title: Investigating the effects of caffeine on executive functions using traditional Stroop and a new ecologically-valid virtual reality task, the Jansari assessment of Executive Functions (JEF(©)).
abstract: Caffeine has been shown to have effects on certain areas of cognition, but in executive functioning the research is limited and also inconsistent. One reason could be the need for a more sensitive measure to detect the effects of caffeine on executive function. This study used a new non-immersive virtual reality assessment of executive functions known as JEF(©) (the Jansari Assessment of Executive Function) alongside the 'classic' Stroop Colour-Word task to assess the effects of a normal dose of caffeinated coffee on executive function.
  
  
  
  Using a double-blind, counterbalanced within participants procedure 43 participants were administered either a caffeinated or decaffeinated coffee and completed the 'JEF(©)' and Stroop tasks, as well as a subjective mood scale and blood pressure pre- and post condition on two separate occasions a week apart. JEF(©) yields measures for eight separate aspects of executive functions, in addition to a total average score.
  
  
  
  Findings indicate that performance was significantly improved on the planning, creative thinking, event-, time- and action-based prospective memory, as well as total JEF(©) score following caffeinated coffee relative to the decaffeinated coffee. The caffeinated beverage significantly decreased reaction times on the Stroop task, but there was no effect on Stroop interference.
  
  
  
  The results provide further support for the effects of a caffeinated beverage on cognitive functioning. In particular, it has demonstrated the ability of JEF(©) to detect the effects of caffeine across a number of executive functioning constructs, which weren't shown in the Stroop task, suggesting executive functioning improvements as a result of a 'typical' dose of caffeine may only be detected by the use of more real-world, ecologically valid tasks.
authors.affiliation: School of Psychology, University of East London, Water Lane, London, E15 4LZ, UK. Electronic address: k.soar@uel.ac.uk.
authors.forename: K
authors.initials: K
authors.lastname: Soar
authors.affiliation: School of Psychology, University of East London, Water Lane, London, E15 4LZ, UK.
authors.forename: E
authors.initials: E
authors.lastname: Chapman
authors.affiliation: School of Psychology, University of East London, Water Lane, London, E15 4LZ, UK.
authors.forename: N
authors.initials: N
authors.lastname: Lavan
authors.affiliation: Department of Psychology, Goldsmiths, University of London, Lewisham Way, London, SE14 6NW, UK.
authors.forename: A S
authors.initials: AS
authors.lastname: Jansari
authors.affiliation: School of Psychology, University of East London, Water Lane, London, E15 4LZ, UK.
authors.forename: J J D
authors.initials: JJ
authors.lastname: Turner
mesh_terms: D000328:Adult; D002110:Caffeine / Q000009:adverse effects / Q000627:therapeutic use*; D000697:Central Nervous System Stimulants / Q000009:adverse effects / Q000627:therapeutic use*; D003069:Coffee / Q000009:adverse effects; D004311:Double-Blind Method; D056344:Executive Function; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology; D008297:Male; D005222:Mental Fatigue / Q000175:diagnosis* / Q000178:diet therapy / Q000517:prevention & control*; D019964:Mood Disorders / Q000209:etiology; D058573:Performance-Enhancing Substances / Q000009:adverse effects / Q000627:therapeutic use*; D011569:Psychiatric Status Rating Scales; D013647:Task Performance and Analysis; D000076142:Virtual Reality
chemical_list: D000697:Central Nervous System Stimulants; D003069:Coffee; D058573:Performance-Enhancing Substances; D002110:Caffeine
keywords: Caffeine; Cognitive; Executive function; JEF(©); Mood; Stroop