Perception of acoustically presented time series with varied intervals

Data from three experiments on serial perception of temporal intervals in the supra-second domain are reported. Sequences of short acoustic signals (“pips”) separated by periods of silence were presented to the observers. Two types of time series, geometric or alternating, were used, where the modulus 1 + δ of the inter-pip series and the base duration T_b (range from 1.1 to 6 s) were varied as independent parameters. The observers had to judge whether the series were accelerating, decelerating, or uniform (3 paradigm), or to distinguish regular from irregular sequences (2 paradigm). “Intervals of subjective uniformity” (isus) were obtained by fitting Gaussian psychometric functions to individual subjects' responses. Progression towards longer base durations (T_b = 4.4 or 6 s) shifts the isus towards negative δs, i.e., accelerating series. This finding is compatible with the phenomenon of “subjective shortening” of past temporal intervals, which is naturally accounted for by the lossy integration model of internal time representation. The opposite effect observed for short durations (T_b = 1.1 or 1.5 s) remains unexplained by the lossy integration model, and presents a challenge for further research.     

Lingual vibrotactile sensation magnitudes: comparison of suprathreshold responses for three different age ranges

Vibrotactile magnitude scaling was performed on three different age groups of six normal subjects each. The psychophysical method of magnitude production was used for the scaling of vibratory stimuli applied to the anterior dorsal surface of the tongue. The older subjects produced shallower upper-slope functions than the younger subjects and also showed greater response variability. Behavioral, anatomical, and physiological factors are discussed.     

Saturation of red: A prothetic continuum

A battery of procedures was used to scale the saturation of colors produced by mixtures of red and gray papers. By direct magnitude estimation, the apparent saturation was found to grow as the1.7 power of the percentage of red in the mixture. The power law was confirmed by the cross-modality matching of loudness to saturation. The inverse continuum, paleness, was also scaled. Saturation appears to be a prothetic continuum because the category scale is curved and the subjective size of the jnd increases as saturation increases.     

Perception of voice and tone onset time continua in children with dyslexia with and without attention deficit/hyperactivity disorder

Tasks assessing perception of a phonemic contrast based on voice onset time (VOT) and a nonspeech analog of a VOT contrast using tone onset time (TOT) were administered to children (ages 7.5 to 15.9 years) identified as having reading disability (RD; n = 21), attention deficit/hyperactivity disorder (ADHD; n = 22), comorbid RD and ADHD (n = 26), or no impairment (NI; n = 26). Children with RD, whether they had been identified as having ADHD or not, exhibited reduced perceptual skills on both tasks as indicated by shallower slopes on category labeling functions and reduced accuracy even at the endpoints of the series where cues are most salient. Correlations between performance on the VOT task and measures of single word decoding and phonemic awareness were significant only in the groups without ADHD. These findings suggest that (a) children with RD have difficulty in processing speech and nonspeech stimuli containing similar auditory temporal cues, (b) phoneme perception is related to phonemic awareness and decoding skills, and (c) the potential presence of ADHD needs to be taken into account in studies of perception in children with RD.     

Relating magnitudes: the brain's code for proportions

Whereas much is known about how we categorize and reason based on absolute quantity, data exploring ratios of quantities, as in proportions and fractions, are comparatively sparse. Until recently, it remained elusive whether these two representations of number are connected, how proportions are implemented by neurons and how language shapes this code. New data derived with complementary methods and from different model systems now shed light on the mechanisms of magnitude ratio representations. A coding scheme for proportions has emerged that is remarkably reminiscent of the representation of absolute number. These novel findings suggest a sense for ratios that grants the brain automatic access to proportions independently of language and the format of presentation.     

The discriminability of remembered magnitudes

Psychometric functions and the associated indices of discriminative performance (i.e., the point of subjective equality [PSE], just noticeable difference, and Weber fraction) were obtained with the method of constant stimuli using perceptual and remembered line-length standards. Three important results were obtained. First, comparisons with a perceptual or a remembered standard were sensitive to variations of absolute stimulus differences with a common ratio; that is, Weber's law was violated. Second, relative to discriminative performance with the longest and shortest remembered standards, comparisons involving mid-range remembered standards displayed increased variability in the PSE and inflated Weber fractions, characteristic of a reduction in the quality of the memorial representation. Finally, large and negative time-order errors (TOE) were observed for successive line judgments but not for those involving remembered standards. The implications of these findings for research concerned with the relationships between perception and memory, as well as the TOE phenomenon, are discussed.     

The discovery and comparison of symbolic magnitudes

Humans and other primates are able to make relative magnitude comparisons, both with perceptual stimuli and with symbolic inputs that convey magnitude information. Although numerous models of magnitude comparison have been proposed, the basic question of how symbolic magnitudes (e.g., size or intelligence of animals) are derived and represented in memory has received little attention. We argue that symbolic magnitudes often will not correspond directly to elementary features of individual concepts. Rather, magnitudes may be formed in working memory based on computations over more basic features stored in long-term memory. We present a model of how magnitudes can be acquired and compared based on BARTlet, a representationally simpler version of Bayesian Analogy with Relational Transformations (BART; Lu, Chen, & Holyoak, 2012). BARTlet operates on distributions of magnitude variables created by applying dimension-specific weights (learned with the aid of empirical priors derived from pre-categorical comparisons) to more primitive features of objects. The resulting magnitude distributions, formed and maintained in working memory, are sensitive to contextual influences such as the range of stimuli and polarity of the question. By incorporating psychological reference points that control the precision of magnitudes in working memory and applying the tools of signal detection theory, BARTlet is able to account for a wide range of empirical phenomena involving magnitude comparisons, including the symbolic distance effect and the semantic congruity effect. We discuss the role of reference points in cognitive and social decision-making, and implications for the evolution of relational representations.     

Unequal reinforcer magnitudes and relative preference for cooperation in the dyad

College-student subjects, who were paired with a confederate, chose to respond either independently or cooperatively for money reinforcers. The subject's relative preference for cooperation was assessed by a procedure (analogous to the psychophysical method of limits) in which response choice was monitored as reinforcer magnitude for one response mode was systematically varied while the other remained constant. Relative preference for cooperation was assessed when the confederate's payoff for cooperation was greater than the subject's (Experiment I) and when the confederate's payoff for independent responding was less than the subject's (Experiment II). For some subjects, changes in the confederate's reinforcer magnitudes resulted in shifts in relative preference for cooperation, which reduced the earnings differences, even though these preference shifts reduced the subject's absolute earnings. For those subjects for whom within-dyad differences in reinforcer magnitude produced no effect, a changeover button was introduced that allowed the subject to eliminate the payoff difference without reducing her own earnings; some subjects used this changeover button to eliminate earnings differences. Thus, the behavior of subjects varied, in part, as a function of reinforcer magnitudes provided for the confederate.     

Discrimination of two neighboring intra- and intermodal empty time intervals marked by three successive stimuli

We investigated the discrimination of two neighboring intra- or inter-modal empty time intervals marked by three successive stimuli. Each of the three markers was a flash (visual—V) or a sound (auditory—A). The first and last markers were of the same modality, while the second one was either A or V, resulting in four conditions: VVV, VAV, AVA and AAA. Participants judged whether the second interval, whose duration was systematically varied, was shorter or longer than the 500-ms first interval. Compared with VVV and AAA, discrimination was impaired with VAV, but not so much with AVA (in Experiment 1). Whereas VAV and AVA consisted of the same set of single intermodal intervals (VA and AV), discrimination was impaired in the VAV compared to the AVA condition. This difference between VAV and AVA could not be attributed to the participants' strategy to perform the discrimination task, e.g., ignoring the standard interval or replacing the visual stimuli with sounds in their mind (in Experiment 2). These results are discussed in terms of sequential grouping according to sensory similarity.     

A magnitude-estimation response pool for production of lingual vibrotactile magnitudes

The present pilot study was designed to obtain samples of numerical vibrotactile magnitude estimations from two groups of 37 randomly selected subjects (Mage = 22.04 yr.) and to determine if these numbers were statistically equivalent. Analysis showed the numerical responses of the two groups of subjects were statistically equivalent. It was suggested that they might be viewed as a representative sample of magnitude-estimation numbers that could be employed in experimentation on lingual vibrotactile magnitude production.     

Desires,magnitudes, and orectic penetration

Dustin Stokes argues for the existence of orectic penetration, a phenomenon in which a desire-like state penetrates our perceptual experience. His candidate for a case of orectic penetration is the most convincing candidate presented thus far. It is argued here that his candidate and his further arguments for the existence of orectic penetration do not support the claim that orectic penetration takes place. As a result, it is concluded that there are no convincing cases of desire-like states penetrating perceptual experience.