Understanding the influence of individual behaviour and social networks in sustainable transitions

309 Pages·2016·3.87 MB·English

Understanding the influence of
individual behaviour and social
networks in sustainability transitions

By Iljana Schubert

A thesis submitted in partial fulfilment of the
requirements of Bournemouth University for
the degree of Doctor of Philosophy.

October 2015
Copyright statement

This copy of the thesis has been supplied on condition that
anyone who consults it is understood to recognise that its
copyright rests with its author and due acknowledgement must
always be made of the use of any material contained in, or
derived from, this thesis.

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Abstract

A behaviour change towards sustainable food purchasing behaviour is crucially
necessary for the survival of the planet. This thesis applied a mixed method approach,
combining results from a cross-sectional online survey (N=474), a lab experiment
(N=134) and an agent-based model (ABM) to explore how a change towards
sustainable food purchasing may be achieved in society. The methodological approach
of this thesis is quantitative confirmatory and exploratory. The online survey, based on
main environmental psychology theories (Theory of Planned Behaviour, Norm
Activation Model and habit theories) and social network theory, explored which factors
significantly influence sustainable food purchasing behaviour. Findings show that social
network factors influence sustainable food purchasing behaviour via psychological
factors; habit, perceived behavioural control, descriptive and personal norms.
Additionally, segmentation of different sustainable behaviour groups (high, medium and
low) let to the development of segment specific intervention strategies. The lab
experiment, measuring actual sustainable food consumption behaviour, validated and
extend these findings by showing that social network members significantly influence
sustainable food consumption behaviour compared to strangers. I further applied the
empirical findings and theoretical knowledge to build an ABM to understand (1) the
spread of sustainable food purchasing behaviour, and, (2) how three social network
factors (i.e. network size, percentage of sustainable shoppers and percentage of food
discussion partners in the social network) influence this spread of sustainable
consumer behaviour via psychological factors shown to be relevant to influence
sustainable purchasing behaviour (i.e. intention, habit, personal and descriptive norm).
Findings provide evidence that there is (1) a threshold effect during the spread of
sustainable food purchasing behaviour in social networks as the spread of sustainable
food shopping behaviour is fastest at the beginning phase of the experiments, slowing
down towards the middle and end phase. The speed of the spread of behaviour is
significantly influenced by the size of the social network and the percentage of initial
sustainable shoppers in the personal network (2). This research provides a first
glimpse of what behaviour change towards sustainable food shopping may look like
with the influence of social networks. Intervention and policy recommendations are
discussed.

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List of contents

Title page...….…………………………………………………………………….…………….1
Copyright statement ...................................................................................................... 2
Abstract ........................................................................................................................ 3
List of contents ............................................................................................................. 4
List of tables ................................................................................................................. 8
List of figures .............................................................................................................. 10
List of appendices ....................................................................................................... 11
Acknowledgement ...................................................................................................... 12
Declaration ................................................................................................................. 13
List of presentations and publications ......................................................................... 14
Chapter 1: Background: historical overview of environmental policies ............... 16
Chapter Overview ................................................................................................... 16
1.1. Introduction ................................................................................................... 16
1.1.1. Early environmental policy developments and achievements (1972-
1999) 17
1.1.2. Environmental policy achievements in the 21st century .......................... 19
1.1.3. Conclusion and research aim ................................................................ 21
1.1.4. Sustainable consumer behaviour: Focus on sustainable food shopping 22
1.2. Thesis overview ............................................................................................ 23
1.3. References ................................................................................................... 25
Chapter 2: Theoretical framework ........................................................................... 27
Chapter overview .................................................................................................... 27
2.1. Psychological theories of sustainable consumer behaviour .......................... 27
2.1.1. Expectancy Value Theories in sustainable consumer behaviour: The
Theory of Planned Behaviour ............................................................................ 28
2.1.2. Normative theories in sustainable consumer behaviour: The Norm
Activation
Model
……………………………………………………………………………………
…...29
2.1.3. Habits and sustainable consumer behaviour ......................................... 30
2.1.4. Combining EVTs, normative theories and habits in sustainable consumer
behaviour ............................................................................................................. 31
2.2. Social networks in sustainable consumption behaviour change .................... 32
2.3. Spread of sustainable consumer behaviour in society .................................. 34
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2.3.1. Theories focussing on the spread of behaviour in society: Tipping points
and change processes ......................................................................................... 34
2.3.2. Researching the spread of sustainable consumer behaviour in society
with simulation models: Agent-based models ...................................................... 35
2.4. Summary ...................................................................................................... 37
2.5. Theoretical Framework ................................................................................. 38
2.6. Research Questions and Hypotheses ........................................................... 39
2.6.1. Research aim and researh questions .................................................... 39
2.6.2. Research Hypotheses ........................................................................... 39
2.7. Methodology ................................................................................................. 40
2.8. References ................................................................................................... 42
Chapter 3: The sustainable food revolution: The influence of social network
characteristics on sustainable food purchasing and its psychological
predictors. ................................................................................................................. 47
Chapter abstract ...................................................................................................... 47
3.1. Introduction ................................................................................................... 47
3.1.1. Predictors of sustainable food purchasing behaviour: Theory of planned
behaviour and moral considerations .................................................................... 48
3.1.2. Social network analysis ......................................................................... 50
3.2. Method ......................................................................................................... 57
3.2.1. Participants ............................................................................................ 57
3.2.2. Questionnaire design ............................................................................. 58
3.2.3. Survey ................................................................................................... 59
3.2.4. Dependent variable ............................................................................... 59
3.2.5. Psychological constructs ....................................................................... 60
3.2.6. Social network characteristics ................................................................ 65
3.3. Results ......................................................................................................... 73
3.3.1. Analyses: Parametric vs. non-parametric tests with Likert scales .......... 73
3.3.2. Testing Normality and Homogeneity of variance .................................... 73
3.3.3. Validity and Reliability ............................................................................ 74
3.3.4. Multiple Group Method (MGM) in SPSS ................................................ 75
3.3.5. Dealing with missing data ...................................................................... 76
3.3.6. Confirmatory Factor Analysis in AMOS .................................................. 77
3.3.7. Explaining current sustainable food purchasing behaviour with social
network characteristics and psychological predictors ........................................... 80
3.4. Discussion .................................................................................................... 84
3.5. References ................................................................................................... 89
Chapter 4: Sustainable shoppers’ social network profiles .................................... 97
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Chapter abstract ...................................................................................................... 97
4.1. Introduction ...................................................................................................... 97
4.2. Method ........................................................................................................... 102
4.2.1. Participants and Procedure ...................................................................... 102
4.2.2. Survey design and variables .................................................................... 103
4.3.2. Survey design and variables .................................................................... 104
4.3. Results ........................................................................................................... 106
4.3.1. Analyses .................................................................................................. 106
4.3.2. Checking assumptions ............................................................................. 106
4.3.3. How do sustainable and non- sustainable shoppers differ in terms of their
social network characteristics? .......................................................................... 107
4.4. Discussion ...................................................................................................... 117
4.4.1. High sustainable consumers .................................................................... 117
4.4.2. Medium sustainable consumers ............................................................... 119
4.4.3. Low sustainable consumers ..................................................................... 120
4.5. References ..................................................................................................... 122
Chapter 5: The influence of social networks on organic consumption behaviour:
An experimental study ........................................................................................... 129
Chapter abstract .................................................................................................... 129
5.1. Introduction ................................................................................................. 129
5.2. Method ....................................................................................................... 135
5.2.1. Procedure ............................................................................................ 135
5.2.2. Participants .......................................................................................... 137
5.2.3. Research Design ................................................................................. 138
5.2.4. Dependent variable ............................................................................. 138
5.2.5. Independent variables ......................................................................... 138
5.3. Results ....................................................................................................... 141
5.3.1. Analyses .............................................................................................. 141
5.3.2. Testing of assumptions ........................................................................ 141
5.3.3. Preliminary data testing: Testing for differences between the setup
positions of the consumables ............................................................................. 142
5.3.4. Descriptive Results .............................................................................. 144
5.3.5. Predicting organic consumption from social network characteristics .... 146
5.4. Discussion .................................................................................................. 149
5.5. References ................................................................................................. 154
Chapter 6: Influence of social networks on sustainable food purchasing
behaviour explored with an empirically grounded agent-based model .............. 158
Chapter abstract .................................................................................................... 158
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6.1. Introduction .................................................................................................... 158
6.1.1. Psychological predictors of sustainable food purchasing behaviour ......... 159
6.1.2. Social network factors influencing sustainable food purchasing
behaviour ........................................................................................................... 161
6.1.3. Applying agent-based modelling to understand the spread of sustainable
food purchasing ................................................................................................. 163
6.2. Method ........................................................................................................... 166
6.2.1. Empirical data applied to ABM ................................................................. 166
6.2.2. Experimental design ................................................................................ 167
6.2.3. Model setup ............................................................................................. 170
6.2.4. Sensitivity analysis ................................................................................... 174
6.3. Results ........................................................................................................... 176
6.3.1. Identification of threshold response .......................................................... 177
6.3.2. Influence of social network factors on sustainable food shopping
behaviour ........................................................................................................... 180
6.4. Discussion ...................................................................................................... 184
6.5. References ..................................................................................................... 187
Chapter 7: General Discussion .............................................................................. 194
Chapter overview .................................................................................................. 194
7.1. Thesis aim and main research question revisited ........................................... 194
7.2. Thesis findings ............................................................................................... 195
7.2.1. Number of sustainable shoppers in the network ....................................... 203
7.2.2. Network size ............................................................................................ 206
7.2.3. Food discussion with network members ................................................... 208
7.2.4. Number of network members directly influencing purchasing decisions ... 210
7.2.5. Relationship length .................................................................................. 211
7.2.5. Non-significant social network characteristics: Food discussion degree,
density, social context diversity and emotional closeness .................................. 212
7.3. Implications .................................................................................................... 213
7.3.1. Theoretical implications ........................................................................... 215
7.3.2. Practical implications: Intervention strategies ........................................... 218
7.4. Strength and limitations .................................................................................. 226
7.4.1. Strength of thesis ..................................................................................... 226
7.4.2. Limitations and future research ................................................................ 229
7.5. Conclusion ..................................................................................................... 231
7.7. References ..................................................................................................... 232

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List of tables

Table 3.1. Psychological constructs, definition, questionnaire items, answer scale and
source ......................................................................................................................... 61
Table 3.2. Lists variable name, definition, questions item, answer scale, question type
and theoretical range of scores for all social network characteristics .......................... 69
Table 3.3. Standardized regression weights (Beta), composite reliabilities (CR) and
average variance extracted (AVE) for measurement model ........................................ 78
Table 3.4. Discriminant validity of measurement model with AVE (bold scores in
diagonal line) and squared correlations scores ........................................................... 80
Table 4.1. ANOVA and Bonferroni post-hoc test comparing consumer segments (low,
medium and high) on their sustainable food purchasing behaviour ........................... 107
Table 4.2. Sustainable food purchasing behaviour per behaviour category and
sustainable food consumer segment; mean, standard deviation and F statistics....... 108
Table 4.3. Sustainable food purchasing intention per behaviour category and behaviour
segment; mean, standard deviation and F statistics. ................................................. 110
Table 5.1. Descriptive data of setup conditions of non-organic vs. organic in the
front .......................................................................................................................... 142
Table 5.2. Chi-square and Fischer’s Exact test results comparing differences between
the setup conditions of non-organic vs. organic in the front ....................................... 143
Table 5.3. Descriptive data for independent variables; number of participants, mean,
standard deviation, standard error and median ......................................................... 144
Table 5.4. Mann-Whitney U test results comparing strangers and social network
member groups on pre-experiment variables ............................................................ 145
Table 5.5. Binary logistic regression analysis predicting organic consumption behaviour
with social network characteristics ............................................................................ 147
Table 5.6. Observed organic consumption choices and predicted choices by the logistic
regression ................................................................................................................. 147
Table 5.7. Chi-square results comparing organic and non-organic consumption choices
in stranger vs. social network member groups .......................................................... 147
Table 6.1. Experimental settings for 3*3*3 independent variable combinations. Values
of the variables generated by the ABM are presented, for each experimental
setting. ...................................................................................................................... 169
Table 6.2. Mean and coefficient of variance for sustainable consumer behaviour for
different experimental scenarios with different numbers of runs (i.e. repeats of the
experiment). .............................................................................................................. 175
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Figure 6.4. Uptake of sustainable food purchasing in a population over time (ticks), as
simulated with the ABM for 27 different experimental scenarios. .............................. 176
Table 6.3. Gradients of the lines fitted to different sections of the curves describing the
spread of sustainable consumer behaviour, derived from model outputs. Values are
means (M) and standard errors (SE) of the gradients of the lines, determined by
regression analysis. .................................................................................................. 178
Table 6.4. Summary of MANOVA results to determine the influence of social network
factors on the rate of spread of behaviour change (gradients). ................................. 180
Table 6.5.. Fisher’s least significant difference (LSD) post hoc test comparing
sustainable shopper scenarios; showing Mean difference, Standard Error (SE),
significant’s value (p) and confidence intervals ......................................................... 181
Table 6.6. Fisher’s least significant difference (LSD) post hoc test comparing
discussion scenarios; showing Mean difference, Standard Error (SE), significant’s
value (p) and confidence intervals ............................................................................ 182
Table 6.7. Gradients of the lines fitted to different sections of the curves describing the
spread of sustainable consumer behaviour, derived from model outputs, organised by
network size and sustainable shoppers. ................................................................... 183

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List of figures

Figure 2.1. Theoretical framework showing established relationships (solid lines),
theorized relationships to be explored with a survey and experiments (dashed line) and
relationships to be explored through social simulation (wavy line). ............................. 38
Figure 3.1. New relationships and expected relationships between ego network
characteristics, psychological factors and sustainable food purchasing behaviour
included in this study. ................................................................................................. 55
Figure 3.2. Full theoretical framework modelled using structural equal modelling ....... 81
Figure 4.1. Theoretical framework modelled using structural equal modelling (from
Chapter 3)................................................................................................................. 102
Figure 4.2. Willingness (i.e. intention) and ability (i.e. perceived behavioural control) for
sustainable purchasing behaviour segments. ........................................................... 109
Figure 4.3. Structural equation model (from Chapter 3) tested for the high consumer
segment. ................................................................................................................... 112
Figure 4.4. Structural equation model (from Chapter 3) tested for the medium
consumer segment. .................................................................................................. 114
Figure 4.5. Structural equation model (from Chapter 3) tested for the low consumer
segment. ................................................................................................................... 115
Figure 6.1. Representation of research model .......................................................... 163
Figure 6.2. Example of a social network created in the ABM for sustainable shopping
behaviour. ................................................................................................................. 171
Figure. 6.3. Single agent decision making process as incorporated in the ABM. ....... 172
Figure 6.4. Uptake of sustainable food purchasing in a population over time (ticks), as
simulated with the ABM for 27 different experimental scenarios. Figures (a) 10%, (b)
30% and (c) 50% sustainable consumers at outset, respectively. ............................. 176
Figure 6.5. Interaction between network size and sustainable shoppers .................. 182
Figure 7.1. Theoretical framework showing established relationships (solid lines),
theorized relationships explored with a survey and experiments (dashed line) and
relationships explored through social simulation (wavy line) (repeat from Chapter 2,
Figure 2.1.). .............................................................................................................. 195

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