This study aims to investigate the effects of increasing the cognitive demands of a task on the perception of task difficulty and on four affective variables (anxiety, confidence, interest and motivation). Thirty-nine Chinese university learners of Portuguese as a foreign Language participated in this research work. All participants performed two monologic information-giving oral tasks. The order of the tasks was counterbalanced. Within Robinson's (2001, 2003, 2005, 2007, 2010, 2011, 2015, 2022a, 2022b) Cognition Hypothesis, two independent variables were chosen: a resource-directing variable ('± few elements') and a resource-dispersing variable ('± planning time'). Learners were asked to answer an affective variable questionnaire in a Likert scale after performing each version of the task (simple task/ complex task). Increasing the elements of a task led to (i) an interaction between task complexity/ difficulty, as the complex task was perceived as more difficult than the simple task, and (ii) a negative impact on learners' confidence. Increasing task demands along resource-dispersing dimensions had positive effects on learners' interest. These findings suggest that as tasks' demands increase, there is no loss of interest or motivation to perform the task. Pedagogical implications are discussed.