT) was then about 200 ms longer in the upside-down image condition. This difference reduced with practice. On the remaining trials the orientation of the test character differed from that of the prepared image. For upright images RT increased monotonically with the angular difference in orientation between test and image. For upside-down images RT did not increase monotonically with angular difference as there was a wide dip around the upright. Further experiments suggested that upside-down images can be rotated, but at considerably slower rates than upright ones, and that the apparent rates of rotation for upside-down images are dependent upon the width of the sector tested. These results indicate that visual short-term memory (STM) and long-term memory (LTM) are distinct; that the process of mental rotation does not operate directly upon LTM; and that functionally, upright and rotated images may differ in important ways.     

Small and large number discrimination in guppies

Non-verbal numerical behavior in human infants, human adults, and non-human primates appears to be rooted in two distinct mechanisms: a precise system for tracking and comparing small numbers of items simultaneously (up to 3 or 4 items) and an approximate system for estimating numerical magnitude of a group of objects. The most striking evidence that these two mechanisms are distinct comes from the apparent inability of young human infants and non-human primates to compare quantites across the small (<3 or 4)/large (>4) number boundary. We ask whether this distinction is present in lower animal species more distantly related to humans, guppies (Poecilia reticulata). We found that, like human infants and non-human primates, fish succeed at comparisons between large numbers only (5 vs. 10), succeed at comparisons between small numbers only (3 vs. 4), but systematically fail at comparisons that closely span the small/large boundary (3 vs. 5). Furthermore, increasing the distance between the small and large number resulted in successful discriminations (3 vs. 6, 3 vs. 7, and 3 vs. 9). This pattern of successes and failures is similar to those observed in human infants and non-human primates to suggest that the two systems are present and functionally distinct across a wide variety of animal species.     

Can Young Children Distinguish Abstract Expressionist Art From Superficially Similar Works by Preschoolers and Animals?

While it is sometimes claimed that abstract art requires little skill and is indistinguishable from the scribbles of young children, recent research has shown that even adults with no training in art can distinguish works by abstract expressionists from superficially similar works by children and even elephants, monkeys, and apes (Hawley-Dolan & Winner, 2011). We presented 4-7- and 8-10-year-olds with 18 paired images, one in each pair by an abstract expressionist and the other by a child or animal, and asked which they preferred and which was better. Each participant viewed the first third of the pairs unlabeled and the rest either with correct or reversed labels (artist, and child, monkey, or elephant). Three unexpected findings emerged. First, even 4-7-year-olds can distinguish works by artists from superficially similar works by children and animals when there are no labels to guide them. Second, children’s aesthetic responses are not aligned with those of adults: children often chose works labeled child or animal whether or not this label was correct, and sometimes justified their choices by crediting the effort the child or animal had made (e.g., “it’s really good for an elephant”). Finally, children, like adults, were more likely to select artist images when making quality judgments than when indicating preferences, showing that they make a distinction between intuitive preference responses and more cognitive quality judgment responses. That even preschoolers can discriminate between works by abstract expressionists and works by children and animals underscores what is wrong with the oft-heard statement, “My kid could have done that.”     

Visual statistical learning produces implicit and explicit knowledge about temporal order information and scene chunks: Evidence from direct and indirect measures

We examined whether visual statistical learning (VSL) produced implicit and/or explicit knowledge about temporal order information and scene chunks, using a rapid serial visual presentation target detection task and a two-alternative forced-choice (2AFC) familiarity test as indirect and direct measures of VSL, respectively. In the familiarization phase, participants viewed a visual stream of natural scenes consisting of four triplets (i.e., three images that always appeared in the same order). In the subsequent target detection task, participants were required to detect target items embedded in a stream of 12 images or 12 words representing each natural scene. In the final 2AFC familiarity test, participants observed two test sequences (statistically related triplets vs. unrelated foils) and decided whether the first or second sequence was more familiar based on the familiarization phase. In both test phases, we included the same (forward) and reverse (backward) order of scenes as presented during the familiarization phase to examine whether the expression of VSL was based on temporal order of scenes or scene chunks. The results of the target detection task showed a learning effect for both temporal order in the forward condition and chunks in the backward condition, irrespective of whether stimuli were images or words; in contrast, we did not observe a learning effect in the backward condition for scene images in the familiarity test. Our findings are compatible with a learning mechanism that has both implicit and explicit components based on temporal order information and scene chunks.     

Comparing objects in memory: Evidence suggesting an internal psychophysics

In this experiment, Ss were visually presented with the names of two animals and were required to throw a switch under the name of the larger animal. Although error rates were relatively low (4.5%), reaction time (RT) was largely an inverse linear function of the logarithm of the estimated difference in animal size. Since RT is similarly related to size differences when Ss make direct perceptual comparisons (e.g., of lengths of line),.it was argued that Ss compare animal names by making an “internal psychophysical judgment.” A more general model was then proposed for answering, from memory, questions of the form, “Which is /X/, /A/ or [B/?” where /X/ is any comparative adjective and /A/and /B/ are any concrete nouns.     

Modeling possible effects of atypical cerebellar processing on eyeblink conditioning in autism

Autism is unique among other disorders in that acquisition of conditioned eyeblink responses is enhanced in children, occurring in a fraction of the trials required for control participants. The timing of learned responses is, however, atypical. Two animal models of autism display a similar phenotype. Researchers have hypothesized that these differences in conditioning reflect cerebellar abnormalities. The present study used computer simulations of the cerebellar cortex, including inhibition by the molecular layer interneurons, to more closely examine whether atypical cerebellar processing can account for faster conditioning in individuals with autism. In particular, the effects of inhibitory levels on delay eyeblink conditioning were simulated, as were the effects of learning-related synaptic changes at either parallel fibers or ascending branch synapses from granule cells to Purkinje cells. Results from these simulations predict that whether molecular layer inhibition results in an enhancement or an impairment of acquisition, or changes in timing, may depend on (1) the sources of inhibition, (2) the levels of inhibition, and (3) the locations of learning-related changes (parallel vs. ascending branch synapses). Overall, the simulations predict that a disruption in the balance or an overall increase of inhibition within the cerebellar cortex may contribute to atypical eyeblink conditioning in children with autism and in animal models of autism.     

Stimulus size matters: do life-sized stimuli induce stronger embodiment effects in mental rotation?

Against the background of the embodied cognition approach this experiment investigated the influence of motor expertise on object-based vs. egocentric transformations in a chronometric mental rotation (MR) task using images of either the own or another person’s body as stimulus material. The present study aimed to clarify two issues: (1) whether stimulus size (life size vs. small) is able to induce embodiment effects and (2) which role self-awareness processes play when using stimuli of the own body. The same design was conducted twice using both small stimuli (Study 1) and life-size human figures (Study 2). Using life-sized figures in Study 2 resulted in an explicit advantage of self-related stimuli and improved performance for motor experts compared to non-motor experts in both object-based and egocentric transformations. In conclusion, these results suggest that life-sized figures do indeed induce stronger embodiment effects in MR.     

Social connection and social networking: Daily conflict increases nightly Facebook use among avoidant participants

Using a daily diary methodology we explored whether attachment style predicted evening Facebook use and whether this effect was moderated by daily interpersonal conflict. High anxiety participants reported spending significantly more time on Facebook at night, regardless of daily conflict. Conversely, participants high in avoidance only reported increased time on Facebook on nights following days of more (vs. less) conflict. Daily conflict did not influence time spent in face-to-face interactions for avoidant participants. Interestingly, increased time on Facebook led to lower self-esteem next day , but increased time in face-to-face interactions led to higher self-esteem. Results suggest people high in avoidance use Facebook as an indirect way to seek connection following conflict, but, ironically, Facebook fails to fulfill avoidant’s belongingness needs.     

Tolerance to effects of cocaine on behavior under a response-initiated fixed-interval schedule

Tolerance to effects of cocaine can be modulated by schedules of reinforcement. With multiple ratio schedules, research has shown an inverse relationship between ratio requirement and amount of tolerance that resulted from daily administration of the drug. In contrast, tolerance to the effects of cocaine on behavior under multiple interval schedules generally has developed regardless of interval value. Under interval schedules reinforcement depends on the animal making one response following a time interval. Thus, as time to respond increases, the time to reinforcement decreases. On the other hand, fixed ratio schedules require a specified number of responses to be made prior to reinforcement. Therefore, delaying the initiation of responding does not coincide with a significant decrease in the time to reinforcement. In the current experiment, 6 pigeons were trained to respond under a three-component multiple schedule, with a different tandem fixed-ratio 1 fixed-interval schedule in each component. The multiple schedule required one response, which was followed by one of three fixed-interval values (5, 15, or 60 s). Thus, the multiple schedule was interval-like because after the fixed-ratio 1, only one more response was required for reinforcement, but it was also ratio-like because the length of the pause at the beginning of each interreinforcer interval affected the time until the next reinforcer. Acute administration of cocaine generally resulted in dose-dependent decreases in responding. Chronic (i.e., daily) administration of a rate-decreasing dose resulted in tolerance patterns similar to those usually obtained with multiple ratio schedules. That is, the magnitude of tolerance was related inversely to schedule size. These results suggest that delay to reinforcement from the initial response may play a role in the development of schedule-parameter-related tolerance.     

Sequential effects in time perception

Taylor and Lupker (2001) reported that in a naming task, stimuli were named more rapidly when preceded by an easy-to-name stimulus than when preceded by a difficult-to-name stimulus (sequential effects). The goal of the present research was to investigate whether sequential effects could be explained in terms of time perception processes (within the context of Lupker, Brown, and Colombo’s [1997] time criterion account). Participants were required to name easy and difficult stimuli (high-frequency words and nonwords in Experiment 1; words only in Experiment 2). Each naming trial was followed by a set of asterisks (*****). The participants were required to press a button when they thought the asterisks had been presented for exactly 1 sec. Time intervals produced after naming difficult stimuli were longer than time intervals produced after naming easy stimuli. That is, time perception was affected by the difficulty of word/nonword naming in a way that carried over to the next stimulus, supporting the idea that carryover effects in time perception may be the source of sequential effects in the naming task.