What does infant perception tell us about theories of perception?

The article begins with a summary of eight well-substantiated conclusions drawn from research on perception in infants that have implications for theories of perception. The following section examines several traditional and modern theories of perception in the light of these conclusions. Finally, some "big issues" that have divided perceptual and cognitive theories are discussed, with the suggestion that research on infants can help reconcile the divided camps. Research on perception in young infants not only flourishes but also presents a challenge to all theories of perception.     

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.     

La perception multisource : une nouvelle approche de la perception de scènes

Research conducted these last years in the field of spatial cognition report empirical findings that are difficult to account for with the traditional visual cognitive model of scene perception. One of the major contributions of these findings has been to invite rethinking scene perception, which would benefit from not being apprehended as centered mainly on the sensory modality considered. On the contrary, the Multisource model of scene perception developed by Intraub et al. offers an alternative theoretical framework considering visual perception as an act of spatial cognition, with spatial information at its core. According to this model, during the initial understanding of a view, the cognitive system would be elaborating a multisource representation, with spatial information constituting an egocentric framework that conveys to the observer a sense of the environment in which he/she is embedded. Scene representation would be organized around an amodal spatial structure combining different sources of information: a bottom-up and external source of information derived from different modalities (e.g., visual, haptic), as well as internal sources of high-level information (i.e., amodal, conceptual and contextual information). These different sources of information would work together to create a simulation of the likely environment, integrating the perceived view into a broader spatial context. Beyond rethinking scene perception, one of the advances of the model is to unify different fields of cognition apprehended until then in isolation. The current paper aims to present this model and some of the results it allows to account for.     

Weber-Fechner behavior in symmetry perception?

The literature contains several allusions to the idea that detection of (mirror) symmetry in the presence of noise follows the Weber-Fechner law. This law usually applies to first-order structures, such as length, weight, or pitch, and it holds that just-noticeable differences in a signal vary in proportion to the strength of the signal. Symmetry, however, is a higher order structure, and this theoretical note starts from the idea that, in noisy symmetry, the regularity-to-noise ratio defines the strength of the signal to be considered. We argue that the detectability of the symmetry follows a psychophysical law that also holds for Glass patterns. This law deviates from the Weber-Fechner law in that it implies that, in the middle range of noise proportions, the sensitivity to variations in the regularity-to-noise ratio is disproportionally higher than in both outer ranges.     

Infants’ perception of musical patterns

This paper examines infants’ ability to perceive various aspects of musical material that are significant in music in general and in Western European music in particular: contour, intervals, exact pitches, diatonic structure, and rhythm. For the most part, infants focus on relational aspects of melodies, synthesizing global representations from local details. They encode the contour of a melody across variations in exact pitches and intervals. They extract information about pitch direction from the smallest musically relevant pitch change in Western music, the semitone. Under certain conditions, infants detect interval changes in the context of transposed sequences, their performance showing enhancement for sequences that conform to Western musical structure. Infants have difficulty retaining exact pitches except for sets of pitches that embody important musical relations. In the temporal domain, they group the elements of auditory sequences on the basis of similarity and they extract the temporal structure of a melody across variations in tempo.     

Is perception discrete or continuous?

How does conscious perception evolve following stimulus presentation? The idea that perception relies on discrete processing epochs has been often considered, but never widely accepted. The alternative, a continuous translation of the external world into explicit perception, although more intuitive and subjectively appealing, cannot satisfactorily account for a large body of psychophysical data. Cortical and thalamocortical oscillations in different frequency bands could provide a neuronal basis for such discrete processes, but are rarely analyzed in this context. This article reconciles the unduly abandoned topic of discrete perception with current views and advances in neuroscience.     

Listeners’ perception of compensatory shortening

English exhibits compensatory shortening, whereby a stressed syllable followed by an unstressed syllable is measured to be shorter than the same stressed syllable alone. This anticipatory shortening is much greater than backward shortening, whereby an unstressed syllable is measured to shorten a following stressed syllable. We speculated that measured shortening reflects not true shortening, but coarticulatory hiding. Hence, we asked whether listeners are sensitive to parts of stressed syllables hidden by following or preceding unstressed syllables. In two experiments (Experiments 1A and 1B), we found the point of subjective equality—that is, the durational difference between a stressed syllable in isolation and one followed by an unstressed syllable—at which listeners cannot tell which is longer. In a third experiment (Experiment 2), we found the point of subjective equality for stressed monosyllables and disyllables with a weak-strong stress pattern. In all of the experiments, the points of subjective equality occurred when stressed syllables in disyllables were measured to be shorter than those in monosyllables, as if the listeners heard the coarticulatory onset or the continuation of a stressed syllable within unstressed syllables.     

Is speech perception modular or interactive?

Norris et al. recently reported experimental evidence that listeners learn phoneme categories in response to lexical feedback. To reconcile these findings with their modular account of speech perception, the authors argue that top-down feedback can be used to support phoneme learning, but not to influence on-line phonemic processing. We suggest that these findings have broader implications than the authors assume, and we discuss potential challenges for integrating a modular theory with top-down learning.     

Is fat perception a thermal effect?

It has been generally assumed that fat is detected by its flavour and by its lubrication of the oral mucosa. A recent study reported a correlation of -.99 between perceived temperature of a product and its fat content. This was significantly higher than correlations of sensory scores for fat flavour, mouthfeel, and afterfeel. This suggested a third detection mechanism; fat may be detected via its effect on the thermal conductivity of the food. In 3 studies, thermal sensitivity in humans was investigated to verify whether oral thermal receptors are sufficiently rapid and accurate to play a role in the perception of fats. The thermal sensitivity of the lips and oral mucosa of the anterior and middle one-third of the tongue were assessed using a Peltier device. Subjects detected 0.5 Hz fluctuations in temperature of 0.08'C on the lower lip, 0.26 degrees C and 1.36 degrees C at the tip and dorsum of the tongue, demonstrating that the lips are sufficiently sensitive to detect small differences in temperature. In two further experiments subjects ingested custards and mayonnaises and then spat out samples after 5, 10, or 20 sec. The temperature of the food and oral mucosa was measured before and after spitting and the rates of heating were calculated. Results suggest assessment of thermal conductivity of food may be used to assess fat content.     

Does gaze perception facilitate overt orienting?

Recent studies have demonstrated the facilitation of responses to peripheral targets cued by the direction of the gaze of a face. However, in the absence of data from an eye tracker, it has been unclear to what extent these effects are due to the participants making small saccades in response to the cue that bring them closer to the congruent location of the cued targets. We used an eye tracker to show that while such cue-driven saccades occur, they do not account for the main cueing effects observed. Additionally, by using the same general paradigm as has previously been used with infants, we suggest that different mechanisms underlie eye gaze cueing effects in infants and adults.     

Naïve realism about unconscious perception

Synthese - Recently, it has been objected that naïve realism is inconsistent with an empirically well-supported claim that mental states of the same fundamental kind as ordinary conscious...     

Does geomagnetic activity effect extrasensory perception?

Data from two kinds of experiments for extrasensory perception were retrospectively analysed for possible relationships with local geomagnetic activity (K-index). ESP scores from 70 Ganzfeld sessions (telepathy-clairvoyance) were found significantly related to high geomagnetic activity of the day prior to the experimental sessions (rs = 0.23, n = 70, P = 0.03, one-tailed) but not to the geomagnetic activity of day of the sessions (rs = 0.03, n = 70, n.s.). The same relationship was found in experiments which consisted mostly of 80 trials clairvoyance computer games per subject (rs = 0.10, n = 269, P = 0.05, one-tailed). The results partially confirm Persinger's earlier findings on three independent samples, i.e. that spontaneous paranormal experience tend to occur on a day of low geomagnetic activity which is preceded by days of high geomagnetic activity.     

Resiliency: A shift in our perception?

Abstract

As our clients often underestimate their own resources and potential, do helpers fall victim to the same phenomena? This article contends that helpers are often overly attentive to client deficits and pathology to the detriment of acknowledging family and other client strengths and resources brought into the therapeutic arena. Much of our professional training results in an overreliance upon pathological lenses which is to the disadvantage of both client and helper. Family therapists must remain vigilant to not becoming seduced into the attractive web of “pathologizing.” Experiences that heightened this awareness for the author are described, followed by illustration of the importance and benefit of therapists becoming more sensitive to the study of human resiliency.     

Infants’ perception of depth from cast shadows

Five- and 7-month-old infants viewed displays in which cast shadows provided information that two objects were at different distances. The 7-month-olds reached preferentially for the apparently nearer object under monocular-viewing conditions but exhibited no reaching preference under binocularviewing conditions. These results indicate that 7-month-old infants perceive depth on the basis of cast shadows. The 5-month-olds did not reach preferentially for the apparently nearer object and, therefore, exhibited no evidence of sensitivity to cast shadows as depth information. In a second experiment, 5-month-olds reached preferentially for the nearer of two objects that were similar to those used in the first experiment but were positioned at different distances from the infant. This result indicated that 5-month-olds have the motor skills and motivation necessary to exhibit a reaching preference under the conditions of this study. The results are consistent with the hypothesis that depth perception based on cast shadows first appears between 5 and 7 months of age.