Reaction Time Testing (Saturday, 10 October 1998) -

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1 Reaction Time Testing (Saturday, 10 October 1998) - by Andrew Brown, Civil & Forensic Pty Ltd  1998 During 1998 two separate exercises were carried to measure the reaction time of subjects. These exercises were conducted by the NSW Region of ASPACI. At Bathurst '98 Conference (April 1998) 'in-vehicle' tests were carried out in an instrumented vehicle to measure the perception and reaction time of drivers. These tests were carried out when the driver was expecting the test and as a surprise test. Details of the 'in-vehicle' tests are provided below. Later in the year (October 1998) a series of 'computer' tests were carried out at an ASPACI meeting to measure the decision-reaction time of participants. Details of the 'computer' tests are provided below. In-Vehicle Tests Data from these tests is available at the Bathurst '98 Conference site. (see Bathurst '98) under the Events menu on this page. Computer Tests (DRT) At the October meeting of ASPACI NSW Andrew Brown held a hands-on demonstration of computer based perception & reaction time testing. This was done using a number of laptop computers and a program written by George Bonnett, with additions for statistical analysis by Andrew Brown. The program (DRT) is currently in beta testing and will form part of Rec-Tec reconstruction software. Results from a sample size of 16 participants (12 at the meeting) have been collated and analysed. The DRT program takes the participant though 6 different decision-rection time tests (or phases) each of increasing complexity. That is more decision making is required during the latter tests than the earlier tests. The participant the test in each phase 10 times for a total of 60 measurements. Each test involved a the participant responding to the random display of graphic symbols on the screen and then responding with specified keystrokes based on the type of symbol, relative position and ultimately colour. As the task involved gets more complicated it is possible to enter the incorrect keystroke sequence. In this case the time for that individual test is put aside and the test repeated until 10 successful attempts are made. The program keeps track of the number of errors and the decision-reaction time for each test error. When a participant starts the test sequence they are requested for information on there identity, age, alcohol and drug consumption for comparison purposes. These inputs are shown below. MULTI-PHASE DECISION-REACTION TIME TEST IDENTIFIER OR NAME [FIRST MI LAST]? NAME WITHHELD SEX [M/F]: F AGE: 21 BAC (PRESS ENTER IF NONE OR UNKNOWN): 0 NUMBER OF DRINKS IN LAST 6 HOURS (PRESS ENTER IF NONE): 0 BEER/WINE/LIQUOR [B/W/L] (PRESS ENTER IF NONE): 0 ARE YOU TAKING ANY DRUGS/MEDICATION [Y/N]: N Screen 1: Data entry screen for DRT

2 The participant is prompted through each of the six phases with instructions on each test preceding each phase. PRESS Q TO STOP TEST AND EXIT SERIES INCLUDES 6 PHASES WITH 10 PARTS EACH PLACE FINGERS ON KEYS DURING ALL TESTS PRESS ANY KEY TO CONTINUE Screen 2: There are 6 types of test to be carried out. The first phase requires a simple response to the random display of a filled circle in a fixed position. NON DISCRIMINITORY SIMPLE REFLEX When a CIRCLE appears press the SPACEBAR Screen 3: First Test - Circle will appear in middle of the screen. The second phase requires the same simple response to the random display of a filled circle in a random position. REACTION TIME TEST - PHASE 2 MOVING POINT NON DISCRIMINITORY REFLEX When a CIRCLE appears press the SPACEBAR Screen 4: Second Test - Circle will appear at random position on the screen. The third phase requires the participant to identify the random display of a filled circle or square in a random position. The required keystroke is dependent on the shape displayed. REACTION TIME TEST - PHASE 3 MOVING POINT DISCRIMINITORY REFLEX Either a CIRCLE or a SQUARE will appear Press the SPACEBAR when a CIRCLE appears Press ENTER when a SQUARE appears Screen 5: Third Test - Circle OR Square will appear at random position on the screen. The forth phase requires the participant to identify the random display of a filled circle and square arranged horizontally in a random position. The required keystrokes are dependent on the relative position of the shapes displayed. REACTION TIME TEST - PHASE 4 MOVING POINT COMPLEX DISCRIMINITORY REFLEX If the CIRCLE is to the left of the SQUARE press the SPACEBAR and then ENTER If the SQUARE is to the left of the CIRCLE press ENTER and then the SPACEBAR Screen 6: Forth Test - Circle AND Square will be aligned horizontally at random position on the screen.

3 The fifth phase requires the participant to identify the random display of a filled circle and square arranged vertically in a random position. The required keystrokes are a fixed key followed by a sequence dependent on the relative position of the shapes displayed. REACTION TIME TEST - PHASE 5 MOVING POINT COMPLEX DISCRIMINITORY COMPLEX REFLEX Press the ESCAPE key as soon as any object appears THEN If the CIRCLE is above the SQUARE press the SPACEBAR and then ENTER If the SQUARE is above the CIRCLE press ENTER and then the SPACEBAR Screen 7: Fifth Test - Circle AND Square will be aligned vertically at random position on the screen. The sixth phase requires the participant to identify the random display of a filled circle and square arranged vertically in a random position. The required keystrokes are a fixed key followed by a sequence dependent on the relative position of the shapes and colours displayed. This is the same as Phase 5 except the keys strokes are reversed if both shapes are of the same colour. REACTION TIME TEST - PHASE 6 MOVING POINT VERY COMPLEX DISCRIMINITORY VERY COMPLEX REFLEX Press the ESCAPE key as soon as any object appears IF THE OBJECTS ARE DIFFERENT COLORS If the CIRCLE is above the SQUARE press the SPACEBAR and then ENTER If the SQUARE is above the CIRCLE press ENTER and then the SPACEBAR IF BOTH OBJECTS ARE THE SAME COLOR If the CIRCLE is above the SQUARE press ENTER and then the SPACEBAR If the SQUARE is above the CIRCLE press the SPACEBAR and then ENTER Screen 8: Sixth Test - Circle AND Square will be aligned vertically at random position on the screen. The individual tests results and averages for each test phase are show on the first of the results output screens. This data is for the 10 successful tests completed in each phase. MULTI-PHASE DECISION-REACTION TIME TEST :38:09 Licensed to Civil & Forensic TEST SUBJECT: NAME WITHHELD [F21000N] TOTAL DECISION-REACTION TIME: NO PHASE - 1 PHASE - 2 PHASE - 3 PHASE - 4 PHASE - 5 PHASE

4 AVRG Results 1: Data entry screen for DRT The second results output screen shows the symbols displayed in phases 3 to 6 and the time to first keystroke in phases 4 to 6. PHASE - 3 PHASE - 4 PHASE - 5 PHASE - 6 OD OD FIRST KEY OD FIRST KEY OD FIRST KEY 1 S S/C C/S S/C-N C C/S C/S C/S-N C S/C S/C S/C-R C C/S S/C C/S-R S S/C C/S S/C-N C S/C C/S C/S-N C S/C C/S S/C-R C S/C C/S S/C-R S C/S S/C S/C-R S C/S C/S S/C-N AVRG Results 2: Data entry screen for DRT The second results output screen shows the errors that occurred during testing (phases 3 to 6). This output also shows the symbol / sequence displayed and the time to first keystroke for each error. PHASE - 3 PHASE - 4 PHASE - 5 PHASE - 6 RUN:OD RUN:OD ERROR KEY RUN:OD ERROR KEY RUN:OD ERROR KEY 1 7:C 9:C/S :C/S :S/C-R :S/C-N AVRG LEGEND: S = SQUARE C = CIRCLE N = NORMAL ORDER R = REVERSE ORDER Results 3: Data entry screen for DRT The results can be printed or saved to file for further analysis. In this case the results were saved to a disk file and analysed with DRTStats v1.1 by Andrew Brown. (NB: This routine has since been incorporated into DRT and will form part of the release program.) DRT Statistics DRTStats allows a simple statistical analysis based on normal distribution of data. The program reads in test data from

5 all of the data files and produces Mean, Standard Deviation, 15th Percentile and 85th Percentile values for each of the phases. The time taken to complete the keystroke sequence (from display of symbols until the last required key is pressed) is analysed for all phases. In addition the time taken to press the first keystroke is analysed for phases 4, 5 and 6. The results from our testing is shown below. This is from a sample of 16 people, 14 male, 2 female, average age 37 years (actual ages - 21; 31; 32; 36(4); 42; 48; 51; 54; 55(2); 61; 62; 72), none affected by alcohol or drugs. DRTStats v 1.1 by Andrew Brown, 1998 Using data from the Multi-Phase Decision Reaction Time (DRT) test program DRT was written by George M Bonnett Sample Size is 16 People ( 160 Tests) Results for Complete Sequence: Phase 1 Phase 2 Phase 3 Phase 4 Phase 5 Phase 6 Mean Std Dev th %ile th %ile Results for First Keystroke: Phase 4 Phase 5 Phase 6 Mean Std Dev th %ile th %ile Press 'P' to Print OR ANY other key to exit? Results 4: Output of statistical analysis of DRT data files.