It is often claimed that stock splits, in and of themselves, lead to higher stock prices; research, however, does not bear this out. What is true is that stock splits are usually initiated after a large run up in share price. Momentum investing would suggest that such a trend would continue regardless of the stock split. In any case, stock splits do increase the liquidity of a stock; there are more buyers and sellers for 10 shares at $10 than 1 share at $100. Some companies have the opposite strategy: by refusing to split the stock and keeping the price high, they reduce trading volume. Berkshire Hathaway is a notable example of this.
Other effects could be psychological. If many investors believe that a stock split will result in an increased share price and purchase the stock the share price will tend to increase. Others contend that the management of a company, by initiating a stock split, is implicitly signaling its confidence in the future prospects of the company.
In a market where there is a high minimum number of shares, or a penalty for trading in so-called odd lots (a non multiple of some arbitrary number of shares), a reduced share price may attract more attention from small investors. Small investors such as these, however, will have negligible impact on the overall price.