A simple,inexpensive stimulus waveform generator

A simple circuit for a sine wave generator is described. The total cost for construction is approximately $30.00. At present, the unit is used to generate a sinusoidally modulated light stimulus for steady state visual evoked response experiments. Modifications of the circuit for other applications are discussed.     

An inexpensive digital millisecond timer and event counter

A simple circuit for a digital millisecond timer and event counter is described. The total cost of the unit including all components, a power supply, and an enclosure is less than $30. Daily use in simple reaction time experiments has demonstrated the reliability of the design.     

Use of on-line computers in experimental psychology: Hardware considerations

A series of modules provide students with the basic skills to set up and use a computer to run psychological experiments. The modules include basic knowledge of AC/DC power supplies, relay switching, analog/digital conversion, integrated circuit board design and soldering, and elementary programming (FORTH and BASIC). These skills are then utilized to build an interface board and to design and run actual on-line experiments. The hardware orientation is combined with computer skills and experimental methodology to allow students to experience all stages of modem psychological experimentation.     

Concurrent measurement of heart rate and instrumental avoidance behavior in the Rhesus monkey

A graphical method has been developed for the concurrent recording of heart beats and lever responses during behavioral experiments. The EKG signal fed into any DC amplifier goes to a fixed level trigger circuit and relay driver with its own power supply. The signal from this drives any standard cumulative recorder. Lever response rates are recorded concurrently on an additional cumulative recorder using the same paper speed.     

Chunking in recall of symbolic drawings

Three experiments explored memory for symbolic circuit drawings using skilled electronics technicians and novice subjects. In the first experiment a skilled technician reconstructed circuit diagrams from memory. Recall showed marked “chunking”, or grouping, by functional units similar to Chess Masters’ recall of chess positions. In the second experiment skilled technicians were able to recall more than were novice subjects following a brief exposure of the drawings. This advantage did not hold for randomly arranged symbols. In the third experiment the size of chunks retrieved systematically increased with additional study time. Supplementary analyses suggested that the chunking by skilled subjects was not an artifact of spatial proximity and chunk statistics, and that severe constraints are placed on any explanation of the data based on guessing. It is proposed that skilled subjects identify the conceptual category for an entire drawing, and retrieve elements using a generate-and-test process.     

A self-contained,regulated, burst-firing constant-current ac shock generator

A line- and load-regulated constant-current ac shock generator has been designed for animal behavior experiments. The self-contained unit has four operating modes, amplitude adjustment, and a leakage current detection circuit. A unique feature of this generator is that the good load regulation achieved by using a high-voltage source is preserved without such problems as arcing and high current density effects. Circuit schematics, along with a discussion of selected circuits, are included. Experimental data are presented to demonstrate the utility of the device.     

An integrated circuit for stepwise or continuous microdrive advancement

A circuit for inexpensive automation of a hydraulic microdrive is described. The circuit uses two integrated timing circuits with output periods defined by resistance-capacitance circuits. The output of this circuit operates a relay that controls a small electric motor that runs the microdrive. This system can operate in either a continuous mode for long-term infusion of solutions or in a stepwise fashion for lowering electrodes. When attached to an appropriate microdrive, the circuit can be employed in experiments in which brain-behavior relationships are investigated within anatomical, pharmacological, or electrophysiological paradigms.     

Individual Differences in Reward-Based Learning Predict Fluid Reasoning Abilities

The ability to reason and problem-solve in novel situations, as measured by the Raven's Advanced Progressive Matrices (RAPM), is highly predictive of both cognitive task performance and real-world outcomes. Here we provide evidence that RAPM performance depends on the ability to reallocate attention in response to self-generated feedback about progress. We propose that such an ability is underpinned by the basal ganglia nuclei, which are critically tied to both reward processing and cognitive control. This hypothesis was implemented in a neurocomputational model of the RAPM task, which was used to derive novel predictions at the behavioral and neural levels. These predictions were then verified in one neuroimaging and two behavioral experiments. Furthermore, an effective connectivity analysis of the neuroimaging data confirmed a role for the basal ganglia in modulating attention. Taken together, these results suggest that individual differences in a neural circuit related to reward processing underpin human fluid reasoning abilities.     

Apparatus noiseless electronic switch and timer

In psychoacoustic testing and experimentation the avoidance of extraneous stimuli is most important, but the elimination of such cues is often difficult. A circuit is described which enables sound stimuli to be switched on and off in a manner which produces no unwanted transient signals. The circuit may be adapted to function as a noiseless changeover switch.     

An electronic stimulus randomizer

A circuit is described which enables two stimuli to be presented in random sequence with either equal or different probabilities. The choice of stimuli is determined by sampling the condition of a two-state circuit. Experimental tests of randomness have been satisfactory.     

Macromolecular synthesis, distributed synaptic plasticity, and fear conditioning

Recent work from a number of laboratories has provided new and important insights about how gene expression is altered by experience and how these molecular changes may provide a substrate for the long-term storage of new memories. Here, we review a series of recent studies using aversive Pavlovian conditioning in rats as a well characterized model system in which experience-dependent alterations in gene expression can be manipulated and quantified within a specific neural circuit. We highlight some of the issues involved in using broad-spectrum inhibitors of mRNA and protein synthesis to study cellular changes underlying the formation and long-term stability of memory and discuss the idea that these changes occur over widespread, behaviorally-defined, networks of cells. We also discuss the idea that the maintenance of memory and its susceptibly to disruption after retrieval may relate to local protein synthesis in dendrites. Finally, a series of recent experiments from our laboratory studying the role of a specific signaling pathway (mTOR) which regulates translational processes and memory formation in the amygdala and hippocampus during fear conditioning are reviewed.     

CCTV on trial: Matching video images with the defendant in the dock

The experiments reported in this paper investigated simultaneous identity matching of unfamiliar people physically present in person with moving video images typical of that captured by closed circuit television (CCTV). This simulates the decision faced by a jury in court when the identity of somebody caught on CCTV is disputed. Namely, ‘is the defendant in the dock the person depicted in video’? In Experiment 1, the videos depicted medium‐range views of a number of actor ‘culprits’. Experiment 2 used similar quality images taken a year previously, some of which showed the culprits in disguise. Experiment 3 utilised high‐quality close‐up video images. It was consistently found that in both culprit‐present and culprit‐absent videos and in optimal conditions, matching the identity of a person in video can be highly susceptible to error. Copyright © 2008 John Wiley & Sons, Ltd.     

The propensity to recall another's completed and uncompleted tasks as a consequence of varying social relationships

Two laboratory experiments are reported. Each investigates the bias that social relationships exert on a subject's propensity to recall another's completed and uncompleted tasks. Using closed circuit television, subjects in both experiments observed a bogus other working on a set of puzzles. The person working completed only one-half of the puzzles. In three of the six experimental conditions in both experiments, subjects believed that the remaining puzzles could be completed at a later time. In the first experiment, a subject's relationship to the other was determined by cooperative, competitive, or individualistic economic incentives. In the second, the relationship was determined simply by their similarity or dissimilarity on a bogus personality test. Utilizing a combination of Lewinian assumptions and contemporary theory about memory, we hypothesized that the opportunity to resume work would result in an increased propensity to recall uncompleted tasks in the competitive (or dissimilar) conditions and a decreased propensity to do so in the cooperative (or similar) conditions. Results confirmed this hypothesis. Additional data in both experiments suggest that subjects' relationships with the bogus other altered the accessibility of this information. Theoretical implications of these findings and their relationship to research on prosocial behavior are discussed.     

Functional neuroimaging studies of reading and reading disability (developmental dyslexia)

Converging evidence from a number of neuroimaging studies, including our own, suggest that fluent word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipito-temporal) circuit. This posterior system is functionally disrupted in developmental dyslexia. Reading disabled readers, relative to nonimpaired readers, demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the dorsal circuit predominates at first, and is associated with analytic processing necessary for learning to integrate orthographic features with phonological and lexical-semantic features of printed words. The ventral circuit constitutes a fast, late-developing, word identification system which underlies fluent word recognition in skilled readers.     

Matching the faces of robbers captured on video

Recent research has shown that unfamiliar face matching from both high‐ and low‐quality closed circuit television video images to photographs is highly prone to error, even when viewpoint and expression are matched as closely as possible. The current experiments made use of a filmed, staged reconstruction of a bank raid that was captured on CCTV and on high‐quality broadcasting video. Experiment 1 tested the ability of members of the public to match actors captured on CCTV to photo‐spreads containing similar‐looking distractors. Further experiments, each testing different groups of subjects, investigated matching ability using both high‐quality photographs (Experiment 2) and broadcast‐quality video material (Experiment 3). Experiment 3 also investigated the effect of disguising hairstyle, and varied whether or not the target was present in the photo line‐up. The results of these experiments confirm those of previous work, that matching the identity of unfamiliar faces is highly fallible, even when high‐quality footage is used. Experiments 4 and 5 tested matching ability using two‐alternative forced‐choice and single‐item verification tasks. Performance remained highly error‐prone even with the simplest question asked. The legal implications of the results are discussed. Copyright © 2001 John Wiley & Sons, Ltd.     

Comparison of two exercise protocols on fitness score improvement in poorly conditioned Air Force personnel

A 12-wk. study was conducted to contrast the effects of a longer and more frequent aerobic exercise protocol with a shorter and less frequent circuit strength-training protocol for improving U.S. Air Force physical fitness test scores of subjects who previously failed to achieve a passing point total. 83 men and women of the U.S. Air Force (M age = 32.7 yr.) participated in either the unsupervised standard conditioning program, which recommended approximately 60 min. of aerobic activity 4 to 5 days per week (n=26), or the supervised circuit strength-training program, which required approximately 25 min. of alternating strength and endurance exercises 3 days per week (n=57). Subjects were assessed on a 2400-m (1.5-mile) run, abdominal circumference, push-ups completed in 1 min., and abdominal crunches completed in 1 min. Dependent t tests with Bonferroni adjustment indicated that significant improvements were attained by the circuit strength-training group only on each of the aforementioned measures. Significantly more participants in the circuit strength-training group (26%) achieved a passing point total than in the standard conditioning group (19%) at Wk. 12 (chi1(2) =3.96, p = .05). Implications for enhancing physical fitness in poorly conditioned adults were discussed.     

Durable,efficient, and economical electronic toilet-training devices for use with retarded children

Instrumented behavior observation and modification is typically an expensive process, yet the instruments used are often relatively simple and limited in function. Two sets of electronic devices were constructed to aid in training correct toileting behavior with retarded children. The body-worn alerting unit monitors the residents’ elimination as he moves through his environment. This set consists of a moisture detection circuit enclosed in a durable plastic box which is worn by the resident in either a harness or vest. The body-worn alerting unit is connected, via a cord, to underwear which have pliable wires running along their midline. The other set of units monitors elimination on a commode or toilet, and consists of a signaling box containing the moisture-detection circuit and a circular plate which is hung on the toilet or commode. Over 3 years of field testing have shown the units to be very durable and efficient.     

Visual complexity: a review

The idea of visual complexity, the history of its measurement, and its implications for behavior are reviewed, starting with structuralism and Gestalt psychology at the beginning of the 20th century and ending with visual complexity theory, perceptual learning theory, and neural circuit theory at the beginning of the 21st. Evidence is drawn from research on single forms, form and texture arrays and visual displays. Form complexity and form probability are shown to be linked through their reciprocal relationship in complexity theory, which is in turn shown to be consistent with recent developments in perceptual learning and neural circuit theory. Directions for further research are suggested.     

Integrated circuit measurement of skin conductance

An active skin-conductance measuring device, utilizing integrated circuit operational amplifiers, is described. The transducer offers accurate measurement despite fluctuations in source voltage. The circuit also provides protection in case of accidental short circuit.     

The perceived onset time of self- and other-generated actions

Awareness of actions is partly based on the intentions accompanying them. Thus, the awareness of self- and other-generated actions should differ to the extent that access to own and other's intentions differs. Recent studies have found a brain circuit (the mirror-neuron system) that represents self- and other-generated actions in an integrated fashion. This system does not respond to actions made by nonagents, such as machines. We measured the estimated onset time of actions that subjects either executed themselves or observed being executed by someone else or by a machine. In three experiments, the estimates of the machine actions always differed from those of self- and other-generated actions, whereas the latter two were indistinguishable. Our results are consistent with the view that intentions are attributed to others but not to machines. They also raise the interesting possibility that people attribute intentions to themselves in the same way as they do to others.