Human auditory-evoked response: Specific effects of signal strength and performance criterion

Computer-averaged auditory-evoked responses were recorded from the scalp of seven human Sa in order to study the effects of both low-signal levels and different performance criteria upon specific components of the waveform. Noise bursts of ?2, 0. +2. or +6 dB seDl8tion level (SL) were presented contingent upon the S’s correct bisection of a temporal interval as the degree of accuracy required from him was systematically varied. Analyses of variance indicated that a positive peak in the waveform at a latency of approximately 300 msec increased in amplitude as the stringency of the performance criterion increased but showed no change as signal strength varied. The negative peak at approximately 125 msec latency increased with increasing signal strength but remained constant as the stringency of the performance criterion was varied.     

The amount seen in brief exposures

The experiments reported are a series of attempts to test the consequences of assuming that a subject exposed to briefly presented tachistoscopic information does not have access to a visual image. The partial report procedure is examined under several conditions with the letter row cues immediately following stimulus exposure, and at different levels of cue delay.

The results of eye movement monitoring, and of instructing subjects where to look, agree with the guessing data of a previous experiment in showing a sharp decline in the number of letters correctly reported when the subject is looking at the wrong row, in conformity with the anticipative selection hypothesis. The result of varying the subject's uncertainty about what is to be reported is to vary the slope of the delay curve; with the implication that inefficient strategies of rehearsal, rather than visual image decay, are responsible for the reported delay effects.     

Audio analgesia: Lack of a cross-masking effect on taste

The effects of intense acoustic stimulation on the sense of taste were examined in two experiments. In the first, a yes-no psychophysical method was used to obtain psychometric functions for the discriminability of weak solutions of NaCl or sucrose from distilled water. The functions for NaCl were about 10 times steeper than those for sucrose. In the second experiment, suprathreshold concentrations of these substances were used in conjunction with a magnitude-estimation technique. With neither technique were there any systematic differences in the data taken with and without audio analgesia.     

The effects of preexposure to a learning apparatus

ICR mice were given exposure to a one-way shuttle apparatus until locomotor activity had been habituated. When compared with nonexposed animals, the exposed animals displayed superior shuttle avoidance learning. Animals exposed to both the apparatus and the CS did not differ from the nonexposed group. It was concluded that preexposure to the learning apparatus facilitated acquisition, while preexposure to the apparatus in the presence of the CS did not. The relationship between this effect and habituation was considered.     

The partial punishment effect following minimal acquisition training: Sodium amobarbital and the stimulus properties of early punished trials

In a runway investigation, six groups of rats received limited runway training such that partial punishment, partial reinforcement, or continuous reinforcement was accompanied by sodium amobarbital or saline. Following an interpolated phase of continuous reinforcement without injections, all groups were given punished extinction. The entire experiment was conducted under widely spaced conditions (ITI = 24 hr). It was found that partial punishment increased resistance to punished extinction relative to partially and continuously reinforced controls when acquisition was given under saline. When partial punishment training was accompanied by amobarbital this effect was eliminated. The drug was observed to have no effect on the punished extinction performance of the partial reinforcement and continuous groups, respectively. Moreover, the partial reinforcement effect (PRE) did not generalize to punished extinction. These data provide information concerning the difference between the stimuli associated with the early trials of punishment and nonreward and indicate that the former but not the latter contain emotional elements.     

Reading and visual search

Four experiments were conducted comparing the ways in which reading and search are affected by manipulations of word shape and word boundary. Word shape was manipulated by variations in type (normal, capitals, and alternating upper- and lowercase), while word boundary was manipulated by variations in spacing (normal, filled, and absent). The variations were combined factorially for nine space-type combinations. Experiments I and II were basic studies examining the effects of the manipulations on reading and on search, respectively. Search was found to be 2 to 2.5 times faster than reading. Reading and search both slowed to one-third of the normal speeds when spaces were removed and type altered. A significant interaction of Type by Space was found for reading but not for search. Experiments III and IV examined contextual and typographical effects on high-speed visual search through paragraphs. Form-class expectancy and target word predictability, respectively, were manipulated. In both experiments, subjects found the expected predictable words faster than the unexpected unpredictable words. The data were interpreted as providing support for the peripheral and cognitive search guidance processes hypothesized to be active in reading.     

Temporal discrimination of recycled tonal sequences: Pattern matching and naming of order by untrained listeners

Sets of recycled sequences of four successive tones were presented in all six possible orders to untrained listeners. For pitches within the musical range, recognition (as measured by matching of any unknown order with an array of permuted orders of the same tones) could be accomplished as readily for tonal durations and frequency separations outside the limits employed for melodic construction as inside these limits. Identifying or naming of relative pitches of successive tones was considerably more difficult than matching for these tonal sequences, and appeared to follow different rules based upon duration and upon frequency separation. Use of frequencies above the pitch limits for music (4,500 Hz and above) resulted in poor performance both for matching and naming of order. Introduction of short silent intervals between items was without effect for both tasks. Naming of order and pattern recognition appear to reflect different basic processes, in agreement with earlier formulations based on experiments with phonemic sequences of speech and sequences of unrelated sounds (hisses, tones, buzzes). Special characteristics of tonal sequences are discussed, and some speculations concerning music are offered.     

APPLICATIONS OF SELF-CONTROL PROCEDURES BY CHILDREN: A REVIEW

Self-control procedures as used by children to affect their own behavior were reviewed. Particular emphasis was placed on self-instruction, self-determined criteria, self-assessment, and self-reinforcement. Self-punishment, comprehensive programs, and innovative self-control procedures (distraction and restatement of contingencies) were also evaluated. Basic effectiveness, comparisons with similar externally imposed interventions, maintenance, and the augmental value of the procedures were assessed. Important problems for future research were identified.     

Counterconditioning and exposure-only in the treatment of specific (conditioned suppression) and generalized fear in rats

In Experiment 1 the conditioned suppression technique was used to condition specific fear, suppression of operent lever pressing for food to a discrete CS. The efficacy of four treatment conditions on fear reduction was evaluated. Counterconditioning in which exposure to the CS was contiguously paired with food was significantly less effective than noncontiguous CS exposure and food. An exposure-only effect was indicated by the superiority of all three treatments involving CS exposure (the above two plus a typical conditioned suppression extinction procedure) to treatment consisting of food only. The reverse counterconditioning effect and the exposure effect are consistent with current views that emphasize the centrality of aversive stimulus exposure in fear reduction. Experiment 2 investigated elimination of generalized fear produced by unsignalled, inescapable shocks in the lever-pressing apparatus. Two treatments (counterconditioning and exposure-only) were equally effective and they were superior to no exposure control treatment. The results of the two experiments reinforce recent attempts toward a reevaluation of the role of anxiety-competing responses in elimination of fear.