Effect of “backward” masker fringe on the detectability of pulsed diotic and dichotic tonal signals

The effects of backward masker “fringe” on performance in homophasic and antiphasic masking conditions were investigated. The results of the study indicate that (1) the presence of a backward masker fringe has only a small effect on performance in homophasic masking conditions; (2) under antiphasic masking conditions, the presence of a backward masker fringe improves performance; (3) similar to the results of studies investigating the effects of forward masker fringe, the magnitude of the improvement in performance increases as the duration of the fringe increases; and (4) the magnitude of the improvement caused by the presence of backward masker fringe is considerably smaller than the magnitude of the improvement caused by the forward masker fringe. It appears, then, that the presence of backward masker fringe may provide a baseline or reference phase similar to that which the forward fringe is presumed to provide. The presence of this reference phase after the offset of the signal apparently makes the phase shift associated with the signal-plus-noise waveform more discernible, thus leading to higher detectability. However, for reasons not yet clear, the presence of a baseline or reference phase after the offset of the signal (backward fringe conditions) does not make the signal-plus-noise phase shift as discernible as do either the presence of that same reference phase before the onset of the signal (forward fringe condition) or the presence of that same reference phase both before signal onset and after signal offset (continuous masker condition).     

Differential specialization of the cerebral hemispheres for the perception of sameness and difference

The Johns Hopkins University, Baltimore, Maryland 21218 Pairs of letters were presented 4 deg left or right of fixation, and Ss were asked to indicate as quickly as possible whether the letters in a pair were the same or different. Reaction times for “different” responses were faster when stimuli were in the left visual field than in the right, but reaction times for “same” responses were faster when stimuli were in the right visual field than in the left. These results may indicate that the right hemisphere is better specialized for difference detection, while the left hemisphere is better specialized for sameness detection.     

A primate restraint and handling system for auditory research

A set of devices is described that enables daily handling and restraint of large primates. The animals live in cages and wear a special collar that fits into a modified primate restraining chair. A chain and pole arrangement simplifies the daily chairing procedure. A method of head restraint and earphone mounting is also described.     

Some punishing effects of response-force

The present experiment explored the punishing effect of different response-force requirements by means of a two-operant design analogous to a two-component chain schedule. The first component of the chain required a lever pull through 0.25 in. (0.64 cm) at 1 lb (4.45 N) of force. The second component required a lever pull through an additional 0.75 in. (1.90 cm) with the force varied between sessions from 1 lb to 50 lb (4.45 N to 223 N). Completion of the second component of the chain was reinforced after variable intervals averaging 1 min. The average rate of first-component response decreased as the force requirement for second-component responses was increased. This rate reduction did not appear to be due to increased response duration, “fatigue”, or differing rates of reinforcement. If the force requirement for the second-component response is viewed as a consequence for the first-component response, then the results of the experiment show that a high force requirement is a punisher.     

Reinforcing self-help group activities of welfare recipients

The attendance rates of welfare recipients at self-help group meetings was compared when supplementary reinforcement was given for attending and when it was not. Reinforcers included donated items, such as clothing and household goods, and information about welfare services. It was found that the attendance at meetings averaged three recipients per meeting without reinforcement and 15 recipients per meeting with reinforcement. There was evidence that attendance was associated with participation in other self-help activities. It was concluded that practical forms of reinforcement can be found to maintain the participation of severely disadvantaged populations in self-help groups.