The present research was aimed at identifying the cause for poor performance of adult English as foreign language (EFL) learners in Saudi Arabia, as well as to test the hypothesis that one of the major causes behind learners' failure may be affective filters. The basic question to answer for the research was whether adult EFL learners raise their affective filters to block the input under the influence of certain affective factors, and whether a change in the class environment brings a change in learner motivation. To this end, data were collected through questionnaires, and a model teaching programme, based on a change in classroom environment, was developed and tested with a group of learners at the selected university in Saudi Arabia. The results obtained from the study show that EFL learners in Saudi Arabia raise affective filters, and that a change in classroom environment does help learners lower their affective filters. The study is very significant as its findings may prove helpful to EFL teachers in Saudi Arabia to create a conducive environment in their classes to help learners feel at ease to learn English, which at times is emotionally intimidating to some learners. The study is concluded with a recommendation that EFL teachers may replicate the experiment in their settings to test the efficacy of the hypothesis on psycholinguistic aspects of foreign language learning.