Solondz purges all sentimentality from his tale. No swain awaits to turn this duckling into a swan; Dawn’s torment does not serve to ennoble her. Preyed upon by the stronger and more popular, she apes their cruelty by casting her own epithets – ““retard,’’ ““faggot’’ – upon those even lower on the pecking order. The beauty of ““Welcome to the Dollhouse’’ is its pokerfaced objectivity, which neither condescends to its pubescent victim nor romantically inflates her plight. Solondz, whose film won the top prize at Sundance, refuses to let the audience traffic in nostalgia: you’ll laugh and wince simultaneously – and be very grateful that you’ll never be 11 again.