2. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study ‘Hemisphere deconnection and unity in conscious awareness’ American Psychologist 23 pp723-33

3. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study introduction brain has 2 hemispheres connected by commissural fibres lateralisation of function –each has different functions –cognitive / motor split to treat extreme epilepsy

4. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study

5. psychlotron.org.uk Mark Souter

6. Sperry (1968) Split brain study the studies: subjects 11 'most radical disconnection' 2 benefited; others 'recent'

7. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study designs: natural experiments variables occur 'naturally e.g. socio-economic- but in this case surgical procedures carefully controlled tests also case studies open ended interviews etc

8. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study procedure one hand feeling unseen objects attention to one ‘visual field’ image shown for 1/10 th sec (to prevent eyes moving to prevent use of other visual field) 2 images shown for 1/10 th s; one to each field etc

9. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study results: visual test 1 subject show image in one visual field recognised if in that field before not recognised if re-shown in other field

10. psychlotron.org.uk Mark Souter Right visual field Left visual field

11. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study results: visual test 2 RH subjects shown objects in each field could describe object in R field said no object in L field, or ‘just a flash' able to respond non-verbally (pick up object with L hand) to object in L field

12. psychlotron.org.uk Mark Souter

13. Sperry (1968) Split brain study results: visual / drawing test 2 objects shown 1in LVF, 1RVF drew object with shielded L hand reported they had drawn object in R field!

14. psychlotron.org.uk Mark Souter When asked to say what they had drawn they would name the object shown to their RVF (e.g. banana)! they could draw, with the left hand, the object (e.g. pen) that had been presented to their LVF.

15. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study results: tactile test objects in R hand => verbal description object in L hand => only NV response L hand unable to respond to stimulus in R hand

16. psychlotron.org.uk Mark Souter When they felt and object with the right hand patients could name the object When they felt and object with the left hand patients could not name object (but could identify it non- verbally, by picking it out from a group) Patients would feel one object with each hand Left hand could not respond to what the right hand felt

17. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study results: 'competing tasks' R and L hand had different tasks could do both at same time non-split brain subjects slowed by this only useful for odd lab tasks!

18. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study discussion: Sperry’s conclusions apparent doubling of most areas of conscious awareness hemispheres appear unaware of each other easier to think of two hemispheres as two people

19. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study discussion: not a simple tale! R side could (literally) tell L side what it knew! in lab had to be prevented from talking = sides not so isolated so personality / intelligence effects limited some STM / concentration difficulties

20. psychlotron.org.uk Mark Souter Sperry (1968) Split brain study discussion difficult to generalise! variation even between only 11 subjects