Stop! But How? Multiple Inhibitory Processes in 5- and 6-year-olds Christopher H. Chatham1, Katharine A. Blackwell2, Melody Wiseheart3 & Yuko Munakata4 1Brown University 2Salem College 3York University 4University of Colorado Boulder Inhibition Is Critical to Cognitive Control Everyday situations require us to stop inappropriate actions: Stop paying attention to the radio so we can focus on driving Stop reaching for a slice of cake so we can adhere to a diet Task Switching Override a prepotent response 3D card sort task: match first by shape, then by color, then by size (12 trials each). Children categorically switch (near perfect on both post-switch blocks) or perseverate (continue sorting by shape on both postswitch blocks) (Blackwell et al., 2009; Deák, 2003) Switchers Better at Selective Stopping Only Switchers (n = 19) were slightly older (M = 6.3 years) than perseverators (n=28, M = 6.0 years; t(45) = 2.5, p < .05) so age was controlled. Switchers and perseverators were equally fast to stop a single action (F < 1) Switchers were faster to stop one action while continuing another (F(1,38) = 6.8, p = .01), regardless of cueing. Discussion Switchers showed an advantage at selective stopping only, not global stopping. This contrasts a switcher disadvantage at global stopping observed in other stop signal tasks (Blackwell et al., under review). Complexity of primary task (simple reaction vs. choice reaction) may influence children’s stopping efficiency. Switchers showed advantage at selective stopping, but not expected reduced interference found in adults. Theories of inhibitory control should consider developmental changes in stopping efficiency for insight into how inhibitory pathways function and interact. Inhibition May Involve Multiple Processes Two paths may be global vs. selective (Aron & Verbruggen, 2008) Inhibition Stop a single action One banana appears; press button to get banana for monkey, unless the banana turns brown. Global inhibition stops all responses uses hyperdirect route from prefrontal cortex (PFC) to subthalamic nucleus used when we “freeze” (e.g., stop reaching for slice of cake) Selective inhibition stops some responses but not others uses indirect route from PFC through basal ganglia to subthalamic nucleus used when we substitute actions (e.g., stop fiddling the the radio to steer the car) Switchers Still Have Go-Hand Stopping Interference Cost Adults using a selective stopping mechanism show less stopping-interference cost: still-going response (e.g., to yellow banana) is not slowed as much as when a global stopping mechanism is used (Aron & Verbruggen, 2008). Switchers and perseverators have same stopping-interference cost (F < 1) References Aron, A. R., & Verbruggen, F. (2008). Stop the presses: Dissociating a selective from a global mechanism for stopping. Psychological Science, 19, 1146-1153 Blackwell, K. A., Cepeda. N. J., & Munakata, Y. (2009). When simple things are meaningful: Working memory strength predicts children’s cognitive flexibility. JECP, 103, 241-249. Blackwell, K. A., Chatham, C. H., Wiseheart, M., & Munakata, Y. (under review). A developmental window into trade-offs in executive function: The case of task switching versus response inhibition in 6-year-olds. Deák, G. O. (2003). The development of cognitive flexibility and language abilities. In R. Kail (Ed.). Advances in child development and behavior (Vol. 31, pp. 271–327). San Diego: Academic Press. Stop one action while continuing another Two bananas appear; press two buttons simultaneously to get both bananas If one turns brown, don’t press that button but do press the other to get the yellow banana How Do Distinct Inhibition Pathways Develop? Acknowledgements This research was supported by NIH (RO1 HD37163 and P50-MH079485) Thanks to: Wolfgang Pauli and members of the Cognitive Development Center at CU Boulder. Global and selective stopping investigated in 5- and 6-year olds Relations of each compared to task-switching Switchers may be using a different process for stopping one action while continuing another than adults use. Contact Questions can be sent to chatach@gmail.com or katharine.blackwell@salem.edu