Reflex augmentation of a tap-elicited eyeblink: the effects of tone frequency and tap intensity

The amplitude of the human eyeblink elicited by a mild tap between the eyebrows can be increased if a brief tone is presented simultaneously with the tap. In two experiments we examined how this reflex augmentation effect varies with changes in the frequency characteristics of the tone and with changes in the intensity of the tap. We also examined how these effects change in the course of development. For newborn infants and for adults, fixed intensity tones with frequencies of either 1, 2, or 4 kHz produced equivalent amounts of reflex augmentation. Furthermore, while blink amplitude was an increasing function of tap intensity in both populations, the amount of reflex augmentation engendered by a simultaneously presented tone was independent of the intensity of the tap.     

Sex differences in categorization of tactile stimuli

This experiment investigated the effect of sex differences in categorization of tactile stimuli. 9 men and 9 women rated the perceived similarity between pairs of stimuli varying in texture and shape. The magnitudes of sex-related differences, using omega 2 and d, were relatively large and indicated that men had better categorical abilities in processing haptic information.     

Effects of uncertainty on melodic information processing

In three experiments, musically trained and untrained adults listened to three repetitions of a 5-note melodic sequence followed by a final melody with either the same tune as those preceding it or differing in one position by one semitone. In Experiment 1, ability to recognize the final sequence was examined as a function of redundancy at the levels of musical structure in a sequence, contour complexity of transpositions in a trial, and trial context in a session. Within a sequence, tones were related as the major or augmented triad; within a trial, the four sequences began on successively higher notes (simple macrocontour) or on randomly selected notes (complex macrocontour); and within a session, trials were either blocked (all major or all augmented) or mixed (major and augmented randomly selected). Performance was superior for major melodies, for systematic transpositions within a trial (simple macrocontours), for blocked trials, and for musically trained listeners. In Experiment 2, we examined further the effect of macrocontour. Performance on simple macrocontours exceeded that on complex, and excluded the possibility that repetition of the 20-note sequences provided the entire benefit of systematic transposition in Experiment 1. The effect of musical structure (major/augmented) was also replicated. In Experiment 3, listeners provided structure ratings of ascending 20-note sequences from Experiment 2. Ratings on same trials were higher than those on corresponding different trials, in contrast to performance scores for augmented same and different trials in previous experiments. The concept of functional uncertainty was proposed to account for recognition difficulties on augmented same trials. The significant effects of redundancy on all the levels examined confirm the utility of the information-processing framework for the study of melodic sequence perception.     

Spatial learning of visual 'nonsense figures' during experimental ethanol intoxication

The interaction of alcohol and visuospatial learning was evaluated during two experimental sessions. During one session, participants were experimentally intoxicated to obtain a blood alcohol concentration of at least 0.10%. During another session, a nonalcohol placebo was administered. The learning task consisted of a paired-associate paradigm requiring participants to learn the distinct spatial positions of 6 visually presented "nonsense shapes." The visuospatial learning of participants in the placebo condition was generally superior to their learning while intoxicated. However, intercorrelations of performance measures indicated that the relation between alcohol ingestion and performance differences across conditions was not linear.     

Illusory conjunctions inside and outside the focus of attention

This article addresses 2 questions that arise from the finding that visual scenes are first parsed into visual features: (a) the accumulation of location information about objects during their recognition and (b) the mechanism for the binding of the visual features. The first 2 experiments demonstrated that when 2 colored letters were presented outside the initial focus of attention, illusory conjunctions between the color of one letter and the shape of the other were formed only if the letters were less than 1 degree apart. Separation greater than 2 degrees resulted in fewer conjunction errors than expected by chance. Experiments 3 and 4 showed that inside the spread of attention, illusory conjunctions between the 2 letters can occur regardless of the distance between them. In addition, these experiments demonstrated that the span of attention can expand or shrink like a spotlight. The results suggest that features inside the focus of attention are integrated by an expandable focal attention mechanism that conjoins all features that appear inside its focus. Visual features outside the focus of attention may be registered with coarse location information prior to their integration. Alternatively, a quick and imprecise shift of attention to the periphery may lead to illusory conjunctions among adjacent stimuli.     

The effects of interference tasks on recency in the free recall of action events

Summary Lists of verbal instructions were read aloud and each was enacted either by the subject (SPTs) or by the experimenter (EPTs). In Experiment 1 free recall was made of lists of SPTs and EPTs either immediately after presentation, after an empty 20-s delay interval, or after a 20-s delay interval filled with backward counting. The recall of recency items was unaffected by the empty delay interval, but was somewhat reduced by the counting task. In Experiment 2 free recall was made of lists of SPTs and EPTs either immediately after presentation or after a delay that was filled with a single SPT or a single EPT, 20 s in length. The recency effect evident in the immediate-recall condition was virtually wiped out in the delay conditions, irrespective of whether the delay task matched those in the free-recall list or not. These results are discussed in terms of the mnemonic similarity of the two types of action event.     

A network of influences on adolescent drug involvement: neighborhood, school, peer, and family

The interrelationship of neighborhood, school, peer, and family factors and adolescent drug involvement was investigated. Data were collected separately from 518 adolescents and their mothers when the children were between 9 and 18 years of age and again two years later. Neighborhood and school effects were not directly related to adolescent drug use. Neighborhood effects were mediated through the domains of school, peer, and family; school effects were mediated through the peer domain. Family and peer variables had a direct impact on adolescent drug involvement. Risk factors in the adolescents' peer environment can be ameliorated by protective factors in their school environment. Implications for the prevention of drug use are discussed.     

Prenatal, perinatal, and early childhood risk factors and drug involvement in adolescence

This study examined prenatal, perinatal, and early childhood risk factors in relation to the etiology of adolescent involvement in cigarettes, alcohol, marijuana, and other illicit drugs. Over a span of 10 years, data were collected on 638 mainly White mother-child pairs at three points in time: at T1, when the children were 1 to 10 years old; at T2, when they were 9 to 18, and again at T3, when they were 11 to 20. Results showed that the early risks of an unwanted pregnancy and major illness were linked to all of the drug categories except "other illicit drugs." Aspects of mutual attachment in the mother-adolescent relationship were negatively correlated with adolescent drug use. Data on the interrelationship of the domains (i.e., sets of variables) of early risk factors and mother-adolescent relations supported an independent model with respect to cigarette and marijuana involvement, a finding in keeping with results showing that early risk did not significantly affect mother-adolescent relations. However, mother-adolescent protective factors were able to mitigate the impact of early risk factors on adolescent drug involvement.