Journalists, being fed news of some dreadful event, are prone to ask their studio guests: “Can I have a quick reaction?” Almost always the Talking Head comes up with an off-the-cuff reaction, also known as an opinion, as to whether the event is the end of: a dictator/a government/a country/low cost oil/Western civilization/the planet.
I would not dream of criticising this response, particularly because in former times on TV I sometimes ventured minor versions of such a response. I have not yet been asked to comment in a public arena as to whether the finding that contemporary reaction times are slower than in times of yore indicates the decline and fall of our civilization. You know the story full well: the much championed Flynn effect suggests that good food, free education and proper drains have boosted our intelligence, as well they might have; the Woodley effect suggests we are slowing up, losing our intellectual sparkle, becoming more specialised in our abilities but very probably sinking into the mire of soggy stupidity.
Now we have some even more solid findings to favour The Woodley Effect. (By the way, Charles Murray, responsible for coining The Flynn Effect, suggested to me that the contemporary lowering of intellect should be named in this way).
Secular Slowing of Auditory Simple Reaction Time in Sweden (1959–1985) Front. Hum. Neurosci., 18 August 2016 | http://dx.doi.org/10.3389/fnhum.2016.00407
They say: There are indications that simple reaction time might have slowed in Western populations, based on both cohort- and multi-study comparisons. A possible limitation of the latter method in particular is measurement error stemming from methods variance, which results from the fact that instruments and experimental conditions change over time and between studies. We therefore set out to measure the simple auditory reaction time (SRT) of 7,081 individuals (2,997 males and 4,084 females) born in Sweden 1959–1985 (subjects were aged between 27 and 54 years at time of measurement). Depending on age cut-offs and adjustment for aging related slowing of SRT, the data indicate that SRT has increased by between 3 and 16 ms in the 27 birth years covered in the present sample. This slowing is unlikely to be explained by attrition, which was evaluated by comparing the general intelligence × birth-year interactions and standard deviations for both male participants and dropouts, utilizing military conscript cognitive ability data. The present result is consistent with previous studies employing alternative methods, and may indicate the operation of several synergistic factors, such as recent micro-evolutionary trends favoring lower g in Sweden and the effects of industrially produced neurotoxic substances on peripheral nerve conduction velocity.
The authors have collected new data on a large sample, with 7081 usable respondents on which there was much background material from previous testing. They pursued the respondents with reminders, and tested them online, using the best available software to ensure consistent exposure and recording of responses. This cannot be the same as bringing them in to a standard experimental set up of reaction time equipment, but on the other hand it generates much higher numbers of respondents. They have also considered the impact of these variations in methods which, if anything, would obscure rather than reveal underlying trends.
Reaction times seem to slow up after 1970. The authors say:
We found clear trends toward slowing auditory SRT when birth year was regressed against year-on-year SRT means for the years 1959–1985. It is notable that even without adjustment for aging, the SRT speed of the oldest participants is about the same as that of the subsequent generation, whom in the late twenties are supposed to have the shortest SRTs of all age groups (Der and Deary, 2006).
the secular slowing trend was present in all cohort comparisons (males, females, and both sexes combined), and was significant across the entire range of birth years for both the males and the whole sample, but not for the females, who nonetheless exhibited an overall negative trend in SRT performance consistent with potential secular slowing.
A potential cause of the apparent slowing may be exposure to neurotoxic industrial by-products such as heavy metals (Silverman, 2010) and dioxins (ten Tusscher et al., 2014), which may reduce SRT performance via their effects on peripheral nerve conduction velocity. However, as Silverman notes, known neurotoxins have come under tight governmental regulation, emissions have tended to decrease, and serum levels of lead, for example, have decreased since 1970 in the USA (Silverman, 2010, p. 46).
Another possible cause of this trend may be relatively recent micro-evolutionary trends favoring lower g in the population of Sweden. Several studies have revealed that g and fertility are inversely related in the US and the UK (as reviewed in Woodley of Menie, 2015) among cohorts born as far back as the 1890s (Lynn and Van Court, 2004; Lynn, 2011). However, the relationship between g and fertility in Scandinavian countries is less well characterized. Only one study has attempted to examine these trends across birth cohorts in Sweden (Vining et al., 1988). Utilizing aggregate data on fertility and IQ for a mixed-sex sample of Swedish cohorts resident in Stockholm county and born between 1909 and 1940 from Vining et al. (1988), it was possible to reconstruct predicted generational changes in genotypic IQ (I.e., the heritable variance component of IQ) due to the changing patterns of selection (I.e., the correlation between IQ and fertility established for each cohort) for four cohorts (see Appendix 2 for details of the method).
Main result here, but see the full paper:
In sum, this is strongly suggestive of a slowing of reaction times in Sweden, itself suggesting a possible drop in mental alertness and intelligence in that country. If the Flynn effect were a deep-seated real improvement in functioning then one would expect faster reaction times, not slower. An alarming result, worthy of further testing and attention.