Sources of Flexibility in Human Cognition: Dual-Task Studies of Space and Language

Orientational manoeuvres in the dark: dissociating allocentric and egocentric influences on spatial memory

“…This would explain the finding that when rats are systematically disoriented by spinning before each trial, their search is constrained only by the geometry of the environment, ignoring the visual cues within it (Cheng, 1986) unlike non-disoriented rats (Biegler & Morris, 1993, 1996Fenton et al, 1994;Lenck-Santini et al, 2002;Maurer & Derivaz, 2000;O'Keefe & Conway, 1980;Suzuki et al, 1980). It might also explain similar findings in the searching patterns of young children (Hermer & Spelke, 1994) and of adults performing verbal shadowing (Hermer-Vazquez et al, 1999), but cannot explain why non-shadowing adults do use visual landmarks despite having been disoriented.…”

“…However, this would not predict the positive effect of rotating the cue with the table versus rotating the table alone (condition table&cue-card versus table), since the test display is inconsistent with any egocentric representations in both conditions. A related interpretation might concern the process of reorientation of updatable egocentric representations relative to the environment, even though this process is thought to apply after disorientation of the subject (Hermer & Spelke, 1994;Hermer-Vazquez, Spelke, & Katsnelson, 1999;Wang & Spelke, 2002). However, for this to produce an effect of consistency with the external cue, the updatable egocentric representation would have to reliably follow the movement of the cue rather than the movement of the subject, even when the subject's viewpoint does not change (as in condition table&cue-card versus table).…”

Verbal interference suppresses exact numerical representation

“…We performed the same set of tasks that we used with the Pirahã with English-speaking participants in Boston, MA while these participants verbally shadowed radio news broadcasts (repeating words out loud as they were heard over headphones) to block access to number words (Hermer-Vazquez et al, 1999;Newton & de Villiers, 2007). Although this design would normally require a control group that performed the tasks without shadowing, pilot testing convinced us that, for numerate adults, performance would be at ceiling without the presence of a concurrent verbal task like shadowing.…”

“…Yet verbal shadowing, the interference task we used in Experiment 1, has no directly analogous non-verbal correlate. It is both easier to learn-most participants require only a minimum of training or explanation-and more complex than comparable non-verbal shadowing tasks-conveying far more information than a simple clapped rhythm (New-ton & de Villiers, 2007;Hermer-Vazquez et al, 1999). Therefore, in order to match our verbal and non-verbal interference tasks as closely as possible, we made use of verbal and spatial short-term memory tasks.…”

“…In each of these domains, meaningful cognitive differences have been demonstrated between people who have words for particular concepts and those who don't, either because their language does not encode those concepts (Frank et al, 2008;Gordon, 2004;Pica et al, 2004;Pyers & Senghas, 2009;Winawer et al, 2007) or because they haven't yet learned the relevant words (de Villiers & de Villiers, 2000;Le Corre et al, 2006). These group differences are mitigated or disappear entirely when the people who do know the relevant words cannot access these words (for example, when they are required to occupy their verbal resources with interfering material or when tasks are speeded) (Hermer-Vazquez et al, 1999;Ratliff & Newcombe, 2008;Newton & de Villiers, 2007;Winawer et al, 2007).…”