BRAIN MECHANISMS AND LEARNING 



experiments, twenty-seven birds) the models were always abnormal — 

 the songs being artificial, re-articulated or reversed — and the results were 

 always negative. The contrast when hand-reared isolated birds are used is 



AAA A 



\ 



3-0 



Fig. 9 

 Song of Continental tree pipit {Aiithtis trividlii) used for tutoring 



Fig. 10 



'Copy' of tree pipit song produced by chaffinch R/R after tuition 



on 'song tutor'. Apnl 21st, 1956. 



mxnt 



Fig. II 

 'Improved' tree pipit copy. R/R, May 3rd, 1956. 



Striking. Thus during 1954-59, thirteen experiments involving sixteen 

 hand-reared birds were carried out using similar song models. Of these, 

 ten experiments (eleven birds) were positive, in the sense of yielding a 



