Mind-wandering with and without awareness: An fMRI study of spontaneous thought processes

Mind-wandering with and without Awareness: An fMRI study of spontaneous thought processes Rachelle Smith 1 (rachelle@psych.ubc.ca) Kamyar Keramatian 2 (kamyar@psych.ubc.ca) Jonathan Smallwood 1 (jsmallwood@psych.ubc.ca) Jonathan Schooler 1 (jschooler@psych.ubc.ca) Brian Luus 1 (cblm@psych.ubc.ca) Kalina Christoff ,1,2 (kchristoff@psych.ubc.ca) Department of Psychology, 2136 West Mall, Vancouver, V6T 1Z4 Canada Neuroscience Program, 2136 West Mall, Vancouver, V6T 1Z4 Canada research on human thought processes has focused on goal- directed thinking and problem solving, equating these processes with executive functions and thinking in general. Nonetheless, strong evidence is beginning to accumulate suggesting that spontaneously occurring thought processes share executive and cognitive mechanisms with goal- directed thought (Christoff, Ream & Gabrieli, 2004; Smallwood & Schooler, in press). Such evidence has been provided by a number of behavioral studies (Antrobus, 1968; Giambra, 1977,1979,1995; Klinger & Cox, 1987; Teasdale, Proctor, Lloyd, & Baddeley, 1993; Teasdale, Dritschel, Taylor, Proctor, Lloyd, Nimmo-Smith, et al., 1995; for review, see Christoff et al., 2004). Given these shared mechanisms, it is not surprising that the generation of spontaneous thought interferes with executive tasks. A prime example of this interference is the decreased degree of randomness in a random number generation task associated with periods of task-unrelated thoughts (Teasdale et al., 1995). A further line of evidence linking spontaneous thoughts with executive mechanisms is the parallel decline of spontaneous thoughts and executive resources with age (Giambra, 1989). This effect of decreasing spontaneous thought with increasing age has been reported across five different vigilance tasks (Giambra, 1989). In addition, there is evidence at the neural level that spontaneous thought processes share executive mechanisms with goal-directed thought. Thus, functional magnetic resonance imaging (fMRI) studies investigating the spontaneous cognitions present during rest are consistent with conclusions drawn on the basis of behavioural studies. These studies have found consistent rest-related activations in brain structures that support higher order cognitive functions such as long-term memory and executive processes (Binder, Frost, Hammeke, Bellgowan, Rao & Cox, 1999; Stark & Squire, 2001). These findings suggest that conceptual processes such as semantic retrieval, representation, information manipulation (Binder et al., 1999) and long term memory processes (Stark & Squire, Abstract Much of our daily mental life is occupied by spontaneous thought processes. Evidence is accumulating that such spontaneous thought processes, which are often experienced as mind-wandering, share the same cognitive and neural resources that subserve goal-directed thought. While a distinction between mind-wandering with and without awareness has been made at a cognitive level, the mechanisms underlying this distinction at a neural level remain unknown. The present study employs a novel paradigm that was designed to examine this question by directly investigating instances of mind-wandering, using fMRI. A continuously engaging background task was employed, combined with a thought sampling approach that determined whether subjects were mind-wandering at a given moment of time, and whether they were aware of where their thought processes were focused. A clear distinction between spontaneous thought processes that occurred with and without awareness emerged. Temporal lobe structures were activated during mind-wandering in the absence of awareness, while prefrontal cortex was activated when subjects were aware of their own thoughts. These findings complement recent cognitive theories of spontaneous thought, by providing evidence for neural distinction between these two kinds of mind-wandering in addition to the previously proposed cognitive distinction. As well, the results suggest that an important aspect of human thought processes, which has been largely ignored thus far, may be the spontaneous generation of thoughts in the absence of awareness or explicit conscious goals. The implications for cognitive theories of human thought are discussed. I ntroduction Much of our daily mental life is occupied by spontaneous thought processes. These thoughts, also referred to as mind- wandering, are often unrelated to the task at hand and may occur with or without our awareness. Despite the prevalence of these types of thought processes in everyday life (Klinger & Cox, 1987), their cognitive mechanisms remain largely unknown. Instead, the vast majority of

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.