Optimal spectral templates for triggered feedback experiments

In the field of songbird neuroscience, researchers have used playback of aversive noise bursts to drive changes in song behavior for specific syllables within a bird’s song. Typically, a short (~5-10 msec) slice of the syllable is selected for targeting and the average spectrum of the slice is used as a template. Sounds that are sufficiently close to the template are considered a match. If other syllables have portions that are spectrally similar to the target, false positive errors will weaken the operant contingency. We present a gradient descent method for template optimization that increases the separation in distance between target and distractors slices, greatly improving targeting accuracy. Applied to songs from five adult Bengalese finches, the fractional reduction in errors for sub-syllabic slices was 51.54±22.92%. At the level of song syllables, we use an error metric that controls for the vastly greater number of distractors vs. target syllables. Setting 5% average error (misses + false positives) as a minimal performance criterion, the number of targetable syllables increased from 3 to 16 out of 61 syllables. At 10% error, targetable syllables increased from 11 to 26. By using simple and robust linear discriminant methods, the algorithm reaches near asymptotic performance when using 10 songs as training data, and the error increases by <2.3% on average when using only a single song for training. Targeting is temporally precise, with average jitter of 3.33 msec for the 16 accurately targeted syllables. Because the algorithm is concerned only with the problem of template selection, it can be used as a simple and robust front end for existing hardware and software implementations for triggered feedback.

Rule Emission: A Possible Variable for Improved Therapeutic Practice

It has been suggested that achieving greater effectiveness in psychotherapeutic treatment requires analyzingwhattherapists actuallydoand say,howthey do this andwhenit is done. Based on this approach, in this study we focused on the rules emitted by therapists, since providing rules is thought to be of fundamental importance in promoting effective and efficient clinical change. Specifically, we sought to determine whether the experience level of therapists and the brevity of therapy would be related to patterns of therapist rule emission as categorized by the Category System of Rules emitted by the Therapist (SISC-RULES-T) (Vargas-de la Cruz & Pardo-Cebrián, 2014). Greater therapist experience and shorter therapy duration were found to be reliably predictive of more rule emissions across most rule categories (Zvalues between:Z= –3.68 andZ= –2.05;pvalues:p< .05 andp< .001). These variables were also predictive of more emissions of rules that specified all three operant contingency elements (situation, behavior, and consequence) rather than fewer elements (Z= –2.59,p< .05;Z= –2.26,p< .05). In the expert therapists and therapist with shorter cases, there was a nonsignificant tendency for the emission of general and conceptual rules to increase over sessions whereas emissions of concrete and particular rules tended to decrease; the explicitness of the three contingency elements also tended to decrease as treatment progressed. These findings may help to identify verbal characteristics of therapists that could lead to improved therapeutic practice.

The Instrumentally Derived Incentive-Motivational Function

Though differential reinforcement, a discriminative stimulus (SD) acquires two properties. The operant contingency is responsible for the SDs response-discriminative property. However, as stimulus control develops an SD also acquires incentive-motivational properties through its association with reinforcement changes. A systematic series of experiments are described that breaks the usual co-variation of response and reinforcement rates in most discriminative operant situations. In three groups, SDs (a tone and a light) occasioned steady moderate lever pressing in rats that ceased when neither SD was present. Probably of reinforcement in these SDs, relative to when both were off, was systematically manipulated to make them incentive-motivationally excitatory, neutral or inhibitory. In each SD, for the “excitatory” group reinforcement (food) probability increased from 0 to 100%, for the “neutral” group it was unchanged and for the “inhibitory” group it decreased from 100 to 0%. Although behaviorally indistinguishable in training, a stimulus-compounding assay revealed that tone-plus-light tripled response rate in the incentive-excitatory group, doubled rate in the incentive-neutral group and didn’t increase rate in the incentive-inhibitory group – producing the instrumentally derived incentive-motivational function for the first time. This is discussed context of two-process learning theory, a functional analysis of transfer-of-control research plus how the response-discriminative and incentive-motivational properties acquired by an SD contribute to the stimulus control of behavior.