Which component of the response time process is

affected by red stimuli?

- Specific colours can form associations found to be important in

basic psychological functions (Moller et al., 2009).

- Red stimuli were found to be associated with failure,

whereas other colours, such as green, were associated

with success when used as the stimulus.

- Brandtstadter et al. (2003) found that stimuli associated

with negativity enhanced perceptual sensitivity.

- The colour red has a has both an evolutionary and social

significance as a ‘signal function’ and a potential ‘threat-cue’ (Elliot

& Aarts, 2011).

- Studies have shown that valid threat-cues can improve

reaction times (Koster et al., 2006).

- Red stimuli have been found to enhance basic motor functioning in

terms of both velocity and force in reaction tests (Elliot & Aarts,

2011).

- Little evaluation of the potential effect of certain colours,

specifically those of a red hue, on reaction time, and the

underlying cognitive processes, has been made.

Introduction:

Hypotheses: 1. When colour is deemed irrelevant,

reaction times will be faster to red

stimuli than to black stimuli in a two-

choice reaction time task.

2. If stimulus colour needs to be relevant

to the task in order to impact upon

reaction time, red stimuli should only

affect reaction time when stimulus

colour is the key task component.

3. Red stimuli will induce a reduction in

the response-caution process of

reaction time in both experiments.

Project: Jack Fantham

Supervisor: Jim Grange

Method:

Research Questions: 1. Can red stimuli affect results in a

two-choice reaction time task?

2. Does colour need to be identified as

relevant to a task in order to prove

influential on reaction time?

Upon signing a consent

form, participants will

allocated to one of two

experiments.

Experiment 1

Experiment 2

Colour deemed irrelevant.

Participants must react as

quickly and accurately as

possible to shape being

‘square’ or ‘circle’.

Colour deemed relevant.

Participants must react as

quickly and accurately as

possible to a shape being

‘red’ or ‘black’.

e.g:

e.g:

or

or

or

Reaction times will

be recorded for

data analysis.

Participants: - 64 undergraduate students total

selected through opportunity sampling.

Apparatus: - QWERTY keyboard. One key

allocated to each option in both

experiments.

- Monitor. Reaction time tasks will rely on

reaction to visual stimuli presented via

computer screen.

Ethical considerations: - Participants will be told that they can choose to

halt the experiment at any time without being

required to justify their decision.

Controls & Measures: - Reaction times will be

recorded in milliseconds.

- Response times shorter

than 100 milliseconds

will be discounted in data

analysis.

Procedure:

Data Analysis: In both experiments, it must first be determined whether or not red stimuli

induce a faster response time than black stimuli. Therefore, a t-test will be

applied to the two reaction time means of each experiment. In turn, the first

and second hypotheses can be evaluated and the research question can be

answered.

Secondly, the Ratcliff Diffusion Model (Ratcliff, 1978) (see Figure 1)

parameters of drift rate, boundary separation, and starting point will be

applied to the results . T-tests will again be used to evaluate the final

hypothesis and determine whether response caution is reduced in reactions

to a red stimulus.

The Ratcliff Diffusion Model &

reaction time process overview

Figure 1 – The parameters of the Ratcliff Diffusion Model

z = starting point/response bias.

v = drift rate/evidence accumulation.

a = boundary separation/caution. A motor response (known as don-decision time) completes

the process.

Response selected

References: Brandtstadter, J.; Voss, A. & Rothermund, K. (2003). Perception of danger signals: The role of control. Experimental Psychology 51(1), p24-32).

Elliot, A.J. & Aarts, H. (2011). Perception of the colour red enhances the force and velocity of motor output. Emotion, 11(2), p445-449.

Koster, E.H.W.; Crombez, G.; Verschuere, B.; Van Damme, S. & Wiersema, J.R. (2006). Components of attentional bias to threat in high trait anxiety: Facilitation engagement, impaired disengagement, and attentional avoidance. Behaviour Research and Therapy, 44, p1757-1771.

Moller, A.C.; Elliot, A.J. & Maier, M.A. (2009). Basic hue-meaning associations. Emotion, 9(6), p898-902.

Ratcliff, R. (1978). A theory of memory retrieval. Psychological Review, 85, p59-108.

Implications: Future research into the effects of colour on reaction time could benefit from this study.

Should red be found to have a significant effect on reaction time, attention can then be

paid to the potential significance of other colours in reaction time and reaction time

processes. Is red the only colour to have an effect on reaction time? If others do have

significant effects, will the dependent component of the reaction time process vary?

or