dd is 15 months, she didnt eat food at all until a yr, she was allergic to a ton and was nursing fine, and hated purees, so she had no interest, but at a yr she began table food and was ok...then came the infamous tossing on the floor...that was about a month and a half ago...it was cute the first couple times, then i equated it to her being finished n since i didnt remove ehr from her chair, it was a way she kept herself occupied, then i was at moms and i ended up feeling really embarrassed that she kept tossing all the food to the floor, so i really yelled at her, "no!" "no throwing food!" "bad, no throwing!" ...and then a couple days later i noticed she wasnt doing it at all anymore...in fact when even a small noodle fell by accident, she looked down n said uh oh...i was amazed that she had learned so quickly after being told so sternly.
im not that stern often, but when she is in danger (like climbing sofa to play with sink) i get loud with her...so i guess u can say at around 14 months i started. even today, at barnes n noble, she was tossing books on the floor, so i grabbed her and looked at her and sternly told her to pick up...i let her go, and she walked off, so i grabbed her hand again and pointed to the books...i repeated about 2 more times, and then she picked it up...
i thnk they have a "playful" attitude at this age...so choose ur battles i guess.