The Observer: A software system for collection and analysis of observational data

The Observer is a general-purpose software package for event recording and data analysis in behavioral research. It allows any IBM-type personal computer to serve as an event recorder. In addition, The Observer can generate dedicated event-recording programs for several types of non-IBM-compatible portable and hand-held computers and transfer files between the PC and such computers. The user specifies options through menus. The configuration can be either used directly for event recording on the PC or passed on to a program generator that creates a program to collect data on a hand-held computer. Observational data from either type of computer can be analyzed by the program. Event-recording configurations can be tailored to many different experimental designs. Keys can be designated as events, and modifiers can be used to indicate the limits of an event. The program allows grouping of events in classes and distinction between mutually exclusive versus nonexclusive events and duration events versus frequency events. Timing of events is accurate to 0.1 sec. An on-line electronic notepad permits notes to be made during an observation session. The program also includes on-line error correction. User comments as well as independent variables can be stored together with the observational data. During data analysis, the user can select the level of analysis and the type of output file. The Observer calculates frequency of occurrence and duration for classes of events, individual events, or combinations of events. For analysis of concurrence, one can select the number of nesting levels and the order of nesting. Output can be generated in the form of sorted event sequence files, text report files, and tabular ASCII files. The results can be exported to spreadsheet and statistical programs.     

A hierarchical LSI-11 system for real-time control,interevent time storage,and data analysis

A general-purpose laboratory computer system using two Digital Equipment Corporation LSI-11 s in a master-slave relationship is described. The implementation includes hardware to install an LSI-11 as a slave parallel processor, to provide special-purpose functions such as a real-time clock and a 4K FIFO interprocessor buffer, and to establish a bus that permits the use of inexpensive interfaces to experimental equipment. The slave processor generates a complete log of each input or output event. Data in the form of the time of each event are continuously passed through the FIFO to a foreground task in the main LSI-11, which in turn stores the raw data on a hard disk. A macro library allows the easy development of experimentcontrol programs. A library of FORTRAN routines provides a pointer-based conditional and iterative search facility that can sift out any specifiable event or set of events from the data records for subsequent analysis. This computer system provides the user with an inexpensive facility to run up to 32 simultaneous experiments with complete data logging in foreground while program development, analysis, and word processing are concurrently being done in background.     

A computer-compatible multichannel event counting and digital recording system

An inexpensive multichannel event counting digital recording system has been designed for compatibility with automated data analysis equipment. For as many as 16 channels, events are simultaneously summed over preselected repetitive time intervals and recorded. Each data entry is marked with the time of day and a code identifying each channel’s data. The data is formated to be computer compatible and is logged on inexpensive readily available digital magnetic tape cassettes.     

The KIM-1 microcomputer as an eight-channel data logger

A machine language program and interface hardware to operate the KIM-1 microcomputer as an eight-channel data logger are described. All channels can operate simultaneously, and the data are stored in a specified area of memory. Double precision is used, enabling numbers greater than 255 to be recorded. Data can be collected over sampling intervals of 1 to 255 times 5 sec or 1 to 255 times 10 min. The time base is derived from 50- or 60-Hz mains ac. A method of transferring the data to a PET microcomputer and storing it on eight separate tape or disk files is also given.     

ODAP: a stand-alone program for observational data acquisition

A software program written to collect real-time, observational data is described. The flexible program allows customized behavior codes and observational durations and simultaneously records both timed and counted events. The data are collected by means of single keystrokes, automatically stored to disk with 100th of a second resolution and summarized for each observational session. The program’s database files are dBASE III PLUS compatible and may be browsed, edited, or converted to ASCII files from the program’s main menu. Field testing demonstrated the efficiency and interobserver reliability of the program (for frequency,r=0.81; for durational behaviors,rs=0.89 and 0.96). The software operates on IBM XT/AT/PS 2s and most clones with PC/MS DOS version 2.0 or greater.     

Contiception: A program to study the effects of contingency parameters on judgments of control

Little is known about the heuristics people use in evaluating the degree to which they control events. The DOS-basedContiception program allows users to independently set the extent to which subjects’ actions are necessary and sufficient (the two components of contingency) to cause a change in an animated display. Up to four subject actions (keypresses) can each cause up to four dimensions of the display to change according to independently set contingencies. The task within which subjects judge their control involves interacting with the display in real time. To facilitate modeling of the possible algorithms used by different groups of subjects or under different conditions, the program provides several calculations of contingency magnitude and algebraic rules upon which the literature suggests subjects might base their control judgments. The program also allows sessions (trial sequences) to be saved and provides raw and summarized data output.     

SPLIT: A sound editor for a PDP-8 computer

SPLIT is a program that helps prepare sounds for use in psychological experiments. Analog signals are converted to digital form and stored on a disk in real time. Digital sound files can be viewed on an oscilloscope display and played back for on-line auditory inspection. Interactive commands allow the user to segment and combine sounds with precise temporal control.     

An economical system for collecting and reducing heart-rate data,using someone else’s small computer

Hardware and program are described for a heart-rate data collection and reduction system that uses a small computer at a time removed from the actual data collection. The system is portable and inexpensive; exclusive of the computer, it can cost under $1,500. It uses an ordinary tape recorder to record discrete signals upon each occurrence of a heart beat, and it returns edited second-by-second averages of interheart-beat intervals.     

Representing within-session response rates proportionally and entirely.

In this technical article, methods for collecting and representing response rates maintained by schedules of reinforcement are presented. First, the time in a session that each important event (e.g., responses, reinforcers) occurs is collected and stored by a computer. Another computer program is used, then, to convert each response to a percentage of the total responses in a session and to plot these percentages cumulatively as a function of the time in the session that they occurred. In this manner, response rates may be expressed proportionally (i.e., using the same y-axis scale regardless of absolute response rate) without requiring the arbitrary selection of an interval over which responses are aggregated and expressed relative to the entire-session rate. A property of these records is that deviations in the slope of the obtained record from the diagonal, which connects (x, y) = (start of session, 0%) to (x, y) = (end of session, 100%), occurring at any point and for any duration, represent changes in the local response rate from the entire-session rate. This method of representing ongoing responding is illustrated by several records of key pecking of a pigeon on a variable-interval 60-s schedule of food reinforcement. Relative local response rates were also computed from these data at several levels of resolution (i.e., the time over which responses were aggregated), including the level typically employed by those interested in within-session changes in response rates.     

Testing the accuracy of timing reports in visual timing tasks with a consumer-grade digital camera

This study tested the accuracy of a visual timing task using a readily available and relatively inexpensive consumer grade digital camera. A visual inspection time task was recorded using short high-speed video clips and the timing as reported by the task’s program was compared to the timing as recorded in the video clips. Discrepancies in these two timing reports were investigated further and based on display refresh rate, a decision was made whether the discrepancy was large enough to affect the results as reported by the task. In this particular study, the errors in timing were not large enough to impact the results of the study. The procedure presented in this article offers an alternative method for performing a timing test, which uses readily available hardware and can be used to test the timing in any software program on any operating system and display.     

Analyzing sequential relations in observational data: A practical guide

Many observational systems in basic and applied research produce a record of sequences of events over time. Within such observational systems, important information may be found in the frequency of the transitions between events that does not emerge in the typical researcher's focus on absolute event frequency. Indeed, if many behaviors are controlled by closely adjacent preceding events, then substantial prediction and control can be obtained through knowledge and manipulation of causal event transitions. A method for analyzing and testing sequential dependencies between events is proposed as part of an integrated package of computer-based data entry, storage, and analysis procedures. The mathematical portion of these techniques is based on the statistic, kappa,which is applicable to determining whether particular transitions among events differ from chance and whether particular transitions differ significantly across groups of subjects. Low-cost hardware and software to implement the proposed procedures are described.This work has been supported by Grant 1 RO1 HD19245-01A1 from the National Institute of Child Health and Human Development to the two senior authors and by grants of equipment from Commodore Computers, Inc., Koala Corporation, and NEC Telephones, Inc.     

A computer system for processing eye-movement records

A computer system using the LINC-8 computer was developed to process eye-movement records from two 16-mm cine film input sources : the Mackworth stand camera and the Mackworth wide-angle camera. Data reduction was accomplished by projecting the films onto an X-Y plotting table. An operator marked, using a cursor, either the eyespot, in the case of the stand camera, or the pupil and display center, in the case of the wide-angle camera, in order to digitize the locus of the gaze. This information was normalized and stored on magnetic tape as: ordinal fixation number, fixation duration, and fixation coordinates (X and Y). A software library was created to analyze the three eye-movement measures. One program calculates interfixation distance, fixation time, and dispersion of fixations about a point. A second program operates on data matrices to: calculate area covered by a fixation pattern, frequency of redundant fixations in a fixation pattern, and distribution of fixations over features of the visual display. Data are displayed on either scope or the Calcomp plotter.     

Identification of sequential dependencies in conversations: A Pascal program

A Pascal program that provides an analysis of the sequential dependencies between conversational events (e.g., speech acts) generated by two sources is described It produces z scores, chirsquare values, and confidence limits for the difference between estimated unconditional probabilities of the occurrence of selected events (valid events) and estimated conditional probabilities of these events following specified target events immediately (at Lag 1) and, if required, more distantly (at Lags 2, 3, etc.). Valid events and target events may be independently selected from the set of events generated by the first source, the second source, or both. Events not selected are ignored. The user may also elect to exclude the target event from the set of valid events (an adjustment for autocorrelation). The program is especially appropriate for conversational events because it does not assume that two events from the same category can never follow one another.     

What constitutes an episode in episodic memory?

The idea of episodic memory implies the existence of a process that segments experience into episodes so that they can be stored in memory. It is therefore surprising that the link between event segmentation and the organization of experiences into episodes in memory has not been addressed. We found that after participants read narratives containing temporal event boundaries at varying locations in the narrative, their long-term associative memory for information across event boundaries was lower than their memory for information within an event. This suggests that event segmentation during encoding resulted in segmentation of those same events in memory. Further, functional imaging data revealed that, across participants, brain activity consistent with the ongoing integration of information within events correlated with this pattern of mnemonic segmentation. These data are the first to address the mechanisms that support the organization of experiences into episodes in long-term memory.     

A model of fixed activation time scheduling

A model for the fixed activation time scheduling of events is presented. Activation time is defined as the time needed for an event to regain dominance in the stream of events measured from the point in time at which it lost dominance. The fixed activation time scheduling rule states that some event must be ongoing at all times, that an ongoing event will continue until interrupted by another event, that every event has a predetermined activation time and that fulfilling the activation time requirement is the necessary and sufficient condition for an event to interrupt an ongoing event. The last condition sets this rule apart from those employed in quequeing theory since it does not allow events to be completed or queues to form. Derivations from the model concerning the dynamic organization of the stream of events, written in terms of the frequency and duration of events and the transitions between pairs of events, are given. Special attention is paid to issues that arise in deciding on the coding of events. It is suggested that the fixed activation time scheduling rule will apply to a wide variety of settings, environmental and behavioral, and this is illustrated by a detailed application of the model to observations on the stream of free behavior.     

Direct measurement of the system latency of gaze-contingent displays

Gaze-contingent displays combine a display device with an eyetracking system to rapidly update an image on the basis of the measured eye position. All such systems have a delay, the system latency, between a change in gaze location and the related change in the display. The system latency is the result of the delays contributed by the eyetracker, the display computer, and the display, and it is affected by the properties of each component, which may include variability. We present a direct, simple, and low-cost method to measure the system latency. The technique uses a device to briefly blind the eyetracker system (e.g., for video-based eyetrackers, a device with infrared light-emitting diodes (LED)), creating an eyetracker event that triggers a change to the display monitor. The time between these two events, as captured by a relatively low-cost consumer camera with high-speed video capability (1,000 Hz), is an accurate measurement of the system latency. With multiple measurements, the distribution of system latencies can be characterized. The same approach can be used to synchronize the eye position time series and a video recording of the visual stimuli that would be displayed in a particular gaze-contingent experiment. We present system latency assessments for several popular types of displays and discuss what values are acceptable for different applications, as well as how system latencies might be improved.