Satiation or availability? Effects of attention,memory, and imagery on the perception of ambiguous figures

The prolonged-inspection technique has been used to demonstrate effects of satiation on the perception of ambiguous figures. We propose that the inspection phase, in which subjects view an unambiguous version of the stimulus prior to observing the ambiguous figure, does not create neural fatigue but rather provides a context in which the alternative percept is apprehended and gains perceptual strength through processes such as imagination or memory. The consequent availability of the alternative organization drives the perceptual phenomena that have been thought to reflect satiation. In Experiment 1, we demonstrated that (1) preexperimental exposure to the target figures and (2) allocation of attention to the-inspection figures-were both necessary in order to obtain results similar to those predicted by the satiation model. In Experiment 2, we obtained similar results, finding that effects of prior inspection were greater the greater the amount and availability of information regarding the alternative percept during the inspection phase. Subjects who generated visual images of the noninspected alternative during inspection yielded results comparable to those from subjects to whom both versions were presented isuaily.     

Children's understanding that ambiguous figures have multiple interpretations

In three experiments we compared 5- and 6-year-old children's understanding of multiple interpretations arising from an ambiguous figure (e.g., the duck/rabbit) and other ambiguous partial input. Children found it equally easy to switch between alternative interpretations of ambiguous figures and partial views (Experiment 1, N = 19) and more difficult to accept two characters' conflicting interpretations of ambiguous figures, than partial views (Experiment 2, N = 29). Children found it more difficult to accept explicitly that one stimulus could simultaneously give rise to two interpretations, than to switch between them (Experiment 3, N = 40). Children's handling of multiple interpretations was not primarily affected by the type of input, but results suggest that there are two distinct stages in children's handling of multiple interpretations.     

Priming effects with ambiguous figures

We varied the format and semantic content of primes to determine the degree to which they would influence the interpretation of ambiguous figures. The primes were objects or object names that were related in some way to one of the two organizations of the ambiguous figures. In Experiment 1, we provided some normative data regarding the stimulus materials, whereas in Experiment 2, an orienting question was used to focus attention on the semantic relationship between the prime and the figure. In Experiment 3, we used the orienting question to divert attention away from the relationship by asking about physical features of the figures. Recognition responses to biased versions of the figures and to new figures were measured. Primes that were loosely and indirectly associated with one of the two interpretations of an ambiguous figure were found to be effective at biasing the interpretation of an ambiguous figure in the direction of the primed alternative but only if attention was focused on the semantic relationship between the two stimuli. Attention to the physical characteristics of the stimuli during encoding eliminated the prime's influence on complex object perception. These findings are consistent with the conceptual priming literature and extend those of some recent studies (Balcetis & Dale, 2007; Feist & Gentner, 2007), which show that the interpretation of complex figures can be biased by the advanced presentation of related verbal information.     

The relationship between bilingualism and selective attention in young adults: Evidence from an ambiguous figures task

Previous research has shown that bilinguals outperform monolinguals on a variety of tasks that have been described as involving executive functioning, but the precise mechanism for those effects or a clear definition for “executive function” is unknown. This uncertainty has led to a number of studies for which no performance difference between monolingual and bilingual adults has been detected. One approach to clarifying these issues comes from research with children showing that bilinguals were more able than their monolingual peers to perceive both interpretations of an ambiguous figure, an ability that is more tied to a conception of selective attention than to specific components of executive function. The present study extends this notion to adults by assessing their ability to see the alternative image in an ambiguous figure. Bilinguals performed this task more efficiently than monolinguals by requiring fewer cues to identify the second image. This finding has implications for the role of selective attention in performance differences between monolinguals and bilinguals.     

Coherent EEG indicators of cognitive binding during ambiguous figure tasks

We tested the hypothesis that perception of an alternative image in ambiguous figures would be manifest as high-frequency (gamma) components that become synchronized over multiple scalp sites as a "cognitive binding" process occurs. For 171 combinations of data from 19 electrodes, obtained from 17 subjects and 10 replicate stimuli, we calculated the difference in correlation between the response to first seeing an ambiguous figure and when the alternative percept for that figure became consciously realized (cognitively bound). Numerous statistically significant correlation differences occurred in all frequency bands tested with ambiguous-figure stimulation, but not in two kinds of control data (a reaction-time test to sound stimuli and a no-task, mind-wandering test). Statistically significant correlation changes were widespread, involving frontal, parietal, central, and occipital regions of both hemispheres. Correlation changes were evident at each of five frequency bands, ranging up to 62.5 Hz. Most of the statistically significant correlation changes were not between adjacent sites but between sites relatively distant, both ipsilateral and contralateral. Typically, these correlation changes occurred in more than one frequency band. These results suggest that cognitive binding is a distinct mental state that is reliably induced by ambiguous-figure perception tasks. Coherent oscillations at multiple frequencies may reflect the mechanism by which such binding occurs. Moreover, different coherent frequencies may mediate different components of the total cognitive-binding process.     

Simultaneous perception of both interpretations of ambiguous figures

When viewing ambiguous figures like the classic duck/rabbit, people alternately perceive one interpretation and then the other, but not both interpretations at once. When two identical ambiguous figures appear together, the majority of observers perceive them as identical, and they typically alternate in unison. Just as most observers cannot see a single figure as both a duck and a rabbit, most cannot see one figure in a pair as a duck and the other as a rabbit even though the two figures and their features are spatially distinct. Is this inability to see both interpretations an inherent limitation of the visual system or is it just due to differences in top-down processing? We show that a simple prompt immediately allows people to see both interpretations, to their own surprise.     

Coherence and transparency of moving plaids composed of Fourier and non-Fourier gratings

We examined the perceptual coherence of two-component moving plaids. The gratings that constituted the plaids were either standard Fourier gratings (F), in which luminance was determined by a drifting sinusoid, or non-Fourier gratings (NF), in which the contrast of a random background was modulated by a drifting sinusoid. These NF gratings are examples of stimuli that generate a compelling percept of motion, even though they fail to elicit a motion signal from motion analyzers based on standard cross-correlation (Chubb & Sperling, 1988). Naive observers viewed three types of stimuli consisting of superpositions of these two components: (1) two standard drifting gratings (F/F), (2) two non-Fourier drifting gratings (NF/NF), and (3) one standard and one non-Fourier drifting grating (F/NF). As expected, the F/F stimulus yielded a compelling percept of coherent motion. The dominant percept of all the observers for the NF/NF stimulus was one of coherent motion, provided that both gratings were visible and of approximately equal contrast. None of the observers reported a dominant percept of coherent motion for the F/NF condition, over a wide range of contrasts for the two grating components and across two varieties of NF gratings. In view of the results of Albright (1992) and Albright and Chaudhuri (1989), that show that single cells in macaque V1 and MT respond to both F and NF motion, one cannot interpret our findings as evidence that F and NF motion are processed independently. Alternative, “higher level” interpretations based on the intrinsically ambiguous nature of the stimuli and physical laws governing the appearance of transparent objects are discussed.     

Coherence and transparency of moving plaids composed of Fourier and non-Fourier gratings.

We examined the perceptual coherence of two-component moving plaids. The gratings that constituted the plaids were either standard Fourier gratings (F), in which luminance was determined by a drifting sinusoid, or non-Fourier gratings (NF), in which the contrast of a random background was modulated by a drifting sinusoid. These NF gratings are examples of stimuli that generate a compelling percept of motion, even though they fail to elicit a motion signal from motion analyzers based on standard cross-correlation (Chubb & Sperling, 1988). Naive observers viewed three types of stimuli consisting of superpositions of these two components: (1) two standard drifting gratings (F/F), (2) two non-Fourier drifting gratings (NF/NF), and (3) one standard and one non-Fourier drifting grating (F/NF). As expected, the F/F stimulus yielded a compelling percept of coherent motion. The dominant percept of all the observers for the NF/NF stimulus was one of coherent motion, provided that both gratings were visible and of approximately equal contrast. None of the observers reported a dominant percept of coherent motion for the F/NF condition, over a wide range of contrasts for the two grating components and across two varieties of NF gratings. In view of the results of Albright (1992) and Albright and Chaudhuri (1989), that show that single cells in macaque V1 and MT respond to both F and NF motion, one cannot interpret our findings as evidence that F and NF motion are processed independently. Alternative, "higher level" interpretations based on the intrinsically ambiguous nature of the stimuli and physical laws governing the appearance of transparent objects are discussed.     

Ambiguous figures: role of context and critical features

Context and attention to critical features as factors in determining the perceptual organization of ambiguous figures were investigated in the present two studies. In the first study, a fixation point directed attention to a critical or to a neutral feature of an ambiguous figure. Placement of the fixation point on different features of an ambiguous figure did not affect the figure-ground organization of the figure, but it did influence the speed of the identification response. In the second study, presentation of an ambiguous figure was preceded by a biased figure or by features of the figure. Results indicated that the interpretation of the ambiguous figure was overwhelmingly influenced by the advanced presentation of a biased drawing but only slightly influenced by the advanced presentation of a critical feature. These findings support analysis-by-synthesis (Neisser, 1967) as an explanation of the perception of ambiguous figures over other contemporary attention theories.     

Ambiguous figure perception and theory of mind understanding in children with autistic spectrum disorders

Researchers in early social‐cognition have found that the ability to reverse an ambiguous figure is correlated with success on theory of mind tasks (e.g. Gopnik & Rosati, 2001 ). The present experiment examined children with autistic spectrum disorders (ASD) without mental delay to see whether a similar relationship existed. Ropar, Mitchell, and Ackroyd (2003) demonstrated that children with ASD with mental delay were impaired on theory of mind tasks, but were as likely as mentally delayed controls to generate both interpretations of an ambiguous figure when informed of its ambiguity. The present study replicated this finding on children with ASD without mental delay. However, overall perception of ambiguous figures was different. These children were less likely to spontaneously generate both interpretations of the figure, and more likely to perseverate on a single interpretation than the comparison children. Like Ropar et al., we found no correlation between theory of mind and informed reversals, but spontaneous reversals were correlated with performance on an advanced theory of mind task. These data suggest that reversals of ambiguous figures are linked to higher‐level representational abilities, which might also be involved in social functioning, and impaired in children with ASD.     

Creativity and ease of ambiguous figural reversal

Two studies examined the relationships between self-rated and objectively measured creative ability and ease of perceiving alternative interpretations of the ambiguous Duck-Rabbit figure. The studies found empirical support for what has previously been a largely analogical connection between figural reversal and creativity, using both self-rated trait creativity and objectively scored creative productivity. We discuss the hypothesis that executive functioning is the likely common cognitive factor linking perception of ambiguous figures and creative ability.     

Can People Creative in Imagery Interpret Ambiguous Figures Faster than People Less Creative in Imagery?

The purpose of the research study was to investigate whether people creative in imagery are better than people non‐creative in imagery at interpreting ambiguous figures. Creativity, in the imagery paradigm, is said to involve two processes: combinational play and discovery. Discovery plays a major role in creativity as it is the process of discerning, judging or interpreting the value of a mental construction. Furthermore, creative people have been said to be insightful thus supporting the proposition advanced here that people creative in imagery are faster at interpreting and finding alternative interpretations for ambiguous figures than people less creative in imagery. This study reports both latencies and discoveries in perception and mental imagery as measured on a figure combination task. The data support the conclusion that people creative in imagery are more capable in reinterpreting ambiguous figures and that they are quicker in their discoveries than people less creative in imagery. The analysis to the questions of how the subjects arrived at their discoveries may also illustrate the Gestalt literature on insight as a rapid pattern recognition.     

Probabilistic assignments of sentence relations on the basis of differentially weighted interpretive cues

Recent treatments of comprehension have emphasized the role of surface structure characteristics. In many circumstances, meanings that are inferred on the basis of such cues will not be deterministic. This study investigated a probabilistic system of sentence comprehension. Hebrew-speaking university studients interpreted utterances that varied and balanced the contradictory and complementary effects of three interpretive cues. Sentence interpretations were systematically affected by the relative weights of cues that supported and opposed different interpretations. Adults therefore seemed to deploy a probabilistic strategy of assigning internal relations to a preferred alternative, a greatest composite of component likelihoods. While the present treatment emphasized a syntactic level of processing, it was suggested that the probabilistic strategy could easily accommodate pragmatic and semantic effects as well. The probabilistic strategy implies that given a conflict between interpretive cues, a decision needs to be made between alternative assignments of internal relations. It was therefore suggested that ambiguous and unambiguous utterances typically may be processed in a similar fashion; for both, more than one meaning may be processed at least in part before a single probabilistic interpretation is finally assigned to the utterance.     

The effect of repetition on the perception of single letters

Single letters were presented for from one to five flashes, with S required to report what he saw after each flash. The clarity of the letter increased sharply with repetition. Since the letters were no larger than one-third of a degree in size, clarity could not have been increased by S making different fixations from flash to flash and combining them into a total percept. Nor was S guessing, since this could be ruled out by other indicators. Thus, it was concluded that repetition of the stimulus can have a direct effect on the clarity of a S’s percept of that stimulus.     

Children's understanding of ambiguous figures: Which cognitive developments are necessary to experience reversal?

In two experiments involving one hundred and thirty-eight 3- to 5-year-olds we examined the claim that a complex understanding of ambiguity is required to experience reversal of ambiguous stimuli [Gopnik, A., & Rosati, A. (2001). Duck or rabbit? Reversing ambiguous figures and understanding ambiguous representations. Developmental Science, 4, 175–183]. In Experiment 1 a novel Production task measured the ability to acknowledge both interpretations of ambiguous figures. This was as easy as and significantly correlated with a False Belief task, and easier than a Droodle task. We replicated this finding in Experiment 2, and also found that perceiving reversal of ambiguous figures was harder than either the False Belief or Production tasks. In contrast to previous findings, the Reversal and Droodle tasks were not specifically related. We conclude that children only attempt reversal once they can understand the representational relationship between the figure and its two interpretations. The process resulting in reversal however is hard, probably requiring additional developments in executive functioning and imagery abilities.     

Biasing Effects in Ambiguous Figures: Removal or Fixation of Critical Features Can Affect Perception

The role of so-called critical features in the perception of ambiguous figures was examined in two experiments. In the first, selective removal of certain features was found to bias the initial perception of the wife mother-in-law figure. In the second, the position of the fixation point was found to influence the dominance of aspect of the wife mother-in- law figure. During an extended viewing period, when the fixation point was close to a critical feature (as defined in the first experiment), the tendency was for the figure to be less ambiguous, and for large figures to be less ambiguous than small. The effects are discussed with reference to the hypothesis that changes of visual attention between different features underlie the perceptual alternations of the figure.     

The effect of repetition on the perception of single letters)

Single letters were presented for from one to five flashes, with S required to report what he saw after each f1ash. The clarity of the letter increased sharply with repetition. Since the letters were no larger than one-third of a degree in size, clarity could not have .been increased by S making different fixations from f1ash to f1ash and combining them into a total percept. Nor was S guessing, since this could be ruled out by other indicators. Thus, it was concluded that repetition of the stimulus can have a direct effect on the clarity of a S’s percept of that stimulus.