What's next? New evidence for prediction in human vision

Everyday visual experience involves making implicit predictions, as revealed by our surprise when something disturbs our expectations. Many theories of vision have been premised on the central role played by prediction. Yet, implicit prediction in human vision has been difficult to assess in the laboratory, and many results have not distinguished between the indisputably important role of memory and the future-oriented aspect of prediction. Now, a new and unexpected finding - that humans can resume an interrupted visual search much faster than they can start a new search - offers new hope, because the rapid resumption of a search seems to depend on participants forming an implicit prediction of what they will see after the interruption. These findings combined with results of recent neurophysiology studies provide a framework for studying implicit prediction in perception.     

A cognitively-gated place? The role of need for closure in a biased perception of the place’s past

Biased memory of the past is often a starting point for intergroup conflicts. In three correlational studies, we examined the relationship between need for closure (NFC) and historical ethnocentric bias, a tendency to overestimate the role of one’s ethnic group in the multicultural history of the city of residence. In addition, we checked whether this relationship would be mediated by an individual preference for essentialist places. We found that higher NFC was related to increased historical ethnocentric bias. Moreover, this relation was mediated by preference for an essentialist type of a place. Our results may contribute to understanding the role of individual differences and preferred type of place in shaping a biased representation of the past. Furthermore, our research findings point to the importance of raising awareness of the multicultural past among high NFC individuals.

     

“Parts” of perceived visual forms: New evidence

The Pulfrich effect (the illusory displacement of a moving stimulus when it is viewed with an optical filter over one eye) was measured repeatedly during a 20 min period following the initial filtering of the eye. For each of 10 filter densities, the Pulfrich effect always occurred immediately upon filtering the eye, but subsequently increased greatly during the adaptation period. The results indicate that the perceptual latency of the filtered eye is increased by two factors: the reduction in stimulus luminance due to the filter and progressive dark adaptation. Dark adaptation is apparently the more important of these two factors.     

Informational affordances: evidence of acquired perception–action sequences for information extraction

Visual objects can automatically prime actions allowing efficient interaction with them. The present study examined whether object perception can automatically prime actions leading to efficient information extraction. Participants in Experiment 1 learned to rotate a cube in a specific way with the end goal of efficiently revealing object-identifying information. In Experiments 2 and 3, the end goal of obtaining object-identifying information was removed, but the stimulus-response associations were preserved. Only object views associated with actions learned in the context of obtaining identifying information caused response interference and benefits in a subsequent test phase where the object was irrelevant. These results demonstrate the existence of informational affordances: perception-action sequences acquired with the goal of information extraction that are automatically primed during later exposure to the object. Perceptual priming of actions for efficient information extraction is an important component of expert performance and its use of action systems to optimally deal with the world.     

A “labial” feature analyzer in speech perception

A selective adaptation experiment was conducted to determine the ability of various adapting stimuli to alter the perception of a series of 13 synthetic speech syllables. The synthetic test syllables, which varied acoustically in the starting frequency and direction of second- and third-formant transitions, included stop consonant distinctions ofplace of articulation for the syllable types [bae], [dae], and [gae]. A systematic adaptation effect was produced in the locus of the bae-bae phonetic boundary for these stimuli after repetitive listening to each of the following adapting syllables: [bae], [p^hae], [mae], and [vae], indicating that perception ofplace distinctions among the stop consonants can be altered even by repetitive listening to certain speech sounds not belonging to the stop-consonant class.     

“Perceptual centers” in speech production and perception

Morton, Marcus, and Frankish (1976) report that listeners hear acoustically isochronous digit sequences as anisochronous. Moreover, given a chance to adjust intervals in the sequences until they are perceptually isochronous, the listeners introduce systematic deviations from isochrony. The present series of studies investigates these phenomena further. They indicate that when asked toproduce isochronous sequences, talkers generate precisely the acoustic anisochronies that listeners require in order tohear a sequence as isochronous. The acoustic anisochronies that talkers produce are expected if talkers initiate the articulation of successive items in the sequence at temporally equidistant intervals. Items whose initial consonants differ in respect to manner class will have acoustic consequences (other than silence) at different lags with respect to their articulatory onsets thereby generating the observed acoustic anisochronies. The findings suggest that listeners judge isochrony based on acoustic information aboutarticulatory timing rather than on some articulation-free acoustic basis.     

Auditory event perception: The source—perception loop for posture in human gait

There is a small but growing literature on the perception of natural acoustic events, but few attempts have been made to investigate complex sounds not systematically controlled within a laboratory setting. The present study investigates listeners’ ability to make judgments about the posture (upright—stooped) of the walker who generated acoustic stimuli contrasted on each trial. We use a comprehensive three-stage approach to event perception, in which we develop a solid understanding of the source event and its sound properties, as well as the relationships between these two event stages. Developing this understanding helps both to identify the limitations of common statistical procedures and to develop effective new procedures for investigating not only the two information stages above, but also the decision strategies employed by listeners in making source judgments from sound. The result is a comprehensive, ultimately logical, but not necessarily expected picture of both the source—sound—perception loop and the utility of alternative research tools.     

What is “marked” in visual marking? evidence for effects of configuration in preview search

Visual search for a conjunction target is facilitated when distractor sets are segmented over time: the preview benefit. Watson and Humphreys (1997) suggested that this benefit involved inhibition of old items (visual marking, VM). We investigated whether the preview benefit is sensitive to the configuration of the old distractors. Old distractors changed their location prior to the occurrence of the new items, while also either changing or maintaining their configuration. Configuration changes disrupted search. The results are consistent with object-based VM, which is sensitive to the configuration of old stimuli.     

An apology for the “New Atheism”

In recent years, a series of bestselling atheist manifestos by Sam Harris, Richard Dawkins, and Christopher Hitchens has thrust the topic of the rationality of religion into the public discourse. Christian moderates of an intellectual bent and even some agnostics and atheists have taken umbrage and lashed back. In this paper I defend the New Atheists against three common charges: that their critiques of religion commit basic logical fallacies (such as straw man, false dichotomy, or hasty generalization), that their own atheism is just as “faith-based” as the religious beliefs they criticize, and that their expressed disrespect for religious belief is immoral.     

The role of “chirp” identification in duplex perception

Duplex perception occurs when the phonetically distinguishing transitions of a syllable are presented to one ear and the rest of the syllable (the “base”) is simultaneously presented to the other ear. Subjects report hearing both a nonspeech “chirp” and a speech syllable correctly cued by the transitions. In two experiments, we compared phonetic identification of intact syllables, duplex percepts, isolated transitions, and bases. In both experiments, subjects were able to identify the phonetic information encoded into isolated transitions in the absence of an appropriate syllabic context. Also, there was no significant difference in phonetic identification of isolated transitions and duplex percepts. Finally, in the second experiment, the category boundaries from identification of isolated transitions and duplex percepts were not significantly different from each other. However, both boundaries were statistically different from the category boundary for intact syllables. Taken together, these results suggest that listeners do not need to perceptually integrate F2 transitions or F2 and F3 transition pairs with the base in duplex perception. Rather, it appears that listeners identify the chirps as speech without reference to the base.     

Holistic processing in mother’s face perception for infants

In this study, we created composite faces using mothers’ faces to examine holistic face processing in infants aged 5–8 months. The composite-face effect occurred only in infants aged 7–8 months, suggesting that infants older than 7 months are able to process familiar faces holistically.     

Hitting ability and perception of object’s size: evidence for a negative relation

We examined the relation between motor performance and perception of object’s size in near space. The general task was to repeatedly hit a target by means of pointing movements and to estimate target’s size. In contrast to the results of previous studies, Experiment 1 and Experiment 2 revealed a negative relation between action ability and perceived target size: Participants who hit the target relatively often and whose motor variability was relatively low judged targets to be smaller than did participants whose motor performance was relatively poor. In Experiment 3, the size judgments were made in the presence of the target before, as well as after, pointing movements. The target was judged as smaller when it was easy, rather than difficult, to hit before as well as after the movement. Altogether, these results indicate that under certain conditions, an increased action ability reduces the apparent size of the actions’ target objects.     

An “outside-in” processing strategy in the perception of form

The discriminability of line segments in a number of different geometric forms was examined. The procedure used was to have one of the lines within a given form drawn thinner than the other lines. The location of the thin line varied randomly within the form, and subjects were required to detect its location. Three observations were made. First, outer line elements were discriminated more accurately than inner line elements. Second, the outer line advantage appeared to reflect an attentional strategy: By presenting inner and outer lines independently, and informing subjects in advance as to whether target lines would be in the inner or outer area of the form, the outer line advantage could be eliminated. Third, consonant with a global attentional strategy, and in opposition to any retinally tied, peripheral-to-central scanning process, an outer-line advantage was evident regardless of whether the fixation point was positioned within or outside the forms, or whether outer lines were more peripheral than inner lines.     

The influence of verbal labeling on the perception of odors: evidence for olfactory illusions?

Using the definition that an illusion is observed when a stimulus is invariant but context alters its perception, we examined whether verbal context could produce olfactory illusions. To test this effect, we chose five odors with minimally fixed sources and that could be interpreted with various hedonic connotations. The odors were violet leaf, patchouli, pine oil, menthol, and a 1:1 mixture of isovaleric and butyric acids. Subjects individually sniffed each odor at two different sessions separated by one week. At each session an odor was given a different verbal label (either positive or negative) and subjects rated the odors on several hedonic scales and provided perceptual and interpretative responses to them. Results showed that the perception of an odor could be significantly influenced by the label provided for it. We propose that the cases where verbal labels inverted odor perception are the first empirical demonstrations of olfactory illusions.     

“Proactive” in many ways: Developmental evidence for a dynamic pluralistic approach to prediction

The anticipation of the forthcoming behaviour of social interaction partners is a useful ability supporting interaction and communication between social partners. Associations and prediction based on the production system (in line with views that listeners use the production system covertly to anticipate what the other person might be likely to say) are two potential factors, which have been proposed to be involved in anticipatory language processing. We examined the influence of both factors on the degree to which listeners predict upcoming linguistic input. Are listeners more likely to predict book as an appropriate continuation of the sentence “The boy reads a”, based on the strength of the association between the words read and book (strong association) and read and letter (weak association)? Do more proficient producers predict more? What is the interplay of these two influences on prediction? The results suggest that associations influence language-mediated anticipatory eye gaze in two-year-olds and adults only when two thematically appropriate target objects compete for overt attention but not when these objects are presented separately. Furthermore, children's prediction abilities are strongly related to their language production skills when appropriate target objects are presented separately but not when presented together. Both influences on prediction in language processing thus appear to be context dependent. We conclude that multiple factors simultaneously influence listeners’ anticipation of upcoming linguistic input and that only such a dynamic approach to prediction can capture listeners’ prowess at predictive language processing.     

The role of closure in defining the “objects” of object-based attention

Many recent studies have concluded that the underlying units of visual attention are often discrete objects whose boundaries constrain the allocation of attention. However, relatively few studies have explored the particular stimulus cues that determine what counts as an “object” of attention. We explore this issue in the context of the two-rectangles stimuli previously used by many investigators. We first show, using both spatial-cuing and divided-attention paradigms, that same-object advantages occur even when the ends of the two rectangles are not drawn. This is consistent with previous reports that have emphasized the importance of individual contours in guiding attention, and our study shows that such effects can occur in displays that also contain grouping cues. In our divided-attention experiment, however, this contour-driven same-object advantage was significantly weaker than that obtained with the standard stimulus, with the added cue of closure—demonstrating that contour-based processes are not the whole story. These results confirm and extend the observation that same-object advantages can be observed even without full-fledged objects. At the same time, however, these studies show that boundary closure—one of the most important cues to objecthood per se—can directly influence attention. We conclude that object-based attention is not an all-or-nothing phenomenon; object-based effects can be independently strengthened or weakened by multiple cues to objecthood.     

The preschool child's perception of adult approval in “nondirective” statements

Twenty children of nursery school age participated in a study of adult approval/ disapproval as conveyed by nondirective statements relating to play aggression. Though all sentences were tape recorded in a neutral voice, 10 of 15 conveyed disapproval in a significant proportion of judgments. All statements explicitly mentioning aggression were judged disapproving. It was concluded that nondirective play therapists must convey acceptance through other modes in order to avoid suppressing aggressive play.     

A “word length effect”for sign language: Further evidence for the role of language in structuring working memory

We report a sign length effect in deaf users of American Sign Language that is analogous to the word length effect for speech. Lists containing long signs (signs that traverse relatively long distances) produced poorer memory performance than did lists of short signs (signs that do not change in location). Further, this length effect was eliminated by articulatory suppression (repetitive motion of the hands), and articulatory suppression produced an overall drop in performance. The pattern of results, together with previous findings (Wilson & Emmorey, 1997), provides evidence for a working memory system for sign language that consists of a phonological storage buffer and an articulatory rehearsal mechanism. This indicates a close equivalence of structure between working memory for sign language and working memory for speech. The implications of this equivalence are discussed.     

Distinguishing “slit” and “split”—an invariant timing cue in speech perception

The effect of speech rate on the distinction between “slit” and “split” was investigated. This distinction may be cued solely by a silent interval (SI) of sufficient duration between the [s] and the [1], and the boundary SI, at which “slit” and “plit” are perceived with equal probability, determined. In this experiment, although subjects showed good identification of the stimulus categories within the range of silent intervals used, no shift in the boundary SI was found for a twofold increase in speech rate. This finding is contrasted with most recent experiments which demonstrate “compensation” for changes in speaker characteristics, such as speech rate. Implications for models of speech perception are discussed.