Neil's BBC Software Projects

Introduction

The BBC was great for psychometric projects as it had all the essentials built-in. It could perform millisecond timing, and hardware interfacing (analogue and digital) without any additional hardware or software.

Except where noted, BASIC is used for the user interface, data display and file operations, whilst the data logging and timing routines are written in 6502 assembly language.

Picture Imagibility, August 1991, April 1993

This project tests the role of visual depth in the picture imagability. The computer controls a system that times a subject’s vocal response to a tachistoscopically presented image. Stimuli are selected by the computer and timing results are output in tabular format. A number of analysis programs are provided.

The Stroop Effect, April 1992

The same Stroop paradigm as described above but with a BBC computer. In this project, an additional system of biophysiological isolation and analogue-to-digital converter devices are used to record a continuous ECG during the experiment.

Visual Inspection Time (Flicker Threshold), April 1992

Measures a subject’s Inspection Time, which is a measure of a person's ability to discern the size difference between two simple images presented for extremely short periods. The stimulus is the lighting of two vertical rectangles of lamps, with the computer randomly selecting one bar to appear smaller than the other. The subject responds by pressing one of two buttons to indicate which bar was shorter. The duration of the stimuli's appearance is varied using a “Parameter Estimation by Sequential Testing” algorithm until a time threshold is determined. This threshold is the minimum appearance time the subject required to discern the difference between the stimuli within a specified error rate.

Cross-Modal Cueing, February 1992

This project tests the time taken by subjects to respond to variably cued targets where the cues and targets are either auditory or visual. Similar to the Posner Paradigm, described below. Subjects had auditory neglect as a result of brain injury.

Reaction Time Performance with Noise, February 1992

This project measures the effect of noise on a person's reading accuracy and speed. The computer controls the simultaneous presentation of the visual stimuli and the auditory distracter. The stimuli are a random set of letters and the subject's task is to count the number of vowels contained in the set. One of six buttons was pressed corresponding to the number of vowels in the set. The computer records the subject’s response speed and accuracy.

Finger Tapping Rhythm, May and December 1991

This project measures the differences in hand-motor timing performance of left and right handers using their dominant and non-dominant hand. A BBC microcomputer is connected to a Morse key and the subject’s is to tap the Morse key either at a steady-rate or as fast as possible. The output is a tabular histogram of tapping rate.

Posner Paradigm, April 1991

The program implements the Posner paradigm, wherein a cue and target stimuli can sometimes appear on opposite sides of a central reference point in either auditory or visual modalities. In this case, the cue is a letter or arrow displayed at the centre of the screen, indicating the place where the target should appear. A valid cue correctly predicts the target's position; an invalid cue predicts the opposite direction. The target appears inside one of four outlines, one each at the top, bottom, left and right of the screen. The computer records the speed and accuracy of subjects, whom had been diagnosed with Parkinson’s disease.

HRRSCR, January 1991

This system measures brain-injured people's emotional response to a cognitive test. Galvanic skin conductance and heartbeats were measured in real time. Markers are inserted into the data to synchronise these data with the experimental stimuli. The experimenter presses a button monitored by the computer to indicate when key events occurred.


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Content last updated: 2010-10-12