Merging the senses into a robust percept

To perceive the external environment our brain uses multiple sources of sensory information derived from several different modalities, including vision, touch and audition. All these different sources of information have to be efficiently merged to form a coherent and robust percept. Here we highlight some of the mechanisms that underlie this merging of the senses in the brain. We show that, depending on the type of information, different combination and integration strategies are used and that prior knowledge is often required for interpreting the sensory signals.     

Reorganization in coping behavior at 1 1/2 years: dynamic systems and normative change

By the age of 1 year toddlers demonstrate distinct coping habits for dealing with frustration. However, these habits may be open to change and reorganization at subsequent developmental junctures. We investigated change in coping habits at 18-20 months, a normative age for major advances in social cognition, focusing on the dynamic systems principles of fluctuation and novelty at transitions. Specifically, we asked whether month-to-month fluctuation, novel behavioral habits and real-time variability increased at the age of a normative transition, despite individual differences in the content of behavior. Infants were given frustrating toys while their mothers sat nearby without helping, on monthly visits at 14-25 months (before, during and after the hypothesized transition). State space grids representing patterns of behavioral durations were constructed for each episode and compared over age. As predicted, month-to-month fluctuation in grid patterns increased temporarily between 17 and 20 months, partly independently of a concurrent peak in distress, and new behavioral habits replaced old ones at the same age. Coping habits changed differently for high-and low-distressed toddlers. However, changes in real-time variability did not generally meet our expectations.     

The size of the cross-lingual masked phonological priming effect does not depend on second language proficiency

Using a masked phonological priming paradigm, Brysbaert, Van Dyck, and Van de Poel (1999) showed that Dutch-French bilinguals perform better at identifying tachistoscopically presented L2 words (e.g., oui [yes]) when those words are primed by L1 words or nonwords that are homophonic to the L2 target word according to the L1 grapheme-phoneme conversion rules (e.g., wie [who]). They noted that this priming effect was smaller for balanced bilinguals than for less proficient bilinguals, although the interaction failed to reach significance. Findings of Gollan, Forster, and Frost (1997) suggest that this could be attributed to a greater reliance on phonology in L2 reading, caused by a smaller proficiency in this language. However, in this study we show that the Dutch-French cross-lingual phonological priming effect is equally large for perfectly balanced and less proficient bilinguals. Our findings are in line with more recent work of Van Wijnendaele and Brysbaert (2002).     

Electronic monitoring and counseling to improve medication adherence

Electronic caps, pill caps that record the date and time of pill bottle opening provide an objective measure of adherence to prescribed medication. A promising intervention to improve adherence, cue-dose training, involves reviewing patients' pill cap-generated reports concerning their medication-taking and offering individualized recommendations for remembering to take medications at specific times of day. In this preliminary study, 79 patients prescribed the antihyperglycemic medication metformin had adherence assessed during a 4-week baseline period. Adherence, defined as proportion of prescribed doses taken within a predetermined 4-h window, was measured using electronic MEMS caps. Those who had less than 80% baseline adherence (n = 33) were randomly assigned to either receive 4 months of cue-dose training (n = 16) or to a control group (n = 17). Cue-dose training was associated with significantly better adherence to metformin (mean improvement of 15%). The effects of cue-dose training on adherence to other antihyperglycemic medication did not reach statistical significance. Glycosylated hemoglobin (a measure of blood sugar control) did not differ between groups. Data from nine patients who reviewed pill cap-generated data with their primary care providers suggested that both patients and providers found the discussion moderately helpful and not at all uncomfortable.     

Are consonant intervals music to their ears? Spontaneous acoustic preferences in a nonhuman primate

Humans find some sounds more pleasing than others; such preferences may underlie our enjoyment of music. To gain insight into the evolutionary origins of these preferences, we explored whether they are present in other animals. We designed a novel method to measure the spontaneous sound preferences of cotton-top tamarins, a species that has been extensively tested for other perceptual abilities. Animals were placed in a V-shaped maze, and their position within the maze controlled their auditory environment. One sound was played when they were in one branch of the maze, and a different sound for the opposite branch; no food was delivered during testing. We used the proportion of time spent in each branch as a measure of preference. The first two experiments were designed as tests of our method. In Experiment 1, we used loud and soft white noise as stimuli; all animals spent most of their time on the side with soft noise. In Experiment 2, tamarins spent more time on the side playing species-specific feeding chirps than on the side playing species-specific distress calls. Together, these two experiments suggest that the method is effective, providing a spontaneous measure of preference. In Experiment 3, however, subjects showed no preference for consonant over dissonant intervals. Finally, tamarins showed no preference in Experiment 4 for a screeching sound (comparable to fingernails on a blackboard) over amplitude-matched white noise. In contrast, humans showed clear preferences for the consonant intervals of Experiment 3 and the white noise of Experiment 4 using the same stimuli and a similar method. We conclude that tamarins' preferences differ qualitatively from those of humans. The preferences that support our capacity for music may, therefore, be unique among the primates, and could be music-specific adaptations.     

How research in behavioral pharmacology informs behavioral science

Behavioral pharmacology is a maturing science that has made significant contributions to the study of drug effects on behavior, especially in the domain of drug-behavior interactions. Less appreciated is that research in behavioral pharmacology can have, and has had, implications for the experimental analysis of behavior, especially its conceptualizations and theory. In this article, I outline three general strategies in behavioral pharmacology research that have been employed to increase understanding of behavioral processes. Examples are provided of the general characteristics of the strategies and of implications of previous research for behavior theory. Behavior analysis will advance as its theories are challenged.     

The impact of Parkinson's disease on vocal-prosodic communication from the perspective of listeners

An expressive disturbance of speech prosody has long been associated with idiopathic Parkinson's disease (PD), but little is known about the impact of dysprosody on vocal-prosodic communication from the perspective of listeners. Recordings of healthy adults (n=12) and adults with mild to moderate PD (n=21) were elicited in four speech contexts in which prosody serves a primary function in linguistic or emotive communication (phonemic stress, contrastive stress, sentence mode, and emotional prosody). Twenty independent listeners naive to the disease status of individual speakers then judged the intended meanings conveyed by prosody for tokens recorded in each condition. Findings indicated that PD speakers were less successful at communicating stress distinctions, especially words produced with contrastive stress, which were identifiable to listeners. Listeners were also significantly less able to detect intended emotional qualities of Parkinsonian speech, especially for anger and disgust. Emotional expressions that were correctly recognized by listeners were consistently rated as less intense for the PD group. Utterances produced by PD speakers were frequently characterized as sounding sad or devoid of emotion entirely (neutral). Results argue that motor limitations on the vocal apparatus in PD produce serious and early negative repercussions on communication through prosody, which diminish the social-linguistic competence of Parkinsonian adults as judged by listeners.     

Comparing the EthoVision 2.3 system and a new computerized multitracking prototype system to measure the swimming behavior in fry fish

Coming from the framework of unmarked fry tracking, we compared the capacities, advantages, and disadvantages of two recent video tracking systems: EthoVision 2.3 and a new prototype of multitracking. The EthoVision system has proved to be impressive for tracking a fry using the detection by gray scaling. Detection by subtraction has given less accurate results. Our video multitracking system is able to detect and track more than 100 unmarked fish by gray scaling technique. It permits an analysis at the group level as well as at the individual level. The multitracking program is able to attribute a number to each fish and to follow each one for the whole duration of the track. Our system permits the analysis of the movement of each individual, even if the trajectories of two fish cross each other. This is possible thanks to the theoretical estimation of the trajectory of each fish, which can be compared with the real trajectory (analysis with feedback). However, the period of the track is limited for our system (about 1 min), whereas EthoVision is able to track for numerous hours. In spite of these limitations, these two systems allow an almost continuous automatic sampling of the movement behaviors during the track.     

A state space analysis of emotion and flexibility in parent-child interactions

Negative emotion has been shown to reduce flexibility in cognition and behavior. We examined interpersonal flexibility during negative emotional episodes within parent-child interactions. Fifty-five mothers and early-adolescent daughters were observed during a positive discussion, a negative (conflict) discussion, and another positive discussion. Codes of moment-to-moment changes in emotion expression were used to create state space grids from which measures of emotional valence and flexibility were derived. As expected, mean flexibility was lowest during the conflict discussion when negative emotion peaked, suggesting that interpersonal flexibility decreases with increasing negative emotion. Sub-groups identified as low or high in stress were also compared. Dyads with girls reporting more stressful events showed lower flexibility during the first positive discussion. However, dyads expressing more negative emotion during the conflict discussion were also more flexible, suggesting that flexible dyadic styles permit more negative emotion. These individual difference findings are discussed in terms of the suppression versus expression of negative emotions.