Commercial Orientation and its Effects on Plant Diversity in Homegardens: An Empirical Investigation of Rural Households in Sri Lanka

It could be argued that commercially oriented famers pay more attention on reaping short term commercial benefits from their home-gardens and hence would not focus on longer term benefits that could be derived through enhanced biodiversity. Although empirical studies have been conducted to measure trade-offs between commercial orientation and plant diversity, hardly any research has carried out with the focus on homegardens in Sri Lanka. The main objective of this study is to explore the trade-offs between commercial orientation of farmers and plant diversity in homegardens in three districts in Sri Lanka, viz, Batticaloa Kandy and Kurunegala. The specific objectives are to (i) measure the degree of plant diversity in home gardens, (ii) measure the degree of commercial orientation of farmers, and (iii) to econometrically estimate the relationship between plant diversity and commercial orientation of farmers. Data for this study were collected through a survey carried out in the three districts in 2009. Plant diversity was measured using three indices, namely Richness index, Shannon index and Simpson index and the degree of commercial orientation of farmers was measured using a number of proxies to capture the extent of market transactions and perceptions among farmers towards the purpose of farming. A set of multiple regression models were specified treating the levelof commercialization, land size, employment status, education, household income and the geographical region as independent variables and plant diversity as the dependent variable. The results of the calculated indices revealed that homegardens in Kandy and Kurunegala districts are quitediverse in plants and it is not that diverse in Batticaloa district. Approximately one half of the famers in Kandy and Kurunegala districts and four fifth of the farmers in Batticaloa are commercially oriented. The regression results showed that the farmers with commercial orientation tend to maintain home gardens with relatively higher plant diversity in Kandy district. However, commercial oriented farmers in Kurunegala district tend to maintain homegardens with less plant diversity compare to that of noncommercial oriented. The results also revealed that the plant diversity increases with the increase in land extent and 0.42 ha and 0.53 ha was estimated to be the land area which brings about the maximum plant richness in homegardens in Kandy and Kurunegala districts respectively

A neuroscientific approach to choice modeling : electroencephalogram (EEG) and user preferences

Discrete choice experiments have traditionally focused on improving the prediction of static choices that are measured through external reflection and surveys. It is argued that considering the underlying processes of decision making across a variety of contexts may further progress decision research. As a pilot study in this field, this paper explores the dynamic nature of decision-making by examining the associated brain activity, Electroencephalogram (EEG), of people while undertaking choices designed to elicit their preferences. To facilitate such a study, the Tobii-Studio eye tracker system was utilized to capture the participants' choice based preferences when they were observing seventy two sets of objects of three images offering potential personal computer backgrounds. Choice based preferences were identified by having the respondent click on their preferred image. In addition, the commercial Emotiv wireless EEG headset with 14 channels was utilized to capture the associated brain activity during the period of the experiments. Principal Component Analysis (PCA) was utilized to preprocess the EEG data before analyzing it with the Fast Fourier Transform (FFT) to observe the changes in the four principal frequency bands, theta (3 - 7 Hz), alpha (8 - 12 Hz), beta (13 - 30 Hz), and gamma (30 - 40 Hz). A mutual information (MI) measure was then used to study left-to-right hemisphere differences as well as front-to-back difference. Across six recruited participants there was a clear and significant change in the spectral activities taking place mainly in the frontal (theta and alpha across F3 and F4) and occipital (alpha and beta across O1 and O2) regions while the participants were indicating their preferences.

Choice modeling and the brain : a study on the electroencephalogram (EEG) of preferences

Eighteen participants were recruited to perform the experiments with the average results showing clear and significant change in the spectral activity in the frontal (F3 and F4), parietal (P7 and P8) and occipital (O1 and O2) areas while the participants were indicating their preferences. The results show that, when considering the amount of information exchange between the left and right hemispheres, theta bands exhibited minimal redundancy and maximum relevance to the task at hand when extracted from symmetric frontal, parietal, and occipital regions while alpha dominated in the frontal and parietal regions and beta dominating mainly in the occipital and temporal regions.