Sentiment—"a thought or reflection coloured by or proceeding from emotion" (OED)—can be a valuable aesthetic or dynamic in literature, especially Romantic literature that values human feelings in addition to reason or logic.
Sentimentality—"an appeal to shallow, uncomplicated emotions at the expense of reason" (Wikipedia)—is derided by serious critics for appealing to cheap, easy emotions. Put another way, sentimentality or sentimentalism "pushes our buttons," attempting to stimulate automatic responses instead of productive thought.
People generally like Romantic literature, but if they don't, it's often because Romantic literature can cross the line from honest sentiment into exploitative sentimentality--i.e. push-button reactions for or against familiar types.
On the other hand, overly negative rejections against sentimentality can rob literature of its human warmth or attraction.
Examples of sentimentality:
Little House on the Prairie
Sports reports on retiring players: the camera really wants the guy to cry. (Compare news interviews with families of victims.)
Steven Spielberg, E.T., Schindler's List (One good man makes all the difference)
Kevin Costner, Dances with Wolves (American Indians as noble savages, white man earns their respect)
Advice books by Bill Cosby
Hallmark cards (Sentimental themes webpage)
Patriotic songs and poetry are usually celebratory rather than critical; e.g. people honor small farms and small businesses but support corporate farming & chain stores; nostalgia vs. complications of modernity or city life
a child's tears, a child's smile, a child's smile through tears
the faithful servant
an all-forgiving father
kindly old grandpa on the farm
kindly old grandma in the kitchen or at church
aging athletes breaking down at retirement announcements
virtuous, honorable, noble youth
Familiar responses to sentimental literature
"aawww . . . "
kindly grandparent--crusty exterior but heart of gold
individual stands up for right
stereotypical / sentimental characters in contemporary action movies:
familiar sentimental feelings
endangered innocents (threatened by insensitive bullies or authority figures)
peaceful domestic scenes
Sentimenal and domestic literature often overlap or are used as synonyms.
Sentiment may simply be a synonym for feeling, emotion, or attitude. In literary criticism, however, sentimentality usually signifies a facile exploitation of emotions that are unearned or automatic.
Domestic literature expresses affection for the home and family relations and values.
In literary criticism, "sentimentality" or "sentiment" may be dismissed as cheap, too-easy emotions. Why?
Everyone loves children, motherhood, old folks at family reunions, faithful dogs, family heirlooms and traditions, and the good old days . . .
So why does Literature habitually diminish these subjects?
However, sentiment may be artfully done so that even skeptical readers may feel desired emotional responses--though usually so subtle that these responses feel fresh and earned rather than stale and sentimental.
Reasons to rethink such attitudes against sentimentality?
Sentiment as common ground for humanity?
Anti-sentimentality as product of men leading literary scholarship and college teaching?
Box Full of Puppies / Kittens
sample of greeting card sentiment:
May each day be happy and bright,
Overflowing with pleasure and love;
May your Christmas be filled with delight.
Recent quote on Sentimentality:
(Review of Anthony Doerr's popular novel All The Light We Cannot See)
Sentimentality is a potent and cheap smokescreen. It shelters us from the barrage of deeper emotions, and spares us from their ethical implications. It substitutes surfaces for depths, and glamor for complexity. A failure of taste is always an ethical failure, too. . . .
Ethical dilemmas, sadistic violence, technological cruelties, and sexy uniforms are all splendid sources of period style and emotional intensity. But, like rations of ersatz coffee and powdered egg, they are ready-made substitutes for the real thing. Realism brings us closer to the past, and to an understanding of its difference. The aesthetic perspective distances, and flattens difference. Instead of horror or heroism, we see only a lazy reflection of our own preferences and prejudices.