Temporal Bisection Task

Field	Value
Name	Temporal Bisection Task
Version	v0.1.0-dev
URL / Repository	E:/Taskbeacon/T000043-temporal-bisection-task
Short Description	Chinese temporal bisection task with a learning block, a test block, and forced-choice short-vs-long judgments.
Created By	TaskBeacon
Date Updated	2026-04-05
PsyFlow Version	0.1.12
PsychoPy Version	2025.2.4
Modality	Behavior
Language	Chinese
Voice Name	zh-CN-YunyangNeural

1. Task Overview

This task implements the canonical temporal bisection paradigm as a Chinese-localized PsyFlow protocol. The participant first reads the instructions, then completes a learning block that exposes the short and long anchor durations, and finally completes a test block that classifies probe durations as closer to the short or long standard.

Each trial presents a centered white square flash on a black background. In the learning block, the flash is followed by an explicit anchor label. In the test block, the participant responds with left and right arrows on a two-choice screen. The task records long-choice rate, response time, and miss rate rather than an objective accuracy score.

2. Task Flow

Block-Level Flow

Step	Description
1. Load mode and config	main.py loads human, qa, or sim mode and resolves the matching YAML config.
2. Initialize runtime	Subject info, window, triggers, and the stimulus bank are initialized.
3. Show instructions	The participant reads the Chinese temporal-bisection instructions and presses space to begin.
4. Run learning block	The first block presents short and long anchor flashes so the participant can learn the referents.
5. Run test block	The second block presents probe durations and collects forced-choice short-vs-long judgments.
6. Finish	The goodbye screen appears with summary metrics, and the data are saved.

Trial-Level Flow

Step	Description
Instruction	Explain the short and long anchor durations and start with the space key.
Learning fixation	A centered fixation cross marks the start of a learning trial.
Learning stimulus	A white square flashes for either 400 ms or 1600 ms.
Learning label	The screen states whether the flash was the short or long standard.
Learning ITI	A brief fixation separates learning exposures.
Test fixation	A centered fixation cross marks the start of a test trial.
Test stimulus	A white square flashes for one probe duration from the timing ladder.
Test response	A two-choice screen asks whether the duration was closer to short or long; left arrow = short, right arrow = long.
Test ITI	A brief fixation separates test judgments.
Goodbye	The final screen reports summary metrics and exits on space.

Controller Logic

Component	Description
Condition generation	BlockUnit.generate_conditions() produces block labels, and build_temporal_bisection_schedule() reconstructs the per-trial anchor/probe order from the block seed.
Phase order	instruction -> learning_fixation -> learning_stimulus -> learning_label -> learning_iti -> test_fixation -> test_stimulus -> test_response -> test_iti -> good_bye.
Response handling	space starts the instruction screen and dismisses the goodbye screen; learning trials have no choice response, while test trials use left/right arrows.
Timing control	Human mode uses the canonical anchor and probe timings; QA and sim configs keep the same logic while enabling short smoke-test runs.
Summary metrics	The task reports long-choice rate, mean RT, miss rate, and elapsed time.
Triggering	Each participant-visible phase emits a dedicated onset trigger so the trial stream is auditable.

Other Logic

Component	Description
White-square flash	The judged stimulus is a centered white rectangle rendered with PsychoPy primitives.
No reward logic	There are no points, tokens, rewards, or correctness feedback in the task.
No adaptive staircase	The task uses a fixed anchor/probe schedule rather than an adaptive timing controller.
QA/sim coverage	QA and both simulation profiles cover the same full phase sequence with short durations.

3. Configuration Summary

All human settings are defined in config/config.yaml. QA and smoke-test overrides live in config/config_qa.yaml, config/config_scripted_sim.yaml, and config/config_sampler_sim.yaml.

The QA and simulation configs keep the same block structure but shorten the run to 16 total trials for smoke testing.

a. Subject Info

Field	Meaning
subject_id	3-digit participant identifier used to seed the run.

b. Window Settings

Parameter	Value
size	[1280, 720]
units	pix
screen	0
bg_color	black
fullscreen	false
monitor_width_cm	35.5
monitor_distance_cm	60

c. Stimuli

Name	Type	Description
instruction_text	text	Chinese instructions describing the short and long standards and the space key to start.
learning_label_text	text	Short Chinese label that explicitly names the short or long standard after each anchor flash.
response_prompt_text	text	Two-choice prompt asking whether the flash was closer to short or long.
choice_short_box / choice_long_box	rect	Left and right response boxes centered on the screen.
choice_short_label / choice_long_label	text	Large Chinese labels for short and long inside the boxes.
choice_short_hint / choice_long_hint	text	Arrow-key hints placed below each response box.
fixation	text	Centered plus sign used during fixation and ITI screens.
stimulus_flash	rect	Centered white square used for the timed flash.
good_bye_text	text	End-of-task summary and exit screen.

d. Timing

Parameter	Value
anchor_short_ms	400
anchor_long_ms	1600
probe_durations_ms	400, 500, 650, 800, 950, 1100, 1300, 1600
fixation_duration_s	0.5
learning_label_duration_s	0.6
iti_duration_s	0.4
response_timeout_s	3.0
qa.timing_scale	0.2

The shared timing values are also mirrored in the top-level timing section so PsyFlow validation can flatten them into runtime settings.

e. Triggers

Event	Code
Experiment onset	1
Experiment end	2
Block onset	10
Block end	11
Trial onset	20
Instruction onset	21
Learning fixation onset	22
Learning stimulus onset	23
Learning label onset	24
Learning ITI onset	25
Test fixation onset	26
Test stimulus onset	27
Test response onset	28
Test short response	29
Test long response	30
Test timeout	31
Test ITI onset	32
Goodbye onset	40

f. Adaptive Controller

Parameter	Value
phase_order	instruction -> learning_fixation -> learning_stimulus -> learning_label -> learning_iti -> test_fixation -> test_stimulus -> test_response -> test_iti -> good_bye
conditions	learning, test
condition_weights	learning: 1, test: 1
total_blocks	2
practice_trials	8
test_trials	48
response_key_short	left
response_key_long	right
start_key	space
seed_mode	same_across_sub
overall_seed	42043
block_seed	[42043, 42044]

4. Methods (for academic publication)

The temporal bisection task is a classic interval-timing paradigm in which participants learn a short standard and a long standard, then classify probe durations according to which standard they seem closer to. The resulting response curve estimates subjective duration and the location of the psychometric midpoint.

This implementation preserves that structure in Chinese with PsychoPy primitives. A white square flash is shown centrally on a black background, the learning block reinforces the short and long referents, and the test block collects forced-choice short-versus-long judgments with left/right arrow keys. The task is therefore suited for behavioral or psychophysiological studies that need a reproducible interval-timing sequence without relying on external media assets.