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The Theory of Reasoned Action and The Theory of Planned Beha

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Clíona Hurst

on 19 September 2013

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Transcript of The Theory of Reasoned Action and The Theory of Planned Beha

The Theory of Reasoned Action (TRA) Ajzen & Fishbein (1975)
The Theory of Reasoned Action
The Theory of Planned Behaviour

This theory was proposed to help predict and explain
volitional behaviour.
It states that a person's
to perform, or not perform a behaviour is the immediate determinant of that action.
In combination, it looks at the determinants of intentions -
towards the behaviour (determined by salient beliefs about behaviour)
subjective norms

The Theory of Reasoned Action: Strengths, Applications and Limitations
Strengths of the TRA
The TRA has been shown to be a powerful predictor of behaviour
A meta-analysis conducted by Sheppard, Hartwick & Warshaw (1988) indicated that:
The importance of subjective norms and attitudes towards predicting behaviour was substantial (r = .67)
behavioural intentions explained future behaviours (r = .62)
These correlations were stronger than those in the Health Belief Model
Applications of the TRA
The Theory of Reasoned Action is very good at predicting behaviour which is under
volitional control
Hale et al. (2002) stated that the TRA has been tested across many areas including
(Sejwacz, Ajzen, & Fishbein, 1980),
condom usage
(Greene, Hale, & Rubin, 1997; Jemmott & Jemmott, 1991),
sun-care regimes
(Hoffman, 1999) and the
consumption of genetically engineered foods
(Sparks, Sheppard, & Frewer, 1995).
Issues may arise with model and behaviours not under conscious or volitional control.
Limitations of the TRA
There are not enough longitudinal studies on the TRA, resulting in an over-reliance on cross-sectional studies.
The theory deals solely with behaviour under volitional control.
Inter-relationships between variables are not considered.
The TRA is now virtually obsolete due to the Theory of Planned Behaviour.

The Theory of Planned Behaviour (Ajzen, 1985; 1991)

TRA; leading to behaviuor
Perceived Behavioural Control
PBC - a person's belief that they have control over their own behaviour in certain situations, even when facing certain barriers (Morrison & Bennett, 2012).
Applications of TPB
Chang (1998) found that
PCB was a better predictor of behavioural intention
than attitude, when examining moral or unethical behaviour.
The results from Chang (1998) have been replicated across a variety of behaviours, many of them relating directly to health, e.g.
Condom usage
(Albarracin, Fishbein, Johnson & Muelleriele, 2001; Sheeran & Taylor, 1999),
(Ajzen & Driver, 1992),
(Nguyen, Potvin & Otis, 1997) and
(Conner, Kirk, Cade & Barrett, 2003)
nutrition interventions
have been shown to be very successful using the TPB (e.g. Sweitzer, 2011).
Limitations of TPB
Meta-analysis by Plotnikoff et al. (2010) examined PA in diabetes:
In cross-sectional studies, TPB explained 19-23% of behaviour.
In longitudinal studies, this was 8-13%.
Prediction of intention is greater than prediction of behaviour. One reason may be a lack of a temporal element (Ajzen, 1985).
Armitage & Conner (2001) found subjective norms to be a weak indicator of intention.

Acknowledge interrelationship between variables.
Recognise the role played by moderator variables e.g. choice among alternatives (Sheppard, Hartwick, Warshaw (1988).
Strengths of TPB
The added element of
allows us to address the non-volitional behaviours not covered in the TRA
A study conducted by Godin and Kok (1996) found that the
TPB was very good at explaining intentions
(R2 = .41)
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