Task demands and the oddball fast periodic visual stimulation paradigm
Human readers are remarkably proficient at reading words rapidly and with minimal effort, and to an extent, automatically. However, there has been a recent shift in the literature surrounding what is claimed to be automatic and the role task demands play. A novel paradigm offers an exciting opportunity to explore visual word recognition as it claims to measure implicit brain responses to visual categorisation or recognition, known as the oddball fast periodic visual stimulation (oddball FPVS) paradigm. Using this paradigm, researchers found evidence of automatic brain processes dedicated to word-meaning discrimination irrelevant to the task (with a basic colour-changing fixation task). This result is surprising in a context that presumes task demands drive visual word discrimination. This thesis focused on investigating the automatic nature of the oddball FPVS paradigm for visual word recognition through task manipulations. The aims were to replicate a previous task modulation performed by Yan et al. (2019) using novel face stimuli and to extend this to visual word recognition. To do so, this thesis created a Lexical task that manipulated participants’ attentional awareness of the word stimuli. The results showed a task effect using novel face stimuli. Extending this to visual word recognition, this thesis replicated findings of a word discrimination response (Lochy et al., 2015) and found a task effect with an attentional shift in the Lexical task increasing the word discrimination responses. To conclude, this opens up possibilities for the oddball FPVS paradigm to be used as a new tool for measuring how our brain discriminates words. However, questions surround the sensitivity of this effect as it might not be detectable in every person. In addition, the task effect questions the automaticity of this word discrimination response as it appears vulnerable to attentional mechanisms.