Intelligence

 In 1944, the National Opinion Research Center asked "In general, do you think Negroes are as intelligent as white people--that is, can they learn just as well if they are given the same education?"  44% of whites said yes, 47% said no.  NORC asked the same question [adding "and training" starting in 1956] a number of times until 1968.  From 1965 until 1991, the Harris Poll sometimes asked people if they agreed or disagreed with the statement "Negroes [Blacks starting in 1971] have less native intelligence."  I combined the results into a figure showing the percent who thought that blacks were as intelligent as whites--that is, answered yes to the NORC question or disagreed with the Harris statement.  All the questions were asked of whites only.  I just include people with an opinion because some of the Harris results are from printed sources which presented them that way.

Both show a decline from about 1964/5 to 1968--perhaps a case of backlash against the civil rights movement?  However, the main pattern is a strong upward trend for both.  The Harris numbers were substantially lower, probably because the NORC added the "can learn just as well if they are given the same education."  Although "native intelligence" in the Harris question suggested the same idea, the way that the NORC question put it made it harder to miss.  

Finally, in 1990 the GSS asked people to rate different groups on a 1-7 scale running from "unintelligent" to "intelligent."  Blacks and whites were two of the groups.  The gap in average ratings of blacks and whites:

Until 2018, the GSS asked people if their race was black, white, or other, but they changed the way they asked about race in 2021.  I show the figures for whites only to make it comparable to the NORC and Harris results, but also those for all respondents in order to get 2021 in.  Either way, there is a strong trend towards equality.  In 1990, the most common combination among whites was 4 for blacks and 4 for whites (24.8%) and the second most common was 4 for blacks and 5 for whites (12%); in 2018, the 4/4 combination had risen to 44.8%, 5/5 was second at 13.4%, and 4/5 had fallen to 6.7%.   In 1990, about 15% saw a difference of 3 or more in favor of whites; in 2018, that was only 3%.*

Putting these results together, there has been a trend towards seeing blacks and whites as equal in intelligence running from the 1940s through today (although the fact that a trend could go on that long means that the gap was very large to start with).  Of course, you might say that the change could just involve social desirability bias rather than a change in real opinions.  However, as I've mentioned before, surveys are designed to be a low pressure situation--if people want to avoid the possibility that some person who they will never see again and who is just politely recording whatever they say is going to think that they are prejudiced, then it's reasonable to think that in natural settings they will try to avoid doing or saying things that might make people think that they are prejudiced.  So for most purposes, I don't think that it matters.  

*Among blacks, the average rating for white intelligence is 4.65 and the average rating for black intelligence is 4.57--the standard error is about .045.  

[Data from the Roper Center for Public Opinion Research]