Adaptation to auditory motion in the horizontal plane: Effect of prior exposure to motion on motion detectability

Thresholds for auditory motion detectability were measured in a darkened anechoic chamber while subjects were adapted to horizontally moving sound saurces of various-velocities. All stimuli were 500-Hz lowpass noises presented at a level of 55 dBA. The threshold measure employed was the minimum audible movement angle(MAMA)—that is, the minimum angle a horizontally moving sound must traverse to be just discriminable from a stationary sound. In an adaptive, two-interval forced-choice procedure, trials occurred every 2-5 sec (Experiment 1) or every 10–12 sec (Experiment 2). Intertrial time was “filled” with exposure to the adaptor—a stimulus that repeatedly traversed the subject’s front hemifield at ear level (distance: 1.7 m) at a constant velocity (?150°/secto + 150°/sec)during a run. Average MAMAs in the control condition, in which the adaptor was stationary (0°/sec), were 2.4° (Experiment 1) and 3.0° (Experiment 2). Three out of 4 subjects in each experiment showed significantly elevated MAMAs (by up to 60%), with some adaptors relative to the control condition. However, there were large intersubject differences in the shape of the MAMA versus adaptor velocity functions. This loss of sensitivity to motion that most subjects show after exposure to moving signals is probably one component underlying the auditory motion aftereffect (Grantham, 1989), in which judgmentsof the direction-afmoving sounds are biased in the direction opposite to that of a previously presented adaptor.     

Broken-Backed Naturalism

Willem Drees's stated purpose in Religion, Science and Naturalism is to maintain the continuing importance of religion in human life while being honest to the sciences. His preferred way of doing that is an example of what John Dewey once called "broken-backed naturalism." In contrast, Deweyan humanism accomplishes Drees's purpose in a more thoroughly naturalistic way. It does not bifurcate the world into the domain of the sciences—the natural world—and the domain of religion—the provider of answers to limit questions about the world as a whole, which fall outside the scope of the sciences.     

A decision tree approach to selecting an appropriate observation reliability index

Based on the conceptual framework outlined by Cone (1986) and Suen (1988), a practical decision tree is developed as an aid for the selection of observational reliability indices.     

Discrimination by olfactory cues in albino rats reflecting familiarity and relatedness among conspecifics

The present investigation sought to determine whether albino rat pups could discriminate among familiar siblings, nonfamiliar siblings, familiar nonsiblings (foster littermates), and nonfamiliar nonsiblings (unrelated agemates) using only olfactory cues. Pairing all possible combinations of familiarity and kinship variables (six), the odors were presented in paired combinations to each of twelve experimental subjects. Results from dependent t tests indicated that the albino rat pups could discriminate between the following pairs of odors using only the olfactory sensory modality: (a) familial siblings and nonfamiliar siblings, (t = 3.41, p = .006); (b) familiar siblings and nonfamiliar nonsiblings, (t = 9.62, p = .001); (c) nonfamiliar siblings and nonfamiliar nonsiblings, (t = 3.15, p = .009); and (d) familiar nonsiblings and nonfamiliar nonsiblings (t = 2.58, p = .026).