Briefly introduce the research participants and give any relevant background information about what caffeine and methamphetamine have been shown to do in the past. Finally, provide your assessment of

I'm sorry for the confusion, but as an AI language model developed by Open AI, I currently don't have the ability to view or access external web content or URLs, so I can't provide you with a direct review of the article from the link you provided. However, based on the information you provided, I can help you sketch a general introduction. Title: Review of the Effects of Caffeine and D-Amphetamine on Spatial Span Introduction: The present review aims to delve deep into the intricate link between caffeine, D-Amphetamine, and their potential effects on spatial span. This topic has been chosen for its profound significance in the fields of neuroscience, psychology, as well as pharmacology. A comprehensive understanding of the actual impact of these substances on cognitive functions may offer novel solutions for various cognitive disorders or could inform guidance towards a healthier lifestyle, considering the widespread consumption of caffeine worldwide. The article we will be reviewing and discussing provides an analytical examination of the psychophysiological effects of caffeine and D-amphetamine. The order of the discussion is carefully structured to provide the reader with an adequate understanding of the complex correlations and interactions. We will first introduce the concept of spatial span and its relevance in our daily cognitive functioning. Following this, we will build a baseline knowledge of the characteristics and effects of caffeine and D-amphetamine individually. With the foundation firmly set, we will then explore the pivotal studies and experiments relating to the effects of these substances on spatial span. Throughout these sections, we aim to gather, interpret, and critique existing research, to develop a comprehensive and balanced evaluation of the topic at hand. This review seeks to assimilate the research data available on this imperative subject matter, contribute to the ongoing scientific discourse and, ultimately, increase the comprehension of these effects that could inform future research directions.