Consumer attitudes showed more signs of improvement heading into the holidays as an early reading on consumer sentiment in December beat expectations.

The University of Michigan said Friday that its consumer sentiment index jumped to 95.7 in a preliminary report on December, up from the final 92.8 logged in November. Economists were expecting smaller gain to 93.5.

If the upside holds, that would extend the index's upward streak to two months, following a four-month decline that started in July.

Recent progress coming from the Michigan report stands in contrast with the Conference Board's consumer confidence index, which recorded an unexpected decline in November. That index dropped from 92.9 to 90.5, after economists had predicted a gain to 96.

The mixed signals have stoked debate about the future strength of consumer spending. Bulls maintain that the economic recovery is transitioning into robust job growth that will help American shoppers contend with rising interest rates and continue to spur economic growth with healthy spending levels.

An increasingly vocal crowd of skeptics point to recent economic data that showed the average worker is spending at a higher rate than wage growth allows, creating an unsustainable consumption level. Citing an uneven pattern of job growth, high oil prices and record debt-levels, these observers forecast a consumer spending slowdown in the new year that could threaten the economic recovery.

Retail sales data on November, including the post-Thanksgiving shopping rush, showed disappointments. The International Council of Shopping Centers, or ICSC, said overall same-store sales rose just 1.7% compared with the same month last year, based on a tally of results from 71 national retailers. That figure was below the organization's forecast calling for a 2.5% to 3% gain, even after it had lowered expectations from the original estimate of 3% to 4%.

On the basis of November's results, the ICSC lowered its estimates for the holiday season results to 2.5% to 3% from the previous 3% to 4% range. Still, others point out that the ICSC's results fail to capture key pieces of the holiday spending puzzle, such as online and catalogue sales.

Further light will be shed on the subject next week when the government reports November retail sales results on Monday morning. Economists are predicting the growth to have remained steady, with a 0.3% gain excluding auto sales.